Technical Research On Distribution Static Synchronous Compensator

As one of new technology of reacetive power compensation, the static synchronous compensator on the distribution side is a good solution to solving the problem of power quality.For compensating the reactive power of the three-phase four-wire system in distribution side, the background and development status of the reactive power compensation at home and abroad is analyzed at the first beginning of this thesis. Based on the major circuit topology and the basic operating principle, four kinds of operating mode are introduced. Moreover, major parameters of the elements are caculated and selected. Two kinds of methods for reactive and harmonic current detecting are also compared. In the end, the zero sequence separated algorithm based on the instantaneous reactive power theory will be much more suitable for the three-phase four-wire system.According to present control algorithm of D-STATCOM, the PWM hysteresis-band control is slected as one of the control strategy. PI regulation is slected as the control method of the voltage on DC side.Besides, some hardware circuits of the D-STATCOM are designed, including the synchronization sampling circuit, the IGBT driven circuit, the communication module, the display circuit, the power supply circuit, the switch input and output circuit and so on.From the results of the simulation and experiments, the D-STATCOM based on these control strategy is good enough in dynamic reactive power compensating, system balancing and power factor improving.