【摘要】 当永磁机构真空断路器投切电容器组、空载长线等容性负载时,若随机进行投切,通常会产生很大的涌流和过电压。为了减小涌流和过电压,通常采用同步关合技术以实现选相分合。考虑到实际的同步关合技术控制,给出包含程序运行时间的同步关合时序。采用FIR数字滤波对电压信号中的谐波进行滤除,获得基波电压,用以检测电压波形的过零点。当断路器介电绝缘强度降低时,在关合过程中通常会发生预击穿,导致断路器不在预先设定的相位关合。为此分析介电绝缘强度衰减率对最佳相位选择的影响。在预测合闸时间时,采用平面点法式方程算法计算结果与实际的合闸时间相比,误差在工程允许范围内,证明了该方法是可行的。更多还原

【Abstract】 If capacitors or unload lines are thrown into power system by a vacuum breaker with permanent magnetic actuators randomly, a high inrush current and overvoltage might be stimulated for power system. The inrush and overvoltage would be reduced as the breaker is shut down at an appointed phase angle, which is called synchronous switching technique(SST). Considering the program executing time, this paper proposes the time sequence of SST involving the executing time of programs. And a FIR digital filter is utilized to remove harmonics for detecting the zero crossing of voltage wave. The pre-strike happens as the dielectric strength of breaker reduces and it leads to an unexpected close of breaker. So the relation between the decreasing rate of dielectric strength and the target phase is analyzed. The point french equation algorithm is employed to predict the closing time of breakers and the calculated closing time is compared with experimental results. It is proven that the proposed method is feasible and the error meets the needs of engineering.更多还原