Public Service Company (PNM) Blackwater Synchronous

Condenser Outage Remedial Action Scheme Overview

Malati Chaudhary (PNM Transmission Planning)

Thomas Duane (PNM Transmission Planning)

Daniel Marquis (PNM System Protection)

February 27th, 2019

Outline

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• Eastern New Mexico system

• Overview of RAS Scheme, Purpose and

Classification

• Studies assessing RAS performance

• RAS Design, Operational Control and Monitoring,

and Functional Testing

• Operating procedures for RAS unavailability

• NERC CIP Compliance

• Conclusion

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Location

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Overview of Eastern NM System

• 216 mile 345 kV line from BA to Blackwater (BB line) is located in an area of NM with very large wind generation potential.

292 MW, Type 3

90 MW, Type 1 200 MW, Type 3

297 MW, Type 4

Grady Wind 200 MW, Type 4, 2019

Blackwater HVDC, 200 MW

Synchronous Condenser, 170 MVA, 2019

Short circuit MVA requirement at Broadview and at Blackwater

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• Low short circuit conditions exist at the far eastern end of the line.

• Short circuit ratio of 1.6 MVA/MW is required for Broadview and

Grady windfarms at Broadview.

• Short circuit ratio of 2.1 MVA/MW is needed at Blackwater HVDC.

• A synchronous condenser is being installed to allow total generation

to be increased to 497 MW. Also allows for simultaneous operation

of Blackwater HVDC.

• Synchronous condenser is sized to provide 969 MVA of short circuit

MVA at Blackwater.

Purpose of RAS

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What happens when Blackwater synchronous condenser is out of service?• Results in immediate reduction of short circuit MVA at Blackwater causing potential

HVDC control instability and inner current control instability of wind turbine

generators.

• Balance can be restored by reducing total power from inverter based equipment to

a level that can be supported by the available short circuit MVA without the

synchronous condenser.

Purpose:

• Mitigate control instability caused by the insufficient short circuit capacity when

synchronous condenser is out.

Purpose of RASContd.

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Note: Insert graphic diagram showing operating points with and without synchronous condenser.

Classification of RAS

• Local Area Protection Scheme (LAPS) Generation subject to control instability is limited to Broadview and Grady

windfarms (497 MW) that feed radially into the Blackwater 345 kV station.

RAS can interrupt up to 697 MW of transfers between Broadview and Grady

windfarms and the Blackwater HVDC Converter.

HVDC Converter firm commitments are only 15 MW.

Cascading effects beyond eastern New Mexico are not expected.

RAS redundancy is more in line with Wide Area Protection Scheme.

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Breaker level one-line diagram of Blackwater 345 kV Station and overview of RAS functionality

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B B B

B

To Taiban 345 kVTo Blackwater HVDC

B

B

B B

Broadview KW SubstationGrady Windfarm

Broadview JN Substation

Broadview Western Interconnect

Broadview 345 kV Station

Blackwater 345 kV Station

These two breakers will be tripped to trip Grady windfarm when

transfer trip signal is sent by RAS for tripping Grady windfarm.

RAS will isolate these two breakers to isolate

Broadview station from Blackwater in case Grady is

not tripped.

RAS will trip these two breakers to trip HVDC

GCB

RAS will sense the status of Generator

Circuit Breaker (GCB) to determine the status of synchronous condenser

Generator Step Up Transformer362/17.5/12.47 kV

PNMWesternInterconnect

33 mile

RAS scheme

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Total MW flow from Broadview and Grady Windfarm at

Broadview>297 MW

MW Transfer from Blackwater HVDC > 17 MW**

Synchronous Condenser Out of Service

Trip signal sent to Pattern Energy for Tripping Grady Windfarm

Both Grady Breaker Statuses “Open”

30 Cycle

15 Cycle

Trip Broadview Tie at Blackwater

Trip Blackwater HVDC Converter

30 Cycle

15 Cycle

10 Cycle

10 Sec

10 Cycle

10 Sec

Curtailment Active Signal to Power Operations (for

PNM), GridForce (for Pattern)

Blackwater SynCon RAS Simplified LogicPROPOSED

Revision Date: 2019-Feb-04

BOTH RAS Controller Relays Out Of Service

Curtailment Active Signal to GridForce (for Pattern Curtailment Action)RAS Alarm to PNM Power Ops (for PNM Curtailment Action)

NOT GateAND Gate

KEY: Pickup Delay Dropout

Delay

If output is low, input must remain high continuously for a period equal to pickup delay before output goes high.If output is high, input must remain low continuously for a period equal to dropout delay before output goes low.

