Conductor temperature monitoring for the fully insulated busbar prefabricated joint considering contact resistance

Abstract

Abstract The fully insulated busbar system, which has been extensively used in the industry, contains a large number of joints due to its limited length, and thus it is prone to overheating failure caused by poor contact. Taking the uncertainty of contact resistance into account, this paper presents an indirect approach to monitor the conductor temperature for the fully insulated busbar prefabricated joint using the busbar surface temperatures. The model is composed of radial direction temperature calculation (RDTC) in the busbar and axial direction temperature calculation (ADTC) in the conductor. The equivalent thermal resistance of joint is defined to characterize the influence of contact resistance, based on which RDTC and ADTC are corrected by an iterative method. The temperature rise test of the prefabricated joint was carried out. When the contact state is normal, the transient and steady‐state error is within 4 and 1 K, respectively. When the contact state is abnormal, the steady‐state error under rated current is less than 5 K, and the transient error with the step load is about 10 K, which is thoroughly analyzed. From an engineering point of view, the proposed algorithm can effectively monitor the joint hotspot temperature and evaluate the contact state.