基于电压控制特性的电压源型多端直流/交流系统潮流求解

由于基于电压源型换流器的高压直流(VSC-HVDC)输电技术具有良好的可控性,对负荷中心供电、风电消纳、孤岛电力传输等适应能力强,电压稳定性好,因此具有良好的应用前景。当前对VSC-HVDC系统主要基于定功率控制模式进行潮流计算,而很少考虑到实际的换流器电压控制能力。为了更加精确地反映实际电网中VSC的电压控制特性,文中建立了基于VSC的电压控制模型,考虑了换流器损耗、交流滤波器、换流器容量限制等的影响,并基于电压控制特性提出了VSC多端直流/交流系统的通用潮流求解方法。对直流电网功率分布变化和N-1故障以及多端直流/交流系统的潮流算例分析表明,所提的潮流算法能够反映直流换流器的电压控制调节能力,验证了基于VSC的多端直流/交流系统在考虑换流器电压控制特性后的潮流方法的有效性、合理性以及算法的快速性。

Power Flow Solving of VSC Multi-terminal DC/AC System Based on Voltage Control Characteristics

The voltage source converter based high voltage direct current(VSC-HVDC)transmission technology has good application prospects owing to its excellent controllability, voltage stability and good adaptability to power supply for load center, wind power accommodation, and power transmission among islands. The present research on power flow of VSC-HVDC system is mostly based on constant power control mode without considering the practical converter voltage control characteristics. In order to more accurately reflect the voltage control characteristics of VSC in the actual power grid, a voltage control model based on VSC is developed. As well, converter loss, AC filter, and converter capacity limit are considered in the power flow model. And a general power flow algorithm is proposed for power flow of the VSC based multi-terminal DC/AC system. Some cases with changed DC grid power injection, N-1 contingency and multi-terminal DC/AC system, are built and analyzed. The case analysis indicates that the power flow algorithm is able to reflect the voltage control ability of DC converters, while verifying the effectiveness, rationality and algorithm rapidity based on voltage control characteristics.