RAS schemeContd.

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• Tripping Grady will reduce the power injection from Broadview to 297 MW.

• If the trip confirmation signal is not received within 30 cycles, then the tie to Broadview

switchyard is opened at Blackwater.

Note:

• PSCAD studies are currently underway to provide a better understanding of the inverter based

controls at Blackwater under insufficient short circuit MVA and may indicate that operating

time frames can be relaxed at a future date, however, overall coordination should not change.

Study to assess performance of the RAS

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• Positive Sequence Power Flow and stability programs do not adequately demonstrate

control system operations under insufficient short circuit MVA conditions. The study is

used primarily to ensure that RAS does not create adverse effects on the

interconnected system.

Scenario Cases

• Scenario 1: 1000 MW of wind generation connected in eastern New Mexico with the

Blackwater HVDC transferring 17 MW to SPP (east)

• Scenario 2: 750 MW of wind generation connected in eastern New Mexico with 497

MW of wind generation coming from Broadview and with the Blackwater HVDC

transferring 200 MW from SPP to WECC (west)

Contingency• Trip of the Blackwater synchronous condenser.

Study to assess performance of the RASContd.

Scenario 1: Power flow response when tripping Grady within 30 cycles

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Study to assess performance of the RASContd.

Scenario 1: Voltage response when tripping Grady within 30 cycles

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Study to assess performance of the RASContd.

Scenario 1: Power flow response when isolating Broadview station after 30 cycles instead of tripping Grady

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Study to assess performance of the RASContd.

Scenario 1: Voltage response when isolating Broadview station after 30 cycles instead of tripping Grady

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Study to assess performance of the RASContd.

Scenario 2: Power flow response when tripping Grady within 30 cycles

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Study to assess performance of the RASContd.

Scenario 2: Voltage response when tripping Grady within 30 cycles

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Study to assess performance of the RASContd.

Scenario 2: Power flow response when isolating Broadview station after 30 cycles instead of tripping Grady

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Study to assess performance of the RASContd.

Scenario 2: Voltage response when isolating Broadview station after 30 cycles instead of tripping Grady

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Coordination with other RAS and Protection Scheme

• Other Protection System (Most Likely Candidates) Reactor insertion relay system Automatic Reactor Switching Scheme

• No interactions were found between the proposed RAS and other RAS and protection scheme.

Impact to the WECC power gridIf RAS operates as designed:• Could cause slight frequency decline in the western grid, however, declines will be well within

the range of normal generation and transmission disturbances and should not present any

unique problems locally or to the western grid.

If RAS fails to operate as designed:• Could produce oscillations due to inner current control instability of wind turbine generators

and Blackwater HVDC control instability.

• Control instability that could lead to the shut down of Broadview and Grady wind turbines

and Blackwater HVDC.

• The oscillations will be local to the radial transmission system between BA and Blackwater.

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RAS Design.

Redundancy

• The RAS is designed to ensure failure is a non-credible event by using redundant

system 1 and system 2.

• Failure of any single relay will not interfere with ability of other redundant relay to

detect RAS trigger conditions and to initiate transfer trip and trip signals.

• There is no credible common mode of failure, including CT and VT secondaries.

• RAS will be continuously armed with no means of completely disarming via SCADA.

• If both systems become unavailable, automatic curtailment or alarms are sent via

SCADA.

• If transfer trip to Grady breakers at Broadview fails, the RAS ensures connected

inverter based generation is reduced by opening Broadview-Blackwater tie after a

short time delay.23

RAS DesignContd.

