Reason Analysis Of The Spark Gap Self-trigger Of Series Compensation Capacitor System

The transient stability problem limits the transmission power of EHV long distance transmission lines,which seriously affects the transmission capacity of EHV transmission system.So,the researchers put forward the technical measures to install the series compensation capacitor system in the transmission line.Using series capacitance compensation line reactance,the electric distance of line is shortened,the transient stability of transmission system is improved,and transmission capacity is improved.But last few years,the spark gap of series compensation systems has been self-triggered several times,resulting in series of bypass,the problem of self-triggered of the gap poses a threat to the safe and stable operation of the power grid,especially the out-of-area fault.A transmission line fault,resulting three series compensation capacitor systems self-triggered at the same time?That made a very bad effect about the power transmission limit of the power system,the problem of self-triggered spark gap should be solved as soon as possible.In order to find the reasons of spark gap self-triggered of series compensation capacitor system,according to the composition of the spark gap and working principle,Through a series of tests about the self-trigger voltage of trigger gap,parameters of equalization capacitor and breakdown characteristics of forced trigger type spark gap,test results show that the breakdown voltages of the main gap of the spark gap have great dispersion if the surface of the graphite electrode has burr,water or pollutions,and the lowest AC breakdown voltage is about 65%of normal value,it is found that pollutions on the surface of graphite electrode are root reasons of the spark gap self-triggered.The research results of this project,not only find out the sreasons of the spark gap self-triggered,but also put forward the improvement measures to strengthen the operation and maintenance of the spark gap,which is helpful to improve the reliability of the series compensation capacitor system.