基于功率和电压组合分段的变电站无功控制

为了防止变压器分接头频繁动作,提出根据有功、无功和系统电压组合分段的方法来进行变电站电压无功的优化控制。该方法采用人工神经网络预测负荷和系统电压,并用计算潮流的方法计算出变压器低压侧归算到高压侧的电压,然后依此电压按变压器分接头动作次数的限制进行初步组合分段。因电压质量比分接头次数的限制更为重要,如果初步组合分段后的电压合格率不满足要求,则将电压合格率最低的段分为两段重新优化,直到满足要求为止。对于电容器,为了减少有功和电压损耗,在不发生倒送无功的情况下应尽量多投入。但在负荷较轻、系统电压太高时则应全部退出。此外,电容器可轮换投切,故对动作次数无需再限制。工作时依据已发生的实际数据,重新预测后续值并修正分段以使控制更切合实际。该法克服了仅按照有功或无功分段的缺陷,提高了控制的准确性。仿真算例证明了该法的有效性。

Substation Voltage & Reactive Power Control Based on Combined Sections of Power and Voltage

In order to limit tap operating times of transformer in a period of time, a strategy for substation voltage & reactive power control based on combined sections of active, reactive load and system voltage is proposed in this paper. Forecast active, reactive load and system voltage in a period of time of future using an artificial neural network short term load forecasting method firstly, and calculate the voltage of low voltage side of transformer which is converted to high voltage side of transformer with power flow calculating method. Then, divide the voltage into several primary combined sections according to the maximum of tap operating times in a period of time. The voltage quality is more important than the limit of tap operating times of transformer. If the eligibility ratio of voltage after optimizing in every combined sections can't fit the demand, divide the section whose eligibility ratio is lowest into two ones, then optimize in the new two sections until the eligibility ratio of voltage is eligible. For capacitors, in order to reduce load and voltage loss, it is necessary to turn on more ones if there no reactive power moving backward and turn all off if load is low and system voltage is too high. Otherwise, capacitors could turn on or turn off by turns, so their operating times is not need to limit. In the fieldwork, it is necessary modify load and voltage forecasting data with actual data of past sections if forecasting data is far away from actual data, and forecast them again, then calculate, divide and optimize again, so that the control measure should be more proper. The combined sections of active, reactive load and system voltage based optimizing and controlling method overcomes the disadvantage of method only considering active or reactive load, and improves the accuracy of voltage & reactive power control.