P37.102: Circuit Breaker Life Management and SF6 Management

Effect of Component Degradation on Circuit Breaker Operation intends to characterize possible consequences of degraded components on circuit breaker operation (for example, slow trip, abnormal mechanism wear, lubrication, compressor/pump failures) with the following:

• Catalog failure reports and other information available from circuit breaker failure events and/or utility root cause analysis

• Document industry practices in circuit breaker routine maintenance, diagnostic testing, and overhaul

• Catalog utility experiences of using digital relays for circuit breaker diagnostics

Circuit Breaker Online Monitoring Effectiveness Assessment aims to develop and apply assessment metrics to various circuit breaker online monitors to determine which monitors and tests provide the most useful information. The objective is to provide information to assist in monitor application and specification.

• Tasks in 2025 plan to:

• Work with funders to identify specific circuit breaker monitors of the highest interest, and use publicly available information to perform systematic investigations to understand what capabilities are claimed, make comparisons, and assess their applicability

• Perform tests in EPRI laboratories, when possible, to confirm that monitor measurements match comparable offline tests—for example, breaker timing

• Document utility experiences with using online monitors

• Maintain awareness by scouting commercially available and emerging technologies

Circuit Breakers Diagnostics Effectiveness Assessment intends to continue to assess the effectiveness of dynamic resistance measurements (DRM) and develop and apply metrics to assess the effectiveness of various additional circuit breaker diagnostic techniques. The objective is to provide utilities with guidance on the most informative and cost-effective procedures for nonintrusive diagnostics to support condition-based maintenance.

• Tasks in 2025 plan to:

• Better determine the relationship between DRM waveforms and contact condition and build a library for different circuit breaker interrupter models. The tests would rely on field-aged circuit breaker arcing contacts provided by utilities or by simulating defects using the circuit breaker in EPRI’s 138 kV substation laboratory.

• Maintain awareness by scouting commercially available and emerging technologies.

• Expand efficacy assessments to additional techniques, for example, X-rays, acoustics, and partial discharge.

New Markers for Circuit Breaker Dielectric Condition Assessment proposes to undertake a multi-year effort to research, develop, and apply new chemical markers that could assist in providing information for effective condition-based maintenance of oil-filled and SF6 circuit breakers. Initial focus will be on concept development. Future work may include methodology enhancement, prototyping, and additional experience gathering. Associated supplemental projects may be initiated to assist with field demonstrations and testing.

Leak Sealing for Circuit Breakers and Gas-Insulated Substations investigates methods that utilities can use to cost-effectively seal dielectric gas (SF6 and non-SF6) leaks. The emphasis is on identifying materials and techniques that can seal while maintaining equipment operating pressures and are easy for utility personnel to apply and remove. Novel techniques for sealing SF6 leaks on circuit breaker and gas insulated substation (GIS) component geometries at ground potential were developed, and three successful techniques identified in the laboratory are in field tests at eight utility sites. Tasks in 2025 plan to:

• Continue monitoring the performance of the field trials

• Develop application guides and “how-to” videos for techniques that are successful in the field and make them available through the Transmission Resource Center (TRC): Circuit Breaker Life Management

• Continue investigations to find sealants that cure at lower temperatures

• Scout innovative methods used by other industries and investigate whether they can be used for sealing breaker and GIS leaks

• Develop techniques for additional geometries, for example, the bushing flange interface; some of these new geometries may not be at ground potential

• Investigate scaling application of existing techniques to larger flange diameters

• Initiate a new effort to investigate:

  • Challenges that may be encountered in sealing leaks of SF6 alternatives
  • Applying techniques successful in sealing SF6 to SF6 alternative gases

Circuit Breaker Reference Guide. There are plans to continue developing a comprehensive reference on circuit breaker procurement, operation, maintenance, and life-cycle management to serve as a resource for less experienced personnel. The goal is to develop a guide that provides information on fundamental design descriptions, operation, selection, and application principles, maintenance, monitoring, and replacement and captures the knowledge of leading circuit breaker experts. To date, nine sections have been written, including sections on circuit breaker installation, diagnostics, problem and failure investigation, lubrication, pump and compressor maintenance, specifications and procurement, and interrupter cleaning. New works aims to:

• Develop guidance material for performing factory visits and design reviews for SF6 circuit breakers

• Develop content on emerging circuit breaker technologies such as non-SF6 circuit breaker technologies

• Develop content on handling SF6 and SF6 alternatives

Technical Webinars on the Circuit Breaker Guidebook intends to develop and host a series of technical webinars based on sections in the Circuit Breaker Guidebook. Content will be selected to accelerate learning on key topics in the Circuit Breaker Guidebook for those with less circuit breaker experience. Webinar material will be published for continued and convenient future access.

Circuit Breaker Mechanism Maintenance Guides. Maintenance supplements written for specific breaker models serve as training tools and guidance for proper mechanism field disassembly, cleaning, lubrication, and reassembly. Gaining importance as experienced personnel retire, the guides communicate information in step-by-step illustrated tasks, cover material not included in manufacturers’ instruction manuals, can be readily incorporated in a utility’s maintenance procedure, and have been developed for 11 models. The intent is to expand the library with new guides annually. Model selections will be prioritized based on advice from the task force.

HVCB Life Management Workshop proposes an annual workshop that will include tutorials on the material contained in the project’s products, presentations on utility experiences, and examples of the application of the project’s results.