面向配电网接地故障暂稳态协同调控的UPQC优化运行方法

UPQC Optimal Operation for Transient-and Steady-state Coordinated Regulation of Grounding Fault in Distribution Network

针对现有有源消弧装置存在稳态时直流侧取电难、直流电容难以稳压,暂态时接地故障瞬时过电压等问题,充分解析了接地故障全过程中统一电能质量调节器(unified powerqualityconditioner,UPQC)主动参与调控的潜力,提出一种面向配电网接地故障暂稳态协同调控的UPQC优化运行方法。将使用此方法的装置简称为具备消弧功能的统一电能质量调节器(arcsuppression-unifiedpowerquality conditioner,AS-UPQC)。首先,通过分析消弧稳态模式下AS-UPQC系统的功率流向,提出一种适用于AS-UPQC的能量主动平衡方法,通过控制AS-UPQC串联侧从电网吸收一定的有功来补偿并联侧消弧时消耗的有功。该方法在无需额外储能设备的前提下,有效保证了消弧装置直流侧电容能量平衡。其次,对接地故障的暂态模式进行分析,提出一种暂态响应优化的控制方法。在发生接地故障瞬间,控制串联侧从电网中吸收的有功,其等效增大系统阻尼,加快暂态过渡过程,从而抑制瞬态过电压的幅值。最后,通过仿真和实验验证了所提调控方法的有效性与可行性。

There have been problems in the existing active arc suppression devices,for example,it is difficult to obtain power at the DC side or to stabilize the DC capacitor in the steady state;and there is transient overvoltage of a grounding fault in the transient state.Aiming at these problems,this paper fully analyzes the potential of unified power quality regulator(UPQC)to actively participate in the regulation in the whole process of a grounding fault.An optimal operation of UPQC for transient-and steady-state coordinated regulation of a grounding fault in distribution network is then put forward.The device with this method is referred to as AS-UPQC(Arc Suppression Unified Power Quality Conditioner).Firstly,by analyzing the power flow direction of AS-UPQC system in the arc suppression steady-state mode,the method of active energy balance suitable for AS-UPQC is proposed.By controlling the series side of AS-UPQC to absorb certain active power from the power grid,the active power consumed during the arc suppression at the parallel side is compensated.On the premise of no additional energy storage equipment,this method effectively ensures the capacitance energy balance at the DC side of the arc suppression device.Secondly,the transient mode of a grounding fault is analyzed,and a control method of transient response optimization is proposed.At the moment of a grounding fault,the control series side absorbs the active power from the power grid,which effectively increases the system damping and speeds up the transient transition process so as to suppress the amplitude of transient overvoltage.Finally,the effectiveness and feasibility of the proposed control method are verified by simulation and experiments.