Gas tightness test methods for gas insulated MV and HV switchgear

This paper elucidates the methods used in type testing and factory routine testing to ensure the tightness of SF₆ gas used in Medium Voltage (MV) and High Voltage (HV) switchgear as per the latest IEC and CIGRE guidelines. Gas insulated MV (>1 kV to ≤52 kV) and HV (>52 kV) switchgear are frequently being used in electrical power system throughout the world. Mostly, gas insulated MV and HV switchgear contains SF₆ as a pure gas or combined with other gases (i.e.: N2) to form a gas mixture. Recent times, distinct emphasis is being paid to reducing gas leakage during design, manufacturing and operation by enhancing gas handling procedures in compliance with Greenhouse gases emission regulations. Typically the assurance of gas tightness of MV and HV Switchgear shall be defined as the lowest possible quantity of SF₆ released to the atmosphere. Various test methods are used for tightness test measurement depends upon sensitivity of measurement, quantity and necessity