Countermeasures of abnormal heating of cable grounding line near three-phase reactor

Cable termination near to three-phase dry-type air-core reactor (DAR) is prone to abnormal heating. In response to this problem, this paper firstly establishes the finite element model of the reactor and the cable and calculates the electromagnetic field distribution to obtain the current of the grounding wire of the cable armor layer. It is analyzed that the main reason for the abnormal temperature of the cable terminal is the eddy current in the grounding wire of the cable armor layer, which is caused by the leakage magnetic field of the reactor. Meanwhile, the influence of cable laying mode near the reactor on the current of armored grounding wire is further discussed. Secondly, the finite element model of the cable terminal is established and the temperature of the cable terminal is obtained by calculating the current-fluid-thermal coupling field. Considering the influence of adding shielding to reactor operation, the scheme of adding laminated silicon steel sheet slot box to cable is put forward and simulated. After adding slot box, the grounding wire current of armor layer is reduced by about 87% similar to 89%. The test results show that when the input voltage of the coil is constant, the eddy current measured after installing the slot box decreases significantly, and with the increase of the coil voltage, the suppression effect of installing the slot box on the induced circulating current is better. This paper provides a certain reference value for the laying of cables near three-phase DAR in substations and the solutions to the abnormal heating of cable terminals.