Research On Statcom In Distribution System

The current development of static synchronous compensator, DSTATCOM, is discussed in this paper, and the operation principle of DSTATCOM is analyzed through its circuit structure, then the mathematical model is established based on the equivalent circuit. The mathematical model demonstrates that either adjusting the control angle individually or adjusting both the control angle and the modulation index can compensate reactive power dynamically.In this paper, the main circuit and the control system of DSTATCOM is built. The control system is composed of two parts; the VSI unit based on the DSP(TMS320LF2407A), and the reactive power detecting unit based on the MCU, C8051F021.In the detecting unit of reactive power, the correlation theory is used to extract the synchronous signal of the utility, which avoids the effect of harmonics on detecting precision and correctness from the harmonics; Compared with the result from power analyzer HIOKI 3166, the method proposed in this paper is testified to be correct.As the control strategy of DSTATCOM, aiming to the poor dynamic performance in general control strategy, a novel strategy based on the critical station and prediction table is proposed. The experimental results show that the improved strategy has a faster dynamic response and a more stable transferring process.