Chris Rutledge

Chris Rutledge

Dynamic Ratings

Biography:

Chris Rutledge is currently an Applications Engineer at Dynamic Ratings, Inc.

He joined the Dynamic Ratings team in July 2019.

Prior to his present position, he served Substation Asset Manager and chairman of the Substation Safety Committee at Memphis, Light, Gas and Water. He has 27 years of experience in the utility industry, primarily focused on the installation, service and maintenance of both substation and distribution equipment. He has done extensive research and published multiple papers concerning the interpretation of dissolved gas analysis testing. Chris is dedicated to assisting customers in finding creative cost-effective solutions for improving safety and reliability across their entire electrical system. 

 

Abstract:     

Breaker Monitoring:  Improving Reliability Through directed Maintenance

Circuit Breakers are highly critical to the power-protection system given their assignment of physically interrupting power flow for the protection of critical assets. However, mis-operation of breakers remains one of the most common root cause failures present within the substation. These failures can often be attributed to the circuit breaker’s mechanical systems remaining in a static state for extended periods of time, while still being required to operate at optimum levels in order to clear high magnitude faults within a few cycles of their inception. These long periods of inactivity in conjunction with exposure to thermal variations and the ingress of contaminants can lead to degradation of the mechanism’s lubrication and control systems. While cyclic testing and maintenance of a circuit breaker’s operating systems by maintenance personnel is the most common means of keeping breakers in optimal operating

condition, this approach can at times lead to misdiagnosis of potential failure modes. Some factors which contribute to this misdiagnosis are limitations of the testing and maintenance procedures being implemented, excessive operations occurring between maintenance cycles, and in some instances, intrusive internal inspections resulting in a subsequent mis-operation.

This paper illustrates the effectiveness of online breaker monitoring, utilizing the analysis of high-speed waveform capture, as a means of ascertaining a breaker’s operational condition. Through waveform analysis of the main contacts and trip coil, the asset owner can evaluate many of the breaker’s vital operational parameters, such as degradation of the breaker’s lubrication, integrity of the trip coil, problems within the breaker’s operating mechanism and slow operating times. The implementation of online monitoring allows parameters to be recorded in real time under actual operating conditions.

This offers many advantages over off-line testing, which can often cause many abnormalities to go misdiagnosed, as any operation of the breaker before testing and simulated test voltages can lead to the early development of problems going undetected. Online monitoring raises the asset owner’s awareness of the breaker’s real-world performance, allowing resources to be directed in a more proactive manner, thereby reducing the chance of a problematic condition being misdiagnosed or possibly created as the result of traditional cyclic testing and intrusive internal inspections.