电机电源切换冲击扰动机理分析及防护

Study on transsient response due to fast reclosing of the electrical sources of the motor

以交流电动机为例 ,进行理论分析 ,研究了电机系统电源和后备电源快速切换引起的冲击扰动问题 .模拟实验证明电源快速切换引起的冲击电流远大于电机设备常规起动电流 .该扰动冲击可使电力电子设备损坏 ,线路保护装置误动作 ;电机电源快速切换会造成瞬态电磁转矩值大范围波动 ,影响系统工作特性 ,降低设备使用寿命 .文中提出了电压周波过零快速切换的控制方案 ,它有助于减少系统电源和后备电源切换引起的冲击扰动 。

During the fast reclosing operation, the current and torque developed in an induction motor can be several times larger then than the staring current and torque. The transient response caused by the fast reclosing of the electrical sources of the motor system was investigated. This paper presents a performance analysis of fast reclosing transients in induction motors showing that the optimum time instant for reclosing depends on the supply voltage and load parameters. This transient response can prevent electronic devices in the system from working normally and can disable the circuitry\|protecting devices. Consequently, provision of a controlling means to switch the periodical voltage wave over the zero\|point is most valuable for resolution of this problem. In the reclosing operation, the induction motor reaches steady\|state mode of operation faster than the starting mode.