Research On Voltage-Sharing Measures Of AC Filter Multi-break Circuit Breaker In Converter Station

In the process of direct current transmission,in order to avoid the harmonics generated by the rectification station or the inverter process of invading the AC system,the AC filter banks needs to be installed on the AC side of the converter station.The filter circuit breaker will withstand the interaction of AC and DC voltages when breaking the filter bank.The multi-break circuit breakers have different voltages in different breaks after breaking,and the current voltage equalization measures can no longer meet the actual needs.In this paper,a 1000 kV converter station model on the AC side is established,and the transient recovery voltage generated by the breaking filter bank of normal and fault conditions is analyzed.The effects of different fault condition on the AC system side and the time of different resection faults with the transient voltage of the filter breaker is analyzed.Finally,the breaking condition of the breaking filter group is the most serious,and then voltage distribution of each break of the four-break circuit breaker is analyzed.In this paper,the voltage distribution characteristics of the porcelain-cylinder four-break filter circuit breaker are studied.Firstly,the electrostatic field simulation of the four-break SF6 circuit breaker is carried out to establish the electrostatic field model.The series static voltage distribution characteristics of the AC filter series circuit breaker are obtained,and the potential,electric field distribution characteristics and distributed capacitance parameters are obtained.Secondly,the ATP-EMTP simulation software is used to establish the dynamic model of the four-break circuit breaker and the transient recovery voltage simulation circuit model.The voltage distribution of each break under capacitive breaking and short circuit is analyzed.Under the capacitive breaking,the influence of the break leakage resistance and the pillar leakage resistance to the voltage distribution is analyzed,and the necessity of the parallel resistance equalization is obtained.Through the simulation,the overall influence law of the RC connection between with the voltage distribution characteristics of the multi-break circuit breaker is obtained,and the parallel RC capacity optimization configuration scheme is extracted.Under the short-circuit breaking,the influence of different post-arc characteristics on the transient voltage distribution is analyzed,and the influence mechanism of the voltage distribution of the initial stages and the stable stage of the transient recovery voltage(TRV)are revealed.TRV distribution characteristics of multi-break circuit breakers under off-state conditions.Compare the voltage division of each break under different equalization measures.Finally,the break voltage distribution test was carried out under a 24 kV two-break circuit breaker.Static powers frequency,high frequency,dynamic synthesis loop voltage test were carried out.Compare the static and dynamic voltage of the two-break circuit breaker under different equalizing measures.In the dynamic breaking,the difference between the dynamic voltage distribution of the synchronous breaking and the non-synchronous breaking are verified,and the difference between the static and dynamic equalizing voltage of the resistance-capacitor parallel equalizing measure is verified.When static power frequency is divided,the capacitance,resistance,resistance and capacitance are all connected in parallel.In the static high-frequency voltage and dynamic high-frequency voltage,the resistance is not affected by the frequency change,and the resistance is not as good as the capacitor equalization when the high-frequency voltage is applied,which verifies the simulation result.