Power Network Harmonics Dynamic Detection And Measures

The harmonics of the power system have become a serious problem in many countries. The use of nonlinear loads such as static power converters has deteriorated power quality in power transmission/distribution systems. Active power filter is rapidly developed as an advanced power electronic device, which can be used for integrated compensating harmonic, reactive current.Based on both neural network theory and instantaneous reactive power theory, a new control method for active power filter is presented and the source current spikes that occur due to sudden changes in load current are eliminated. This method measures the first derivative of the load current in real time to judge if there is a sudden change in the load current. If there is, the neural network program module will be put into operation to control the harmonic current compensation. The neural network program module is trained off-line, and uses error back propagation (BP) algorithm, which is realized through a three-layered feed forward neural network module.Studies on the main circuit of active power filter are developed and the calculating method for the parameters of the power electronics elements and their peripheral circuits are given.In this paper, the results of simulation in SIMULINK environment of MATLAB and practical experiment indicate validity of the mixed method...