哈郑特高压直流送端电网静态电压薄弱点研究与无功补偿

Study on the Weak Point of Static Voltage of Transmission End in Hazheng UHVDC Transmission System and Reactive Power Compensation

随着风电场容量的不断增大,大规模风电出力的强波动性会影响接入地区电网的电能质量。因此,风电场接入系统时,必须结合所接入地区电网的实际情况和风电场无功补偿等因素进行综合分析。首先,推导了风电并网时静态电压稳定机理,通过连续潮流法,利用DIg SILENT电力仿真软件绘制哈密地区风电场的P-U、Q-U曲线;其次,根据所得数据,运用多属性综合评价法计算哈郑直流送端电网的电压薄弱点;最后,在电压薄弱点对比3种无功补偿方式对静态电压稳定性的影响。仿真结果表明所提出的计算电压薄弱点的方法具有计算量小、灵活性强等优势,在电压薄弱点加入无功补偿装置可以可满足哈郑送端地区风电外送要求,提高系统静态电压稳定极限,是一个很好的方法。

With the constant increase of capacity of wind farms,the strong fluctuations of large-scale windpower will affect the power quality of regional grid. Therefore,in case of wind farm connecting to the sys-tem,our comprehensive analysis must be performed as per the actual situation of the grid at the connectedregion and the reactive power compensation of wind farm etc. Firstly,the static voltage stability mechanismin case of interconnection of the wind power is deducted and the P-U and Q-U curves of the wind farm inHami area is plotted through the continuous flow method and also by the use of DIg SILENT electric simula-tion software. Then,the weak point of the voltage of the transmission end network of Hazheng HVDC is cal-culated as per the obtained data and also by the use of multiple attribute comprehensive evaluation method.Finally,the influence of three types of reactive power compensation modes to the stability of static voltageis compared at the weak point of the voltage. It is shown by the simulation result that the proposed methodto calculate the weak point of voltage has such advantages as small calculation amount and strong feasibilityetc and,addition of reactive power compensation device at the weak point of voltage can meet the powertransmission requirement of wind power of Hazheng line and improve static voltage stability limit of the sys-tem,it is a very good mentnod.