含分布式电源的中压柔性直流配电网研究

Research on flexible medium voltage DC distribution network with distributed generation

直流配电技术大量减少了换流器的使用,可显著降低电网运行成本、提高系统可靠性和稳定性。在此背景下,从两端直流配电网入手,提出典型城市中压直流配电网拓扑并进行仿真分析。首先,通过探讨直流配电网相较于传统交流配电网的技术优势,分析两端直流配电网结构的可行性。然后,建立AC/DC变流器的功率和电压控制模型以及DC/DC变流器的控制模型,分析光伏和储能电池的特点,说明分布式电源直接接入直流电网减少换流器的投入,具有高效低成本的优势。最后,基于PSCAD/EMTDC平台对两端直流配电网系统进行建模仿真,仿真结果表明在光伏、储能以及负荷功率波动时通过有效控制能够使直流配电网稳定运行。

DC power distribution technology greatly reduces the use of converters.After applying this technology.the cost of power grid operation can be significantly reduced and the system reliability and stability is improved also.Under this background,a DC distribution net work with both ends is considered,and a typical urban medium-voltage DC distribution network topology is proposed and simulated.Firstly,the technical advantages of the DC distribution network is explored and compared with the traditional AC distribution network.Then,the feasibility is analyzed for structure of DC distribution network with both ends.Secondly,the power and voltage control model of AC/DC.converter and the control model of DC/DC converter is established.Furthermore,the characteristics of photovoltaic and energy storage batteries are analyzed.It is found that the DC distribution network can reduces the converter's Investment and has the advantage of high efficiency and low cost.Finally,the DC distribution network system with both ends is modeled and simulated on the PSCAD/EMTDC platform.It is shown that stable operation of the DC distribution network is achieved by the effective control when photovoltaic,energy storage,and ldad power flctutions exist.