特高压交直流混合电网协调电压控制策略及仿真研究

摘要

The characteristics of the UHVDC/AC hybrid grid have put forward new demands on the construction of AVC system. This paper firstly analyzes four operating modes which AVC system needs to cope with when the disturbances occur in the AC gird and the UHVDC grid respectively with different time constants. According to that, the coordinated control strategy including adding the coordinated bus voltage constraints of the converter station, adaptively refreshing the voltage constraints in the AVC system, adjusting the optimal control calculation time as well as control objectives is given. On basis of the continuous AVC simulations on standard IEEE 39 example system and by comparing the system response before and after the coordinated strategy is adopted when the AC and UHVDC grids’ operation modes have changed, the coordinated control strategy will reduce the unreasonable switching times of var compensation equipment is verified. The proposed coordinated control strategy will be applied in Sichuan grid.%特高压交直流混合电网的电压运行特性对AVC系统的建设提出了新的需求。首先分析了AVC系统需应对的当交直流系统分别发生不同时间常数扰动后的四种工况，提出了增加直流换流站母线协调电压约束、自适应地调整AVC系统中母线电压限值、调节优化计算的时刻以及控制目标等手段的协调控制策略。基于AVC仿真平台和IEEE39节点标准算例系统的连续仿真，通过比较当交流和直流系统分别发生方式变更时，采用协调策略前后的系统响应，验证了协调策略可以减少无功补偿设备不合理的投切。提出的协调策略将在四川电网得以实际应用。