有源滤波器电流差动保护方法研究仿真

摘要

It has great significance in aspect of improving service life of filter to protect the current differential of active power filter.The fluctuation of various loads makes the voltage of the common coupling point of active powder filter generate large fluctuation.The distributed capacitance current influences the current differential protection of traditional method easily.It leads to big judgment error and inaccurate protection.This paper proposes a protection method for current differential of active power filter based on instantaneous power theory.Firstly,the Fourier transform is used to three-phase instantaneous current at two ends of voltage circuit in filter.Then,the low-pass filtering is used to transformed current to obtain the active current component of three-phase fundamental wave at two ends of circuit.Finally,the relationship between power loss and DC side voltage of active power filter is given out and the protection scheme for current differential of active power filter is presented.The simulation results show that the method mentioned above has good protection performance.%对有源滤波器的电流差动进行保护,在提高滤波器使用寿命方面具有重要意义.由于各种负载的波动,使得有源滤波器公共耦合点电压产生较大波动.传统的有源滤波器电流差动保护方法,电流差动保护容易受到分布电容电流的影响,导致判断误差大、保护不准确的问题.提出基于瞬时功率理论的有源滤波器电流差动保护方法,首先先对滤波器电压线路两端的三相瞬时电流进行傅里叶变换,并对变换后的电流进行低通滤波,获取线路两端的三相基波有功电流分量,然后给出的有源滤波器功率损耗和直流侧电压之间的关系,设定了有源滤波器电流差动保护方案.仿真结果表明,所提方法保护性能较强,能够有效地完成对有源滤波器电流差动保护.