Hydro One Dg Technical Interconnection Requirements Distribution Interconnections
DG interconnection protection ieee 1547
-
Upload
michaeljmack -
Category
Engineering
-
view
593 -
download
7
Transcript of DG interconnection protection ieee 1547
DG Interconnection ProtectionDG Interconnection Protection
ProtectingUtility Distribution with Interconnecting
Distributed Generation
Technical & Industry Practice Background What IEEE Standard 1547 Doesn’t Tell You
n
Presentation Objectives
DG Interconnection Protection
Distributed Generation Overview- What is distributed generation (DG)?- Explore Types of DGs- Define interconnection protection- Tell you what IEEE 1547 Doesn’t
Protection Variables & Standards- Interconnection types
Transformer grounding makes a big difference!- Protection to meet interconnection challenges- Comparison of various power company and standards
Including IEEE 1547- Distribution protection coordination issues
IEEE Distribution Survey Data (for DG issues)
Introduction to DG Interconnection Protective Relays (M-3410A & M-3520)
Dispersed Generator Interconnection Protection AreasDetection of loss of parallel operation with utilityFault backfeed detectionDetection of damaging system conditionsAbnormal power flowRestoration
Tripping, Automatic Restoration and Automatic Reclosing on Utility SystemTrip of generator or main incoming breaker to separate from utility—how to decideAuto restoration strategiesUtility auto reclosing—how to protect your generator
Use of Digital Technology for DG Interconnection/Generator Protection and Beckwith M-3520 and M-3410 Relays
Advantages of the technologyUser-selectable functionalitySelf-diagnosticsCommunications capabilityOscillographic capabilitySoftware demo
Outline
DG Interconnection Protection
n
Major ReasonCost of utility power is very high in many parts of the U.S. due to:
Deregulation problems (CA)Settlement of stranded investment (East Coast-Midwest)
DGs Can Generate Power Cheaper Than Utility Power From A Central Plant
Use of waste heat enhances DG economicsNew Technologies Are Being Tried
MicroturbinesFuel CellsWind
Federal and State Government Push for Renewable Resources(Green Power)Many Utilites are Receptive to DGs That Can Provide Power During System Peak Load
DG Interconnection Protection
Why is DG so Popular?
UTILITY CONCERNS:
Protection of the system from damageSystem Short Circuit Damage:loss of coordination, customer outages
Transient Overvoltage:during islanding, transformer connections, Ferroresonance
Power Quality:during islanding
DG OWNER CONCERNS:
Protection of the generator from damage
Automated Reclosing:shaft to torque on generator
Transient Overvoltage:also affects generator
Power Quality:affects load served from generator bus
Protection Objectives
DG Interconnection Protection
n
Projection: A significant amount new generating capacity in the maybe be supplied by DGs in the next decade and beyond.This new capacity will take two forms:
Large capacity plants owned & operated by non-utility entities (IPPs and NUGs)- Gas turbines & combined cycle plants- Typically greater than 10MW- Connected into utility’s transmission and subtransmission systems
Protection integrated into transmission and subtransmission systems
Small dispersed generating units - Connected into utility’s distribution system- Typically less than 10MW
Installations require DG interconnection protection
DG Interconnection Protection
IEEE PSRC WG Report- Intertie Protection of Consumer-Owned Sources of Generation 3
MVA or Less
First guideline addressing DG
Published in 1985
Good work and full of application information
DG Standards History
DG Interconnection Protection
Std 1001 from IEEE SCC23- IEEE Guide for Interfacing Dispersed Storage and Generation
Facilities with Utility Systems
First standard addressing DG
Published in 1988
Although withdrawn, still a good work and full of application information
DG Standards History
DG Interconnection Protection
Standard 929- Focus: Small inverter based systems sourced from PV, Fuel
Cells, Microturbines
IEEE 1547- Focus: Produce a “universal” DG interconnection protection
document to be used as a minimum technical requirement base
Can be purchased from IEEE
Recent History & Today
DG Interconnection Protection
IEEE 1547 Says DG’s Shall :
Not Cause Overvoltages or Loss of Utility Relay Coordination
Disconnect When No Longer Operating in Parallel With the Utility.
+ Only Discusses 81O/U and 27, 59
Not Energize the Utility when it is De-energized
Not Create an Unintentional Islands
Use “Utility Grade” Relays
Not Cause Objectionable Harmonics
Not Cause Loss of Synchronism That Results in Objectionable Flicker
DG Interconnection Protection
Impact of size- Intended to cover up to 10MW
Impact of Islanding- Creation of unintentional islands must be detected and
eliminated as fast as possible
Local Disturbances- Quality of service on the utility system should not be degraded
IEEE 1547: Addressed Areas
DG Interconnection Protection
1547.1: Draft Standard for Conformance Test Procedures for Equipment Interconnecting DR with EPS
- Scope: Specifies the Type, Production and Commissioning tests that shall be performed to demonstrate that interconnection functions and equipment of a DR conform to IEEE 1547
P 1547.2: Draft Application Guide for IEEE Std. 1547 for Interconnecting DR with EPS
- Scope: Provides technical background and application details to support understanding for IEEE 1547 Standard for Interconnecting DR with EPS
More IEEE 1547
DG Interconnection Protection
IEEE 1547.3: Draft Guide for Monitoring, Information Exchange and Control of DR Interconnected with EPS
Other 1547.4: Address DG Installation on Low VotageNetworks– both Spot and Street Neworks
- Scope: Facilities interoperability of one or more DRsinterconnected with EPS
More IEEE 1547
DG Interconnection Protection
Factors that will accelerate DG installationsare:
Continued deregulation of the utility industry
Open transmission access and transmission congestion
Divestiture of generation by utilities- New England- Pennsylvania
Dwindling utility reserve margins- Summer of 2000 Midwest “Generation Crisis”- California Capacity Crisis
DG Interconnection Protection
Low-cost natural gas- That has changing for the worse and de-accelerated DG
High electricity rates
The advance of CHP as driver
New technology : microturbines and fuel cells. Microturbines arepretty much a dead technology.
Unreliability of utility supply to critical process and loads
The Northeast blackout of August 2003 and Calif. Rotating Blackout.Government Mandated Green Power – High Buy Back and/or Mandating a Percent of Future Power be Green.
