海上风电经交流电缆汇集送出系统暂态无功电压建模及特性分析

海上风电经交流电缆汇集送出系统送端暂态过电压威胁系统安全稳定运行，为定量分析暂态电压对海上风电机组的影响，指导海上风电无功电压控制系统配置，亟须研究海上风电经交流电缆汇集送出系统暂态无功电压模型。首先，分析计及交流电缆的送出系统等效网络特性，明确等效网络呈现感性与容性特性的边界条件；然后，基于等效网络容性特性，建立计及交流电缆的海上风电暂态无功电压数学模型，基于控制硬件在环（control hardware in the loop，CHIL）实时仿真实验平台，验证了数学模型的正确性；最后，基于海上风电暂态无功电压模型，定量分析交流电缆线路长度、风电机组网侧变流器电流环控制带宽与阻尼比对机端暂态过电压的影响规律，为定量评估海上风电经交流电缆汇集送出系统暂态过电压运行风险奠定了理论基础。

Transient Voltage-Reactive Power Modeling of Offshore Wind Power Collection and Transmission System with AC Cables and Characteristic Analysis

The transient overvoltage at the sending terminal of the offshore wind power collection and transmission system with AC cables threatens the safe and stable operation of the system. To quantitatively analyze the impact of transient voltage on offshore wind turbines and thereby guide the configuration of the voltage-reactive power control system for offshore wind power, we need to develop a transient voltage-reactive power model of the offshore wind power collection and transmission system with AC cables as soon as possible. This paper approaches this problem by analyzing the characteristics of the equivalent network of the transmission system considering AC cables and clarifying the boundary conditions for the equivalent network to demonstrate inductive characteristics or capacitive ones. Then, for the case of the equivalent network displaying capacitive characteristics, we build a mathematical transient voltage-reactive power model of offshore wind power considering AC cables and verify the validity of the mathematical model on the control hardware in the loop (CHIL) based real-time simulation experiment platform. Finally, with the transient voltage-reactive power model of offshore wind power, we quantitatively analyze the influences of AC cable line length and the control bandwidth and damping ratio of the current loop in the wind turbine grid-side converter (GSC) on transient overvoltage at the generator terminal to lay a theoretical foundation for quantitatively assessing the risk of transient overvoltage in the offshore wind power collection and transmission system with AC cables.