摘要
为解决大规模光伏电站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,光伏电站应具备较灵活的无功调压能力向电网提供无功支撑。为此,本文建立大规模光伏电站等效聚合模型,在光伏电站未配置无功补偿装置且逆变器无功输出为零的前提下,分析由于线路及变压器阻抗的存在,光伏接入降低电网电压稳定性的问题。基于上述原因,本文从无功补偿装置与并网逆变器相互配合的角度,提出一种光伏电站三层无功功率控制策略。该策略协调无功补偿装置与光伏发电单元之间及单个光伏发电单元逆变器之间的无功输出。在该控制策略下,光伏电站能更有效地调节电网电压,在维持电网电压在要求范围的前提下,电网有功、无功损耗最小。结合光伏阵列降功率运行策略,在光伏电站无功输出能力一定的前提下,确保电网的稳定运行。最后,通过算例验证该策略的正确性和有效性。
Grid-connected PV plants should have independent control of reactive power to support the grid. The equivalent aggregation model of large-scale photovoltaic （PV） plants is established firstly. With the existence of the line and transformer impedance, the grid voltage stability is reduced caused without the reactive power compensation device in PV plants and reactive power of the inverter. The three-level reactive power control strategy is proposed based on the cooperated control between the reactive power compensation device and the inverter. The strategy coordinates the reactive power output among the reactive power compensation devices, PV generation unit and inverters, which regulates the voltage very effectively. Then the grid active and reactive power losses can be minimized while maintaining the voltage in the required range. In order to ensure the stable operation of the grid, the PV array carries out lower power operation strategy when the reactive power output of PV plants is fixed. Moreover, the validity and the effectiveness of the method are validated by means of simulation results.
出处
《电工技术学报》
EI
CSCD
北大核心
2015年第20期168-175,共8页
Transactions of China Electrotechnical Society
基金
国家高技术研究发展计划(863计划)资助项目(2011AA05A301)
关键词
光伏电站
并网逆变器
无功补偿
灵敏度
电压控制
PV plants, grid-connected inverter, reactive power compensation, sensitivity, voltage control
