A Coupled Electrical-Mechanical-Thermal Analysis of EHV Disconnecting Switch for Short Circuit Current Condition

Abstract

This paper presents the pwformane prediction technique of a disconnecting switch in case of short circuit current conduction The thermal characteristics caused by the applied force to the contacts and contact resistance are analyzed by solving a coupled electrical-mechanical-thermal problem Extra high voltage @HV) disconnecting switch (DS)consists of electrical contacts and mechanical parts which actuate the contacts. When the short circuit condition occurs, large current flows through the electrical contacts and this causes amount of Joule heating. If the temperature rise due to the Joule heating is higher than the melting point of the contact material, then the contacts become melting.This paper presents the calculation of the DS performance according to the applied f m and the Joule energy using a couplcd clcctricd-mcchanicd-thmal analysis. Thc prcscntcd analysis technique is verified through the test results. IL MECHANICAL ANALYSIS OF THE ~~ECHANICAL PARTSFirst, the force distribution at the interface between the contacts is calculated using a mechanical analysis. Next the heat W e r analysis is conducted. The flowchart of t h~s analysis is shown Fig. 1. Analpis of the force diatributim 3 I Calculation of the contact resistance with respect to the force I Calculation of the temperature rise I Vcrificatim of thc analysis through thc ternpeatun tile tent Fig. 1. Flowchart of the analysisThe structure of DS for an analysis is shown in Fig. 2 (a). Fig. 2 (b) shows the force distribution at each blade of the moving contacts. IIL CALCULATION OF THE CONTACT RESISTANCE To cd~ulale Ihe w n k l resislmcx wilh respect lo lhe applied force, the calculation method is developed and the contact resistance is measured using a rnicroahm meter. Fig. 3 shows the measurement system of a contact resistance and the comparison of calculations and measured results. (a) m u l u u e n t system @) c o m p~o n of contact resistance Fig. 3. Comparison of contact resistance with respect to the applied force.

Inversion Method for Contact Temperature of GIS Disconnect Switch

“…The finite element analysis divides complex models into a finite number of regular elements, and solves complex problems through a series of calculations. Reference [12] provides a summary of the application and analysis process of methods of thermal path and finite element analysis in temperature rise experiments. Reference [13] used an equivalent thermal path model to calculate the temperature of GIS disconnect switches, and provided simulation and calculation of the temperature field under different operating conditions, considering factors such as environmental temperature, contact resistance, and load current.…”