Download - Distributed Generation Technical Interconnection Requirements Honi

8/11/2019 Distributed Generation Technical Interconnection Requirements Honi

1/195

DT-10-015 R2

D ISTRIBUTED G ENERATION

T ECHNICAL I NTERCONNECTIONR EQUIREMENTS

I NTERCONNECTIONS A T V OLTAGES 50 K V AND B ELOW

COPYRIGHT 2011 HYDRO ONE NETWORKS LTD. ALL RIGHTS RESERVED


2/195

This Page is Intentionally Left Blank


3/195

D ISTRIBUTED GENERATION TECHNICAL INTERCONNECTION REQUIREMENTS INTERCONNECTIONS AT VOLTAGES 50 KV AND BELOW

DT-10-015 REV. 2H YDRO ONE NETWORKS INC . J UNE 2011

i

LIMITATION OF LIABILITY AND DISCLAIMER

Hydro One Networks Inc.s (Hydro One) Distributed Generation Technical InterconnectionRequirements: Interconnections at Voltages 50kV and Below (the DG Requirements) identifiesminimum requirements for generation projects connecting to Hydro Ones distribution system.

Additional requirements may need to be met by the owner of the generation project to ensure thatthe final connection design meets all local and national standards and codes and is safe for theapplication intended. The DG Requirements are based on a number of assumptions, only someof which have been identified. Changing system conditions, standards and equipment may makethose assumptions invalid. Use of this document and the information it contains is at the userssole risk. Hydro One, nor any person employed on its behalf, makes no warranties orrepresentations of any kind with respect to the DG Requirements, including, without limitation, itsquality, accuracy, completeness or fitness for any particular purpose, and Hydro One will not beliable for any loss or damage arising from the use of this document, any conclusions a userderives from the information in this document or any reliance by the user on the information itcontains. Hydro One reserves the right to amend any of the requirements at any time. Any

person wishing to make a decision based on the content of this document should consult withHydro One prior to making any such decision.

C ONTACT /P UBLISHER

Please forward questions/comments regarding this Document to the following email address:

EMAIL: [email protected]

R EVISION H ISTORY

DATE VERSION COMMENTS

June 2011 Rev. 2

Updated several sections as per the DistributedGeneration Technical Interconnected Requirements(TIR) Amendments Webinars, Part 1 and 2 whichcan be seen via:http://www.hydroone.com/Generators/Pages/Webinars.aspx

February 2010 Rev. 1

Updated voltage & power factor requirements;minor adjustments in all diagrams; replaced tapline requirement with new line requirement;

added missing definitions; minor modifications toCapacity Limitations ; clarified PCC and Point ofConnection.

November 2009 Rev. 0 New Report
mailto:[email protected]:[email protected]://www.hydroone.com/Generators/Pages/Webinars.aspxhttp://www.hydroone.com/Generators/Pages/Webinars.aspxhttp://www.hydroone.com/Generators/Pages/Webinars.aspxhttp://www.hydroone.com/Generators/Pages/Webinars.aspxhttp://www.hydroone.com/Generators/Pages/Webinars.aspxmailto:[email protected]


4/195

This Page is Intentionally Left Blank


5/195



1

T ABLE OF C ONTENTS

LIMITATION OF LIABILITY AND DISCLAIMER .............................................................................................................. I

CONTACT/PUBLISHER ........................................................................................................................................ I

REVISION HISTORY ............ ............. ............. ............. ............. ............. ............. ............. .............. ............ ............. I

TABLE OF CONTENTS ........................................................................................................................................ 1

LIST OF FIGURES ....................................................................................................................................................... 5

LIST OF TABLES ......................................................................................................................................................... 6

1 INTRODUCTION ............ ............. ............ .............. ............. ............. ............. ............. ............. ............. ............. ... 7

1.1 SCOPE ..................................................................................................................................................................... 8 1.2 OBJECTIVES.............................................................................................................................................................. 9 1.3 RESPONSIBILITIES.................................................................................................................................................... 11 1.4 REQUIREMENTORIGINS ........................................................................................................................................... 12 1.5 TERMINOLOGY ........................................................................................................................................................ 18 1.6 CAPACITYLIMITATIONS ONGENERATORINTERCONNECTIONSFEEDERLOADINGLIMITS......................................................... 18

1.6.1 Three Phase Generators ................................................................................................................................ 19 1.6.2 Single Phase Generators................................................................................................................................ 19

1.7 DOCUMENT REPRODUCTION ..................................................................................................................................... 20 1.8 TERMS ANDDEFINITIONS.......................................................................................................................................... 21

2 TECHNICAL INTERCONNECTION REQUIREMENTS ............................................................................................ 29

2.1 GENERALREQUIREMENTS ......................................................................................................................................... 29 2.1.1 Safety ............................................................................................................................................................ 29 2.1.2 Active Power .................................................................................................................................................. 29 2.1.3 Reactive Power .............................................................................................................................................. 29 2.1.4 Equipment Rating and Requirements............................................................................................................ 29 2.1.5 Point of Common Coupling ............................................................................................................................ 31 2.1.6 New Line ........................................................................................................................................................ 32 2.1.7 Isolation Device ............................................................................................................................................. 33 2.1.8 Interrupting Device Rating ............................................................................................................................ 35 2.1.9 Phasing .......................................................................................................................................................... 36 2.1.10 Temporary Over-Voltage (TOV) ..................................................................................................................... 36 2.1.11 Grounding ..................................................................................................................................................... 37 2.1.12 Interconnection Transformer Configuration ................................................................................................. 41

2.1.12.1 DG Interconnection to 4-Wire Distribution Systems .............................................................................................. 42 2.1.12.2 DG Interconnection to 3-Wire Distribution Systems .............................................................................................. 53 2.1.13 High Voltage Interrupting Device (HVI) ......................................................................................................... 55 2.1.14 Station Service for Essential Loads ................................................................................................................ 57 2.1.15 Batteries/DC Supply ...................................................................................................................................... 58 2.1.16 Fault Levels .................................................................................................................................................... 59 2.1.17 Insulation Coordination ................................................................................................................................. 59 2.1.18 Instrument Transformers for Use in Protection Systems ............................................................................... 60 2.1.19 Power Quality Monitoring Device ................................................................................................................. 60


6/195



2

2.1.20 Protection from Electromagnetic Interference (EMI) .................................................................................... 61 2.1.21 Surge Withstand ............................................................................................................................................ 61 2.1.22 DG Facility Acceptance .................................................................................................................................. 62 2.1.23 Generators Paralleling for 6 Cycles or Less (Closed Transition Switching) ................................................... 62 2.1.24 Provision for Future Changes ........................................................................................................................ 62

2.2 PERFORMANCEREQUIREMENTS ................................................................................................................................. 64 2.2.1 General .......................................................................................................................................................... 64 2.2.2 Power Quality ................................................................................................................................................ 64

2.2.2.1 Voltage.................................................................................................................................................................... 64 2.2.2.2 Voltage and Current Unbalance ............................................................................................................................. 66 2.2.2.3 Voltage Fluctuations (Flicker) ................................................................................................................................. 68 2.2.2.4 Voltage and Current Harmonics ............................................................................................................................. 70 2.2.2.5 Frequency ............................................................................................................................................................... 72 2.2.2.6 Power Factor .......................................................................................................................................................... 72 2.2.2.7 Limitation of DC Injection ....................................................................................................................................... 73

