采用阻尼电阻并接模型的主动式抑制、消除PT铁磁谐振方法

Active Suppression and Elimination of PT Ferromagnetic Resonance Using a Damping Resistor Parallel Model

中性点不接地系统中,由于对地容抗与电磁式电压互感器感抗的不利组合,在系统电压出现大扰动时,常常会产生铁磁谐振现象,造成PT损坏。对此,提出一种采用阻尼电阻并接模型抑制、消除PT铁磁谐振的方法,于PT开口三角处并接阻尼电阻并接模型,利用阻尼大电阻实现提前抑制高频谐振;通过分析PT一次零序电流和开口三角零序电压,区分单相接地故障和谐振,控制阻尼小电阻投入消除谐振。利用MATLAB/Simulink建立的仿真模型验证了所提出的方法的可行性。

In ungrounded neutral systems,due to the unfavorable combination of ground capacitance and electromagnetic voltage transformer inductance,ferromagnetic resonance often occurs when the system voltage undergoes large disturbances,resulting in PT damage.To this end,a method of suppressing and eliminating PT ferromagnetic resonance by using a damping resistor parallel model is proposed.The damping resistor is parallelly connected to the model at the PT open triangle,and a large damping resistor is used to achieve early suppression of high-frequency resonance.By analyzing the PT primary zero sequence current and open triangle zero sequence voltage,single-phase grounding fault and resonance are distinguished,and the damping small resistor is controlled to eliminate resonance.A simulation on model established by MATLAB/Simulink verifies the feasibility of the proposed method.