550 kV快速断路器气流场仿真与开断性能

Simulation of Airflow Field and Breaking Capacity of 550 kV Fast Circuit Breaker

快速断路器能够显著缩短开断时间,提高系统暂态稳定性,保证电力系统的安全稳定运行。为此提出快速断路器灭弧室结构设计方案,建立磁流体动力学(magnetohydrodynamics,MHD)电弧数学模型,计算不同燃弧时间的快速断路器开断过程气室压强、喷口气流速度和电弧温度变化趋势,对比分析气压特性、电弧电导、弧后电流等关键开断参量,综合评估快速断路器开断性能,确定样机设计方案。研究结果表明:分闸速度11.7m/s、超程33 mm、充气压强0.65 MPa的灭弧室设计方案,具备7 ms短燃弧、11.5 ms中燃弧和16 ms长燃弧开断能力。样机顺利通过了T100(a)开断试验,短燃弧时间为7.4 ms、中燃弧时间为10.8 ms、长燃弧时间为16.1 ms,验证了仿真计算的有效性。该550 kV快速断路器成功将开断时间缩减至25 ms以内,对提高电网稳定性、可靠性具有重大意义。

The high voltage and large capacity fast circuit breaker can significantly shorten the breaking time,improve the transient stability of the system,and ensure the safe and stable operation of the power system.Therefore,we proposed a design idea and overall scheme of fast circuit breaker.Based on the magnetohydrodynamics theory,a multi-physics arc mathematical model suitable for fast circuit breaker was established.Multi-field coupling simulation calculation was carried out for the breaking process of the circuit breaker under different arcing time.The gas pressure,velocity and arc temperature inside the compression chamber and the nozzle were calculated,and the pressure characteristics,arc conductance and post-arc current were compared and analyzed.The breaking capacity of fast circuit breaker was evaluated and the prototype design scheme was proposed.The research results show that the design scheme of the arc chamber with the opening velocity of 11.7 m/s,the overtravel of 33 mm,and the inflation pressure of 0.65 MPa has a breaking capacity of 7 ms,11.5 ms and 16 ms arcing time.The T100(a)breaking test of the prototype is carried out,and the short,medium and long arcing time are 7.4 ms,10.8 ms,and 16.1 ms,respectively,verifying the effectiveness of the simulation calculation.The breaking time of the 550 kV fast circuit breaker is reduced to less than 25 ms,which is of great significance for improving the stability and reliability of the power grid.