2.2.3 Disturbances .................................................................................................................................................. 74 2.2.4 Resonance Analysis ....................................................................................................................................... 74 2.2.5 Self-Excitation Analysis .................................................................................................................................. 74

2.3 PROTECTIONREQUIREMENTS .................................................................................................................................... 75 2.3.1 General Requirements ................................................................................................................................... 75 2.3.2 Sensitivity and Coordination ......................................................................................................................... 77 2.3.3 Protection Operating Times .......................................................................................................................... 77 2.3.4 Breaker Fail (BF) ............................................................................................................................................ 77 2.3.5 Single Phase Generators................................................................................................................................ 80 2.3.6 Three Phase Generators ................................................................................................................................ 82 2.3.7 Phase and Ground Fault Protection .............................................................................................................. 94 2.3.8 Open Phase Protection .................................................................................................................................. 96 2.3.9 Feeder Relay Directioning ............................................................................................................................. 97 2.3.10 Over Frequency/Under Frequency Protection ............................................................................................... 98 2.3.11 Overvoltage/Undervoltage Protection .......................................................................................................... 99 2.3.12 Anti-Islanding Protection ............................................................................................................................. 100 2.3.13 Transfer Trip ................................................................................................................................................ 102 2.3.14 Distributed Generator End Open (DGEO) .................................................................................................... 104 2.3.15 Low Set Block Signal (LSBS) ......................................................................................................................... 105 2.3.16 DGEO and LSBS Design ................................................................................................................................ 105 2.3.17 Special Interconnection Protection.............................................................................................................. 106 2.3.18 Protection Scheme Failures ......................................................................................................................... 106 2.3.19 Interconnection Protection Acceptance ...................................................................................................... 107 2.3.20 Protection Changes ..................................................................................................................................... 108

2.4 OPERATINGREQUIREMENTS .................................................................................................................................... 109 2.4.1 General ........................................................................................................................................................ 109 2.4.2 Islanding ...................................................................................................................................................... 110 2.4.3 Unintentional Energization ......................................................................................................................... 110 2.4.4 Synchronization ........................................................................................................................................... 110 2.4.5 Single Connection Path ................................................................................................................................ 111 2.4.6 Automatic Disconnection of Generation and HV Ground Sources .............................................................. 113 2.4.7 Automatic Reconnection of Generation and HV Ground Sources ............................................................... 115 2.4.8 Automatic Reconnection of DG Facility Generation Following a Sustained Outage or Shutdown .............. 118

2.5 CONTROL ANDMONITORINGREQUIREMENTS............................................................................................................. 119 2.5.1 General ........................................................................................................................................................ 119


7/195



3

2.5.2 Control Facilities .......................................................................................................................................... 120 2.5.3 Operating Data, Telemetry and Monitoring ............................................................................................... 120

2.5.3.1 Class 1 Generators ................................................................................................................................................ 121 2.5.3.2 Class 2 Generators ................................................................................................................................................ 121 2.5.3.3 Class 3 Generators ................................................................................................................................................ 122 2.5.3.4 Class 4 Generators ................................................................................................................................................ 122 2.5.3.5 Telemetry Reporting Rates ................................................................................................................................... 122

2.6 TELECOMMUNICATIONSREQUIREMENTS.................................................................................................................... 123 2.6.1 General ........................................................................................................................................................ 123 2.6.2 Telecommunications Facilities for Teleprotection ....................................................................................... 123 2.6.3 Telecommunications Facilities for Real-Time Control and Monitoring ....................................................... 123 2.6.4 Reliability Requirements.............................................................................................................................. 124

2.6.4.1 Teleprotection ...................................................................................................................................................... 124 2.6.4.2 Real-Time Control and Monitoring ....................................................................................................................... 125

2.7 REPORTINGREQUIREMENTS .................................................................................................................................... 126 2.7.1 General ........................................................................................................................................................ 126 2.7.2 Power Quality Recording ............................................................................................................................. 127 2.7.3 Disturbance Fault Recording ....................................................................................................................... 128 2.7.4 Sequence of Events Recording ..................................................................................................................... 129

2.8 METERINGREQUIREMENTS ..................................................................................................................................... 130 2.9 COMMISSIONING ANDVERIFICATIONREQUIREMENTS .................................................................................................. 131

2.9.1 Hydro One Networks Inc. COVER Process .................................................................................................... 131 2.9.2 Commissioning and Verification Generic Requirements ............................................................................. 131 2.9.3 Documentation of Test Results.................................................................................................................... 133

2.10 MAINTENANCEREQUIREMENTS ............................................................................................................................... 135 2.10.1 Protection and Control Systems Equipment ................................................................................................ 135

2.11 CONNECTIONPROCESSREQUIREMENTS ..................................................................................................................... 138

3 REFERENCES ...................................................................................................................................................139

A APPENDIX A HYDRO ONE SYSTEM CHARACTERISTICS(INFORMATIVE) ........................................................145

A.1 GENERALCHARACTERISTICS.................................................................................................................................... 145 A.2 SYSTEMFREQUENCY .............................................................................................................................................. 145 A.3 VOLTAGE ............................................................................................................................................................. 145 A.4 VOLTAGEREGULATION ........................................................................................................................................... 146 A.5 VOLTAGE ANDCURRENTUNBALANCE....................................................................................................................... 146 A.6 POWER Q UALITY................................................................................................................................................... 146 A.7 FAULTLEVELS....................................................................................................................................................... 147 A.8 SYSTEMGROUNDING ............................................................................................................................................. 147 A.9 HYDROONE NETWORKSINC. DISTRIBUTIONSYSTEMFEEDERPROTECTION...................................................................... 147 A.10 AUTOMATIC RECLOSING(FAULTCLEARING) ............................................................................................................... 148 A.11 PHASING ............................................................................................................................................................. 148 A.12 MULTIPLESOURCE(NETWORKED) SYSTEM ................................................................................................................ 148 A.13 FREQUENCY OFINTERRUPTION ................................................................................................................................. 148 A.14 ABNORMALCONDITIONS ........................................................................................................................................ 149

B APPENDIX B DEVICE NUMBER DESCRIPTION (INFORMATIVE) .....................................................................150

C APPENDIX C NEUTRAL REACTOR AND GROUNDING TRANSFORMER IMPEDANCE CALCULATIONS FOR DGFACILITIES(INFORMATIVE) ....................................................................................................................................151

C.1 INTERCONNECTING TOHONIS 4-W IREDISTRIBUTIONSYSTEM..................................................................................... 151


8/195



4

C.2 INTERCONNECTING TOHONIS 3-W IREDISTRIBUTIONSYSTEM..................................................................................... 152

D APPENDIX D ANTI-ISLANDING PROTECTION (INFORMATIVE) ......................................................................153

D.1 DG ISLANDING ..................................................................................................................................................... 153 D.2 SUMMARY OFADVERSEIMPACTS CAUSED BYDG ISLANDING......................................................................................... 153 D.3 RISKS .................................................................................................................................................................. 154 D.4 TYPES OFDG ISLANDS ............................................................................................................................................ 155 D.5 DG ISLANDINGNOT PERMITTED.............................................................................................................................. 158 D.6 AUTOMATIC-RECLOSURE ........................................................................................................................................ 160 D.7 BENEFITS OFAUTOMATIC-RECLOSURE....................................................................................................................... 160 D.8 HOW AUTOMATIC-RECLOSUREWORKS ..................................................................................................................... 160 D.9 AUTOMATIC-RECLOSUREREQUIRESDG TO DISCONNECTQ UICKLY................................................................................. 161 D.10 LIMITATIONS OFDG SELF-CLEARINGPROTECTIONRESPONSETIMES ............................................................................... 161 D.11 MAXIMUMDETECTIONTIMESAVAILABLE FORDG SELF-CLEARINGPROTECTIONS............................................................. 162 D.12 TRANSIENTRESPONSE OFDG ISLANDS(THE BASIS OF THE50% RULE) .......................................................................... 163

