振荡中心侵入机群场景下的刚性外推策略  

Inflexible extrapolation strategy when oscillation center into generator group

作　　者：李振兴[1] 王振宇 翁汉琍[2] 王露 谢志豪 LI Zhenxing;WANG Zhenyu;WENG Hanli;WANG Lu;XIE Zhihao(College of Electrical Engineering and New Energy,China Three Gorges University,Yichang 443002,China;Hubei Provincial Key Laboratory for Operation and Control of Cascaded Hydropower Station,China Three Gorges University,Yichang 443002,China)

机构地区：[1]三峡大学电气与新能源学院,湖北宜昌443002 [2]三峡大学梯级水电站运行与控制湖北省重点实验室,湖北宜昌443002

出　　处：《电力自动化设备》2020年第9期110-117,共8页Electric Power Automation Equipment

基　　金：国家自然科学基金资助项目(51607106);三峡大学学位论文培优基金资助项目(2019SSPY050)。

摘　　要：大规模电力外送基地机群失步场景下,振荡中心易侵入机群内部,仍采用现有发电机失步保护应对策略将可能导致机组"雪崩式"切机。从切机切负荷有损控制入手,提出了一种通过调整负荷或机组数量维持系统稳定性的振荡中心刚性外推策略。针对振荡中心落入电力外送基地某机群场景,从理论上分析了该刚性策略的可行性;推导了系统内任意一点处电压幅值的解析表达式,并结合振荡中心处的电压特性,得到中心位置表达式;基于此,在振荡中心外推出机群条件下对受端系统负荷或对侧机群机组切除数量进行预测,制定防止过切的约束,进一步判断系统的稳定性,并确定源荷调整有效范围。最后,基于PSCAD/EMTDC仿真软件建立多机并联外送系统仿真模型,通过仿真验证了系统失步过程中发电机失步保护阻抗轨迹和功角变化,采取外推策略后振荡中心外推出机群且功角趋于稳定,该结果说明了所提策略的有效性。The oscillation center is easy to invade the interior of generator group in the case that the genera⁃tor group is out-of-step in large-scale power transmission base.At present,the response strategy of genera⁃tor out-of-step protection may lead to cut generators like an avalanche.An inflexible extrapolation strategy for the oscillation center is proposed to maintain the system stability by adjusting the load or the number of power units.The feasibility of this strategy is theoretically analyzed based on the scenario that the oscil⁃lation center falls into the power transmission base.The analytical expression of the voltage amplitude at any bus is derived,and the expression of the center position is obtained by combining the voltage charac⁃teristics at the oscillation center.On this basis,when the oscillation center is operated out of the cluster,the load at the receiving bus or the number of units that are cut off from the opposite cluster is predicted.At the same,the constraints are made to avoid overcutting.Furthermore,the system stability is analyzed and the effective range of source and load adjustment is determined.Finally,based on PSCAD/EMTDC simulation software,a simulation model of multi-generator delivery system in parallel is established.The variation of generator out-of-step protection impedance trajectory and power angle during system out-of-step is verified by simulation.The proposed strategy ensures that the oscillation center is operated out of the cluster and the power angle is stable,which verifies the effectiveness of the proposed strategy.

关 键 词：大规模电力外送基地 振荡中心 刚性策略 源荷调整 发电机失步保护 

分 类 号：TM772[电气工程—电力系统及自动化] TM