Factors that will accelerate DG installationsare:
DG Interconnection Protection
n
Peak ShavingNo electrical export
Consumer Shaving Strategies
DG Interconnection Protection
n
Technology Typical Capacity Utility Interface Photovoltaic (Solar) 10’s W to several 100’s W DC to AC Inverter Wind 100’s W to a few MW Induction and synchronous
generators, AC to AC inverter
Geothermal 100’s kW to a few MW Synchronous generator Hydro 100’s W to a few MW Induction or synchronous
generator Reciprocating Engine 100’s W to a few MW Induction or synchronous
generator Combustion Turbine 10’s MW to 100’s MW Synchronous generator Combined Cycle A few 10’s of MW to 100’s MW Synchronous generator Microturbines 10’s of kW to 100’s kW AC to AC Inverter Fuel Cells 10’s of kW to 10’s of MW DC to AC Inverter
DG Types & Capacities
DG Interconnection Protection
Not Green- Burn conventional fuel
GasDiesel, oil, gasoline
Green- Use renewable sources to reduce reliance of fossil fuels:
SolarMethane (from decomposition)WindHydroDiesels Powered by Syn FuelBiomass (burn it)Tidal
DG: Green or Not Green
DG Interconnection Protection
Protection that allows the DG to operate in parallel to the utility
Large non-utility generators do not require specific interconnection protection
- Integrated into transmission system
- Breaker(s) are tripped by transmission line/bus/transformer protection.
Smaller DGs do require specific interconnection protection
What is DG Interconnection Protection?
DG Interconnection Protection
n
Local Loads Local Loads
Utility System
DG System
InterconnectionRelay
InterconnectionTransformer
To Utility SystemTo Utility System
Utility System
DG System
Generator Interconnection
Generator vs. Interconnection Protection
DG Interconnection Protection
n
Greatly complicates restoration- Requires synchronizing at utility substation- Inhibits automatic reclosing
Power quality issue- DG may not be able to maintain voltage, frequency and harmonics within
acceptable levels (load ≠ generation; no harmonic “sink”)
Loads Loads Loads
Loads LoadsLoads Loads Loads
Loads LoadsLoads Loads Loads
Loads
LoadsDG
Utility Substation
If DG creates a feeder island,reclosing requires synchronizing at the uti l i tysubstation
Feeder Island
Islanded Operation of DG with Utility Loadis Generally Not Allowed
DG Interconnection Protection
n
Feeder deenergizes when utility opens feederRestoration responsibility on the DG
- Requires synchronizing to utility- Inhibits automatic reclosing
Loads Loads Loads
Loads LoadsLoads Loads Loads
Loads LoadsLoads Loads Loads
Loads
LoadsDG
Utility Substation
DG can create its own island,and synchronize to the utility
DG Island
DG Facility Islanding to the Utility is Allowed
DG Interconnection Protection
n
Voltage control with high levels of DG require some type of adaptive watt/VAR control
DG Interconnection Protection
High Penetration of DG on Distribution Systems
Seamless integration of DGs into the utility protection system despite:- “Too many cooks in the kitchen”
Owner, consultant, packager, utility
- Ownership boundaries
- Conflicting objectives of DG owners vs. Utility“Want everything for nothing”“Want to pay for nothing”
Making sure protection is correct and operational over the life of the installation- Settings are properly developed
- If system or installation changes, assess the impact on the existing protection
Challenges for the Protection Engineer
DG Interconnection Protection
Loss of parallel operation (anti-islanding)- Voltage and frequency (27, 59, 81-U, 81-O) ; power (32F, 32R-U);
instantaneous overvoltage (59I) , rate-of-frequency change (81R),Transfer Trip
- Based on load (real and reactive) not equaling generationExcept 59I, which is based on self-excitation of resonant induction and synchronous generators with pole top capacitors
Fault backfeed detection- Ground over/under voltage (27N, 27N/59N), ungrounded systems- Phase and ground overcurrent (51V, 51N), grounded systems
Directional overcurrent (67, 67N) and impedance (21) may be used
- Negative sequence overcurrent (46), detects ground faults- All based on sensing abnormally high current or
abnormally low/high voltage as a result of faults
Interconnection Protection: Core Elements
DG Interconnection Protection
Detection of damaging system conditions- Open phase condition or load imbalance (46, 47), negative
sequence current and voltage- Phase sequence reversal (47), negative sequence voltage- Loss of synchronism (78)- Based on severe quantity imbalance (including reverse phase
rotation) or power system and DG going out of step
Abnormal power flow detection- DG Export (32F)- Low DG Import (32R-U)- Transformer magnetizing (32F, very sensitive)- These strategies are used when the DG is sized so it cannot
physically or contractually export (peak shaver)
Facilitate proper restoration- Reconnect timer (all generators)- Sync check (synchronous only)
Interconnection Protection: Core Elements
DG Interconnection Protection
DG Loads Loads
DG InterconnectionProtection
Utility
Point ofCommonCoupling
Interconnection Transformer
Sync
Interconnection Protection Placement
DG Interconnection Protection
DG Loads Loads
Utility
Point ofCommonCoupling
Interconnection Transformer
DG InterconnectionProtection
Sync
Ungrounded Primary
Only
Interconnection Protection Placement
DG Interconnection Protection
DG Loads Loads
Utility
Point ofCommonCouplingInterconnection
Transformer
Ungrounded Primary
Only
DG InterconnectionProtection
Sy nc
Point ofInterconnection
Interconnection Protection Placement
DG Interconnection Protection
Utility-grade interconnection relays
- Pass all pertinent ANSI standards
CT and VT requirements (quantities sensed)
Winding configuration of interconnection transformers
Functional protection
- 81U/O, 27, 59, etc.
- Settings of some interconnection functions
Pick ups
Times (to clear faster than utility reclose)
What Utilities Generally Specify
DG Interconnection Protection
Induction
Synchronous
Asynchronous (Static Power Converters)
Types of Generators
DG Interconnection Protection
Induction- Excitation provided externally by system
VAr drain- Less costly than synchronous machines
No excitation system or controlNo sync equipment needed
- Limited in size to <=500 KVA- May cause ferroresonance after disconnection from
utility (self-excitation from nearby caps)
VAr Source
Induction Generator
DG Interconnection Protection
Ferroresonance can take place between an induction machine and capacitors after utility disconnection from feeder. Ferroresonance can also occur on Synchronous Generators!
Generator is excited by capacitors if the reactive components of the generator and aggregate capacitors are close
This interplay produces non-sinusoidal waveforms with high voltage peaks. This causes transformers to saturate, causing non-linearities to exacerbate the problem
Induction Generator: Ferroresonance
DG Interconnection Protection
The overvoltage can damage insulation, damage arrestors and cause flashovers
Standard overvoltage (59) element may not detect this condition…they “RMS” the waveform, missing the high peaks, and may have a long time delay (e.g. 30+ cycles)
A peak instantaneous overvoltage (59I) element will detect and protect against this condition
- This element should sense all three phases!
