Applicability Of Neutral Grounding Modes For 35kV And Below Distribution Network In Northern Hebei

The issue about neutral-point-grounding mode is an all-around technical problem which associated with not only power system reliability insulation coordination electromagnetic interference but assault safety.In recent years,cable lines are widely used with the development of Northern Hebei city 35 kV and below distribution 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 neutral grounding modes of city power system are far from well working,especially in overvoltage restrain,single phase grounding capacitive current compensation and relay protection.As a result,it is an essential work to study new neutral grounding mode for Northern Hebei city 35 kV and below distribution network which can insure the reliability of power supply,personal and equipment safety and should be economic simple and convenient in assemble and operation.This paper mainly studies selection in Northern Hebei 35 kV and the following distribution network neutral grounding operation mode.Thesis research is divided into the following sections: 1)distribution network neutral grounding situation in Northern now run analyzes,comparative characteristics of different operation modes,and ultimately come to Qinhuangdao and Tangshan in need of renovation Grounding study other cities the company can maintain the status quo.2)Case of Tangshan and Qinhuangdao studied grounding optimization,and to practical optimization.3)Configuration guidelines for the selection and protection currently in use neutral grounding equipment are analyzed in detail.4)Complete flexible grounding system is studied and simulation,combined with flexible Qinhuangdao Yang Zhuang substation grounding pilot applications and transformation analysis.5)The performance of other new grounding device neutral simulation analysis,and gives detailed strengths and weaknesses of various devices.Finally,the neutral grounding in northern Hebei has the following recommendations: 1)the transformation of the more difficult areas of low resistance grounding is recommended that still use resonant grounded neutral grounding mode.2)Try to choose automatic tracking compensation Arc.3)Severe capacitive currents in the region could be considered excessive dispersion compensation methods.4)In the Petersen Coil capacity basically meet the requirements of the region,in order to improve the reliability of power supply;you can consider the pilot applications with line selection function the new grounding device.