“双碳”背景下受端电网火电机组增加调相功能关键技术

随着新型电力系统推进建设，受端电网逐步形成了高比例可再生能源和高比例跨区直流接入的典型特征。在发生直流闭锁、换相失败等故障情况下，受端电网暂态电压支撑需求骤增。由于同步电源开机占比逐渐降低，动态无功资源缺口逐渐加大。静止无功补偿能力较弱，新建调相机成本较高，利用存量火电机组增加调相功能成为技术经济的最优选择。首先分析了“双高”型受端电网的暂态电压支撑需求和调相机的电压支撑机理，并对国内外火电机组增/改调相功能的案例进行了综述。在此基础上，基于河南鸭河口火电机组增加调相功能工程实践，提出了火电机组增加调相功能的关键技术，开辟了一条面向高比例可再生能源接入的受端电网电压暂态支撑能力和存量火电机组利用率提升的有效技术路径。

Key technologies of adding a condenser function in thermal power units in the receiving end powergrid given a background of carbon peak and neutrality

As the proportion of renewable energy increases, the receiving-end power grid has gradually formed the typical characteristics of a high proportion of renewable energy and a high proportion of inter-regional DC connection. In the event of DC blockage and commutation failure faults, the demand for voltage support of the receiving-end grid increases greatly. As the proportion of synchronous power gradually decreases, the gap of dynamic reactive power resources gradually increases. The static var compensation capability is weak and the cost of building a new generation condenser is high. Thus adding condenser function in existing thermal power units has become the best technical and economic choice. This paper first analyzes the transient voltage support requirements of the receiving-end power grid and the mechanism of that support by the condenser. A review of domestic and foreign cases of adding/modifying condenser function in thermal power units is provided. Based on the engineering practice of adding condenser function in thermal power unit in the Yahekou power plant, key technologies are proposed for adding condenser function in thermal power unit. An effective technical path is proposed for the improvement of transient voltage support capacity of the receiving end grid in these conditions.