基于电流平均值的改进无功检测法

Improved Reactive Detection Approach Based on Current Average

由于非线性负载在电力系统中的广泛应用,电网中无功与谐波污染越来越严重,对电网的稳定运行产生了不利的影响,因此,能够快速、准确地检测出无功与谐波电流并给予适当的补偿显得尤为重要。首先,引入一种基于瞬时无功功率理论的改进检测技术来替代传统的无功电流检测法,该方法去除了锁相环,简化了硬件电路的设计;其次采用电流平均值的滤波方法来克服低通滤波器类型、阶数以及截止频率对响应速度的影响;最后利用Matlab/Simulink软件搭建了检测电路的模型,通过对三相电源电压无畸变以及有畸变情况下的仿真来验证改进检测的有效性。仿真结果表明所提出的方法不仅具有检测精度高的优点,而且具有良好的动态响应。

Due to the wide application of nonlinear loads in power system, reactive and harmonic pollution in the grid is getting serious, which influences the stability of power grid operation. Therefore, it is important to detect the reactive and harmonic currents and compensate for them appropriately. First, an improved detection method based on the instantaneous reactive power theory is introduced to replace traditional reactive current detection method, which eliminates phase-locked loop and simplifies the design of hardware circuit. Then the filtering using current average is adopted to overcome the impact of the type, order and cut-off frequency of the low-pass filter on response speed. Finally, Matlab/Simulink software is used to build the model of the detection circuit, and three-phase supply voltages with and without distortion are simulated respectively to verify the validity of the improved detection method. The results show that the proposed method has high accuracy and good dynamic response.