Induction Generator: Ferroresonance
DG Interconnection Protection
n
FERRORESONANCENEW YORK FIELD TESTS –1989
FIELD TEST CIRCUIT
Test Circuit Setup
DG Interconnection Protection
n
Induction/Synchronous Generator: Ferroresonance can also occur on synchronous generators
DG Interconnection Protection
1. DG Must be Separated From the Utility System (islanded condition)
2. KW Load in the Island Must be Less than 3 Times DG Rating
3. Capacitance Must be Greater Than 25 and Less Than 500 Percent of DG Rating
4. There Must be a Transformer in the Circuit to Provide Nonlinearity
SOLUTION : USE 59I ELEMENT
DG Interconnection Protection
Conditions for Ferroresonance
Synchronous
- Dc field provides excitation
- Need to synchronize to utility system
Synchronous Generator
DG Interconnection Protection
Asynchronous- Static Power Converter (SPC) converts generator frequency
to system frequency (ac-dc-ac)- Generator asynchronously connected to SPC, then SPC
matches to utilitymay be self-commutating (needs sync relay)may be line-commutating (no sync relay needed)
VArs
Asynchronous Generator
DG Interconnection Protection
Some have built-in anti-islanding protection
- SPC tries to periodically change frequency
If grid is hot, SPC cannot change the frequency
If grid has tripped, the frequency moves and the controller trips the machine
Difficult to test; some utilities do not trust and requireother protection
Asynchronous Generator:Static Power Converter
DG Interconnection Protection
Ungrounded Primary Transformer Winding
- Overvoltage may be caused by DG when ungrounded primary transformer windings are applied (no ground source) and the DG backfeeds once utility disconnects
Grounded Primary Transformer Winding
- Ground fault current contribution caused by DG grounded primary transformer windings during utility faults
- Source feeder relaying and reclosers responding to secondary ground faults within the DG facility
Impact of Interconnection Transformer
DG Interconnection Protection
n
a
bc
a
bc
ground
Van=Vag
Vbn=VbgVbn=Vbg
n=gvag=0
n
Van= -Vng
Vcn Vbn
VbgVcg
Unfaulted
Ground Fault
DG
Backfeed to Utility
DG Facility
Ungrounded Primary: System Backfeed
DG Interconnection Protection
n
a
bc
a
bc
ground
Van=Vag
Vbn=VbgVbn=Vbg
n=gvag=0
n
Van= -Vng
Vcn Vbn
VbgVcg
Unfaulted
Ground Fault
DG
Backfeed to Utility
DG Facility
59N
Sensing Ungrounded System Ground Faultswith 3 Voltage Transformers
DG Interconnection Protection
n
a
bc
a
bc
ground
Van=Vag
Vbn=VbgVbn=Vbg
n=gvag=0
n
Van= -Vng
Vcn Vbn
VbgVcg
Unfaulted
Ground Fault
DG
Backfeed to Utility
DG Facility
59N
27N
Sensing Ungrounded System Ground Faultswith 1 Voltage Transformer
DG Interconnection Protection
n
Many utilities only allow use of ungrounded primary windings if the DG sustains at least a 200% overload on islandingThe overload prevents the overvoltage from occurring
Saturation Curve of Pole-Top Transformer
DG Interconnection Protection
n
LowVoltage(SEC.)
HighVoltage(PRI.)
DG
Ungrounded Primary Interconnection Transformers
DG Interconnection Protection
n
ProblemsCan supply the feeder circuit from an ungrounded sourceafter substation breaker A trips causing overvoltage
LowVoltage(SEC.)
HighVoltage(PRI.)
DG
Ungrounded Primary Interconnection Transformers
DG Interconnection Protection
n
AdvantagesProvide no ground fault backfeed for fault at F1 & F2
No ground current from breaker A for a fault at F3 Low
Voltage(SEC.)
HighVoltage(PRI.)
ProblemsCan supply the feeder circuit from an ungrounded sourceafter substation breaker A trips causing overvoltage
DG
Ungrounded Primary Interconnection Transformers
DG Interconnection Protection
n
LowVoltage(SEC.)
HighVoltage(PRI.)
DG
Grounded Primary Interconnection Transformers
DG Interconnection Protection
n
LowVoltage(SEC.)
HighVoltage(PRI.)
ProblemsProvides an unwanted ground current for supply circuit faults at F1 and F2
Allows source feeder relaying at A to respond to a secondary ground fault at F3 (Ygnd-Ygnd only)
DG
Grounded Primary Interconnection Transformers
DG Interconnection Protection
n
Advantages
No ground current from breaker A for faults at F3 (delta sec. only)
No overvoltage for ground fault at F1
No overvoltage for ground fault at F2
LowVoltage(SEC.)
HighVoltage(PRI.)
ProblemsProvides an unwanted ground current for supply circuit faults at F1 and F2
Allows source feeder relaying at A to respond to a secondary ground fault at F3 (Ygnd-Ygnd only)
DG
Grounded Primary Interconnection Transformers
DG Interconnection Protection
n
Loss of Parallel Operation DetectionOver/under frequency & over/under voltage “window”
59I may be applied to detect ferroresonance between induction/synchronous machines and capacitor banks.
