互联配电台区故障背靠背无缝模态切换策略

Seamless Mode Switching Strategy for Back-to-Back Devices under Connecting TD's Failure

通过背靠背变流器将相邻配电台区互联,是促进低压配电网协同消纳分布式能源的有效方式。正常运行时,直流母线一端变流器采用功率控制,另一端采用直流电压控制。当直流电压控制侧变流器故障时,需要另一侧变流器从功率控制模式切换到直流电压控制模式。针对现有模式切换策略容易因故障检测阈值不准确或通信延迟导致电压大幅波动或误动作,甚至直流侧供电中断,提出一种基于功率-电压控制的无缝模态切换策略。所提策略受故障检测阈值和通信延迟影响小,可平稳可靠地实现故障模态切换,提高互联配电台区之间能量共享的可靠性。最后,通过MATLAB/Simulink上的仿真结果验证了所提策略的正确性和有效性。

The interconnection of adjacent distribution network through back to back converter is an effective way to consume distributed generation among the low voltage distribution networks,and DC load,even DC micro-grid,can be linked to DC side via back to back converter.Generally,one converter uses power control and the other one is DC voltage control.Therefore,when the DC voltage control side converter fails,the other side converter needs to switch from power control mode to DC voltage control mode.The present mode switching strategy usually depends on the accuracy of fault detection and the speed of communication.The inaccuracy of the fault detection threshold or the delay of communication may lead to a large fluctuation or misoperation of the voltage,and even the interruption of the power supply in the DC side.A seamless mode switching strategy based on power voltage(P-V)control was proposed.The strategy is less affected by the fault detection threshold and communication delay,and the fault mode switching can be realized smoothly and reliably,and the reliability of energy sharing among the interconnected radio stations is improved.Finally,the simulation results verify the correctness and effectiveness of the proposed strategy.