D.13 TRANSFERTRIP PROVIDESPREDICTABLEANTI-ISLANDINGPROTECTIONCLEARANCETIMES.................................................. 164 D.14 DISTRIBUTEDGENERATOREND OPEN ....................................................................................................................... 165 D.15 APPLICATION OFTT AND DGEO 50% RULE REQUIREMENTS TODG ISLANDS................................................................ 165 D.16 INRUSHBLOCKING(LSBS) ...................................................................................................................................... 166

E APPENDIX E DGEO & LSBS DESIGN CONSIDERATION (INFORMATIVE) .........................................................167

F APPENDIX F TIMING DIAGRAMS (INFORMATIVE) ........................................................................................169

G APPENDIX G SEQUENCE OF EVENTS DURING FAULT CONDITIONS: EXAMPLE (INFORMATIVE) ...................176

H APPENDIX H CONFIRMATION OF VERIFICATION EVIDENCE REPORT (NORMATIVE) .....................................178


9/195


10/195



6

LIST OF TABLES

TABLE1: ORIGINS OFREQUIREMENTS ............................................................................................................................................. 12 TABLE2: TSC MAXIMUMFAULTLEVELS .......................................................................................................................................... 59 TABLE3: ARRESTERRATINGS ......................................................................................................................................................... 60 TABLE4: PST AND PLT FLICKERLIMITS .............................................................................................................................................. 68 TABLE5: VOLTAGEDISTORTION LIMITS FORODDHARMONICS ............................................................................................................ 70 TABLE6: VOLTAGEDISTORTION LIMITS FOREVENHARMONICS ........................................................................................................... 71 TABLE7: HARMONICCURRENTLIMITS............................................................................................................................................. 71 TABLE8: OPERATINGFREQUENCYRANGE ........................................................................................................................................ 72 TABLE9: MINIMUM PROTECTIONSREQUIRED FORSINGLEPHASEDG FACILITIES.................................................................................... 80 TABLE10: TYPICALINTERCONNECTIONPROTECTIONS FORTHREEPHASEDGS......................................................................................... 83 TABLE11: OVER/U NDERFREQUENCYPROTECTIONSETPOINTS ANDCLEARINGTIMES ............................................................................. 98 TABLE12: OVER/U NDERVOLTAGEPROTECTIONSETTING ANDCLEARINGTIME .................................................................................... 100

TABLE

13: TT

T

IMINGR

EQUIREMENTS.......................................................................................................................................... 103 TABLE14: RESYNCHRONIZATIONREQUIREMENTS ............................................................................................................................ 111

TABLE15: DG CLASSIFICATION.................................................................................................................................................... 119 TABLE16: TELEMETRYREPORTINGRATES ...................................................................................................................................... 122 TABLE17: VOLTAGELIMITS0 TO 50,000V ON DISTRIBUTIONSYSTEM............................................................................................... 146


11/195


12/195



8

for the planning, design, equipment manufacture and supply, construction, commissioning,operation and maintenance of the DG Facility and Distribution Systems.

1.1 S COPE

This document applies to the following DG Facilities interconnecting to HONIs DistributionSystem (50kV and below):

1. Single-phase installations with an aggregate capacity > 10 kW; and

2. Three-phase installations with an aggregate capacity > 30 kW

The document is intended to be applied to electric power generators using all types of energysources, energy storage and energy conversion technologies directly connected

synchronous and asynchronous rotating machines, and those connecting via inverters or staticpower converters which are above the thresholds mentioned above. This document does notapply to generators paralleling with HONI for less than 100ms (Momentary Closed TransitionSwitching) except as noted in Section 2.1.23.

Section 2 contains minimum requirements that the DG Owner is required to comply with inorder to connect to HONIs Distribution System. Depending on the size of the interconnectingDG Facility, the voltage of the interconnected distribution feeder, and whether the facility issingle-phase or three-phase (3-wire or 4-wire) certain requirements may not apply.

It is the DG Owners responsibility to ensure that all requir ements are met. Theserequirements have been developed to ensure that the integrity and power quality of HONIsDistribution System are maintained to acceptable levels after connection of the DG Facility.

Additional requirements may be necessary to address unique situations and the DG Ownershall be advised of any such requirements at the appropriate stage by HONI. Any exemptionsrequire written approval from HONI.

This document does not specify protection requirements for the generator and equipment atthe DG Facility. The DG Owner should ensure that adequate generator protections as well asprotections for other equipment within the DG Facility are installed. This is to protect them

from damage from faults or abnormal conditions which may originate at the DG Facility or fromHONI Transmission and/or Distribution System.

This document does not constitute a design handbook and is not a substitute for the OntarioElectrical Safety Code. DG Owners who are considering the development of a generation


13/195



9

facility to connect to HONIs system 1 shall engage the services of a professional engineer or aregistered consulting firm qualified to provide design and consulting services for electrical

interconnection facilities in the Province of Ontario.

1.2 O BJECTIVES

HONI is committed to connecting renewable generation to the Distribution System whilepreserving a safe and reliable electrical supply to all of its customers. Interconnection of theDG Facilities must conform to relevant Ontario and Canadian regulations and internationaldesign standards. This Document has been developed in accordance with the followingobjectives. These objectives shall be integrated into all steps to the connection process -design specification, construction, operation and maintenance of the DG Facility

interconnection.

S AFETY

The DG interconnection must not create a safety hazard to the general public, HONIcustomers, HONI employees or other LDC employees that work on the Distribution System,nor to personnel working in the DG Facility.

P OWER Q UALITY

Connection of DG Facilities must not materially degrade the power quality of HONI Distribution

System below acceptable levels.

R ELIABILITY

Connection of DG Facilities must not materially compromise the reliability of the HONIDistribution System as required by the Ontario Energy Board Distribution System Code anddefined by HONI Distribution Customers Conditions of Service.

ACHIEVABILITY

The DG Facility interconnection requirements must be achievable, fair and competitive to allow

equitable access for all DG Owners.

O PERABILITY

The DG Facility connection must not restrict the operation of the HONI Distribution System. All aspects of the interconnection that can impact the HONI Distribution System must be

1 This document also applies to DGs connecting to Hybrid Feeders (feeders owned partially byHONI)


14/195



10

compatible with HONI standard operating, protection, control and metering systems andpractices.


15/195



11

1.3 R ESPONSIBILITIES

Connecting to HONI's Distribution systems involves several steps and both HONI and the DGOwner have distinct responsibilities.

Hydro One Networks Inc. is responsible for:

the safety, reliability, power quality and operation of HONIs Distribution System , andensuring the DG Facility connection does not adversely affect the system or HONIsexisting customers;

maintaining the integrity of HONIs Transmission and Distribution S ystem;

operating in compliance with all applicable Ontario regulatory codes and within the

guidelines of all applicable Ontario, Canadian and international standards; and

establishing the terms and conditions for Operating and Technical Requirementsconsistent with the DG Facility connection Objectives.

