acsetf report - nerc€¦ · • investigate, analyze, and report all bes substation equipment...

ACSETF Report

Michael Lombardi, Manager of System Studies, NPCCPAS Meeting- November 2014

2 RELIABILITY | ACCOUNTABILITY

Background

• 2013 State of Reliability Key Finding 5: AC Substation Equipment Failures are a Second Significant Contributor to Disturbance Events and Automatic Transmission Outage Severity

• The AC Substation Equipment Task Force (ACSETF) convened to: Analyze failed AC substation equipment failure data in event

analysis data and other applicable reports Identify the key factors that exacerbate the impact of AC

substation equipment failure to the BES Identify specific items, actions and develop

recommendations to improve industry performance


Review Status

• Excellent feedback from OC/PC reviewers Improved report with much more clarification and linkages between the

topics Extensive comments process ; all comments addressed by ACSETF and

NERC staff

• Many thanks go to : Jerry Rust (OC) Alan Bern (OC) Todd Lucas (OC) Russell Schussler (PC) Steven Huber (PC) Gary Bownfield (PC) Melinda Montgomery (PAS)


Activities

Data Collection, various sources• Events Analysis• TADS• Supplemental Survey• WECC Substation Work Group (SSWG)• Industry Reports

Data Analysis Identification of observation/recommendation OC/PC review – comments/feedback incorporated Requesting Approval/Endorsement in December

OC/PC meeting


Observation & Recommendation

Reliance on TADS5 data and transmission severity calculation does not provide industry a complete picture of failed AC substation equipment impact on reliability.

NERC should incorporate data from other sources and analyze the impact on BES reliability. NERC should consider improvements in transmission severity calculation as mentioned in report

The failure of a circuit breaker to operate properly increases the probability that additional BPS elements will also be forced out-of-service, increasing the transmission outage severity of the incident.

NERC should evaluate the failure rate of circuit breakers and consider the impact of bus configuration on AC transmission circuit outages.

Observation Recommendation




Bus configuration is the primary determinant of the impact of breaker failure on transmission outage severity.

Entities should evaluate the impact of breaker failures on system performance when choosing bus configurations for new installations or modifying existing substations.

The duration of a BPS element outage is not captured in the transmission outage severity calculation.

NERC should add a duration component to transmission outage severity calculation.




Transformer outages are not included in the transmission outage severity calculation.

NERC should add a component to account for transformer outages to transmission outage severity calculation.

Existing data collection processes are not sufficient for cause analysis of failed AC substation equipment.

NERC and entities should investigate a consistent method for collection of AC substation equipment failure data using industry guidelines and share the results with applicable organizations.




The revised TPL-001 reliability standard will address some of the impact of bus design and breaker failure. The changes to the performance requirements for TPL-001-4 will revise how industry addresses multiple contingencies which are often created from substation equipment failures.

NERC should monitor industryimplementation of TPL-001-4 toverify that planning studies includemultiple contingencies to evaluatethe effect of substation equipmentfailures.

AC substation equipment failures increase the probability that additional BPS elements will also be forced out of service due to the close proximity of BPS elements, potentially increasing the transmission outage severity calculation.

Entities should consider bus configurations when designing new substations or making revisions to existing substations to possibly reduce the impact of outages on adjacent BPS elements.




Bushings as part of a large piece of substation equipment could cause system reliability vulnerabilities to persist with insufficient research or industry wide notification.

High voltage equipment bushings should be categorized and treated as a completely separate piece of substation equipment.

The analysis of ALR6-13 indicates thatthe outage trend of Failed AC substationequipment is declining and immediateintervention is not warranted at thistime.

NERC should continue to monitor andtrend this metric.


Participation, Data Sharing and Best Practices

• Use optimal lubrication practices for each circuit breaker• Define a process for the distribution, tracking and analysis of

manufacturer issued service advisories• Investigate, analyze, and report all BES substation equipment

failures per the applicable IEEE Guideline• Participate in industry groups such as NATF, and EEI, etc. to

share investigation results• Include results in NERC Event Analysis investigations• Proactive replacement of equipment where industry

experience identifies a generic problem in a specific device.


Conclusion

• Though, it is not possible to eliminate all substation equipmentfailures, it is important that entities design, build and maintainsubstation configurations and equipment to minimize adverseeffects (i.e., severity) associated with potential AC substationequipment failures.

• Determination of the bulk power system reliability implicationsand transmission outage severity can provide a basis for systemenhancement.


Questions and Answers

*Some related backgrounds slides are included in the remaining part of presentation

Thank You!


• AC Substation Equipment Failure and Transmission Outage Severity Inherent in AC substation equipment failure is an increased probability

that additional BPS elements will also be forced out of service, potentially increasing Transmission Outage Severity.

The function and arrangement of substation equipment often increases the number of transmission lines forced out of service when substation equipment fails. By design, substation equipment is always located in close proximity to TADS transmission line terminals

• Circuit breakers are the leading equipment failure due to: Frequency of operation Number of circuit breaker in service

Relationship with Transmission Severity


AC Substation Equipment Failures by Equipment Type

39%

28%

10%

5%3% 2% 2%

3%

8% Circuit Breaker

Transformer

Bushing

Instrument Transformer

Switch

Capacitor

Circuit Switcher

Arrester

All Other


• Three common bus configurations are: Straight or radial Bus

o This configuration results in the highest transmission outage severity among the three configuration as a result failed circuit breaker.

Ring Buso This configuration dramatically reduces the impact on transmission outage

severity resulting from a failed circuit breaker

Breaker and a half Buso This configuration further reduces the impact on transmission outage

severity resulting from a failed circuit breaker.

• From survey data, It is worth noting that 67% of the circuit breaker initiated outages were located at substations with a single bus-single breaker bus configuration ( chart on next slide)

Substation configuration


Circuit Breaker Failure by Bus Configurations (Survey Results)

13%

3%

12%

5%

67%

Breaker-and-a-Half

Other

Ring Bus

Sectionalized Bus

Single Bus


ALR6-13 Metric Trend for 2008-2013

.049

.046.044

0.05

.041

.029

0

0.01

0.02

0.03

0.04

0.05

0.06

2008 2009 2010 2011 2012 2013

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