级联H桥SSSC的自励启动方法研究

Research of Self-excitation Methods to Start a Cascaded H-bridge SSSC

为实现系统潮流高效可控、提高暂态稳定性和降低投资等工程应用目标,以天津电网220 kV系统现存潮流问题为研究背景,提出静止同步串联补偿器(static synchronous series compensator,SSSC)工程应用的自励启动方案。该文分析了级联H桥多电平结构的SSSC(H-SSSC)并推导了其数学模型,设计单相锁相环,提出新型两级直流稳压策略,其中上层控制得到稳压角,下层控制基于数学逻辑控单个子模块电容电压,结合底层SPWM调制得到触发信号。最后,通过在PSCAD/EMTDC中搭建含SSSC的220 kV天津网等效模型,验证了所提出自励启动策略的合理性和正确性,能够满足系统平稳和快速启动的要求。

To achieve the controllable power flow, improve the transient stability and save investment, a self-excitation startup scheme for the engineering application of static synchronous series compensator（SSSC） is proposed in this paper against the existing power flow problems in the 220 kV system of Tianjin power grid. The cascaded H-bridge multilevel SSSC is analyzed and its mathematical models are deduced. A single-phase locked loop is designed and a novel two-level DC voltage control strategy is proposed, of which the first level control obtains voltage regulation angle, while the second level controls the single sub-module capacitor voltage based on mathematical logic. And combined with SPWM modulation, triggering signal is obtained. Finally, rationality and validity of the proposed self-excitation startup strategy are verified through the equivalent model of the 220 kV Tianjin power grid with H-SSSC built in PSCAD/EMTDC. It meets the system requirements for a smooth and quick start.