DG Owners are responsible for:

the safety, design, construction, operation, metering, protection and control, andmaintenance of the DG Facility;

operating in compliance with all applicable Ontario regulatory codes and within theguidelines of all applicable Ontario, Canadian and international standards;

connecting a DG F acility that is compatible with HONIs standard operating,protection, control and metering systems and practices.

a biding by the terms and conditions of HONIs Operating and Technical Requirements.


16/195

DISTRIBUTED GENERATION TECHNICAL INTERCONNECTION REQUIREMENTS INTERCONNECTIONS AT VOLTAGES 50 KV AND BELOW


12

1.4 R EQUIREMENT ORIGINS

Table 1 below shows the origins of the requirements found within this document.

Table 1: Origins of Requirements

Hydro One Networks Inc.Requirements are classified as: If:

Verbatim They are a direct application (no change) of stated standards

Selective HONI has chosen the most applicable requirements from standards having varying requirements

Optimal HONI has found an optimal solution for its Distribution System to meet the stated standards

Unique Requirements are unique to meet HONIs Business Practice objectives

Regulation and Standards

# TIR Section HONI OESC IEEE (1547) IEC 60834 C22.3 No. 9-08 DSC

2.1 General Requirements

2.1.1 Safety Verbatim 2-200 1.2 1.4 4.6 Appx. F.1 & F.2

2.1.2 Active Power Optimal 4.1.1 5 Appx. F.1; F.2 - 3.1,5.1

2.1.3 Reactive Power Optimal 4.1.1 5, 7.2.4 Appx. F.1; F.2 3.1,5.1

2.1.4 Equipment Rating and Requirements Verbatim 2-004, 2-010(d), 2-024 4.1.1 5, 7.4.2 6.2.14, 6.2.29, Appx.F.1 & F.2 3.1, 52.1.5 Point of Common Coupling Optimal 84-026 1.2, 3.1.3 1.1,3, Figure 1 Appx. F.2 12.1.6 New Line Optimal 84-020, 84-026 4.1.7 1.1, 7.3.1 Appx. F.2 1

2.1.7 Isolation Device Selective 84-024, 84-026 4.1.7 7.3.1 4.5.2, Appx. F.2 1,12.1.8 Interrupting Device Rating Selective 2-004, 2-024 7.4.2 Appx. F.2 52.1.9 Phasing Verbatim 6.10, 7.3.4

2.1.10 Temporary Over-Voltage (TOV) Selective 4.1.2 7.3.3, 7.4.7.1 Appx. F.2 2


17/195


18/195


19/195



15

Regulation and Standards # TIR Section HONI OESC IEEE (1547) IEC 60834 C22.3 No. 9-08 DSC (Appendix F)

2.3.13 Transfer Trip Optimal 4.4.1 7.4.8, 7.4.12 Appx. F.2 6.1.2

2.3.14 Distributed Generator End Open(DGEO) Optimal 4.2.2 6.11 Appx. F.2 6

2.3.15 Low Set Block Signal (LSBS) Optimal 4.2.2 6.11 Appx. F.2 62.3.16 DGEO and LSBS Design Optimal 4.2.2 6.11 Appx. F.2 62.3.17 Special Interconnection Protection Optimal 2.4.8, 6.2.292.3.18 Protection Scheme Failures Optimal 4.2.2 7.4.20 4.1.6, Appx. F.2 6.4

2.3.19 Interconnection Protection Acceptance Optimal 4, 6.8

2.4.6, 3.1.2, 3.2.11,4.1.1, 4.4.3, 6.2.11,

6.2.11, 6.2.14, 6.2.18, Appx. F.1

2.3.20 Protection Changes Optimal 8.6

2.4 Operating Requirements

2.4.1 General Optimal 3.1.1, 4.1.1, 4.1.4,4.2.6, 4.4.1, Appx.

F.12.4.2 Islanding Verbatim 4.4.1 7.4.8 Appx. F.2 6.1.2

2.4.3 Unintentional Energization Verbatim 4.1.5 7.4.10 Appx. F.2 6

2.4.4 Synchronization Verbatim 4.1.3, 1547.2(8.1.3, 9.2.3) 7.4.14, Table 6 Appx. F.1 3.2

2.4.5 Single Connection Path Optimal 6.12

2.4.6 Automatic Disconnection ofGeneration and HV Ground Sources Optimal 4.1.2 7.3.3 Appx. F.2 2, 6.4

2.4.7 Automatic Reconnection ofGeneration and HV Ground Sources Optimal 4.2.6 7.4.11 Appx. F.2 2, 6.4

2.4.8 Automatic Reconnection of DGFacility Generation Following aSustained Outage or Shutdown

Optimal 4.2.6 7.4.11 Appx. F.2 2, 6.4


20/195



16

Regulation and Standards

# TIR Section HONI OESC IEEE (1547) IEC 60834 C22.3 No. 9-08 DSC (Appendix F)

2.5 Control and MonitoringRequirements

2.5.1 General Selective 1547.3 (Section

4)

Appx. F.2 9, TSC App 1, sch E, Section

1.62.5.2 Control Facilities Selective TSC Schedule G

2.5.3 Operating Data, Telemetry andMonitoring Selective 1547.3 (Section

5)

2.6 Telecommunications Requirements2.6.1 General Unique

2.6.2 Telecommunications Facilities forTeleprotection Unique

2.6.3 Telecommunications Facilities forReal-Time Control and Monitoring Selective 1547.3 (Section

4)

2.6.4 Reliability Requirements Selective 1547.3 (Section4) IEC 60834-1

2.7 Reporting Requirements2.7.1 General Reporting Requirements Selective 4.1.32.7.2 Power Quality Recording Optimal 1547.32.7.3 Disturbance Fault Recording Optimal 1547.32.7.4 Sequence of Events Recording Optimal 1547.3

2.8 Metering Requirements Optimal 6-400 6-412 5.2, Appx. F.1, F.2 7


21/195



17

Regulation and Standards # TIR Section HONI OESC IEEE (1547) IEC 60834 C22.3 No. 9-08 DSC (Appendix F)

2.9 Commissioning and VerificationRequirements Optimal Appx. B 14-102 5.4 8.4 6.2.19, Appx. F.1

2.10 Maintenance Requirements Optimal 2-006, 2-010, 2-300 8.5 4.4, 6.2.15, 6.2.27,6.4.3, Appx. F.2

2.11 Connection Process Requirement Optimal Appx. F.1


22/195



18

1.5 T ERMINOLOGY

In this Document, Distributed Generation Technical Interconnection Requirements:Interconnections at Voltages 50kV and Below, the term:

shall is used to express a requirement i.e. a provision that the DG Owner isobligated to satisfy in order to comply with the requirements of this document;

should is used to express a recommendation or that which is advised but notrequired;

may is used to express an option or that which is permissible within the limits of thisdocument; and

can is used to express possibility or capability.

Requirements may follow with a Background Information and Design Considerationssection below them and do not include requirements or alternative requirements. The purposeof these sections is to provide informative material, rationale on which the requirements in thesection are based on and some design considerations. These sections are included asrequired and are not necessarily present for all requirements. HONI does not take anyresponsibility for this information and the engineering consultant designing the DG Facility candecide whether to take the information into consideration when designing the project.

Appendices are designated normative if they are mandatory or informative if non-mandatory todefine their application.