52I
Programmable I/O
32
UTILITY
Anti-Islanding
60FL
51V
51N 46
27475981
Sequence of Events
Metering
LED Targets
Waveform Capture
User Interface with PC
Communications(Modbus)
3Y
Note 1
25
Note 2
52G
59I
BUS
79
Notes:1) Supply VTs are not necessary if potential to relay terminals is <= 480 VAC2) Bus VTs are not necessary if potential to relay terminals is <= 480 VAC
M-3410A FunctionalDiagram
Typical Interconnection Protection
DG Interconnection Protection
n
Fault Backfeed Removal Detection
Typically not required for induction generator or small synchronous DGs
- can rely on loss of parallel protection
Moderate to large DGs- phase faults: 51V- ground faults: 51N
52I
Programmable I/O
32
UTILITY
60FL
51V
51N 46
27475981
Sequence of Events
Metering
LED Targets
Waveform Capture
User Interface with PC
Communications(Modbus)
3Y
Note 1
25
Note 2
52G
59I
BUS
79
Notes:1) Supply VTs are not necessary if potential to relay terminals is <= 480 VAC2) Bus VTs are not necessary if potential to relay terminals is <= 480 VAC
Fault Backfeed Removal
M-3410A FunctionalDiagram
GroundedPrimary
Typical Interconnection Protection for Wye-Ground (PRI.) Interconnection Transformer
DG Interconnection Protection
n
Same as Grounded System, except:
Fault Backfeed Protection uses 27N/59N or 59N to detect for ground faults on system backfed from an ungrounded primary interconnection transformer
51N cannot detect ground faultfed from ungrounded source
52I
Programmable I/O
32
UTILITY
60FL
51V
51N 46
27475981
Sequence of Events
Metering
LED Targets
Waveform Capture
User Interface with PC
Communications(Modbus)
3Y
Note 1
Note 2
59I
BUS
27N
59N
UngroundedPrimary
79
Notes:1) Supply VTs are not neccessary if potential to relay terminals is <= 480 VAC2) Bus VTs are not neccessary if potential to relay terminals is <= 480 VAC
52G
Fault Backfeed Removal
M-3410A FunctionalDiagram
Typical Interconnection Protection for Ungrounded (PRI.) Interconnection Transformer
DG Interconnection Protection
n
Abnormal ConditionsUnbalanced currents
- open conductor/single phase (46)- phase reversal (47)
Not just for commissioningFerroresonance
- instantaneous overvoltage (59I)Fuse Loss
- Potential loss detection (60FL)
52I
Programmable I/O
32
UTILITY
60FL
51V
51N 46
27475981
Sequence of Events
Metering
LED Targets
Waveform Capture
User Interface with PC
Communications(Modbus)
3Y
Note 1
25
Note 2
52G
59I
BUS
79
Notes:1) Supply VTs are not necessary if potential to relay terminals is <= 480 VAC2) Bus VTs are not necessary if potential to relay terminals is <= 480 VAC
Abnormal Conditions
M-3410A FunctionalDiagram
Typical Interconnection Protection
DG Interconnection Protection
n
Abnormal Power FlowEnforces interconnect contract
- Prohibits DG from providing power to utility in violation of interconnect contract (32F, 32R-U)
- Sometimes used to detect transformer magnetizing (must be very sensitive)
52I
Programmable I/O
32
UTILITY
60FL
51V
51N 46
27475981
Sequence of Events
Metering
LED Targets
Waveform Capture
User Interface with PC
Communications(Modbus)
3Y
Note 1
25
Note 2
52G
59I
BUS
79
Notes:1) Supply VTs are not necessary if potential to relay terminals is <= 480 VAC2) Bus VTs are not necessary if potential to relay terminals is <= 480 VAC
Abnormal Power Flow
M-3410A FunctionalDiagram
Typical Interconnection Protection
DG Interconnection Protection
n
M-3410A DG Interconnection Relay
DG Interconnection Protection
n
Out 1or
Out 2or
Voltages, Phase &Sync
Outputs
Currents
Control/StatusInputs
Power
Fuses
Comm Ports
ExternalConnections
DG Interconnection Protection
n
A
B
C
52G
52I
9 11 1310 12 14
M-3410A
2
9 11 1310 12 14
M-3410A
2
A
B
C
A
B
C
10 129 11
M-3410A
2
10 129 11
M-3410A
2
A
B
C
13 14
Three VT Wye-WyeConnection
1 Two VT Open-DeltaConnection
1
Alternate VT connections
VTs are not necessary if theNominal Rated InterconnectionVoltage is < 480 V ac.
Voltage input for 25 function canonly be used in line-line VTconfiguration.
1
2
13 14
3
3
3
A
B
C
A
B
C
13 14
13 14
M-3410A
M-3410A
2
A B C
5 ACT Configuration
1 ACT Configuration
22 23
19 20
16 17
M-3410A
21 23
18 20
15 17
M-3410A
Forward
Forward
Reverse Revers
eRevers
eForwar
d
RelayDGUtilityPower Flow
Utility System
DG Facility
Phase Voltage
Phase Current
Neutral VoltageM-3410A TypicalConnection Diagram
DG Interconnection Protection
Morning Midday Night
Load
Generation
Load Following – Calf. Rule 21
DG Interconnection Protection
Option 1- Use sensitive 32F relay, set at 0.01 pu (0.1%) of
interconnection transformer rating
Option 2- Use 32R-U relay to guarantee import of at least 5%
of gross generator capacity
California Rule 21: Options for Non-Export
DG Interconnection Protection
Utility System
VT
CT
27, 59,81 U/O,25
G G LocalLoad
32
Forward + -
Reverse -
Two 32 Directional Power Options- 32F, Sensitive forward (+) power - 32R-U, Low reverse (-) power
California Rule 21: Directional Power Options
DG Interconnection Protection
32F relay set to operate on transformer excitation or magnetizing current- Typically about 0.1% of transformer rating
Need transformer test sheet data to calculate value of magnetizing watts
UtilitySystem
VT
CT
G G LocalLoad
32
ExcitationKW
Forward +
Open Switch
32F, Sensitive Forward (+) Power
DG Interconnection Protection
32R-U Relay pickup set to at least 5% (-0.05 p.u.) of total connected generator rated KVA32R-U Relay programmed to trip when imported power falls below thepick-up level
UtilitySystem
120/1CT
G1 G2 LocalLoad
32
480V
Reverse (-)
32R-U, Low Reverse (-) Power
DG Interconnection Protection
These elements can cause nuisance tripping of the DG if large load swings occur in the DG facility
This may call for some adjustment of practices in the DG facility
Low Import Power: 32R-U Minimal Export Power: 32F
DG Interconnection Protection
DG
Utility Source
Generation adjusted to match local loadwith small biasRequires metering and governor control
Circuit breaker closed
395 kVA
Feeder Loads
LocalLoad
400 kVA
Low Import Power (32R-U)Pow er Import
5 kVA
Gen = Load - Bias395 = 400 - 5
“Floating” the Interconnection
DG Interconnection Protection
DG
Utility Source
Generation adjusted tomatch local load withsmall biasPart of load 40 kVA ofmotors
Circuit breaker closed
395 kVA
Feeder Loads
LocalLoad
360 kVA
Low Import Power (32R-U)Pow er Import
5 kVA
Gen = Load - Bias395 = 400 - 5
40 kVA
All circuit breakers closed
M
“Floating” with Large Motor Loads
DG Interconnection Protection
DG
Utility Source
Sudden loss of 40 kVAMomentary poweroutflow develops at PCC
Circuit breaker closed
395 kVA
Feeder Loads
LocalLoad
360 kVA
Low Import Power (32R-U)
Momentaryexport
<= 35 kVA
Gen = Load - Bias395 = 365 - 5
0 kVA
Motor breaker tripped,others remain closed
M
Ouch! Nuisance Trip!
