Abstract The growing deployment of utility-scale photovoltaic (PV) in electricity industries raises many concerns for power system operation. Due to the highly variable and somewhat unpredictable characteristics of short-term PV output, the system operator faces challenges in balancing electricity supply and demand, which increases the need for short-term frequency management. Although many studies have been carried out to enhance the understanding of short-term PV output characteristics, the uncertainty around forecast targets for electricity market dispatch has not been studied. This paper analyses 4-second SCADA output data from PV plants and all other generators operating in the Australian National Electricity Market (NEM) to assess the deviation from their forecast dispatch targets. During the study period, PV penetration was less than 5% of the total generation capacity. The deviations of PV plants from forecast targets increases almost proportionally with their operating level. The correlation between deviations from the targets and system frequency deviations shows that PV plants contribute towards increasing frequency deviations, yet the impact seems minor, with only 0.06-0.09 correlation coefficients. Despite their variability during normal operation, PV plants demonstrate accurate output control when following dispatch instructions during network constrained periods with fluctuations of only ±1% of the plant rated capacity.

中文翻译：

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公用事业规模光伏电站短期运行预测偏差及可控性分析

摘要 公用事业规模光伏（PV）在电力行业的日益普及引起了电力系统运行的许多关注。由于短期光伏出力的高度可变性和一些不可预测的特性，系统运营商在平衡电力供需方面面临挑战，这增加了对短期频率管理的需求。尽管已经进行了许多研究以增强对短期光伏输出特性的理解，但尚未研究电力市场调度预测目标的不确定性。本文分析了来自光伏电站和在澳大利亚国家电力市场 (NEM) 中运行的所有其他发电机的 4 秒 SCADA 输出数据，以评估与其预测调度目标的偏差。在学习期间，光伏渗透率不到总发电量的 5%。光伏电站与预测目标的偏差几乎与其运行水平成正比。目标偏差与系统频率偏差之间的相关性表明，光伏电站有助于增加频率偏差，但影响似乎很小，只有 0.06-0.09 的相关系数。尽管光伏电站在正常运行期间存在差异，但在电网受限期间按照调度指令执行时，光伏电站表现出准确的输出控制，波动仅为电站额定容量的 ±1%。目标偏差与系统频率偏差之间的相关性表明，光伏电站有助于增加频率偏差，但影响似乎很小，只有 0.06-0.09 的相关系数。尽管光伏电站在正常运行期间存在差异，但在电网受限期间按照调度指令执行时，光伏电站表现出准确的输出控制，波动仅为电站额定容量的 ±1%。目标偏差与系统频率偏差之间的相关性表明，光伏电站有助于增加频率偏差，但影响似乎很小，只有 0.06-0.09 的相关系数。尽管光伏电站在正常运行期间存在差异，但在电网受限期间按照调度指令执行时，光伏电站表现出准确的输出控制，波动仅为电站额定容量的 ±1%。