一种同步型分布式电源输出短路电流抑制技术

随着分布式电源（DG）在配电网渗透率的不断提高，其对继电保护尤其是过流保护的影响日益显著。针对短路电流输出能力强的同步DG，提出了一种基于全控型器件的励磁控制技术以抑制DG对配电网过流保护的影响。首先，分析了同步发电机机端短路时输出电流同励磁电流间的数学关联。然后，通过分析电流型逆变器调制策略下励磁能量泄放回路时间常数的影响因素，建立了面向配电网过流保护的同步DG励磁控制方案。最后，通过仿真分析验证了该励磁控制方案的有效性及其对转子匝间绝缘的影响。该方法只需要通过对全控型器件变流器的控制，即可抑制同步DG对过流保护的影响。

A Suppression Technology for Short-circuit Current Output of Synchronous Distributed Generator

With the increasing penetration of distributed generators (DGs) in distribution networks, their influence on relay protection, especially overcurrent protection, becomes increasingly significant. Aiming at synchronous DGs with high output of short-circuit current, this paper proposes an excitation control technology based on fully controllable components to suppress the influence of DGs on the overcurrent protection of distribution networks. Firstly, this paper analyzes the mathematical relation between the output current and the excitation current when the synchronous generator terminals are short-circuit. Secondly, by analyzing the influential factors of the time constant of the excitation energy discharging circuit under the modulation strategy of the current source inverter, a synchronous DG excitation control scheme for overcurrent protection of distribution networks is established. Finally, the effectiveness of the excitation control strategy and its effect on rotor turn-to-turn insulation are verified by simulation analysis. This method can suppress the influence of the synchronous DG on the overcurrent protection only by controlling the converter based on fully controllable components.