Study Of Capacitive Current Compensation In Cable Distribution Networks

We have analyzed the main features of cable distribution network with various neutral grounding ways, including the neutral, resistance grounding and resonant grounding. We also have analyzed the distribution network neutral point grounding operation modes of various single-phase grounding faults comprehensively.In this paper, we use MATLAB Power System Simulation Toolbox (PSB) building a full cable outlet substation model.By way of the simulation of grounding fault of cable distribution network with three types of neutral grounding, We have analyzed the fault current of fault phase, frequency over-voltage and intermittent over-voltage, we have compared the characteristics of single-phase ground fault in cable distribution network with different neutral grounding mode through theoretical study and simulation analysis. We have found out the appropriate neutral grounding for cable distribution network through theoretical study and analysis of the simulation waveform.Beside the study of neutral grounding, we have discussed a capacitive current compensation method that we install a three-phase shunt reactor to substation bus.Under normal operating conditions, the three-phase shunt reactor can reduce the system capacitive current, preventing excessive voltage rise at the end of lines by the formation of capacitive reactive power. In the case of single-phase ground fault, the three-phase shunt reactor can also coordinate the Petersen Coil and do multi-ground capacitive current compensation. With the ground fault capacitance current further increasing, more than 300A, we could consider using neutral grounding via low resistance to ensure the safe operation of distribution network.