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NERC Case Notes: Reliability Standard VAR-002-2b

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NP19-8-000: Catalina Solar, LLC (CATA)

Reliability Standard: VAR-002-2b

Requirement: R2

Violation ID: WECC2017017041

Method of Discovery: Self-Report

Violation Risk Factor: Medium

Violation Severity Level: Severe

Region: WECC

Issue: On February 16, 2017, CATA submitted a Self-Report stating that, as a Generator Operator, it was in violation with VAR-002-2b R2. Specifically, CATA reported that, for its 110 MW photovoltaic power station, it had not consistently monitored voltage and therefore had not maintained or made notifications to the Transmission Operator (TOP) when the generator voltage had traversed outside the voltage schedule. However, during the time in which voltages were not monitored, the interconnecting utility would make requests when the need arose to control voltage and CATA would respond accordingly. CATA failed to maintain the generator voltage schedule directed by the TOP as required by VAR-002-2b R2. The root cause of the violation was CATA's lack of controls to ensure its Facility's voltage monitoring, alarming, and communication equipment support and comply with the TOP's generator voltage schedule.
Finding: This violation posed a minimal risk and did not pose a serious and substantial risk to the reliability of the Bulk Power System (BPS). In this instance, CATA failed to maintain the generator voltage schedule directed by the TOP as required by VAR-002-2b R2. Such failure could potentially result in undamped voltage oscillations and the unplanned tripping of the Facility. CATA owns and operates 110 MW of generation that was applicable to this issue. CATA implemented the practice of responding immediately to requests from the interconnecting utility to control voltage and would respond accordingly.

Penalty: $32,000

Duration of Violation: 14 July 2014 through 17 October 2017

FERC Order: Issued April 8, 2019 (no further review)

Portland General Electric Co., FERC Docket No. NP15-28-000 (April 30, 2015)

Reliability Standard: VAR-002-2b

Requirement: R3

Violation Risk Factor: Medium

Violation Severity Level: High

Region: WECC

Issue: PGE self-reported that system upgrades had inadvertently disabled the Power System Stabilizer (PSS) of a reactive power resource for almost 11 hours before PGE notified the Transmission Operator and re-enabled the PSS.

Finding: WECC found that this issue posed a minimal, but not a serious or substantial, risk to BPS reliability. 116 MW of generation could have been lost if the generator had been unable to respond to fluctuating system voltages. However, the generator would have been able react somewhat to fluctuating voltages because of the resource’s automatic voltage regulator (AVR), the PSS and AVR of another reactive power resource, and PGE’s operators who could manually control voltage. When determining the penalty, WECC viewed PGE’s internal compliance program for meeting reliability standards as a mitigating factor and PGE’s history of noncompliance with VAR-002 R3 as an aggravating factor. To further mitigate this violation, PGE (1) added additional PSS alarms to reactive power resources and (2) trained appropriate operations personnel on the incident.

Penalty: $97,000 (aggregate for 8 violations)

FERC Order: FERC approved the settlement on May 29, 2015.

NP20-14-000: Portland General Electric Company (PGE)

Reliability Standard: VAR-002-2b

Requirement: R3

Violation ID: WECC2017017874

Method of Discovery: Self-Report

Violation Risk Factor: High

Violation Severity Level: High

Region: WECC

Issue: On June 30, 2017, PGE submitted a Self-Report stating, as a GOP, it was in violation of VAR-002-4 R3. In addition, during a Compliance Audit conducted July 10, 2017 to July 21, 2017, WECC determined PGE had additional instances of noncompliance which changed the start date to predate the current version of the Standard and therefore the violation is of VAR-002-2b R3.
Per PGE's self-report, on December 14, 2016, PGE's wind farm plant technician interpreted several distribution static synchronous compensator (DSTATCOM) equipment alarms at the wind farm to indicate a loss of reactive power capability. Understanding DSTATCOM equipment alarms to be a reportable change of a voltage controlling device, PGE's wind plant technician immediately called PGE's System Control Center (SCC) to report the event. PGE's SCC then notified its Transmission Operator (TOP) that the DSTATCOM was out of service with no expected time of return. However, the DSTATCOM equipment alarms only indicated that individual +/- 1 MVAR inverters were off-line and that the status of the wind farm DSTATCOM alternative voltage controlling device had not changed, remaining online and providing reactive power/voltage support.

Later, on January 10, 2017 at 8:29 AM, one of PGE's wind farm plant technicians contacted its SCC's Transmission and Distribution (T&D) dispatcher and required that three breakers be opened so that the plant staff could replace nine individual inverter trays related to the December 14, 2016 DSTATCOM equipment alarms. However, PGE did not notify its TOP of the status change in the alternative voltage controlling device because it assumed that the wind farm DSTATCOM alternative voltage controlling device was out of service and that it had already notified its TOP of the status change of the wind farm DSTATCOM alternative voltage controlling device on December 14, 2016.

On January 12, 2017, at 3:32 PM, the plant technician contacted the SCC's T&D Dispatcher to request that the breakers be closed to return the wind farm DSTATCOM alternative voltage controlling device to service. However, PGE did not notify its TOP of the wind farm DSTATCOM alternative voltage controlling device status change.

In both instances, PGE did not notify the TOP of the wind farm DSTATCOM alternative voltage controlling device status change within the 30 minutes of such change. However, PGE's TOP was provided with the correct information about the status change of the wind farm DSTATCOM alternative voltage controlling device on February 22, 2017. 

The WECC Compliance Audit identified 10 additional instances between December 30, 2013 and October 19, 2015 for which PGE was unable to document that it had notified its TOP of changes in status of the wind farm's DSTATCOM alternative voltage controlling device within the required timeframe. PGE was unable to show that it had notified its TOP of the restoration of power system stabilizer (PSS) operability after scheduled PSS outages at a second plant on October 27, 2015 and at a third plant on January 28, 2014 and February 12, 2015.

Finding: This violation posed a minimal risk and did not pose a serious and substantial risk to the reliability of the BPS. In these instances, PGE failed to notify its associated TOP 12 times of a status change on voltage controlling device within 30 minutes of the change, as required by VAR-002-4 There was no expected loss of generation, load, or transmission elements, for a failure to report the status of the voltage controlling device. Additionally, none of the 12 instances occurred simultaneously. For all three affected plants, a majority of the 12 instances were for failing to notify the TOP of the PSS or voltage control device being put back into service. This fact reduces the impact of potential harm because the device was back in service and operating as expected instead of a more serious condition, such as the TOP not being aware that the device was out of service and would therefore need to take manual action to compensate for the devices. The inverter trays associated with the DSTATCOM at Plant 1 only resulted in a 1 MVAR loss of reactive power capability. The loss of 1 MVAR of reactive power capability would have had minimal, if any, impact on the BPS. Additionally, for Plants 2 and 3, which had PSS, the generating Facilities were small and located in fairly remote areas, thus reducing the impact they could have had for damping oscillations on the system

Penalty: $112,000

Duration of Violation: 20 December 2013 through 22 February 2017

FERC Order: Issued April 30, 2020 (no further review)