Gas pressure monitoring device of gas insulated switchgear, gas pressure monitoring method thereof, and gas leak position identification method

Abstract

A gas pressure monitoring device of a gas insulated switchgear () of the present invention includes at least two cylindrical vessels () that configure the gas insulated switchgear () to receive an insulating gas to be at an internal pressure. The at least two cylindrical vessels () have flanges (), and a plurality of bolts () that fasten the flanges of the at least two cylindrical vessels (). At least one bolt () of the plurality of bolts () includes at least one sensor () provided on the inner peripheral face thereof toward each of an inner diameter side and an outer diameter side of a cylindrical vessel () to measure strain acting in the axial direction of the at least one bolt () with the sensor (). A pressure gauge () is installed on the cylindrical vessel () and reads pressure of the insulating gas when the insulating gas is sealed into the cylindrical vessel (). A measurement recording unit () records pressure values output from the pressure gauge () and values output from the sensor (). An evaluation unit () calculates relationship between the pressure of the insulating gas and the stress acting on the at least one bolt () with the sensor () when the insulating gas is sealed into the cylindrical vessel (), wherein, after an operation of the switchgear () is started, change in the pressure (ΔP) of the insulating gas in the cylindrical vessel () is estimated from change in the stress acting on the at least one bolt () with the sensor (), so as to enhance monitoring the pressure of the insulating gas.