1.6 C APACITY LIMITATIONS ON GENERATOR INTERCONNECTIONS FEEDER LOADINGLIMITS

The capacity for all sections of all feeders, the feeder limitation, is based mainly on thedistance from the Hydro One Networks Inc. supply station to the DGs Point of CommonCoupling (PCC). The feeder limitation applies to all DGs connected or connecting to the feederand considers the rated output capacity of each DG. Any single DG connection can affect thecapacity available for all sections of the feeder.

For all sections of the feeder, the total current shall not exceed:

a) 400 Amps for HONI feeders operating at voltages 13kV or greater; and

b) 200 Amps for HONI feeders operating at voltages below 13kV.


23/195



19

ACCEPTABLE G ENERATION LIMIT AT A TS OR A DS

The acceptable generation limit at a TS or a DS is established by adding together: 60% ofmaximum MVA rating of the single transformer and the minimum station load.

S HORT C IRCUIT (SC) LIMITS

The SC limits at TS low voltage bus or at any portion of distribution feeder shall not beexceeded by the addition of DG Facilities. Refer to Section 2.1.16 for requirement.

1.6.1 T HREE P HASE GENERATORS

i) The acceptable individual generation limits for three-phase DG Facilities

interconnecting to HONI Distribution System feeders shall not exceed:a) 1 MW per connection on feeders operating below 13kV; and

b) 5 MW per connection on 27.6kV feeders supplied via a 44kV:27.6kV step-downtransformer.

ii) The feeder limitation determines the total acceptable three-phase generation allowedfor all sections of HONI`s Distribution System feeders and shall not exceed:

a) 30 MW for feeders operating at 44kV;

b) 19 MW for feeders operating at 27.6kV;

c) 9.6 MW for feeders operating at 13.8kV;

d) 4.3 MW for feeders operating at 12.48kV;

e) 2.9 MW for feeders operating at 8.32kV; and

f) 1.45 MW for feeders operating at 4.16kV.

1.6.2 S INGLE P HASE GENERATORS

i) The maximum single phase generation limits for specific feeders shall not exceed:

a) 150kW for single phase generators connecting to feeders operating at nominalvoltage levels of 13kV or greater; and

b) 100kW for single phase generators connecting to feeders operating at nominalvoltage levels less than 13kV.


24/195



20

Note: While the absolute limits are stated above, the actual acceptable individualsingle phase generation limit for specific feeders or TS/DS is determined in

Connection Impact Assessment (CIA).

1.7 D OCUMENT REPRODUCTION

This document may be reproduced or copied in whole or in part provided that credit is given toHydro One Networks Inc. and is not sold for profit.


25/195



21

1.8 T ERMS AND DEFINITIONS

The Term Is defined as

ANSI American National Standards Institute

Anti-Islanding A protection system aimed at detecting islanded conditions (seeisland) and disconnecting the DG facility from the DistributionSystem if an island forms

AVR Automatic Voltage Regulator

BF Breaker Fail

Breaker Fault Interrupting Device: this may be a breaker, circuit switcher,HVI, LVI

CCE Connection Cost Estimate

CCRA Connection Cost Recovery Agreement

CEA The Canadian Electricity Association

CIA Connection Impact Assessment

Class 1 DG aggregate capacity at PCC 250kW

Class 2 250kW < DG aggregate capacity at PCC < 1500kW

Class 3 1.5MW DG aggregate capacity at PCC 10MW

Class 4 DG aggregate capacity at PCC > 10MW

Clearing Time See Trip Time

CO

Central Office: a local telephone company office that provides acentral point for the termination of telecommunication lines and

trunks, and where they can be interconnected.


26/195



22

COG

Coefficient of grounding - is defined as 100% x E LG/E LL where:ELG is the highest rms, line-to-ground, power-frequencyvoltage, on a sound phase, at a selected location, during aline-to-ground fault affecting one or more phases.ELL is the line-to-line power-frequency voltage that would beobtained, at a selected location, with the power faultremoved. COG for three-phase systems are calculated fromthe phase-sequence impedance components, as viewed fromthe fault location.

The COG is useful in the selection of a surge arrester rating for aselected location

COMTRADE Common Format for Transient Data Exchange

COVER Confirmation of Verification Evidence Report

CSA The Canadian Standards Association

DESN Dual Element Spot Network Type of TS

DCA Distribution Connection Agreement

Demarcation Point The point at which the Hydro One equipment ends and anotherpartys equipment begins.

DFR Disturbance Fault Recorder

DG See Distributed Generation*Formerly referred to as EG Embedded Generator

DGEO

Distributed Generator End Open: a signal used to confirm the statusof the generator breaker used to prevent out-of-phase reclosingonto the generator*Formerly referred to as EGEO Embedded Generator End Open

DGIT See DG Interconnection Transformer

DG Facility All equipment including generators, interface transformer,protections, and line on the DG side of the PCC

DG InterconnectionTransformer

The transformer used to step up the voltage from the DG todistribution voltage levels.

DG Owner The entity which owns or leases the DG facility.


27/195



23

DistributedGeneration (DG)

Power generators connected to a Distribution System through aPoint of Common Coupling (PCC).

DistributedGenerator (DG) See Distributed Generation

DistributionConnection

Agreement

The DG Facility is required to enter into a Distribution Connection Agreement with HONI prior to generating onto the system

Distribution Lines Distribution System lines that operate at nominal line-line voltagesbelow 27.6 kV.

Distribution System

Any power line facilities under the operating authority of the Wiresowner (HONI or LDC) that operate at nominal line-line voltages of 50kV or below. This includes sub-transmission power lines that operate

at 27.6 kV or 44 kV and distribution lines that operate below voltagesof 27.6 kV.

Distributor The electric utility owning or operating the distribution lines.

DNP 3.0 Distributed Network Protocol

DO Drop Out

DS An electrical station that is used to step down a sub-transmissionvoltage to a distribution voltage for distribution to the end usecustomer.

DSC Distribution System Code

Effectively Grounded

A system grounded through a sufficiently low impedance so thatCOG does not exceed 80%. This value is obtained approximatelywhen, for all system conditions, the ratio of the zero-sequencereactance to the positive-sequence reactance, ( X0/X1), is positiveand 3, and the ratio of zero -sequence resistance to positive-sequence reactance, ( R 0/X1), is positive and < 1.

EMI Electromagnetic Interference

ESA Electrical Safety Authority

Essential Loads

Part of the load that requires continuous quality electric power for itssuccessful operation or devices and equipment whose failure tooperate satisfactorily jeopardizes the health or safety of personnel,and/or results in loss of function, financial loss, or damage toproperty deemed essential by the user

F Class Feeder Distribution feeder emanating from a HONI DS or HVDS


28/195



24

Feeder A single-phase or three-phase line emanating from a substation tosupply load.

Ferroresonance A phenomenon caused by the interaction of system capacitance andnonlinear inductance of a transformer, usually resulting in very hightransient or sustained overvoltage

Ferroresonance

Protection (59I)

Ferroresonance detection can be accomplished with a peakdetecting overvoltage element (59I). This type of element is able torespond to the sub cycle high peak voltages that are characteristic ofthe ferroresonance phenomena. Standard overvoltage elementstypically employ RMS calculations to the waveform and may not be

able to detect the high peaks as they will be averaged with low peakvalues that also may occur. Where ferroresonance is expected orfound to be a problem, ferroresonance detection will be required bythe local DG interface protection at the DG location to disconnect thegenerator.

