【摘要】 为解决光伏接入电网引起的并网点电压越限问题,增大光伏在电网中的渗透率,可充分利用并网光伏逆变器的无功调压能力向电网提供无功支撑。为此,从电网电压降落角度研究光伏发电接入电网前后并网点电压的变化,并深入分析了德国电气工程师协会(Verband Deutscher Elektrotechniker)提出的无功功率控制策略,在此基础上,提出一种基于并网点电压幅值与光伏有功出力的Q(U,P)无功功率控制策略。该控制策略继承了德国电气工程师协会提出的策略的优点,在此控制策略下,光伏系统所有逆变器参与电网电压调节,在维持电网电压在要求范围的前提下,无功吸收总量最低,电网有功、无功损耗最小。算例结果验证了该策略的有效性。更多还原

【Abstract】 In allusion to out-of-limit voltage at grid-connected point caused by grid-connection of photovoltaic(PV) system and raising the penetration rate of PV system on power grid, it is possible to fully utilize the reactive power regulation ability of grid-connected PV inverter to provide reactive power support to power grid. For this purpose, in the viewpoint of voltage drop the voltage variation at grid-connected point before and after the grid-connection of PV system is researched, and the reactive power control strategy given by Verband Deutscher Elektrotechniker(VDE) is analyzed in depth. On this basis, a reactive power control strategy based on voltage amplitude at grid-connected point and active output of PV system is proposed. This control strategy inherits the advantages of reactive power control strategy given by VDE, and under the proposed control strategy all PV inverters participate power grid voltage regulation, and under the premise of maintaining the grid voltage within the specified range the total absorbed amount of reactive power is the lowest and the active and reactive loss of power grid are minimized. The validity of the proposed control strategy is verified by case study results.更多还原