Online Monitoring of Partial Discharge by Measuring Air Decomposition By-products under Low and High Humidity

Abstract

Atmospheric air remains as the main insulting material for transmission lines and air insulating substations. The losses in air insulation would happen due to partial discharges which ultimately lead to breakdown of air. In this paper we have studied the online monitoring of partial discharge in air by measuring air decomposition by product (such as Ozone and NOx) under low (30% RH) and high humidity (60%RH) conditions. The needle plate experimental setup is used to simulate partial discharge faults at 15 mm, 20 mm, 25 mm and 30 mm gap distances only. A study is conducted to analyze the atmospheric effects including density factor, humidity effect and gap factor on partial discharge for this experimental configuration. The results show that PD could be detected and monitored by measuring air decomposition by product under low and high humidity conditions.