基于VSC的交直流混联网络交流侧对直流侧支持技术研究

发布时间：2018-04-28 23:13

本文选题：VSC + 交直流混联网络　；参考：《华北电力大学(北京)》2017年硕士论文

【摘要】：在全球能源互联网技术的发展趋势下,电网将成为全世界最重要的能源输送和分配网络,其重要性不言而喻。对比传统的电网换相技术,,基于VSC(voltage source converter,电压源换流器)的直流输电技术因具有更高的灵活性、更好的适用性等优点,在近年来得到了快速的发展。因此,基于VSC的交直流混联网络的优化运行和研究越来越受到国内外学者的关注。由于基于VSC的交直流装置接入方式多样、控制方式灵活,对电网运行和分析带来了新的挑战。本文首先探讨了几种VSC接入交直流网络的方式,包括交直流双端互联、交直流背靠背互联以及交直流多端互联等方式,描述了每种连接方式的具体情况。同时分析了VSC换流站交直流两侧的不同控制方式,分析每种组合控制方式的应用条件及其在潮流计算中的等效节点类型。因VSC接入系统的多样性,传统的以节点建模的方法解决含VSC的交直流混联网络的最优潮流问题存在局限性。本文提出了基于扩展支路的含VSC-HVDC交直流系统最优潮流模型,对含VSC的交直流混联进行统一建模,。通过对2组不同接入方式下的算例进行仿真计算,结果表明,本文提出的模型可应用于含VSC的交直流混合网络、背靠背直流输电系统、多端直流输电系统等领域的最优潮流计算。在多端交直流互联算例中,结果表明,相比多个交流网络单独运行,通过VSC将多个交流网络互联,可以提高交流网络的发电机经济效益。VSC的交直流混联网络中,交流侧和直流侧系统电压存在着相互影响关系。本文应用系统负荷裕度指标,描述系统的静态电压稳定裕度。分析交直流混联网络交流侧对直流侧支持问题的策略和实现方法,提出一种负荷裕度计算模型和交流对直流电压支持计算模型。最后,对一天24小时的负荷波动情况进行负荷裕度计算,当负荷裕度过低时启动电压支持模型进行优化计算,算例结果表明互支持模型的计算可以改善直流侧负荷过大时,直流电压和VSC传输功率的越限问题。
[Abstract]:With the development of global energy Internet technology, the power grid will become the most important energy transmission and distribution network in the world, and its importance is self-evident. Compared with the traditional commutative technology, DC transmission technology based on VSC(voltage source converter (voltage source converter) has been developed rapidly in recent years because of its advantages of higher flexibility and better applicability. Therefore, the optimal operation and research of AC / DC hybrid networks based on VSC have attracted more and more attention from scholars at home and abroad. Because of the variety of access mode and flexible control mode of AC / DC equipment based on VSC, it brings new challenges to the operation and analysis of power grid. This paper first discusses several ways of connecting VSC to AC / DC network, including AC / DC dual terminal interconnection, AC / DC back-to-back interconnection and AC / DC multi-terminal interconnection, and describes the specific conditions of each connection mode. At the same time, the different control modes on both sides of AC and DC of VSC converter station are analyzed, and the application conditions of each combined control mode and their equivalent node types in power flow calculation are analyzed. Due to the diversity of VSC access systems, the traditional node-modeling method for solving the optimal power flow problem of AC / DC hybrid networks with VSC is limited. In this paper, an optimal power flow model for AC / DC systems with VSC-HVDC based on extended branch is proposed, and the unified modeling of AC / DC hybrid systems with VSC is carried out. The simulation results show that the proposed model can be applied to AC / DC hybrid network with VSC, back-to-back HVDC transmission system. Optimal power flow calculation for multi-terminal HVDC systems. In the example of AC / DC interconnection with multi-terminal AC / DC, the results show that, compared with multiple AC networks, the AC / DC networks can be interconnected by VSC, which can improve the economic benefit of AC / DC networks of AC / DC networks. The voltage of AC side and DC side system has mutual influence relationship. The static voltage stability margin of the system is described by using the system load margin index. This paper analyzes the strategy and implementation method of AC side support to DC side in AC / DC hybrid network, and puts forward a load margin calculation model and AC DC voltage support calculation model. Finally, the load margin of 24 hours a day load fluctuation is calculated, and the start-up voltage support model is optimized when the load margin is too low. The results show that the calculation of the mutual support model can improve the load at the DC side when the load is too large. The overrun problem of DC voltage and VSC transmission power.
【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】：2017
【分类号】：TM721.3

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