Gas-insulated transmission lines state classification and fault chamber location based on the divergence characteristics of temperature parameters

Abstract

SuTong GIL (Gas-insulated transmission lines) is a critical connection for the UHV AC loop network in East China, therefore, its state classification and fault chamber location are extremely important for the operation and maintenance. Besides, because of the slow and flat temperature change of the GIL, it is difficult to realize state classification and fault chamber location from the perspective of temperature. Based on the temperature rise effect, this paper defines the ratio of heat-temperature (QT) and the change rate of the ratio of heat-temperature (θ) as the characteristic parameters. Based on the boundary equations, the state is divided into the normal, the critical and the abnormal state. More importantly, the fault chamber location can be achieved by studying the temperature transition characteristics. To verify the effectiveness of this method, the three-dimensional Multi-physics coupling model is established through COMSOL. Each state is simulated at different current changes. The trend and value range of the characteristic parameters in different states are obtained. The result shows that the value of QT and θ at the abnormal state are dozens of times higher than other two states. The fault location simulation shows that the QT on the left is 4 times higher than that on the right, and the θ on the left is 10 times higher than that on the right. This method can realize state classification and fault chamber location accurately.