考虑RAML环节的特高压直流整流侧动态响应特性及其对送端交流电网稳定性影响

Dynamic response characteristic of rectifier side of UHVDC considering RAML link and its influence on the power angle stability of sending side power grid

计及整流侧最小触发角限制(RAML)环节的影响,对特高压直流工程在整流侧交流故障情况下的控制行为及响应特性进行了分析。首先,在PSCAD/EMTDC中搭建了与实际直流工程控保逻辑一致的直流输电模型,基于该模型探讨了RAML控制环节在系统暂态过程中对直流送端响应特性的影响。分析结果表明,当整流侧控制保护系统中配置了RAML环节,在交流电压恢复期间,直流电压和直流电流的超调现象被消除。然而,由于RAML环节的作用系统直流电压、直流电流以及直流有功功率的恢复速度也相应变慢。同时,换流器吸收的无功功率也会较无RAML环节时更多。其次,基于EEAC理论,分析了RAML环节的配置对送端交流电网功角稳定性的影响。最后四川电网算例表明了结论的有效性。

The control activities and response characteristics of UHVDC projects subjecting to AC system faults at the rectifier side are studied, considering the effect of Rectifier Alpha Minimum Limiter link（RAML）. First, an HVDC system model which has the same control logic as that used in a real UHVDC system is built in PSCAD/EMTDC. Based on this model, the effect of RAML on the dynamic responses of the rectifier side during transient process of the system is investigated. The analysis results show that, with RAML, the overshoot of the DC voltage and DC current is avoided. However, the recovery speed of the DC voltage, DC current as well as the active power delivered by the HVDC link is slowed down. Furthermore, with RAML, the converters will consume more reactive power. Second, the effect of RAML on the angle stability of the AC system at the sending end is analyzed based on EEAC theory, and the analysis results are verified by simulations on Sichuan power system.