Research & Technical Content

Supplemental projects to enhance learning of polymer bushings

Evaluation of Resin Impregnated Paper Bushing Failure Propagation Time:

To minimize costly outages due to bushing failures, many utilities are investigating dry-type bushing alternatives, such as Resin Impregnated Paper (“RIP”) and Resin Impregnated Synthetic (“RIS”) bushings. These types of bushings are considered not to cause extensive transformer damages or other collateral damages. However, the time frame from initiation of a failure inside the bushing to the bushing failure remains unknown. Also unknown is whether a bushing monitoring system on a RIS or RIP bushing could detect the failure propagation, so unexpected outages might be prevented. This project intends to equip funders with a better knowledge of the time to failure once the dry-type bushing has been compromised, and to learn if monitoring the power factors and capacitance could detect possible insulation failure of the bushings early to prevent transformer failures. EPRI plans to utilize an HSP 138 kV RIP bushing (manufactured in 2014) in this investigation.

Establishing Baseline criteria for DFR on Bushing:

This supplemental project is a new supplementals to investigate good baseline DFR trace library- depending on manufacturer, batch of bushing production, and voltage class. A good DFR baseline is critical for creating good interpretation guidelines for DFR on bushing measurements.

Evaluation of 34.5 kV & 69 kV Bushing under cyclic loading & ambient condition:

Experience from the field (especially from a renewable substation) has shown that some OIP & RIP bushings unexpectedly have an increased power factor. The reason for increased power factor is not known. This project will test the bushings, in a controlled way, to cyclic loading and temperature swing similar to conditions in the field and monitor the increase of power factor and other bushing condition changes to understand the cause of power factor change in certain type of bushings.

Evaluation of Infrared Monitoring Analytics in Lenox 138 kV Yard:

Transformers are key assets in a substation and the performance of a transformer is an important is very important to maintain the electrical grid reliability. The open research question is if infrared monitoring of transformers and analytics of such solutions is effective in predicting degradation and preventing the resulting failure such as bushing failures. This research project intends to address this research need by implementing IR technology in the 138 kV yard and creating different transformer failure mechanism to evaluate the effectiveness of commercially available IR analytical tools.

Research of Substation Robot Application:

An important question related to the reliable and cost-effective supply of electricity is the prevention of failure of substation assets such as transformers and breakers. Performance of substation assets is very important, and the open research question can these assets be effectively inspected on-line 24/7 by a mobile autonomous substation robotic technology to prevent unscheduled outages and unexpected failure. This project will review available robotic technologies and evaluate them to learn on possibilities and challenges of having these 24/7 in a substation environment to provide utilities with online inspection for real-time assessment without personnel onsite

Services and Capabilities

EPRI has several capabilities available to utilities as part of research work, supplemental projects, or service agreements. Those capabilities include technical knowledge, laboratories, and failure analysis services.

Laboratory Capabilities
Detailed Lenox laboratory capabilities can be found here

For the polymer bushing project most of the work is performed on the EPRI Lenox Laboratory where a 138 kV research substation was built in 2018

In 2022 a new bushing aging chamber is being built for accelerated bushing aging tests.