RESA Power Surveys Dozens of MV Metal-Clad Switchgear Assemblies for Major U.S. Utility

At RESA Power, we take pride in showcasing our extensive portfolio of services and solutions tailored to the ever-evolving needs of our customers in the utility industry. We are excited to present a brief case study that exemplifies our commitment to delivering exceptional results.

In this case study, we delve into a survey conducted for a major U.S. utility, addressing their pressing concerns related to medium voltage (MV) switchgear equipment. Through the strategic application of advanced techniques, RESA Power’s dedicated team successfully identified critical defects, providing actionable insights that ultimately helped the utility mitigate the risk of future unplanned outages.

The Challenge

In recent times, a major U.S. utility experienced insulation failures in their medium voltage (MV) switchgear equipment, which led to service disruptions. Concerned about the condition of their aging switchgear assets, the utility sought a solution to address the issue.

The Issue

One of the leading causes of MV insulation failures is partial discharge (PD) activity. PD refers to a localized partial failure of the insulation at a defect site. If left unaddressed, these discharges progress and eventually result in complete failure, leading to unplanned outages and safety risks.

The Solution

RESA Power’s team of service technicians conducted substation surveys using advanced partial discharge detection techniques. These techniques allowed for non-intrusive identification of defects from the outside of the switchgear, eliminating the need to remove panel covers or schedule outages.

Survey Results

Within a span of just two weeks, RESA Power efficiently surveyed 40 substations, encompassing hundreds of switchgear sections. This comprehensive assessment identified the critical defects that had active discharges occurring, affecting approximately 3% of the utility’s total assets.

Customer Findings

Following the partial discharge survey conducted by RESA Power, the utility arranged internal inspections of the identified suspect areas. These inspections confirmed the presence of critical insulation defects that were on the precipice of complete failure. The accompanying photos showcase typical partial discharge issues discovered during the survey.

Cable Termination partial discharge
Cable Termination PD – the white areas on the cables occur due to dangerous partical discharge activity which creates highly corrosive nitric acid by-products.
erosion damage due to the partical discharge
Advanced stages of insulator tracking and erosion damage due to the partical discharge


By leveraging RESA Power’s partial discharge detection survey techniques, the customer quickly obtained valuable insulation condition data for their switchgear. This significantly reduced the time required for traditional maintenance outage inspections, which would typically take years. Armed with this data, the utility could allocate resources to address the areas that required immediate attention, greatly mitigating the likelihood of future unplanned outages.

About This Service: Partial Discharge Testing

RESA Power’s non-intrusive partial discharge testing is applicable to various MV assets, including switchgear, transformers, busways, cables, breakers, switches, and generators. By utilizing this service, asset managers can assess the insulation condition and focus resources on addressing “failures in progress,” thereby improving the overall reliability of their electrical systems. To learn more about RESA’s capabilities in applying PD techniques and eliminating unplanned outages, reach out to your local RESA office today or discuss our extensive range of service offerings or check out our Partitial Dischage Cable Testing webpage here

Abouth the Author

Don A. Genutis is a General Manager at HALCO, a RESA Power company. With over 35 years of experience in the power industry, Don is a true leader in electrical testing and a driving force in advancing no-outage testing techniques. He has authored 50 technical articles for NETA World and has been featured in EC&M and Uptime magazines. In 2019, he published his book, “Partial Discharge & Other No-Outage Testing Methods,” which summarizes his extensive work and findings. In 2023 HALCO Testing Services joined RESA Power.

Disclaimer: This article represent a specific RESA Power service

About RESA Power

RESA Power, a portfolio company of Investcorp, a global alternative investment firm, is a market leader in power systems services and life extension solutions for power distribution equipment used in mission-critical environments. With locations across the United States and Canada, RESA Power is uniquely capable of ensuring its customers’ critical power systems are safe, reliable, and operating at peak efficiency. The technicians and engineers at RESA Power are experts in testing and servicing transformers, relays, breakers, and other key components of power distribution and control systems. RESA Power also provides quick turn-around custom manufactured or retrofit switchgear and breaker solutions and maintains an extensive inventory of obsolete and hard-to-find components. For more information about how to join the RESA Power group, visit or follow @RESAPower on LinkedIn

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