Research On Harmonic Source Identification Method Based On Harmonic State Estimation

The importance of power quality for the whole society is obvious, it is urgent to guarantee the power quality to suppress harmonic wave. Harmonic not only affects the quality of power supply of power grid, but also pose a threat to the safety of the user,So how to find the harmonic source has become a big issue. Modeling and calculation are the key of harmonic state estimation.This paper introduces the related basic knowledge of power system, understands t he components of the power grid, explains the process of establishing power grid harmonic state equation, gets the measurement data by using phasor measurement an d filters measurement data according to the error, the node voltage equation and the i njection current equation are established by using the harmonic current as state variabl e and the the harmonic voltage as in the measurement under the condition that load a nd line parameters have kown. After that, the equations are solved by optimization alg orithm.According to the condition that whether load node is suspicious and whether su spicious node is measured, the state variables without considered are removed and the equations showed by using known measurement and power grid parameters are simpli fied.Then the phasor equation turn into two sets of equations about real part and imag inary part to speed up the operation. finally harmonic estimation values are find out simulation is carried out by using the IEEE-14 network.Then load harmonic source is identified according to the estimation value of har monic state estimation. the several commonly used harmonic source identification meth ods are studied such as the direction method of harmonic power and the identification method of load parameters in this paper. The advantages and disadvantages of inject ion harmonic active power and reactive power are analyzed and the method of harmo nic source identification based on harmonic state estimation is proposed on the basis o f nonlinear load impedance imaginary part and symbolic relations of the injection har monic active power and reactive power. Compared with the method of the method of harmonic active power direction identification,the method of harmonic source identificat ion based on harmonic state estimation have higher veracity and the calculation is sim pler.After harmonic source identification, it's necessary to consider the pollution liability issue of user side and grid side.The last part, harmonic responsibility division index of the improvement process are briefly introduced, from a single extended to multiple harmonic sources harmonic source condition, the connections and the circuit simulation calculation. At last, the basic requirements of harmonic pollution liability index is put forward combining with calculation example.