光储接入牵引供电系统应急供电方案下低频稳定性研究

Low-frequency stability under emergency power supply scheme of photovoltaic and battery access traction power supply system

“双碳”目标背景下,新能源较大规模接入牵引网可能成为铁路运输新趋势。为对意外失电的列车紧急牵引并打破铁路领域传统用能壁垒,实现铁路能源自给型低碳供电并与电网互为备用,各系统能量互联互通,首次提出一种应急供电方案灵活利用牵引网侧接入的光储装置牵引列车并对“光-储-车网”耦合系统的低频稳定性展开研究。首先,制定RPC双模式单相全桥逆变器的控制方法结合光储运行状态协调控制策略划分工作模态;然后,利用小信号及状态空间平均法建立光储、客车(CRH3型动车)以及投影到dq坐标系下铁路功率调节器直流侧阻抗模型;最后,利用所得“光-储-车网”3个子系统的导纳模型,引入一种适应多工况的无源判据,揭示控制器参数及多源对牵引供电系统电气稳定性的影响规律。研究结果表明:所提方案通过新能源及储能装置在昼夜多工况下均能长时持续稳定牵引列车,当新能源或电网供电出现意外二者可互补切换,故障条件下机车仍可受电稳定行走。此外,光储电压环比例增益对该系统阻抗匹配性稳定性有较强的电气敏感性,所建模型结合无源判据指导调参接入不同供电源补偿系统阻抗可治理部分失稳现象,该方案下储能系统具有良好的补偿特性。在Starsim半实物实验平台验证了“光-储-车网”耦合系统应急供电方案的可行性及稳定性研究的正确性。

Given the“carbon-neutral”context,the large-scale integration of new energy sources into the traction grid can become a new trend in railway transportation.To address unexpected power outages and break through traditional energy barriers in the railway sector,a novel emergency power supply scheme was proposed.It utilized the traction grid-connected photovoltaic energy storage system to provide emergency traction for trains,and explored the low-frequency stability of the“photovoltaic-battery-vehicle network”coupled system.The control method for the RPC dual-mode single-phase full-bridge inverter was developed,combining the operation status coordination control strategy of the photovoltaic energy storage system to define working modes.The small-signal and state-space averaging method was applied to establish the impedance models of the photovoltaic and energy storage systems,the passenger vehicle(CRH3 type high-speed train),and the railway power conditioner in the dq coordinate system.The obtained impedance models of the three subsystems were used to introduce a passive criterion adaptable to various operating conditions.This criterion revealed the impact of controller parameters and multiple power sources on the electrical stability of the traction power supply system.The research results show that the proposed scheme can stably provide traction to trains using new energy and energy storage systems under various operating conditions,including day and night.In case of unexpected power supply failures from either new energy or the grid,the two sources can complementarily switch,ensuring stable train operation even in fault conditions.Furthermore,the photovoltaic storage voltage loop proportional gain has strong electrical sensitivity to the impedance matching stability of the system.The constructed model,combined with the passive criterion,guides the control parameters and compensates for the impedance of different power sources,addressing certain instability phenomena.The energy storage system in this scheme exhibits good compensation characteristics.The feasibility and stability of the“photovoltaic-battery-vehicle network”coupled system’s emergency power supply scheme have been validated on the Starsim semi-physiological experimental platform.