GPRGround Potential Rise: IEEE defines this as the voltage that astation grounding grid may attain relative to a distant grounding pointassumed to be at the potential of remote earth.

GPS Global Positioning System

Harmonics Sinusoidal voltages and currents at frequencies that are integralmultiples of the fundamental power frequency (60Hz).

High Voltage In this document, high voltage refers to the HONI system voltage andcan be referred to as medium voltage.

HONI Hydro One Networks Inc.

HVDS

High Voltage Distribution Station: the distribution station connecteddirectly to HONI transmission system (115kV system) which stepsdown transmission voltage to distribution voltage for distribution tothe end use customer.

HVGT HV Grounding Transformer

HV Ground Source

Three-phase ground sources are any three-phase powertransformers or grounding transformers that provide a ground-current(zero-sequence) return path to phase-ground faults on the HV side ofthe DGIT. That includes separate HV grounding transformers orDGITs that have star-connected HV winding with the star-pointneutral connected to ground, either solidly or through a reactor.


29/195



25

HVIHigh Voltage Interrupter any breaker/fault clearing device that is onthe HONI side of the DGIT voltage rating is usually at mediumvoltage distribution level.

Hybrid FeedersFeeders owned partly by HONI and partly by other entities (e.g.HONI owns the first 50% of the feeder, and an LDC own the rest ofthe feeder).

ICCP Inter-Control Center Communications Protocol

IEEE The Institute of Electrical and Electronics Engineers

IED Intelligent Electronic Device

IESO Independent Electricity System Operator

Interconnectionfacility

Physical connection of DG to HONI's Distribution System whichallows parallel operation to occur

InterconnectionPoint See PCC

Interrupting DeviceThe device used to disconnect generation from HONIs DistributionSystem: this may be a high voltage interrupter (HVI) or through a lowvoltage interrupter/breaker (LVI).

Island An operating condition where a DG(s) is (are) supplying load(s) thatis electrically separated from the main electric utility.

LDCLocal Distribution Company: an entity that owns a DistributionSystem for the delivery of energy to consumers from the IESO-controlled grid.

Load The amount of power supplied or required at a specific location.

Load Factor Ratio of average load during a designated period to the peak(maximum) load in the same period.

Load Flow Study Steady state computer simulation study of voltages and currents inthe Distribution System.

LSBS

Low Set Block Signal signal sent over the same channel as DGEOwhich blocks the Low Set Instantaneous Protections at HONIsstations - to prevent inadvertent trips due to transformer inrushduring energization.


30/195



26

LVGT Low Voltage Grounding Transformer

LVI Low Voltage Interrupter

MCOV Maximum Continuous Operating Voltage

Medium Voltage See High Voltage

M Class Feeder Distribution feeder emanating from a HONI TS

NDZNon Detection Zone range where passive anti-islanding protectionmay not operate within required time due to the small mismatchbetween generation and load

NERC North American Electric Reliability Corporation

NEV Neutral to Earth Voltage

NPCC NorthEast Power Coordinating Council

MTBF Mean Time Between Failure

MTTR Mean Time to Repair

OEB Ontario Energy Board

OESC Ontario Electrical Safety Code

OGCC Ontario Grid Control Centre

Parallel Operation The state and operation where the DG Facility is connected to theDistribution System and supplies loads along with the electric grid.

PCC Point of Common Coupling. It is the point where the DG Facility is toconnect to Hydro Ones Networks Inc. D istribution System

Point of Connection

The point where the new DG Facilitys connection assets or new line

expansion assets will be connected to the existing Hydro OneNetworks Inc. Distribution System

Pst A measure of short-term perception of flicker obtained for a tenminute interval

PSS Power System Stabilizer


31/195



27

Plt A measure of long-term perception of flicker obtained for a two-hourperiod

PQ Power Quality

Protection SchemeProtection functions including associated sensors, relays, CTs, VTs,power supplies, intended to protect a Distribution System orinterconnected facility.

PT Potential Transformer

PU Pick Up

Resonance A tendency of a system to oscillate at maximum amplitude at certainfrequencies, usually resulting in very high voltages and currents.

RLSS Rotational Load Shedding Schedules

ROCOF Rate-of-change-of-frequency

RMS Root Mean Square

RTU Remote terminal unit

SC Short Circuit Current

SCADA Supervisory Control and Data Acquisition

SER Sequence of Events Recorder

Service Provider A Service Provider is an entity that provides services to otherentities.

SLD Single Line Diagram

SPS Special Protection Scheme

Stabilized A Distribution System returning to normal frequency and voltageafter a disturbance for a period of 5 minutes or as determined by theWires Owner.

Sub-transmissionLines 27.6kV or 44kV HONI distribution lines

Synchronized See Parallel Operation


32/195


33/195



29

2 T ECHNICAL INTERCONNECTION REQUIREMENTS

2.1 G ENERAL REQUIREMENTS

2.1.1 S AFETY

i) The DG Facility interconnections installation and operation shall not create a safetyhazard to HONIs personnel, customers, general public and personnel working in theDG Facility.

B ACKGROUND INFORMATION

Safety is of primary concern and shall be the main consideration when designing the DGFacility. The primary concern of this document is to provide interconnection specificationsto ensure that safety will be maintained.

2.1.2 A CTIVE P OWER

i) The DG Facility shall have to restrict their active power export to the project capacitywhich was applied for and assessed in the Connection Impact Assessment.

[Note: Typically Generators Name Plate Capacity or Gen -Set Name Plate Capacityshall be considered as project size.]

2.1.3 R EACTIVE P OWER

i) The DG Facility shall comply with voltage and power factor requirements in Section2.2.2.1 and Section 2.2.2.6 respectively.

2.1.4 E QUIPMENT RATING AND REQUIREMENTS

i) All electrical equipment and its installation shall be approved as required by Rule 2-024 and Rule 2-004, respectively, of the Ontario Electric Safety Code.

ii) The DG Facility shall have a connection authorization from ESA prior to a DistributionConnection Agreement with HONI.

iii) The DG Facility shall be maintained throughout the life of the assets to ensure thatthe DG Facility operates as designed.


34/195



30

iv) The DG Facility interface equipment shall be compatible with HONI DistributionSystem equipment at the connection voltage which includes but not limited to:

a) Maximum Voltage;

b) Basic Impulse Limit;

c) Short Circuit Ratings; and

d) Capacity.

v) Connection of DG Facilities shall not cause the ratings of HONI Distribution andTransmission System equipment to be exceeded for all operating conditions. Thisincludes, but is not limited to:

a) equipment thermal loading limits; andb) equipment short circuit limits.

vi) Where reverse power flow is possible, all existing voltage regulating and meteringdevices shall be made suitable for bi-directional flow.

vii) Changes to HONI`s Distribution and Transmission System equipment ratings due tothe interconnection of DG Facilities shall be assessed by the HONI s CIA.


All existing HONI equipment in the distribution or transmission system shall not beoverloaded beyond acceptable limits. All interrupting devices shall be capable ofinterrupting the maximum fault current under all operating conditions of the DG Facility. Itmust be ensured that conductors, voltage regulators, regulating stations, reclosers, circuitbreakers, transformers, etc. in HONI`s Distribution and Transmission System are operatingwithin their respected ratings.

All regulating devices and metering devices which are designed for unidirectional powerflow may need to be upgraded or replaced to ensure they are capable of handling bi-directional power flow.


