Evaluation and Performance Benchmarking of Partial Discharge Measurement Sensors Technologies Based on Non-conventional PD Measurement System for Medium Voltage GIS Applications

Abstract

Continuous monitoring solutions exist for medium voltage (MV) switchgear which enable real-time monitoring of switchgear health and provide operators with benefits such as lower maintenance costs and reduced risk of failures. They are predominantly used in air insulated switchgear (AIS) or externally in gas insulated switchgear (GIS). However, monitoring solutions inside the critical GIS core vessel are not common due to environmental concerns around SF6 emissions and technical difficulties. Nuventura has developed a MV switchgear that uses dry air as an insulating medium which enables the use of these solutions. An additional advantage is that sensor solutions that can be integrated within the GIS core vessel at manufacturing. Partial Discharge (PD) provides valuable information about the condition of the insulation of high-voltage (HV) electrical equipment such as switchgear and is a key indicator of the asset health. Recent advances in non-conventional measuring techniques have created opportunities to monitor switchgear health in real-time and without interruption. Commercially available methods, such as ultra-high frequency (UHF) range measurement of electromagnetic radiation, are low cost and passive and can be integrated into switchgear at the time of manufacture. They are expected to last for long periods of time without interruption. In the current evaluation, commercially available UHF sensor solutions are benchmarked to identify a technically suitable, economically viable early warning detection system for use inside the MV GIS vessel. Other non-conventional sensing techniques such as Transient Earth Voltage (TEV), High Frequency Current Transformer (HFCT) and acoustic methods are also tested for comparison. The conventional method, described in IEC 60270, is used as a reference.