DG Interconnection Protection
Increase the bias on the DG governor so it produces less power, and a wider margin is maintained to account for the load fluctuations
Although the bias can eventually be widened enough so nuisance trips do not occur, it may not be in the economic best interest of the DG facility to import power when the DG is in operation.
Countermeasures to This Possible Miscoordination Problem (1)
DG Interconnection Protection
81R has been used widely in Europe as a means of anti-islanding protection
In conjunction with wider set 81-U and 81-O, it allows:
- Faster tripping on severe load/generation imbalances post-utility disconnection
- More “forgiving” of slower moving frequency excursions that occur in system emergencies
- As higher DG penetration is forecast, the use of 81R may allow DG to stay on-line during system emergencies, right when the capacity is needed
Special Situation: Use of Rate-of-Change of Frequency – 81R
DG Interconnection Protection
78 may be used to protect a DG from damage from Out-of-Step (OOS) conditions
OOS conditions can occur from uncleared faults, particularly 3-phase, that pull down voltage and reduce power transfer
If mechanical power exceeds synchronizing power, the generator will pull out of step
This can place enormous stress on the shaft (snap!) and cause rapid rotor heating
Power Quality issue for utilities customers
Special Situation: Use of Out-of-Step – 78- Reciprocating Engines
DG Interconnection Protection
n
Special Situation: Reciprocating Engine Out of Synchronism Condition (78)
DG Interconnection Protection
n
1. System frequency will remain at nominal during prolonged fault clearing
2. Voltage may not go down enough for undervoltage protection to protect the pole slip
3. OOS protection will detect the acceleration of the rotor and the resultant angle increase past 90 in the case of a possible unstable swing
Special Situation: Reciprocating Engine Out of Synchronism Condition (78)
DG Interconnection Protection
n
Comprehensive DG Interconnection Package
DG Interconnection Protection
n
Comprehensive DG Interconnection Package: Wye-Grounded Transformer Primary
DG Interconnection Protection
n
Comprehensive DG Interconnection Package: Ungrounded Transformer Primary
DG Interconnection Protection
n
M-3520 Integrated Protection Systems®
DG Interconnection Protection
n
M-3520 Intertie Relay
52I
21
UTILITY
M-3520 Relay
3251V67
3Y
52G
= standard function
= optional function
BUS
79
2747598181R
25
LED Targets (opt)Programmable I/OMeteringIRIG-B InputCommunications (MODBUS or BECO 2200)
Waveform CaptureSequence of EventsUser Interface with PCHMI (optional)
59I
60FL4667
N 50
1
2 or 3
XX
XX
59N
27N
1 or 3
Ungrounded Primary
DG Interconnection Protection
n
M-3520 External Connections
DG Interconnection Protection
n
M-3520 Three-Line Diagram
DG Interconnection Protection
n
CASE #1 - Local Load Exceeds GenerationRestoration Practice
Interconnection relays trip DG generator breakers (B&C)When utility restores, DG generator(s) auto synchronize to return to service
G G
B C L
A
25
Multifunction Intertie Relay
Protection
AutoSync
AutoSync
LOADS
Utility
Trips "B" & "C"
Supervises "A"Reclosing
Trips Breakers B&C if:
Generation cannot support local load
Re-sync at breakers B&C after utility restoration
DG Trip & Restoration Possibilities
DG Interconnection Protection
n
CASE #2 - Local Load Matches GenerationRestoration Practice
Interconnection relays trip main incoming breaker (A)When utility restores, 25 function (with ΔΦ, ΔF, and ΔV) supervises recloses A which is auto sync by switching VT Sources as shown
DG Trip & Restoration Possibilities
DG Interconnection Protection
G G
B C L
A
25
Multifunction Intertie Relay
Protection
AutoSync
AutoSync
LOADS
Utility
Trips "A"
Supervises "A"ReclosingOPEN
CLOSE
Closing of Auto SyncSwitched to Breaker A
Used to ensure utility has gone through successful reclose cycle- Set longer than total reclose cycle
All clearing and shot time, plus longest possible reclaim time
- Uses permissive from voltage and frequency functions to ensure utility source is back and viable
Impact on utility reclosing- Lengthens reclose time
- Reclose delay must be longer than DG protection total clearing time (relay+breaker+margin) for all protections!
DG Reconnect Timer & Reclose Permissive
DG Interconnection Protection
Texa
sEn
terg
yR
ule
21C
om E
d
10kW 50kW 500kW 1,000kW 2,000kW 2,500kW 10,000kW
27, 59, 81U/O, 25
27, 59, 81U/O, 2559N/27N, 51,51N, 32, 21
27, 59, 81U/O, 25 -- Gen. < 50% of minimum load
27, 59, 81U/O, 25
59N or 51N, 32 32 81U TT
27, 59, 81U/O, 25
59N or 51N, 32 32 81U TT
27, 59, 81U/O, 2532
Sensitive (Xfmr Mag.)LFP
27, 59, 81U/O, 25, 32
Gen. > 50% of minimum loadSpecial Constraints, add 50BF, 21-2, TT
3
1
IEEE
1547
DG Interconnection Protection
Texas- Not specified
Entergy- Ygnd/delta or delta with zig-zig/Ygnd
Rule 21 (California)- Not specified
Commonwealth Edison- Delta/not specified
IEEE 1547- Not specified
Transformer Connections
DG Interconnection Protection
2002 Survey- Grounded wye primary – 58%- Delta primary – 9%- Other – 33%
1995 Survey- Grounded wye primary – 33%- Delta primary – 33%- Other – 33%
Interconnection Transformer
IEEE Distribution Practices Survey – 1/02
DG Interconnection Protection
No effect – 22%
Revised feeder coordination – 39%
Added directional ground relays – 25%
Added direction phase relays – 22%
Added supervisory control - 22%
Revised switching procedures – 19%
DG Impact on Distribution Protection
IEEE Distribution Practices Survey – 1/02
DG Interconnection Protection
Revise reclosing practices – 50%
Added voltage relays to supervise reclosing – 36%
Extend 1st shot reclose time – 26%
Added transfer trip – 20%
Eliminate reclosing – 14%
Added sync check – 6%
Reduce reclose attempts – 6%
DG Impact on Utility Reclosing
IEEE Distribution Practices Survey – 1/02
DG Interconnection Protection
n
If high speed reclosing is employed, the DG interconnection protection must be faster!
