基于模型识别的配电网谐波源定位方法

Numerous harmonic sources threaten the safe and stable operation of the power system. Therefore, it is of great significance to locate and control the harmonic sources. In this paper, the output characteristics for different types of devices in the distribution network were analyzed firstly. It could be concluded that the non-harmonic sources have linear characteristics and could be equivalent to resistance inductance series circuits, while harmonic sources have nonlinear characteristics and could only be equivalent to nonlinear circuits. Utilizing the obvious nonlinearity and linearity difference between the equivalent models of the harmonic source and the non-harmonic source, the harmonic source could be effectively distinguished from the non-harmonic source. Therefore, the model recognition-based harmonic source location method was proposed. To calculate the consistent degree between the measured electrical variables of the device and the linear model, and a high consistent degree between the two is a non-harmonic source, otherwise it is a harmonic source. Moreover, the nonlinear degree of harmonic source was quantitatively described by defining the fluctuation degree of model recognition results. The proposed method was verified in IEEE 13 bus test system and the test results have indicated that this method could accurately locate different types of harmonic sources and combined harmonic sources, and the defined nonlinearity index could effectively reflect the harmonic contribution of the harmonic source. Finally, compared with the harmonic state estimation-based method and power direction-based method, the proposed method has obvious advantages in positioning accuracy and data requirements.