Adaptability And Countermeasures Of Neutral Grounding Method For 10kV Distribution Network Of Large Cities In China

The neutral grounding modes of 10 kV distribution networks in large cities in China mainly include un-grounding,arc-suppression coil grounding and smallresistance grounding.In recent years,with the rapid development of the cities,the capacitive current of the system to the ground is increasing.The neutral grounding mode adopted in many cities exposes various safety problems,which has a great impact on the safe and reliable operation of the system.Therefore,it is imperative to analyze the adaptability of the neutral grounding mode for urban 10 kV distribution networks,and then put forward a reasonable countermeasure for the problems found in the analysis.Firstly,this paper analyses the development and current situation of the neutral grounding mode of the urban distribution network in domestic and foreign cities,and expounds the problems faced by the neutral grounding modes of the 10 kV distribution network in large cities of China and the corresponding countermeasures.The characteristics of different neutral grounding modes adopted in the 10 kV distribution network are analyzed one by one,and the applicable scope of different grounding methods is clarified.Secondly,it analyzes the adaptability of neutral grounding mode of 10 kV distribution network in large cities in China.Statistical analysis of the relevant factors affecting the neutral grounding mode of 10 kV distribution network is carried out,and the main indicators and reference indicators are determined.According to the main indicators,the weighting system of the neutral grounding mode is constructed.Based on this,the corresponding weights of different neutral grounding modes are calculated,so as to determine the appropriate neutral grounding mode.The reference index is used to check the determined grounding mode,and the adaptability analysis of the neutral grounding mode is completed.Finally,the accuracy and validity of the method are verified by typical application analysis.Finally,according to the unsuitable situation of the neutral grounding mode of 10 kV distribution network in large cities in China,the reasonable countermeasures are put forward.For the 10 kV distribution network,the grid structure is complex,the distribution network automation level is low,and the power supply reliability is not high.The optimization of the grid structure can be considered.For the distribution network with weak system frame structure,a distributed compensation scheme for arc suppression coil is proposed.For the power grid with strong system frame structure,the transformation scheme of neutral point through small resistance is proposed,which provides a reference for the reasonable selection of the neutral grounding mode 10 kV distribution network in large cities in China.For the resonant grounding system which is not suitable for modification,a new method of capacitive current measurement is proposed,which can effectively improve the accuracy of arc suppression coil tuning and ensure the safe and reliable operation of the system.