Clearing time includes protection operation and breaker opening
The Trouble with Reclosing:Breakers or Reclosers
DG Interconnection Protection
Properly designed interconnection protection addresses concerns of both DG owners and utility
Interconnection transformer configuration plays a pivotal role in interconnection protection
State, National regulators and IEEE continue to struggle to provide meaningful interconnection guidelines- Some of these standards are devoid of substantive technical
guidance
Restoration practices need to be part of the overall interconnection protection
Summary
DG Interconnection Protection
Combined Heating, Cooling & Power Handbook, Marcel Dekker, by Neil Petchers, ISBN# 0-88173-349-0
On-Site Power Generation, by EGSA, ISBN# 0-9625949-4-6
IEEE 1547, IEEE Standard for Interconnecting Distributed Resources with Electric Power Systems,http://grouper.ieee.org/groups/scc21/
Intertie Protection of Consumer-Owned Sources of Generation 3 MVA or Less, IEEE PSRC WG Report
Recommended Reading
DG Interconnection Protection
Update on the Current Status of DG Interconnection Protection--What 1547 Doesn’t Tell You, Charles Mozina, Beckwith Electric, presented at the 2003 Western Protective Relay Conference
Relay Performance in DG Islands, Ferro, Gish, Wagner and Jones, IEEE Transactions on Power Delivery, January 1989
Standard Handbook of Powerplant Engineering, McGraw Hill, Section 4.3, Electrical Interconnections, W. Hartmann, ISBN# 0-07-019435-1
Recommended Reading
DG Interconnection Protection
Meeting the Challenges of ProtectingUtility Distribution with Interconnecting
Distributed Generation
Part 2: Introduction to the M-3410A and M-3520DG Interconnection Protection Relays
Get Connected!Get Connected!
DG Interconnection Protection
DG Interconnection Protection
Meeting the Challenges of DG Interconnection
Get Connected!Get Connected!
M-3410A / M-3520 DG Interconnection Relays
DG Interconnection Protection - Part 2
Design Criteria:
Low Initial Cost: There is not a better price/value relay for the target applications (small DG installations)Low Project Cost:- integrated metering and waveform capture allow wiring errors,
instrument application errors, and setting errors to be observed and rapidly corrected
- software has been designed to allow a relay to be completely programmed in less than 30 minutes
- autodocumentation reduces engineering time and transcription errors- ability to standardize for many repeat projects, facilitating
boilerplatingLow Lifecycle Costs:- self-diagnostics combined with no need to calibrate can reduce or
eliminate periodic testing - no maintenance requirements
M-3410A DG Interconnection Relay
DG Interconnection Protection - Part 2
M-3410A DG Interconnection Relay
DG Interconnection Protection - Part 2
M-3410Intertie / Generator
Protection
PHASE UNDERVOLTAGE 27PHASE OVERVOLTAGE 59/59I
FUSE LOSS 60LOSS OF FIELD 40
VOLTAGE UNBALANCE 47CURRENT UNBALANCE 46
32 DIRECTIONAL POWER51N/51V PHASE OVERCURRENT81 OVER/UNDER FREQUENCYOSC TRIGGERDIAGNOSTICRELAY OK
Target/OutputReset
COM 1
12.00
12.20
10.75
11.00
2.50
10.70
Front View(Dotted line denotes panel cutout)
Side View(Typical for both sides)
Front
Rear
Panel
Panel
Rear View
10.70 12.20
12.00
UP
Terminals
Terminals
M-3410ADG InterconnectionRelay
DG Interconnection Protection - Part 2
M-3410Intertie / GeneratorProtection
Target/OutputReset COM 1
PHASE UV 27PHASE OV 59/59I
FUSE LOSS 60LOSS OF FIELD 40
VOLTAGE UNBALANCE 47CURRENT UNBALANCE 46
32 DIR. POWER51V PHASE OC81 O/U FREQOSC TRIGGERDIAGNOSTICRELAY OK
12.68
11.75
3.46
11.52
10.62
10.62
9.72
Front View
Top View
Terminals Terminals
Panel (for flush mount)
Note: Reversible angle bracketsallow mounting flush or semi-flush. The semi-flush method isused where rear projection spaceis at a premium, and the relay mayproject forward a small distance.
Panel (for semi-flush mount)
Front
Rear
1.80
M-3410ADG InterconnectionRelay
DG Interconnection Protection - Part 2
M-3410A DG Interconnection Relay
M-3410Intertie / GeneratorProtection
Target/OutputReset
COM 1
PH. UV 27PH. OVERVOLT 59/59I
FUSE LOSS 60LOSS OF FIELD 40
VOLT. UNBALANCE 47CURRENT UNBALANCE 46
Front View
3.46
32 DIR. POWER51V PHASE OC81 O/U FREQ
OSC TRIGGERDIAGNOSTIC
RELAY OK
12.67 11.75 10.62
UP
Side View(Right Side)
Terminals
Terminals
Panel (for flush mount)
Panel (for semi-flush mount)
FrontRear
FrontRear
9.72
11.52
10.62
Side View(Left Side)
UPUP
1.80
Note: Reversible angle bracketsallow mounting flush or semi-flush. The semi-flush method isused where rear projection spaceis at a premium, and the relay mayproject forward a small distance.
M-3410ADG InterconnectionRelay
DG Interconnection Protection - Part 2
Analog Sensing- 3 voltage inputs
Direct connect up to 480V
- 3 current inputsBoth 5 and 1 amp inputs on relay
Power Input- 12 VDC- 24 VDC- 48 VDC- 120 Vac and 125 Vdc
M-3410A Analog Sending and Power Inputs
DG Interconnection Protection - Part 2
Out 1or
Out 2or
Voltages, Phase &Sync
Outputs
Currents
Control/StatusInputs
Power
Fuses
Comm Ports
ExternalConnections
DG Interconnection Protection - Part 2
52I
Programmable I/O
32
UTILITY
M-3410 Functional Diagram
Typical Intertie Application
60FL
51V
51N 46
27475981
Sequence of Events
Metering
LED Targets
Waveform Capture
User Interface with PC
Communications(Modbus)
3Y
Note 1
25
Note 2
52G
59I
BUS
GroundedPrimary
79
Notes:1) Supply VTs are not necessary if potential to relay terminals is <= 480 VAC2) Bus VTs are not necessary if potential to relay terminals is <= 480 VAC
M-3410A Relay(grounded primary)
M-3410A
DG Interconnection Protection - Part 2
52I
Programmable I/O
32
UTILITY
M-3410 Functional Diagram
Typical Intertie Application
60FL
51V
51N 46
27475981
Sequence of Events
Metering
LED Targets
Waveform Capture
User Interface with PC
Communications(Modbus)
3Y
Note 1
Note 2
59I
BUS
27N
59N
UngroundedPrimary
79
Notes:1) Supply VTs are not necessary if potential to relay terminals is <= 480 VAC2) Bus VTs are not necessary if potential to relay terminals is <= 480 VAC
52G
M-3410A Relay(ungrounded primary)
M-3410A
DG Interconnection Protection - Part 2
A
B
C
52G
52I
9 11 1310 12 14
M-3410A
2
9 11 1310 12 14
M-3410A
2
A
B
C
A
B
C
10 129 11
M-3410A
2
10 129 11
M-3410A
2
A
B
C
13 14
Three VT Wye-WyeConnection
1 Two VT Open-DeltaConnection
1
Alternate VT connections
VTs are not necessary if theNominal Rated InterconnectionVoltage is < 480 V ac.
