基于无功就地平衡的风电场内部分散决策式精细化无功电压控制策略

Distributed Decision Making and Refined Reactive Voltage Control Strategy for Wind Farm Based on Local Reactive Power Balance

“沙戈荒”大规模汇集系统远离主网,呈现出较强的无功电压敏感特性,风电场整体和内部的无功不平衡在并网送出线路和场内馈线上产生的压差较大,传统的风电场无功电压控制方案难以保证其安全经济运行,为此提出一种风电场内部分散决策式精细化的无功电压控制策略。从无功需求的物理本质出发,详细分析风电场内各元件的无功需求并给出具体计算方法,进而建立风电场分布式多中心无功平衡模型,以非迭代方式直接求解场内各无功电源的无功指令。为衡量场内馈线上不合理无功流动,定义分区无功穿越量的概念,并推导出其计算表达式。算例分析结果表明:风电场内部分散决策式精细化无功电压控制策略能够强化风电场内无功就地平衡,有效改善馈线电压分布,大幅减少馈线上的无功穿越和有功损耗,提高风电场并网运行的安全性与经济性。

The large-scale gathering system of the"desert,Gobi and desertification land"is far from the main grid,exhibiting strong reactive power and voltage sensitivity.The wind farm's overall and internal reactive power imbalance generates a large voltage difference on the grid-connected transmission lines and feeders inside the wind farm.Traditional reactive power and voltage control schemes of wind farm are difficult to ensure their safe and economical operation.Therefore,a distributed decision-making refined reactive power and voltage control strategy within the wind farm is proposed.Starting from the physical essence of reactive power demand,a detailed analysis is conducted on the reactive power demand of various components in a wind farm,and specific calculation methods are provided.Then,a distributed multi-center reactive power balance model for wind farm is established,which directly solves the reactive power commands of each reactive power source in the field in a non iterative manner.To measure the unreasonable reactive power flow on the feeder,this article defines the concept of reactive power pass-through and derives its calculation expression.The analysis results of the example show that the distributed decision-making refined reactive power and voltage control strategy within the wind farm can strengthen the local reactive power balance in the wind farm,effectively improve the distribution of feeder voltage,significantly reduce reactive power pass through and active power loss on the feeder,and improve the safety and economy of wind farm grid connection operation.