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Breakers & Relays


Storm-Hardened Switchgear

How to protect electrical equipment from Mother Nature BY ROBERT A. MURPHY, Trayer Engineering Corporation The U.S. National Weather Service called Hurricane Sandy the most destructive storm of 2012’s unusually active Atlantic hurricane season. Sandy delivered unprecedented damage across a wide...

Protective Relay Frustrations

Solving misoperation with line parameter measurements BY WILL KNAPEK, OMICRON USA Between 80 to 90 percent of all power system faults involve ground. Many protective relaying schemes depend on ground distance protection to accurately sense and locate ground faults on multi-terminal sub-transmission...

Protection of Electrical Power Transformers

INTRODUCTIONIn most large electrical systems, generators and power transformers are the two most expensive pieces of equipment. In addition to the capital cost of purchase, these two key devices are also the most critical to continuous and reliable operation of the system.Consider, for example, the...

Breakers & Relays

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


Protection of Electrical Power Transformers

INTRODUCTIONIn most large electrical systems, generators and power transformers are the two most expensive pieces of equipment. In addition to the capital cost of purchase, these two key devices are also the most critical to continuous and reliable operation of the system.Consider, for example, the...

Selecting Substation Medium-Voltage Switchgear: GIS vs. AIS

Understanding differences between GIS and AIS in five points BY GAETAN DJENANE, Schneider Electric, Inc. Many considerations must be taken into account before selecting the electrical medium-voltage (MV) switchgear that best meets a user’s needs. From a management perspective,...

Gas-insulated Switchgear Options for Substations

Switching gears in the underground BY PETR RUDENKO AND PETER GLAUBITZ, Siemens As demand for energy continues to rise, an increased number of locations around the world require suitable energy solutions that fulfill unique demands. Cities are growing, and so is the demand for power. Urban areas...

Dynamic Resistance Measurement

Condition testing of circuit breaker’s arcing contacts BY BUDO MILOVIC, DV-Power The preventive maintenance on a high-voltage (HV) breaker consists of several routine tests. The timing and motion tests are methods used to assess the breaker’s mechanical condition. When the timing and motion...


Smart Substations and Their Role in the Evolving Smart Grid

A Smart substation digitizes protection and control, enabling utilities to detect faults faster, manage DER volatility, and reduce outage risk. The payoff depends on architecture, cybersecurity, and edge analytics, not just new relays. The shift toward smart substations is inseparable from broader...

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...

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FERC Approves Interconnection for Talen Energy, Amazon Data Center

In a significant move that underscores the growing demand for reliable and sustainable energy to power the expanding digital infrastructure, the Federal Energy Regulatory Commission (FERC) has approved an interconnection agreement between Talen Energy, Amazon Web Services (AWS), and Exelon. This...

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SAME DAY SWITCHING

Same day switching avoids the extended outages and human and equipment costs associated with inoperable and broken switches.The vast majority of air break disconnect and ground switches in electric power networks typically receive no appreciable maintenance. This invariably results in the inability...

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...

Technician working on DILO SF6 gas separator

Reconditioned SF₆ Gas: An Environmentally Friendly Alternative

When it comes to medium and high voltage circuit breakers, there is no better electrical insulator than sulfur hexafluoride (SF6). The manufactured gas is most commonly used to fill circuit breakers within utility substations to prevent and quench arcing events. SF6's impeccable dielectric...

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