第 51 卷 第 9 期 电力系统保护与控制 Vol.51 No.9
2023年5月1日 Power System Protection and Control May 1, 2023
DOI: 10.19783/j.cnki.pspc.221346
不对称故障下考虑光储出力的最优电压支撑策略研究
陈凌彬,夏向阳,李 红,廖一丁,郭 源,关维德
(长沙理工大学电气与信息工程学院,湖南 长沙 410114)
摘要:电网发生不对称故障会导致公共连接点(point of common coupling, PCC)电压下降,严重情况下还存在切机
风险。而传统电压支撑策略易受到机组出力影响,不能灵活支撑 PCC 电压。针对上述问题,提出了一种不对称故
障下考虑光储出力的最优电压支撑策略。首先分析了不对称故障下的电压支撑原理,推导了电压支撑方程。然后
基于上述方程,以并网标准对 PCC 电压的运行要求为目标,考虑电流峰值和有功功率波动幅值为约束条件,得出
了理想的电压支撑方案。进一步根据光储实际出力和理想的有功功率参考值,对光储出力场景进行分类。当理想
的电流参考值无法满足最优解时,联立电压支撑方程和相应约束方程,建立关于电流各分量的非线性方程组,可
解得最优电流参考值。最后通过仿真验证了所提策略的有效性和灵活性。
关键词:不对称故障;光伏;储能;电压支撑;低压穿越
An optimal voltage support strategy considering the photovoltaic and storage
output under asymmetric faults
CHEN Lingbin, XIA Xiangyang, LI Hong, LIAO Yiding, GUO Yuan, GUAN Weide
(School of Electrical and Information Engineering, Changsha University of Science and Technology, Changsha 410114, China)
Abstract: Asymmetric faults in the power grid will lead to voltage drop at the point of common coupling (PCC), even
resulting in severe risk e.g. cutting machine. However, the traditional voltage support strategy is easily affected by the
output of the unit, and cannot flexibly support the PCC voltage. For the above problems, an optimal voltage support
strategy considering the photovoltaic and storage output under asymmetric faults is proposed. First, the principle of
voltage support under asymmetric fault is analyzed, and the voltage support equation is deduced. Then, based on the
above equation, taking the grid-connected standard's operating requirements for PCC voltage as the target, and
considering the current peak value and active power fluctuation amplitude as constraints, the ideal voltage support scheme
is obtained. Further, according to the actual output of photovoltaic and energy storage and the ideal reference value of
active power, the output scenarios of photovoltaic and energy storage are classified. When the ideal current reference
value cannot satisfy the optimal solution, the voltage support equation and the corresponding constraint equation are
combined to establish a nonlinear equation system about each component of the current, and the optimal current reference
value can be solved. Finally, the effectiveness and flexibility of the proposed strategy are verified by simulation.
This work is supported by the National Natural Science Foundation of China (No. 51977014).
Key words: asymmetric fault; photovoltaic; energy storage; voltage support; low voltage ride through
0 引言
为实现“碳达峰,碳中和”目标,光伏大规模
接入电网,但随着光伏装机容量的增大,其出力缺
陷给电网带来了新的挑战,严重影响了电力系统的
可靠运行[1-2]。而储能作为解决光伏平滑接入和灵活
消纳的有效手段,近年来也得到了迅速的发展。并
网变换器是光储并网的关键设备,它不仅在电网正
基金项目:国家自然科学基金项目资助(51977014)
常运行时要保证系统可靠并网,还应该在电网故障
时具备主动支撑电网的能力[3-4],保证系统安全地进
行故障穿越。不对称故障是电网最常见的故障类型,
一旦发生,将对整个并网系统产生较大的冲击,会
造成输出电流峰值增大、功率波动和 PCC 电压跌
落[5-6]等不利影响。因此,研究不对称故障下并网变
换器的控制策略具有重要意义。
早期研究主要针对有功功率波动、无功功率波
动和电流平衡进行控制,常用的控制策略有瞬时有
功无功控制、平均有功无功控制、正序分量瞬时控