Voltage input for 25 function canonly be used in line-line VTconfiguration.
1
2
13 14
3
3
3
A
B
C
A
B
C
13 14
13 14
M-3410A
M-3410A
2
A B C
5 ACT Configuration
1 ACT Configuration
22 23
19 20
16 17
M-3410A
21 23
18 20
15 17
M-3410A
Forward
Forward
Reverse Revers
eRevers
eForwar
d
RelayDGUtilityPower Flow
Utility System
DG Facility
Phase Voltage
Phase Current
Neutral VoltageM-3410A TypicalConnection Diagram
DG Interconnection Protection - Part 2
52G
52I
ForwardForwardReverseReverseReverseForward
RelayDGUtilityPower Flow
A
B
C
LocalDG
FacilityLoads
To Utility
Power Flow Convention
Forward power is from DG to utility
DG Interconnection Protection - Part 2
Two outputs, each can be configured in hardware as form “a” or “b”contact- This must be known at the time of M-3410A order
This facilitates different failsafe philosophies based on type of isolation device- Power-to-trip breaker (shunt trip)- Unpower-to-trip (contactor)
Utilities want failsafe operation, meaning if there is a failure of the relay or power to the relay, the DG will be tripped from the power system
The self-diagnostic contact is a form “c” set and employs a failsafe philosophy- Self-diagnostic relay coil is energized when relay and relay power OK,
deenergizes on failure. The contacts revert back to standard reference condition (“a” open, “b” closed)
Programmable Outputs
DG Interconnection Protection - Part 2
M-3520 DG Interconnection Relay
DG Interconnection Protection - Part 2
Design Criteria:
Large Application Scope: Able to meet all protection requirements for DG installations up to 10 MVA
Low Project Cost:- integrated metering and waveform capture allow wiring errors,
instrument application errors, and setting errors to be observed and rapidly corrected
- software has been designed to allow a relay to be completely programmed in less than 30 minutes
- autodocumentation reduces engineering time and transcription errors- ability to standardize for many repeat projects, facilitating boilerplating
Low Lifecycle Costs:- self-diagnostics combined with no need to calibrate can reduce or
eliminate period testing - no maintenance requirements
M-3520 DG Interconnection Relay
DG Interconnection Protection - Part 2
Outputs
CurrentsVoltages
InputsRS-485Comms
RS-232 Comms
IRIG-B
Fuses
Power
M-3520
DG Interconnection Protection - Part 2
Abnormal Power Flow:- useful as a supplemental means of
loss of parallel operation if DG sizeand load are conducive to usingutility export/import setpoints ortransformer magnetization(extremely sensitive)
Restoration:- elements check that utility supply is
viablereconnect timer, can besupervised by sync-check/voltage verificationfunctions
- sync-check and dead bus/lineelements to assure DG is properlyrestored according to utility policy
Protection Applications:Loss of Parallel Operation Elements:- undervoltage, overvoltage,
instantaneous overvoltage, - underfrequency, overfrequency
Fault Backfeed:- phase overcurrent, groundovercurrent
directional and non-directional- ground overvoltage, ground
undervoltage- phase distance elements (2)
Damaging System Conditions:- negative sequence overvoltage,
negative sequence current, out-of-step
M-3520 DG Interconnection Relay
DG Interconnection Protection - Part 2
52I
21
UTILITY
M-3520 Relay
3251V67
3Y
52G
= standard function
= optional function
BUS
79
2747598181R
25
LED Targets (opt)Programmable I/OMeteringIRIG-B InputCommunications (MODBUS or BECO 2200)
Waveform CaptureSequence of EventsUser Interface with PCIntegral HMI (optional)
59I
60FL4667
N 50
1
2 or 3
151N
50N
XX
XX
59N
27N
1 or 3
Ungrounded Primary
M-3520 DGInterconnection
Relay78
DG Interconnection Protection - Part 2
M-3520 DG Interconnection Relay
52I
21
UTILITY
3251V67
3Y
52G
= standard function
= optional function
BUS
79
2747598181R
25
LED Targets (opt)Programmable I/OMeteringIRIG-B InputCommunications (MODBUS or BECO 2200)
Waveform CaptureSequence of EventsUser Interface with PCIntegral HMI (optional)
59I
60FL4667
N 50
1
2 or 3
1
51N
50N
XX
XX
M-3520 Relay
Grounded Primary
78
M-3520 DGInterconnection
Relay
DG Interconnection Protection - Part 2
Extended Functionality
Self-diagnostics
Metering
Logging
Waveform capture
Digital communications
Excellent PC software for interface and analysis
M-3410A/3520 DG Interconnection Relays
DG Interconnection Protection - Part 2
Immediate detection of relay failure- Provides some assurance to utility that
interconnect protection is working
- Routines check software and A/D converter
- Power supply is monitored for internal as well as external failure
Utilities trip DG on relay failure- Form “c” contact that can be wired to failsafe (trip
the unit in the event of relay system or power supply failure)
M-3410A/3520 Self Diagnostics
DG Interconnection Protection - Part 2
IPScom Example: Relay Configuration
DG Interconnection Protection - Part 2
IPScom Example: Element Setting
DG Interconnection Protection - Part 2
IPScom Example: I/O Assignment
DG Interconnection Protection - Part 2
IPScom Example: Settings Summary
DG Interconnection Protection - Part 2
M-3410A provides comprehensive voltage, current, and calculated quantity metering
- Can interface to utility SCADA or DG plant SCADA
- Use of sequence voltage and currents allow rapid commissioning
If negative and zero sequence quantities are notpresent:
- CT/VT wiring is correctphasingpolarity
- multi-ratio transformers are all on the correct taps- power flow conventions OK
If negative and zero sequence quantities are present, you have a problem
Metering
DG Interconnection Protection - Part 2
Metering – Correct Phase Rotation
DG Interconnection Protection - Part 2
Metering – Incorrect Phase Rotation
DG Interconnection Protection - Part 2
The M-3410A provides an event log (sequence of events recorder -SOE)
SOE available at the “point of common coupling”- Event logs can help identify which system caused the tripping
(utility or DG)- Event logs have settled a number of arguments between utility and
DG owners- Events in a FIFO (newest kept, oldest discarded)- 32 event storage- Events include