35/195



31

2.1.5 P OINT OF COMMON COUPLING

i) The PCC must be identified on the single line diagram (SLD).

ii) The DG Owner shall be responsible for the design, construction, maintenance andoperation of the facilities and equipment on the DG side of the PCC.

iii) All equipment on the DG Facility side of the PCC shall be in accordance with Section2.1.4.

iv) HONI shall be responsible for the design, construction, maintenance and operation ofthe facilities on HONIs side of the PCC.

v) When specifications and parameters (such as voltage, frequency, and power quality)

are mentioned throughout this document, they must be met at the PCC unlessotherwise stated.

vi) HONI or the DG Owner may require that their equipment be located on the other sideof the PCC. In this case, the DG owner must provide the necessary space for HONIto install such equipment and HONI is to approve this site.

vii) A 120V AC power service is to be available for Item (vi) above.


The Point of Connection means the point where the new DG Facilitys connection assets ornew line expansion assets will be connected to existing Hydro One Networks Inc.Distribution System. The Point of Common Coupling (PCC) means the point where the DGFacility is to connect to Hydro Ones Distribution System. The Point of Connection may bethe same as the PCC, especially if the DG Facility lies along the existing HONI DistributionSystem. The PCC may be located somewhere between the Point of Connection and theDG Facility if the new line will be owned by Hydro One Networks Inc. These definitionshave been adopted by HONI to align with the Ontario Energy Boards Distribution SystemCode and not with CSA C22.3 No. 9-08 standard. Refer to Figure 1 for interconnectionterminology. The PCC shall be identified on the single line diagram (SLD), as shown below

in Figure 1.

In addition to the Items mentioned above, HONI will also carry out the engineering, designand construction required for additional changes to HONIs system in order to facilitate theDG interconnection. The DG Owner may be responsible for some or all of the costs of suchchanges.


36/195



32

Figure 1: Simplified SLD Interconnection Terminology

2.1.6 N EW LINE

i) An automatic isolation device for a new line owned by the DG Owner that is 0.2 kmshall be required at the PCC to disconnect the DG Owners line from HONIsDistribution System for faults in the DG Owners line. The DG Owner shall beresponsible for the installation, operation, and ownership of this device.

ii) All DG facilities with more than one interface transformer are required to install an

automatic isolating device at their PCC to disconnect the DG facility for faults on theDG owner s side of the PCC .

iii) Any additional requirements shall be determined in the CIA.


37/195



33

2.1.7 I SOLATION DEVICE

i) A means of electrically isolating the DG Facility from HONIs Distribution System shallbe provided.

ii) The isolation device shall:

a) be in compliance with the OESC 2;

b) be capable of being energized from both sides 3;

c) plainly indicate whether in the open or closed position 3;

d) be capable of being opened at rated load (Load Break Switch )3;

e) be located between the Hydro One system and the DG Facility, upstream of alltransformers, generation and HV ground sources;

f) be readily accessible by Hydro On e 3;

g) not be located in a locked facility;

h) not be located in a hazardous location 4;

i) have provision for being locked in the open position 3;

j) have a manual override;

k) have no keyed interlocks;

l) have contact operation verifiable by direct visible means (be a Visible Breaktype )3;

m) conform to OESC Sections 14, 28, and 36 if it includes an overcurrent devic e 3;

n) be capable of being closed with safety to the operator with a fault on thesystem 3;

o) be capable of being operated without exposing the operator to any live parts;and

p) bear a warning to the effect that inside parts can be energized from sources onboth sides when disconnecting means is open 3.

2 As outlined by the OESC Section 843 In accordance with OESC Section 84-0244 As defined by OESC Section 18


38/195



34

iii) In addition to the requirements in Item (ii) above, all three phase DG Facilitysisolation device shall:

a) be gang operated and disconnect all ungrounded conductors of the circuitsimultaneously 5;

b) be motorized if the DG Facility is larger than:

1) 250 kW when connecting to feeders operating below 15kV; and

2) 500 kW when connecting to feeders operating above 15kV.

c) have a protection interface for tripping if used as a backup for interruptingdevice failure (HVI Breaker Failure or LVI Breaker Failure).

iv) If the isolation device is motorized as required by Item (iii)(b) above, it shall bepowered from a reliable source such as a DC battery to power a DC motor or via abattery-supplied DC/AC inverter to power an AC motor.

v) If multiple generators are connected at the DG facility, one disconnect switch shall becapable of isolating all of the generators simultaneously.

vi) Switching, tagging and lockout procedures shall be coordinated with HONI.

vii) The DG Owner and HONI shall mutually agree to the exact location of the disconnectswitch.


To ensur e a safe and reliable means of electrically isolating the DG Facility from HONIsdistribution system, an isolating device that conforms to OESC Section 84 and additionalHONI requirements is required.

This point of disconnection is required for the purpose of work protection of Hydro One andDG Facility personnel. Operation of the isolation device shall not be a source of injury tothe operator during operation, even when closed into a faulted system. It may also be usedfor breaker fail schemes.

The DG Facility isolation device, if motorized, must have a reliable uninterruptable powersource. An AC motor supplied from the AC station service supply may be used to powerthe motor providing there is an auto-transfer from a DC/AC inverter. For example, if the HVdisconnect switch (isolation device) motor is AC rated and powered from the AC stationservice and if all load derived from the AC station service are considered non -critical ,

5 In accordance with OESC Section 84-024


39/195



35

then, AC power may not be available when the HV disconnect switch is required to operate(example: backup to HVI breaker failure).

If multiple generators are connected at the DG facility, one disconnect switch must becapable of isolating all of the generators simultaneously. There may be other means ofmeeting this requirement and any proposals must be reviewed by HONI.

2.1.8 I NTERRUPTING DEVICE RATING

i) All fault current interrupting devices shall be sized appropriately using present andanticipated future fault levels.

ii) The inter rupting device used to disconnect generation from HONIs Distribution

System shall operate fast enough to meet the timing requirement of the quickestprotection operation and shall:

a) operate in no more than 160ms, which includes the protection elementdetection time for DG Facilities not equipped with Transfer Trip; and

b) operate within the required time for DG Facilities equipped with Transfer Trip asshown in Table 13 maximum interrupting device time is dependent on thespeed of Transfer Trip communications.

Background Information

Fault contribution from both the DG facility and HONIs distribution system shall be used toadequately size all fault current interrupting devices. HONI will provide present andanticipated future fault contribution levels from HONIs distribution system.

For DGs that have a time variant fault contribution characteristics, the characteristicsproducing the highest fundamental component fault current shall be used synchronousand induction generators shall use sub transient reactance to calculate fault contribution.Inverter based DGs typically contribute fault current marginally higher than rated full loadcurrent (usually 1.2 to 1.5 times the rated load current of the inverter for self-commutated

designs and less for line-commutated inverters). Depending on the design, the rotor ofdouble-fed asynchronous motors may be shorted by crowbar action in response to severefaults causing the generator to behave like an induction generator.

The interrupting device shall have a maximum operating time such that when combinedwith the timings of other protection elements will ensure that the minimum clearing timesare achieved. Appendix F contains sample timing diagrams.


40/195



36

2.1.9 P HASING

i) The DG must connect rotating machines as required to match the phase sequenceand direction of rotation of HONI Distribution System.

