| With the continuous development of China’s power system,the structure dominated by the radial overhead line has become the structure dominated by the cable line,and the overhead line has been transformed from a single radiation type to a multi-type combination structure(multiple power supply,ring)The network closed-loop operation),these changes not only put forward new requirements for the traditional relay protection device,but also led to a significant increase in the capacitance capacity of the distribution network to the ground,and the current of the ground fault also increased significantly.The traditional distribution network considers the constraints of power supply reliability and equipment safety.However,as the density of the distribution network in the city is higher and higher,it is widely distributed in the area where people gather.The capacitor current is getting bigger and bigger,and the person is born.The possibility of safety accidents is also increased,so it is necessary to consider the personal safety constraints of the distribution network while considering the operation and planning of the distribution network.This paper mainly analyzes the step voltage of the human body when single-phase ground fault and disconnection plus ground fault occur in the distribution network.The specific content includes the analysis of ground current when single-phase ground fault and disconnection plus ground fault occur.And perform PSCAD simulation on the disconnection plus ground fault;then the human body safety theory,the formula that the human body can withstand the step voltage and the actual generated step voltage,the randomness that affects the step voltage factor,and the ground fault The step voltage generated by the time is based on the finite element analysis of ANSYS software,and the probability density function of the human body injury probability is introduced.The personal safety problem in the grounding fault of the distribution network under different conditions is analyzed.Finally,the Specific measures to reduce the step voltage.A new analysis idea is proposed for the personal safety analysis of the distribution network. |