Element activity- Pick up- Drop out- Trip
I/O activity- Control/status input state- Output state
Event Logging (SOE)
DG Interconnection Protection - Part 2
0.00 0.0
All Voltages and Currents Proper
Phasor Display (Vectors)
DG Interconnection Protection - Part 2
Phase A Current “Rolled”
Phasor Display (Vectors)
DG Interconnection Protection - Part 2
Displays - Impedance
DG Interconnection Protection - Part 2
The M-3410A / M-3520 provide digital oscillography (waveform capture)
Oscillographic records available at the “point of common coupling”- Can identify which system caused the tripping (utility or DG)- Have settled a number of arguments between utility and DG
owners- Are useful for “as found” and “as left” records, and documenting
testing and commissioning- Can be initiated anytime for PQ snapshot- Configurable pre- and post-trigger buffers- Allows you to see before the event, during the event, and post-
eventVery useful in seeing distribution events (they take along time)
Digital Oscillography
DG Interconnection Protection - Part 2
- Large CapacityVery useful in seeing distribution events (they take a long time)
- 120 cycles total- Up to 2 partitions
- Configurable pre- and post-trigger buffers- Allows you to see before the event, during the event, and post-
event- View power flow reversals, current reversals, types of fault
from inspection, power swings, etc.
Digital Oscillography
DG Interconnection Protection - Part 2
B C D
K NMLIG H
J
A
E
F
Waveform Capture (Legend)
DG Interconnection Protection - Part 2
A) All analog traces. This view shows peak values. RMS values may also bedisplayed
B) Controls for going to the beginning or end of a record, as well as nudging forward or backward in time in a record
C) Zoom controlsD) Display controls for analog traces, RMS traces, fundamental waveform display,
frequency trace, power trace, power factor trace, phasor diagram, impedancediagram and power diagram
E) Marker #1F) Marker #2G) Time at Marker #1H) Time at Marker #2I) Control status input and contact output traces (discrete I/O)J) Scaling for each analog trace. This can be set automatically or manually
adjusted.K) Date and timestamp for recordL) Time of trip commandM) Time at Marker #1N) Time at Marker #2
DG Interconnection Protection - Part 2
PQ
R
O
S
Waveform Capture (Legend)
DG Interconnection Protection - Part 2
O) Drop down window for view selection, diagram selection and zoom
P) Delta value between Marker #1 and Marker #2
Q) Value at Marker #1
R) Value at Marker #2
S) Scaling for each analog trace. This can be set automatically or manually adjusted.
DG Interconnection Protection - Part 2
Area of current reversal
Phasor diagram withvalues displayed
Phasor display shown atat Marker #1 location
Waveform Capture (Phasor)
DG Interconnection Protection - Part 2
Area of current reversalPhasor diagram withvalues display
Phasor display shown atat Marker #1 location
Waveform Capture (Phasor)
DG Interconnection Protection - Part 2
M-3410A- Rear port: RS-485 (MODBUS RTU) or RS-232- Front port: RS-232 (use IPScom)
M-3520 - Rear port: RS-485 (MODBUS RTU) or RS-232- Front port: RS-232 (use IPScom)- IRIG-B port
Moderate to large size DGs may be required to telemeter data on generator operation to the utility:- status: on or off line- Voltage, Current, MW & MVAR
DG plant may want to integrate information into plant DCS orPLC
Relay targets and oscillograph information can also beaccessed through communication channels tofacilitate restoration
Communications Capability
DG Interconnection Protection - Part 2
Benefits for Consultants/OEMs
Reduce project costs:- standardization for most powerpool and utility interconnection
requirementsAccepted by California Rule 21, Texas, NY Powerpool, many others
Beckwith Electric will work with any utility for approval
- Commissioning tools to speed factory acceptance testing and field start-up
- Forensic engineering capabilities for warranty investigations
- Programmable I/O and elements to meet different trip assignment requirements
M-3410A / M-3520 DG Interconnection Relays
DG Interconnection Protection - Part 2
Benefits for Utilities
Meets protection requirements:- Utility-grade relay passing pertinent ANSI and IEC specifications
Includes C37.90, C37.90.1 and C37.90.2
Elements are configurable and selectable to meet protection challenge for different sizes, types of machines, and transformer connections and utility requirements
Forensic engineering capabilities for trip dispute investigations
Beckwith Electric will work with any utility for approval- Evaluation relays and test support
M-3410A / M-3520 DG Interconnection Relays
DG Interconnection Protection - Part 2
DG Interconnection protection will have renewed importance in the next decade and beyond
Properly designed interconnection protection addresses concerns of both DG owners and the utility
This presentation outlines salient points utility and DG Owners, Consultants, and OEMs need to consider when developing protection requirements and schemes
Digital multifunction relays are an ideal technology for UtilityDG Interconnection Protection
The Beckwith Electric M-3410A and M-3520 Interconnection Relays meet the needs of many Utility DG Interconnection Requirements
Summary
DG Interconnection Protection - Part 2
The M-3410A and M-3520 DG Interconnection Protection Relays offer:- Protection that meets or exceeds virtually all utility
guidelines, including IEEE-1547- Simple and straightforward engineering- Informational tools for observation, commissioning and
event analysis- Ease of use that can translate into cost savings
Less trainingQuicker troubleshootingBetter tools for commissioning
- Value: 1st cost, project cost and lifecycle costs- Beckwith Electric Application Engineering and Field Service
Support
Summary
DG Interconnection Protection - Part 2
M-3410A / M-3520 DG Interconnection Relays
Thank You
Get Connected!Get Connected!
M-3410A / M-3520 DG Interconnection Relays
DG Interconnection Protection - Part 2
©2008 Beckwith Electric Co., Inc.