2.1.10 T EMPORARY OVER -VOLTAGE (TOV)

i) Grounding of DG Facilities and interconnection systems shall be in accordance withSection 2.1.11 and not cause any voltage disturbances.

ii) When connecting to HONIs 4 -wire Distribution System, TOV that may be caused bythe DG Facility interconnection should not exceed 125% of nominal system voltage(line to neutral) anywhere on the distribution system and under no circumstance shallexceed 130%.

iii) HONI may advise on action needed to reduce TOV to limits by specifying therequirement of grounding transformer on the HV side.


Connection of DG Facilities causes fault levels, fault current distributions and voltageprofiles to change on the Distribution System. The extent of these changes depends onmany factors associated with the distribution system and the DG Facility connection. Thosefactors include but are not limited to:

Pre-fault voltages of the utility and generator sources;

Type of fault;

Fault resistance;

Utility supply configuration and corresponding source impedances;

DG Facility supply configuration and corresponding source impedances to thePCC. These are affected by:

- generator capacity (MVA);- generator type(s) synchronous, asynchronous (induction), inverters and

static power converters;

- the effective net generator impedances (that will likely change duringvarious fault conditions and time periods);

- generator ground connections;


41/195


42/195


43/195



39

x) For interconnections to HONI`s 3-wire Distribution System, a grounded HV DGIT isnot required. However, if the DG Owner decides to have the DGIT grounded, the

ground source contribution from the DG shall be limited as follows. The neutralreactor, X n or grounding transformer shall be sized by the DG Owner and reviewedduring the Connection Impact Assessment based on a Thevenin Equivalent of thePositive (X DG1 ) and Zero Sequence (X DG0 ) Reactance of the DG Facility (example: atthe Point of Connection with the Point of Connection OPEN) that will result in:

a) For Conventional (Rotating) Generators:

; or

b) For DG Facilities with an Inverter Interface:

[Note that for (a) above, X DG1 is the equivalent of X d plus X t of the DG Facility. In (b)above, X DG1 is the reactance of the DGIT.]

xi) The installation of a wind farm shall not increase the lightning transfer to HONIssystem.

xii) In wind installations, to limit the exposure of lightning to HONI's distribution system,lightning protection grounding shall be electrically separated from the grounding grid

of the wind tower.

xiii) Where the separation in Item (xii) above is not possible or practical, then the groundgrids of the towers shall be electrically separated from the DG Facility Station groundgrid from the point of view of transferred lightning surges. The latter can be achievedby ensuring that the wind towers are not bonded to the station's ground grid.

xiv) Stand alone studies are required to ensure that GPR meets step and touch potentialand OESC requirements.

xv) The report in Item (xiv) must be submitted to HONI.


44/195



40

D ESIGN C ONSIDERATION

Multi-grounded 4-wire distribution feeders are effectively grounded and the DG Facility shallappropriately size its neutral reactor such that for the entire feeder and for all system

conditions the ratio of zero-sequence reactance to positive-sequence reactance ( ) is

positive and less than 3, and the ratio of zero-sequence resistance to positive-sequence

reactance ( ) is positive and less than 1. Further, to restrict ground fault contribution, a

lower limit is placed on .

Lightning drainage conductors must be electrically separated from the wind tower's groundgrid (> 6 ft). If this is not possible or practical, then the ground grid of the tower shall be

separated from the DG Station ground from the point of view of transferred lightning surges.This can be achieved by ensuring that the wind towers are not bonded to the station'sground grid. There are different ways to achieve this, such as ensuring that the cables arenot bonding the two systems together (can be achieved by designing a span or section ofthe line overhead). Separation from a transferred lightning point of view can also beachieved if sufficient lightning drainage is provided between the wind turbine tower and thefacility. A study would have to be provided to support such a solution.


45/195


46/195



42

will be required for any alternate configuration. The DGIT may supply unbalance current tosupport the unbalanced load on the feeder. This unbalance current may be present even if

the generator is out of service. The proportion of unbalance load current from the DGIT willvary based on the feeder topology, unbalanced loads, voltage and the DG location.

2.1.12.1 DG INTERCONNECTION TO 4-W IRE DISTRIBUTION S YSTEMS

i) The DG Facility shall connect to HONIs 4 -Wire Distribution System using one ofthe following options:

a) Wye-Ground:delta DGIT as shown in Figure 2;

b) Wye-Ground:wye-Ground with a Delta tertiary DGIT as shown in Figure 3;

c) Wye-Ground:wye-Ground (LV may be ungrounded) DGIT with a HVGrounding Transformer as shown in Figure 4; or

d) Delta-wye DGIT with HV Grounding Transformer as shown in Figure 6;

ii) In addition to the DGIT options in Item (i), the DG Facility may also connectthrough a Wye-Ground:wye-Ground DGIT without a HV Grounding Transformer asshown in Figure 5 if generators are solidly grounded and the requirements ofSection 2.1.10 and Section 2.1.11 are met. The CIA shall determine whether thisoption is feasible.

iii) In addition to the DGIT options in Item (i) and Item (ii), the DG Facilities smallerthan 1 MVA having generators grounded through an impedance may also connectthrough a Wye-Ground:wye-Ground or a Delta:wye transformer without installing aHV Grounding Transformer as shown in Figure 7 if the CIA determines that theTOV requirements in Section 2.1.10 are met.

iv) For generation being added to existing critical load installations, such as hospitalsand water treatment plants, existing Delta-wye load transformer can be used toconnect the generation as shown in Figure 8 provided that the requirements inItem (vi) below are met and that an HVI is provided to isolate the HV GroundingTransformer from the Distribution System whenever the generation isdisconnected from the Distribution System.

v) A neutral reactor in the primary winding of DGIT options in (i)(a), (i)(b), (ii) and (iii)above may be necessary to limit the ground short circuit current and shall be sizedin accordance with Section 2.1.11 (ix).


47/195



43

vi) A HV Grounding Transformer on the HV side of the DGIT shall be required to keepTOV within limits for DGIT options (i)(c), (i)(d) and (iv) above and shall:

a) be sized in accordance with Section 2.1.11( ix);

b) be located on DG side of the HVI;

c) be a zig-zag design;

d) be either solidly connected (not fused) to ensure that the transformer is inservice at all times, or if fused, the fuses shall be monitored and the DGFacility`s HVI shall be tripped in the event of a failure of the groundingtransformer;

e) have the neutral of the grounding transformer connected to HONI`s neutralconductor; and

f) have adequate protection to provide an alarm when the neutral overcurrentrating of the grounding transformer is exceeded and to automatically removethe grounding transformer from service and disconnect all generation wheninternal phase or ground faults occur.

vii) The DGIT options in Item (i), Item (ii) and Item (iv) above, shall require theinstallation of a high side interrupting device (HVI) in accordance with Section2.1.13 to ensure that the HV Ground Source is disconnected from HONIs

Distribution System during abnormal conditions. The requirement of a HVI for theoption in Item (iii) above, shall be determined in the CIA.

viii) The DGITs ground shall be connected to HONIs neutral conductor.

ix) The DGIT design and installation shall meet all other grounding requirements inSection 2.1.11.

x) The design of the DGIT shall ensure that all Power Quality requirements areadhered to.


48/195



44

LVI

Auxiliary

Load

Utility feed er

G

HVI

4-Wire

Xn

N

Option 1: Wye:delta DG IT

ABC

PCC

ON Is VI

Wye

delta

Fuse

Station Service

T1

Xgn

M