Research On 10kV Power Network Neutral Grounding Of Jiang Jin

The problem about neutral grounding mode of the electric power system is an all-around technical problem which associated with not only power system reliability, insulation coordination electromagnetic interference, but also personal safety, etc.In recent years, cable lines are widely used with the development of civic 10kV power network. The vast usage of cables result in several problems such as the increase of system capacitive current, the occasional occurrence of faults caused by arc grounding or resonant grounding overvoltage. These problems reflect that the neural grounding modes of civic power system are far from well working. In china, the neutral grounding mode of the 10kV network involved of none grounding, grounding by arc suppressing coils or low resistance grounding. It was reported that the over-voltage level of low resistance grounding mode is lower than that of arc suppressing coil mode, but the operation carried out the other way. At substations in Shanghai and Guangzhou it was found that the low resistance grounding mode is successful. But in some areas, such as Zhuhai, substations grounding with low resistance revealed some problems, including power supply reliability rapidly dropping, transmitting line often tripping; and person safety being threatened. So interiorly the grounding mode selection of the 10kV network was disputed, which mainly focused on the fault form of 10kV network grounding, the apply area of suppressing arcing coil grounding mode, power supply reliability level of the two modes, person safety, communication interfere and the workload of maintenance.This paper studied on how to select the neutral grounding mode of 10kV network. Calculation models for systems with this new grounding mode of arc grounding overvoltage PT resonant grounding overvoltage and break line overvoltage are built in this paper, moreover ,the calculative parameters are collected. In the upper three grounding modes, arc grounding overvoltage PT resonant grounding overvoltage and break line overvoltage are calculated for a 10kV electric network in Jiangjin. Through the calculative values, the paper given feasibility suggestion, in addition, the paper discuss the problem of electromagnetic interference about the communication. Base on the values calculated from the calculation mode, it is suggested to use the arc suppressing coil mode for 10kV power network of Jiangjin.