【摘要】 针对RTDS小步长模型应用的难点。建立了SSSC的小步长(<2μs)仿真模型,其SSSC采用H桥级联加单相耦合变压器的主电路接线方式,调制方法为可在线计算逆变器触发角的阶梯波调制,控制策略为恒阻抗控制。针对RTDS建模的特点,探讨了建立电压源逆变器小步长仿真模型的几点注意问题,给出了建立H桥级联式SSSC的RTDS模型的具体实现方法。对比分析不同运行工况下RTDS模型与EMTDC/PSCAD4.02模型的仿真结果,验证了所建立的SSSCRTDS模型的正确性。更多还原

【Abstract】 Static Synchronous Series Compensator (SSSC) is a sort of FACTS equipments based on the series Voltage Source Converter (VSC). The small-step (<2μs) model of SSSC is built in RTDS in this paper. The main circuit structure of SSSC consists of cascaded H-bridge units and single-phase coupling transformer. Because of the simple and independent connection among three phases, it is easy to present the unbalanced compensation. The modulation strategy of SSSC which adopts staircase modulation can be got on-line; it uses equal area principle to calculate the trigger angels in this way. Constant impedance strategy is also applied, namely the output voltage of SSSC is proportional to the line current in amplitude and leads or lags the line current by π/2. Details for building cascaded multilevel SSSC model in RTDS are shown in this paper; in addition, there are also some tips about how to present the small-step simulation of VSC. Firstly, the VSC module must be arranged suitably on the allowable simulation scale. Secondly, the special transformer has to be used at the interface between large step model and small step one. Thirdly, in order to avoid the "stiff" instance of the interface, the VSC breaker must substitute for the large step side breaker. Finally, the division module must be set properly in that the dividend may equal to zero. Moreover, the results including indices such as P, Q, current of line, modulation index and output voltage under different running conditions have proved that the model in RTDS is almost perfect by comparing with the results got in EMTDC/PSCAD4.02.更多还原