Effect of HV Guard in Reducing Electric Field Intensity of Gas Insulated Switchgear Spacer

As one of the most important parts of gas insulated switchgear, many technologies have been explored to reduce the electric field strength in gas insulated switchgear spacer. This spacer, despite acting as the secondary insulation in gas insulated switchgear, holds a very important role to hold the high voltage conductor and separate it with the grounded tank. Failure in the spacer could result in overall failure of gas insulated switchgear. One of such accessories is the High Voltage Guard. A bulged conductor acting as the HV Guard is placed nearby the surface of the spacer. This accessory is then tested with finite element simulation for 2 types of 1 phase spacer design, conical design and disk design. Each method is proven, electric field wise, could improve the performance of the spacer. Both electric field in the surface, mainly on the triple junction area, and inside spacer could be suppressed to around 15% to 20% in both conical design and disk design.