The Research On Harmonic Current Analysis And Processing Method Of The Fourth District Power System Of Changgang Company

Lots of high harmonic such as arc furnace, rolling mechanical, high-power rectifier which is produced by the nonlinear harmonic source load result in serious harmonic pollution as well as unsafety operation of the load and power-supply system, so the research on the harmonic is more and more valued. Early harmonic compensation is completed by the passive filter which can not implement perfect and random management for its design principle and the intrinsic defects, while the active filter can conquer the defects but its capacity is very small. The appearance of the high-power electronic devices makes it possible to implement the active power filter. And the essential condition is to work out the compensation signal through detecting the system current. In this paper, Based on fully analyzing many connecting ways of Active Power Filter with LC filter. We choose the Shunt Active Power Filter with LC Filter. And we set the stage for implement the active filter by using Digital Signal Processor (DSP) to select out the harmonic compensation signal in the collection source signals and convert it to the output current analog signal as the controlling signal of the linear power filter.The hardware circuit of harmonic compensation signal is composed of the DSP device TMS320C5410, the analog interface circuit TLC320AD50C and the signal adjustment circuit. The algorithm is based on the Fourier trigonometric series to work out the difference between the master signal and fundamental wave as well as direct current. The analog Phase Lock Loop (PLL) in the TMS320C5410 can reduce the negative influence to the measurement precision due to the changing of the alternating current frequency, and make the negative influence to the measurement precision very small when the input signal changes in the wider frequency scale. Sixteen-bit ADC and DAC channels integrated in the TLC320AD50C which has a interpolated filter before the DAC to make sure the smoothness of the output signal and an abstracted filter to improve the Signal Noise Radio (SNR) of input signal. When the frequency division of the TMS320C5410 is 100MHz, 50Hz industrial frequency signal is sampled 64 points in one period (20ms). When the frequency division is 100MHz, the order period number is 875500 worked out by the CCS and the time is 8.8ms, which can implement the compensation signal completely in an industrial frequency period. In the course of research, the programme algorithm is developed, debugged, downloaded by CCS, then simulated and operated in the computer and experimental board developing system. The...