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RAS DesignContd.

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Detection

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• The synchronous condenser RTU monitors the synchronous condenser status and

continuously provides positive confirmation via independent hardwire contacts to

PNM RAS controllers. Loss of positive confirmation signal results in controllers

concluding the condenser is offline.

• At Blackwater, the current and voltages are monitored from CTs and VTs with

independent secondaries, one analogue CT and VT per line to each controller.

• Applicable Breaker and MOD 52B statuses at Broadview are transmitted over direct

fiber using dedicated and redundant SEL-2506 relays.

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Telecommunication

TelecommunicationContd.

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• All the communication is located within the Blackwater 345 kV station

except for the communications used to monitor and trip the Grady facility at

the Broadview switchyard.

• Communication paths to Broadview consist of direct fiber, with System 1

and System 2 fibers using separate and independent OPGW conductors.

• System utilizes equipment where critical components are protected and

communication paths are diverse providing at least 99.99% reliability in its

operational network.

• Non-deterministic communication systems are not deployed in the network.

• Communication maintenance technicians are on call 24 hours per day to

respond to network outages.

RAS Logic Controllers and Trip Circuits

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• The logic controllers are two redundant and independent 411L1 relays,

each receiving separate inputs and sending separate outputs.

• Both System 1 and System 2 controllers directly trip corresponding coils

of all applicable breakers at Blackwater.

• At Broadview, System 1 directly trips trip coil 1 of applicable breakers and

System 2 directly trips trip coil 2 of applicable breakers.

RAS operational control and monitoring

• Relays and communication equipment have self diagnostics which alarm

through SCADA to power operations.

• SEL 2506 relays have channel monitoring and a hard wired relay failure

alarm. Their status is continuously monitored at Power Operations.

• Loss of signal from synchronous condenser results in arming of the RAS.

• RAS actions are monitored in full by the Power Operations EMS system

SCADA.

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RAS Functional Testing (DRAFT)• Each set of relays can be taken out of service locally or via SCADA for maintenance or repair

without affecting the operation of the redundant relay scheme.

• Taking the controller relay out of service locally or by SCADA is accomplished by changing the

status of its dedicated 43CO relay maintenance switch to the Tagged position.

• Three separate tests will be carried for PNM portion of RAS:

Loss detection of synchronous condenser, and power curtailment for RAS out of service condition

Curtailment for loss of synchronous condenser online signal and if MW outputs are below specified

setpoints

Curtailment for loss of synchronous condenser online signal and if MW outputs are above specified

setpoints

• All the sensing relays, controllers, breaker trip circuits, and applicable communication paths

will be tested over any 5 year period.

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Procedure during RAS unavailability

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• If both controllers are out of service, an automatic power reduction in effect signal is sent to

both PNM system operations via SCADA and Pattern Energy via GridForce.

• The maximum wind generation will be curtailed to a level (297 MW) that can be supported

by the available short circuit MVA without synchronous condenser.

• The Blackwater HVDC output is maintained to no more than 17 MW in either direction.

• Repairs and/or replacements will be made as quickly as possible if there is a failure in one

part of the redundant RAS system making it non-redundant.

NERC CIP compliance• The performance of the RAS equipment at Blackwater station is not sensitive to NERC

CIP compliance because it does not use routable protocols for RAS related

communication.

• Engineering access complies with NERC CIP by following PNM’s standard NERC CIP

compliance design and protocols.

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Conclusion

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• No system performance issues were identified due to the addition and

operation of Blackwater Synchronous Condenser Outage RAS.

• The RAS design has full redundancy.

• The RAS is continuously armed and monitored for failure.

• No coordination issues were found with other RAS or protection schemes.

• NERC CIP compliance is not expected to have any negative impacts on RAS

functionality.

• RAS commissioning and functional testing will be preformed to ensure end-

to-end functionality.

Approval Request

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• PNM is requesting approval of the proposed Blackwater Synchronous Condenser Outage Remedial Action Scheme.

Questions/Comments:

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?

Thank You

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