含分布式电源的配电网故障恢复研究

发布时间：2018-09-11 14:48

【摘要】：近年来全球范围内由极端灾害引起的大停电事故频繁发生,对工业生产、居民生活甚至国家能源安全造成了严重的影响,因此提高配电网在大停电事故后的恢复能力具有重要的经济和社会价值。在极端灾害造成的大面积停电事故中,输电系统往往由于其设备元件受到物理性破坏而无法及时为配电网送电,此时可利用配电网内的微电网等本地电源为失电区域的重要负荷恢复供电。然而,由于微电网内的分布式电源的容量及应对扰动的能力有限,因恢复操作引发的暂态过程可能会造成分布式电源退出运行或系统失稳从而导致恢复失败。因此,本文对故障恢复中分布式电源的暂态特性进行了重点研究,并提出了考虑分布式电源暂态特性的配电网故障恢复方法,研究内容如下:首先,根据同步机接口的燃气发电机组、逆变器接口的微型燃气轮机发电系统和蓄电池储能系统的工作原理,在PSCAD中搭建了这三种分布式电源的暂态模型。建立的模型能较好地反映这些分布式电源的暂态特性,作为后续研究的模型基础。其次,对上述三种不同类型的分布式电源在恢复过程中的暂态特性进行了仿真研究并分析了暂态表现对恢复的影响。仿真分析可知,由于分布式电源容量和惯性相对较小,在恢复过程中大负荷接入可能引起明显的电压、频率波动从而导致发电机失速甚至系统失稳;空载变压器投入产生的励磁涌流可能导致分布式电源逆变器的过流保护动作引起保护跳闸导致分布式电源退出运行。以上分布式电源暂态特性的分析结果为提取可嵌入故障恢复优化决策模型中的暂态约束提供了理论分析基础。最后,本文结合分布式电源并网标准和保护设定的要求,对含有多个分布式电源的微电网在故障恢复中的可用性进行评估,并将分布式电源的暂态特性表示为可嵌入优化模型的暂态解析约束,以最大化关键负荷恢复量和最小化网损为目标建立含暂态约束的故障恢复模型。利用提出的含分布式电源的故障恢复方法,以改进的32节点网络为算例进行仿真,生成利用微网进行恢复的配电网故障恢复方案,并通过在PSCAD里进行恢复方案的暂态校验,验证了文章提出的故障恢复方案的可行性。
[Abstract]:In recent years, major power outages caused by extreme disasters have occurred frequently in the world, which have had a serious impact on industrial production, residents' lives and even national energy security. Therefore, it has important economic and social value to improve the recovery ability of distribution network after blackout. In the large-scale blackouts caused by extreme disasters, the transmission system is often unable to send electricity to the distribution network in time due to the physical destruction of its equipment components. In this case, local power sources, such as microgrid in distribution network, can be used to restore power supply to important load in power loss area. However, because of the limited capacity of the distributed generation and the ability to deal with the disturbance, the transient process caused by the recovery operation may lead to the withdrawal of the distributed power supply from operation or the instability of the system, which may lead to the recovery failure. Therefore, this paper focuses on the transient characteristics of distributed power generation in fault recovery, and proposes a fault recovery method for distribution network considering the transient characteristics of distributed power supply. The research contents are as follows: first of all, According to the working principle of the gas generator set with synchronous machine interface, the micro gas turbine generation system with inverter interface and the storage energy system of battery, the transient models of these three distributed power sources are built in PSCAD. The established model can well reflect the transient characteristics of these distributed power sources and serve as the basis for further research. Secondly, the transient characteristics of the three different types of distributed power supply are simulated and the effect of transient performance on recovery is analyzed. Simulation analysis shows that because of the relatively small capacity and inertia of distributed power supply, large load access during recovery may cause obvious voltage, frequency fluctuation and lead to generator stall or even system instability. The inrush current generated by the no-load transformer may lead to the protection tripping of the distributed power inverter, which may lead to the withdrawal of the distributed power supply from operation. The above results provide a theoretical basis for extracting the transient constraints in the embedded fault recovery optimal decision model. Finally, this paper evaluates the availability of microgrid with multiple distributed power sources in fault recovery by combining with the standard of grid connection and the requirements of protection settings. The transient characteristics of distributed generation are expressed as the transient analytical constraints of the embedded optimization model, and the fault recovery model with transient constraints is established with the aim of maximizing critical load recovery and minimizing network losses. Using the proposed fault recovery method with distributed power supply, the improved 32-node network is used as an example to simulate the fault recovery scheme of distribution network, which is restored by microgrid, and the transient calibration of the recovery scheme is carried out in PSCAD. The feasibility of the proposed fault recovery scheme is verified.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2018
【分类号】：TM732

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