直流配电网的综合调压控制策略研究

发布时间：2018-08-14 18:17

【摘要】：随着分布式发电技术、多端直流输电技术的发展以及新型直流设备的技术突破,直流配电网得到了越来越多的关注和研究。与交流配电网相比,直流配电网能够减少大量的DC/AC换流环节,降低换流站的建设和运行成本,不存在无功环流、频率和功角稳定性等问题,可以有效解决交流配电网中存在的三相不平衡、电网谐波等一系列电能质量问题。本文针对直流配电网的电压调整控制以及综合调压控制策略进行深入研究,主要研究内容如下:(1)分析了直流配电网的典型拓扑结构和电压源换流器(VSC)的基本原理,并建立了VSC的稳态数学模型。在此基础上,分析了直流配电系统的分层控制系统,并对包括外环控制器与内环控制器的换流站级控制器进行了设计,为直流配电网的电压控制策略的设计奠定基础。(2)分析了直流配电网采用直流电压下垂控制的原理及优缺点,针对直流电压下垂控制存在的电压偏差问题,提出了一种附加直流电压偏差补偿控制的改进直流电压下垂控制策略,以减小直流电压偏差和提高直流配电网的可靠性。在仿真平台上搭建了两端直流配电网和三端环状直流配电网模型,进行直流配电网稳态和暂态运行仿真分析,验证了所提控制策略的有效性。(3)研究了直流配电网的综合调压控制策略,设计了直流配电网的电压控制体系,对直流配电网的一次调压和二次调压进行了详细的分析和研究,一次调压采用基于U-P控制特性的多端直流电压下垂控制,二次调压针对不同的优化目标:电压优化、网损优化、电压和网损综合优化,分别提出了基于电压优化算法的综合调压控制策略、基于网损优化算法的综合调压控制策略和直流配电网的电压和网损综合优化控制策略。为未来大规模直流配电网的电压控制和优化运行提供参考。(4)搭建了直流配电网的综合调压仿真模型,对本文提出的基于电压优化算法的综合调压控制策略、基于网损优化算法的综合调压控制策略和直流配电网的电压和网损综合优化控制策略分别进行了仿真分析,验证了所提综合调压控制策略的有效性。
[Abstract]:With the development of distributed generation technology, multi-terminal DC transmission technology and the breakthrough of new DC equipment, DC distribution network has been paid more and more attention and research. Compared with AC distribution network, DC distribution network can reduce a lot of DC/AC commutation links, reduce the construction and operation cost of converter station, and there are no problems such as reactive circulation, frequency and power angle stability, etc. It can effectively solve a series of power quality problems such as three-phase imbalance and harmonic in AC distribution network. The main contents of this paper are as follows: (1) the typical topology of DC distribution network and the basic principle of voltage source converter (VSC) are analyzed. The steady mathematical model of VSC is established. On this basis, the hierarchical control system of DC distribution system is analyzed, and the converter station controller including outer loop controller and inner loop controller is designed. It lays a foundation for the design of voltage control strategy of DC distribution network. (2) the principle, advantages and disadvantages of DC voltage droop control are analyzed, and the voltage deviation of DC voltage droop control is analyzed. An improved DC voltage sag control strategy is proposed to reduce the DC voltage deviation and improve the reliability of the DC distribution network. Two end DC distribution network and three terminal ring DC distribution network model are built on the simulation platform, and the steady and transient operation simulation analysis of DC distribution network is carried out. The effectiveness of the proposed control strategy is verified. (3) the integrated voltage control strategy of DC distribution network is studied, the voltage control system of DC distribution network is designed, and the primary and secondary voltage regulation of DC distribution network is analyzed and studied in detail. The primary voltage regulation adopts multi-terminal DC voltage droop control based on U-P control characteristic. The secondary voltage regulation aims at different optimization objectives: voltage optimization, network loss optimization, voltage and network loss synthesis optimization. The integrated voltage control strategy based on the voltage optimization algorithm, the integrated voltage regulation control strategy based on the network loss optimization algorithm and the integrated voltage and network loss control strategy of the DC distribution network are proposed respectively. It provides a reference for voltage control and optimal operation of large-scale DC distribution network in the future. (4) the integrated voltage regulation simulation model of DC distribution network is built, and the integrated voltage control strategy based on voltage optimization algorithm is proposed in this paper. The integrated voltage regulation control strategy based on the network loss optimization algorithm and the voltage and network loss integrated optimal control strategy of the DC distribution network are simulated and analyzed respectively to verify the effectiveness of the proposed integrated voltage regulation control strategy.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM721.1;TM714.2

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