电动汽车换电站接入中压配电网的保护与控制策略研究

发布时间：2018-02-06 02:08

本文关键词： 电动汽车换电站中压配电网馈线自动化故障电流保护　出处：《华北电力大学(北京)》2015年硕士论文　论文类型：学位论文

【摘要】：随着电动汽车行业的兴起,各地涌现出一些大型的电动汽车换电站示范工程。换电站一般由单元级的充放电机并联组成,而这些充放电机主要由IGBT型电力电子器件和动力电池构成,通过PWM技术可以使得换电站工作于充电和放电两种状态。充电时换电站只是相当于一般的负荷,对配电网故障时故障电流影响不大,但是当换电站向电网放电时,会使传统的单电源配电网转变为多电源配电网,因而当配电网发生故障时,会对保护配合产生影响,甚至误动。研究了换电站的建模方法。构建了充放电机的电路拓扑结构,介绍了充放电机AC/DC环节、DC/DC环节、动力电池的数学模型,在充电和放电状态下对充放电机控制策略进行了研究。研究了换电站接入中压配电网后产生的影响,重点研究了FTU和重合器一熔断器两种馈线自动化设备。分析了换电站接入后系统电流的变化,分别对换电站在近故障点接入、低接地电阻和远故障点接入、高接地电阻进行了故障电流的分析,并对换电站向系统注入无功功率情况下进行了理论分析,发现近故障点接入、低接地电阻、有无功功率注入时对配电网产生的影响更大,更容易使重合器一熔断器型配合误动作。提出一种配电网故障时换电站输出电流控制策略,根据换电站并网点电压跌落的严重程度减小逆变器的电流,以解决保护误配合问题和穿越小干扰,从而不必将换电站完全从系统切除。在PSCAD/EMTDC下以典型的中压辐射型配电网为例,对换电站接入进行了模型仿真,仿真结果表明了本文提出的换电站输出电流控制策略的有效性。
[Abstract]:With the rise of the electric vehicle industry, a number of large-scale electric vehicle power station demonstration projects have emerged. The power station is generally composed of unit level charging and discharging machines in parallel. These charge-discharge machines are mainly composed of IGBT power electronic devices and power batteries. Through PWM technology, the switching power station can work in two states of charging and discharging. When charging, the switching power station is only equivalent to the normal load, which has little effect on the fault current of distribution network. However, when the power station changes to the grid discharge, the traditional single-source distribution network will be transformed into multi-source distribution network, so when the distribution network failure, it will have an impact on the protection coordination. Even misoperation. The modeling method of power station is studied. The circuit topology structure of charging and discharging machine is constructed, and the mathematical model of DC / DC link and power battery of AC/DC link of charging and discharging machine is introduced. The control strategy of charging and discharging machine is studied in the state of charging and discharging, and the influence of switching power station on medium voltage distribution network is studied. In this paper, two kinds of feeder automation equipment, FTU and reclosure / fuse, are studied, and the change of system current after the switch power station is connected is analyzed. The switch power station is connected at the near fault point, the low grounding resistance and the remote fault point respectively. The fault current of the high grounding resistance is analyzed, and the theoretical analysis is carried out under the condition of injecting reactive power into the system. It is found that the near fault point is connected, and the low grounding resistance is found. The influence of reactive power injection on distribution network is greater and it is easier to make receptacle-fuse type mismatch. A control strategy of switching power station output current in distribution network fault is proposed. The current of the inverter is reduced according to the severity of the voltage drop of the switching power station in order to solve the protection mismatch problem and traverse small interference. Therefore, it is not necessary to remove the switching power station completely from the system. Taking the typical medium-voltage radiation distribution network as an example under PSCAD/EMTDC, the model simulation of the switching power station access is carried out. The simulation results show the effectiveness of the proposed output current control strategy.
【学位授予单位】：华北电力大学(北京)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM73;U491.8

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