含分布式电源的交（直）流配电网电压控制

发布时间：2018-03-05 12:37

本文选题：分布式电源　切入点：交(直)流配电网　出处：《上海电力学院》2017年硕士论文　论文类型：学位论文

【摘要】：分布式电源的高效、环保等特点促使其在电力系统中的分布越来越广泛。现代配电网具有适宜于分布式电源接入、供电质量高,减少城市用电紧张等特点,发展现代配电网将是城市电网的必然要求。由于分布式电源出力的随机性和波动性,其接入现代配电网必然造成各节点电压的波动,节点电压作为衡量配电网电压质量的重要指标,因此对电压控制的研究就显得尤为关键。现代配电网内含DG的种类多,在进行潮流分析过程中,对于不同种类的节点采用恰当的方法向PQ节点转换,因而需要对不同种类的分布式电源的输出功率进行建模并确立其节点类型,便于计算;研究含多种类型的交流配电网优化模型,采用改进遗传算法对模型求解,采用随机潮流算法对系统潮流进行求解,算例分析表明本文优化模型能减少配电网网损,提高配电网运行的经济性。对直流配电网的运行模式、控制层次、控制方式进行了分析。指出VSC是连接直流配电网与外部电网的重要设备,控制其输出功率稳定对于直流配电网的稳定运行有重要意义。针对其不同运行模式下VSC的控制问题,提出了适用于直流配电网的电压协调控制方式,提出的将带裕度的电压控制方式与功率电压下垂控制方式相结合的电压协调控制方式结构合理,层次清晰。在DG与负荷的功率发生波动时,能将母线电压控制在有效范围内,保证系统的稳定运行;在直流配电网运行模式发生改变时,换流站控制模式之间能够平滑切换,不会对母线电压带来冲击。所提协调控制模式能够快速响应系统功率的变化,提高了系统的稳定性;直流配电网内无感抗、容抗,潮流分析比交流配电网简单,研究了基于Newton-Raphson法的直流配电网潮流分析,并将其用于后续的直流配电网研究中。针对大量分布式电源并入直流配电网后的电压波动问题,提出一种适用于直流配电网的双阶段电压控制方式,第一阶段通过电压源换流站来控制全网的电压水平,第二阶段通过优化DG的有功出力对系统各节点电压进行调整,且双阶段的控制结果相互反馈,共同实现对直流配电网各节点电压的控制。算例分析表明,本文所提的双阶段控制方式能有效适应大量DG的接入,能有效控制直流配电网各节点的电压,保证系统安全稳定运行。
[Abstract]:The high efficiency and environmental protection of distributed power make it more and more widely distributed in power system. Modern distribution network is suitable for access to distributed power supply, high quality of power supply, reduction of power shortage in cities, and so on. The development of modern distribution network will be the inevitable requirement of urban power grid. Because of the randomness and fluctuation of distributed power generation, its connection to modern distribution network will inevitably cause voltage fluctuation of each node. Node voltage is an important index to measure the voltage quality of distribution network, so the research on voltage control is particularly important. There are many kinds of DG in modern distribution network, so in the process of power flow analysis, For different kinds of nodes, it is necessary to model the output power of different kinds of distributed power supply and establish the type of nodes, so it is convenient to calculate because the appropriate method is adopted to convert to PQ nodes. The optimization model of AC distribution network with various types is studied. The improved genetic algorithm is used to solve the model, and the stochastic power flow algorithm is used to solve the power flow of the system. The example analysis shows that the optimization model in this paper can reduce the network loss of distribution network. The operation mode, control level and control mode of DC distribution network are analyzed. It is pointed out that VSC is an important equipment to connect DC distribution network with external network. It is very important to control the output power stability for the stable operation of DC distribution network. Aiming at the control problem of VSC in different operation modes, a voltage coordinated control mode suitable for DC distribution network is proposed. The proposed voltage coordination control method, which combines the voltage control with margin and the power voltage droop control, has a reasonable structure and clear level. When the power of DG and load fluctuates, the bus voltage can be controlled within an effective range. Ensure the stable operation of the system, when the operation mode of DC distribution network changes, the converter station control mode can be smoothly switched, without impact on the bus voltage. The proposed coordinated control mode can quickly respond to the system power changes. The stability of the system is improved, no reactance, capacitive reactance, power flow analysis in DC distribution network is simpler than that in AC distribution network, the power flow analysis of DC distribution network based on Newton-Raphson method is studied. And it is used in the subsequent research of DC distribution network. Aiming at the voltage fluctuation problem after a large number of distributed generation is incorporated into DC distribution network, a two-stage voltage control method suitable for DC distribution network is proposed. In the first stage, the voltage level of the whole network is controlled by the voltage source converter station. In the second stage, the voltage of each node of the system is adjusted by optimizing the active power output of the DG, and the results of the two-stage control are feedback to each other. The calculation example shows that the two-stage control method proposed in this paper can effectively adapt to a large number of DG access, and can effectively control the voltage of each node in DC distribution network. Ensure safe and stable operation of the system.
【学位授予单位】：上海电力学院
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM714.2

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