适应电网快速调频的热电联产机组新型变负荷控制策略

Load-change Control Strategy for Combined Heat and Power Units Adapted to Rapid Frequency Regulation of Power Grid

大型发电机组的一次调频特性对电力系统频率稳定与电能质量至关重要。热电联产机组热网中存储了大量蓄热,在短时间内利用这部分蓄热可以显著改善机组的调频性能而又不影响热用户需求。建立了机组释放蓄热的静、动态模型与热电耦合特性模型,提出了"供热抽汽快速动作、锅炉燃料精准追踪、供热抽汽缓慢恢复"的快速变负荷控制思路,并据此设计了供热抽汽调节与传统协调控制相结合的新型变负荷控制方法。以某330MW机组为例进行了仿真验证,结果表明所提出的控制策略实现了供热抽汽的快速调节与主动恢复,缩短了机组跨出负荷响应死区的时间,提升了机组的变负荷速率,有效改善了机组的自动发电控制(AGC)性能。

The performance of primary frequency control has a significant influence on the power system stability and power quality.There are plenty of heat stored in the heat supply network of combined heat and power（CHP）units,which can improve the unit load-following performance without affecting the heat demand in a short time period.The static and dynamic model of heat extraction adjustment together with heat-power coupling model are set up.A new load-change idea according to the way of＂rapid heat extraction adjustment,accurate fuel supply following,and steady heat extraction recovery＂is proposed.A new load-change control strategy combining heat extraction adjustment and traditional coordinated control is given.A330 MW CHP unit is taken as an example to verify the idea,and the results show that the strategy proposed can shorten the dead time of load response,quicken the load-change rate,and improve the performance of automatic generation control（AGC）through rapid regulation and active restoration of heat extraction.