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Substation Testing & Maintenance


Vacuum Interrupter Testing for Circuit Breakers

How to predict field life using vacuum interrupters BY FINLEY LEDBETTER, Group CBS Utilities have widely replaced older air-magnetic and oil interrupters for circuit breakers rated at one kilovolt (kV) or higher with vacuum interrupters (VI) due to higher interrupt capability. Vacuum interrupters...

Circuit Breaker Time and Motion Testing

Determining mechanical condition of high-voltage circuit breakers BY JOZEF LEVI, Doble Engineering Company Life expectancy of a newly installed high-voltage circuit breaker is approximately 40 years. Throughout its life, under normal circuit conditions, the circuit breaker will operate less than...

Effective and Safe Testing of GIS Switchgear

To fully assess the functionality of medium and high voltage circuit breakers, various mechanical and electrical parameters must be tested. Gas-insulated switchgear (GIS) in particular poses unique and special challenges, including the connection of the test equipment. In today‘s world, where...

Substation Testing & Maintenance

Power Factor Testing of Circuit Breakers

Detecting contamination and deterioration in SF6 breakers to ensure longevity

BY LINDA NOWAK, Doble Engineering Company

The purpose of “Doble testing”, or power factor testing, SF6 (sulfur hexafluoride) circuit breakers is to detect the presence of contamination and/or deterioration of the breaker’s insulating system. This process will allow corrective actions to be taken to ensure the integrity of the breaker.

The Doble test is completed by measuring the insulation’s dielectric-loss and capacitance and...

Related Articles


switching times on medium and high voltage Gas Insulated Switchgear

Effective and Safe Testing of GIS Switchgear

To fully assess the functionality of medium and high voltage circuit breakers, various mechanical and electrical parameters must be tested. Gas-insulated switchgear (GIS) in particular poses unique and special challenges, including the connection of the test equipment. In today‘s world, where...

Circuit Breaker Lubrication

Developing circuit breaker lubrication procedures BY RICK YOUNGBLOOD, Doble Engineering Company Circuit breaker analyzers are used to determine operating speeds and velocity. This information enables the tester to determine if a breaker is safe to place back into service. The data recorded by a...

Insulation Resistance Test

Insulation Resistance (IR) test, often called Megger test, is more than 100 years old and assumed to be a very straightforward test. During my inspection and testing work in the past 15 years in Canada, US, and internationally, I have seen different practices of performing and interpretation of IR...

Transformer testing and failure analysis

Power Transformer Failures

Electric utilities maximize utilization of their assets, while maintaining reliability. Power transformers are typically reliable, but have been known to fail suddenly and/or prematurely. Transformer failures are both costly and can leave customers dissatisfied, harming the reputation of a utility....


FERC Complaint Targets Duke, PJM Transmission Planning

A coalition of large energy consumers and ratepayer advocates has filed a complaint with the Federal Energy Regulatory Commission (FERC), urging the agency to prohibit transmission owners from independently planning "local" transmission projects exceeding 100 kilovolts (kV). The coalition argues...

Contact Material Recycling and Sustainability in Electronics

The electronics industry is experiencing rapid growth and innovation, with devices becoming more advanced and ubiquitous. As this industry continues to flourish, it’s crucial to consider the environmental impact of electronic manufacturing and the materials used in these devices. One area...

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