基于接地故障类型的交流微电网限流方法的研究

Current Limiting Method for AC Microgrid Based on Grounding Fault Type

交流微电网通过促进新能源消纳来解决能源危机和环境问题,但其固有的过流能力弱导致其应用十分受限。针对交流微电网的弱过流能力,提出了一种基于接地故障类型的交流微电网限流方法。首先,阐述了单分布式发电网络及其带冲洗滤波器的下垂控制模型,推导了LC滤波器和锁相环的输出参考电压。然后,基于传统瞬时功率理论改进了不同接地故障下的电流表达式,引入E-L方程定义并网逆变器的误差存储函数,进而设计改进无源控制器来改善滤波电流,提高电能质量。最后,通过Matlab/Simulink软件对带有6台分布式发电机的交流微电网进行了仿真研究,结果验证了所提故障限流方法的有效性。

AC microgrid solves energy crisis and environmental problems by promoting renewable energy consumption.However,the inherent weak overcurrent capability of the AC microgrid makes its very limited application.Targeting the weak overcurrent capability of the AC microgrid,this paper proposes a current limiting method for the AC microgrid based on ground fault type.Firstly,a single distributed generation network and its droop control model with washout filter is expounded,and the output reference voltage of LC filter and phase-locked loop is deduced.Then based on the traditional instantaneous power theory,the current expressions under different grounding faults are improved,and the E-L equation is introduced to define the error storage function of grid-connected inverter.After that,an improved passive controller is designed to improve the filter current and power quality.Finally,an AC microgrid with 6 distributed generators is simulated by Matlab/Simulink software,and the effectiveness of the proposed fault current limiting method is verified by the simulation results.