考虑储能系统控保协同体系的光伏场站送出线路突变量选相能力恢复策略

Phase Selection Capacity Recovery Strategy for Transmission Line of Photovoltaic Station Based on the Control and Insurance Cooperative of Energy Storage System

针对新能源接入电网后,突变量选相元件动作性能显著劣化,尤其在弱电源侧难以保证选相正确性的问题,提出考虑储能系统控保协同体系的突变量选相能力恢复策略。通过理论分析,得出逆变电源侧负序阻抗基本恒定这一实施选相能力恢复举措的前提条件。在此基础上,提出将光伏场站中储能侧逆变电源控制策略中的负序抑制短时屏蔽,并将故障线路两侧的正序分配系数控制到与负序分配系数相等,以此营造令传统突变量选相元件实现动作的最理想条件。该控制可以通过控制储能设备电流内环中的d轴和q轴电流实现。基于PSCAD/EMTDC的仿真结果表明,在该控制策略作用下,线路两侧正序分配系数与负序分配系数几乎相等,极大程度恢复了弱电源侧的选相特征,在不同故障工况下均有较好的适应性,且不会干扰系统侧选相元件的正常动作,具有很高的可靠性。

After the new energy is connected to the power grid,the operating performance of the phase selection element of difference abrupt change is significantly deteriorated.Especially in the weak power supply side,it is difficult to ensure the correctness of the phase selection.Therefore,a recovery of the phase selection ability based on the control and protection coordination of energy storage system is proposed.Through theoretical analysis,it can be concluded that the negative-sequence impedance of the inverter power supply side is basically constant,which is the precondition for implementing the recovery measures of phase selection capability.On this basis,it is recommended to shield the negative sequence suppression short-term in the control strategy of the inverter power supply on the energy storage side in the photovoltaic power station,and to ensure that the positive sequence distribution coefficient on both sides of the fault line is equal to the negative sequence distribution coefficient.The most ideal conditions for the traditional sudden change phase selection element are created to realize the action.This control can be achieved by controlling the d-axis and q-axis currents in the current inner loop of the energy storage device.The simulation results based on PSCAD/EMTDC show that under the action of this control strategy,the distribution coefficient of positive sequence on both sides of the line is almost equal to the distribution coefficient of negative sequence,which greatly restores the phase selection characteristics of the weak power supply side.It has good adaptability under the system,and will not interfere with the normal operation of the phase selection element on the system side,with high reliability.