A Liability Division Method For Harmonic Pollution Based On Branch-Transferred Power Components

With the development of modern industry and the use of a large number of power electronic devices, the harmonic sources and the cause of harmonic pollution have been increasing in power network. They seriously influence the normal work of sensitive loads and precision devices in the grid. For harmonic pollution, the pollution liability must be divided to achieve the most effective management and ensure the long-term quality of power quality. Therefore, in power network with the coexistence of several harmonic sources, a fair and reasonable liability division method of a source for harmonic pollution has important theoretical and practical engineering significance.One method is proposed based on branch-end-transferred complex power component to divide the harmonic pollution liability. At first, the branch-end-transferred power component owing to a source under all sources action together is determined by the theory of linetransferred power components, and called transferred power component including active component and reactive power. Then, the ration of projection of the source's branch-endtransferred complex power component to absolute value of the total branch-end-transferred complex power is used to divide the harmonic pollution liability.Another method is proposed based on branch-end-transferred active power component to divide the harmonic pollution liability. On the basis of the first method, the ration of the source's branch-end-transferred active power component to the total branch-end-transferred active power is used to divide the harmonic pollution liability.For the two methods based on branch-transferred power components, MATLAB programming is used to realize the simulation calculation.The effectiveness of these two methods is verified by comparing with the results of existing typical methods.The theoretical analysis and simulation results show that, firstly, the liability division methods for harmonic pollution based on current or voltage consider the harmonic electrical characteristics only from current or voltage, whose fairness and rationality are incomplete. Secondly, the method based on single excitation power component achieve the power component of a harmonic source according to superposition theorem, whose fairness and rationality are also not ideal because power does not meet the superposition theorem. Lastly, two methods on the basis of branchend-transferred complex power component and branch-end-transferred active power component to divide the harmonic pollution liability, are based on the branch-end-transferred power component owing to a source under all sources action together, which realize the liability division for harmonic pollution according to the natural result of circuit rule and are thus fair and reasonable naturally. Considering that active power component has more explicit physical meaning comparing with the complex power component, therefore the liability division method for harmonic pollution based on line-transferred active power components is the most ideal one.