Research On Reason Analysis And Restrain Measures Of 10 KV PT Burning In Substation

Voltage transformer is the electrical equipment which connects the primary system and the secondary system of the power grid.It is installed on each node of the power grid to provide the voltage information of the primary system to the secondary system for operation monitoring.When single-phase grounding fault occurs in ungrounded power grid,it is a very important research topic to study the mechanism of abnormal damage of voltage transformer and its suppression measures.At present,in the distribution network of power system,the burnout of 10 kV voltage transformer or abnormal fuse of high voltage fuse are very common.If effective measures are not taken,it may cause equipment damage,more serious power system accidents,and even personal safety accidents in the process of operation and maintenance of equipment.In view of this problem,it is of great practical significance to study the causes of burnout and formulate and implement corresponding suppression measures for the safe and reliable operation of 10 kV distribution network.Based on the investigation of single-phase grounding fault of Shuiquan 66 kV substation in Tuquan area of Xing'an League,this paper studies the causes of burning down of 10 kV voltage transformer and its suppression measures.The main contents of this paper are as follows: First,the purpose and significance of this study are put forward,and the research on burning mechanism of voltage transformer by experts and scholars at home and abroad is summarized.At the same time,the restraint measures adopted at this stage are also discussed.Secondly,three kinds of neutral grounding modes in 10 kV distribution network system are introduced,and the transient process of single-phase grounding fault occurring and disappearing is analyzed emphatically.Through circuit principle analysis and corresponding formula deduction,the causes of fault occurring in neutral non-grounding system are analyzed in depth.Thirdly,the grounding transfer device of low excitation impedance transformer is introduced.The principle and related key technologies are introduced in detail.Fourthly,the scheme of field experiment for active intervention arc suppression device is introduced,which takes the 66 kV Shuiquan substation and Duerji substation in Tuquan area as the pilot.Through the experiment of two instantaneous single-phase grounding faults,i.e.artificial fault point and natural fault point,both of them can achieve rapid arc extinguishing and meet the requirements of safe operation.Fifth,it summarizes the full text and points out the shortcomings of this topic.The proposed scheme has been put into operation in Shuiquan and Durkey transformers.Field operation shows that the proposed scheme can significantly suppress the burnout of voltage transformers and high voltage insurance fuses caused by single-phase grounding faults.At the same time,it greatly improves the fault handling capacity and reduces the harm caused by line fault,which provides an important basis for further optimization and upgrading of distribution network in Tuquan area of Xing'an.