Research On The Capacitive Current Analysis And Control In Nantong

In our country,the process of urbanization is accelerating,the scale of cities is expanding,and the requirements of environment are increasing.The overhead lines in urban areas can no longer meet the requirements of modern city development.The replacement of overhead lines with cable lines under the ground has become an inevitable choice for city distribution.The increasing of cable lines will inevitably lead to the growth of distribution network capacitance,and the exceeded capacitive current will affect the safety and reliability of the gird.We must consider the effect of capacitive current and choose a right network neutral grounding when we transform or build a transformer substation.Then we can solve the problem of excessive capacitive current.This article,combined with the author's practical work,analyzes Nantong's present situation of capacitive current and studies the programs to control it.And the achievements are as follows:(1)First of all,introduces the causes of capacitive current,expounds the methods of estimating the capacitance of overhead lines and power cables,analyzes the the method and technical points of capacitive current measurement.(2)Analyzes the situation of capacitive current in Nantong and gets the conclusion that most of the substations in Nantong can control the capacitive current but some of them can't and points out that now using arc suppression coil is the the main scheme to solve the problem.(3)Conducts a detailed study for the method of arc suppression coil compensation,combined with the development of the using arc suppression coil in Nantong,points out that arc suppression coil compensation plays a good role in the control of capacitive current,and can take the way of arc suppression coil distributed compensation or increasing the arc suppression coil capacity.(4)Studies the low-resistance grounding mode and its relay protection,gets conclusion that the low resistance grounding mode will be one of the methods to control the capacitive current in Nantong in the future,takes Qinzao substation as the analysis object,and designs a program,combined with the actual situation and parameters,for the substation with low-resistance grounding mode.