多直流落点系统换相失败及恢复特性的仿真研究

发布时间：2018-06-18 04:21

本文选题：多直流落点系统 + 换相失败　；参考：《华南理工大学》2014年硕士论文

【摘要】：直流输电本身所具有的经济性、高度可控及快速可调的特性，使其在远距离、大容量输电和区域电力系统联网等方面应用广泛，并逐渐形成了交直流输电并联运行、多回直流集中馈入受端系统的复杂电网，以我国南方电网尤为典型。对于多直流落点系统，换相失败是交直流相互作用下最为典型的问题。至2015年溪洛渡和糯扎渡直流工程投产后，南方电网在“十二五”期间将形成更为复杂的多直流落点系统，某些严重故障可能会引起南方电网受端八回直流输电逆变器同时发生换相失败，多回直流输电逆变器的换相失败特性与功率恢复特性对受端电网的安全稳定运行至关重要。因此对多直流落点系统进行详细地电磁暂态建模，通过仿真的方法研究直流换相失败及恢复特性非常必要。本文首先分析了换相失败的机理及影响换相失败和功率恢复过程的主要因素；使用PSCAD/EMTDC仿真软件，以糯扎渡±800kV特高压直流工程为例，研究逆变侧换流母线电压变化、逆变侧交流系统强度及低压限流控制（VDCOL）对换相失败及功率恢复特性的影响。针对大规模交直流电网电磁暂态仿真精确初始稳态难以确定的问题，提出了一种EMTDC快速建模调试方法，通过分区建模调试的思想将大电网建模问题转化成小电网进行解决，，使建模效率及模型准确度大大提高。对南方电网“两渡”直流投产后的2015水平年丰大规划方式数据进行了动态等值，采用上述方法对等值后系统建立了含全部8回直流详细模型及500kV主网架的交直流大电网PSCAD/EMTDC电磁暂态仿真模型。对2015年南方电网多直流落点系统换相失败特性进行了详细地EMTDC仿真分析，通过对受端主要500kV站点出线进行故障扫描确定了可能引起多回直流同时换相失败的站点，并重点对直流逆变站出线典型故障下各直流的响应特性及恢复过程进行了分析。最后对南方电网受端系统500kV北郊站、水乡站和木棉站分别配置±200Mvar静止同步补偿器（STATCOM）装置对多直流落点系统换相失败及恢复特性的影响进行了仿真分析。
[Abstract]:Because of its economical, highly controllable and fast adjustable characteristics, DC transmission has been widely used in long-distance, large-capacity transmission and regional power system networking, and has gradually formed a parallel operation of AC / DC transmission. The complex power grid with multiple DC centralized feed into the receiver system is especially typical in China Southern Power Grid. Commutation failure is the most typical problem under AC / DC interaction for multiple DC drop point systems. By 2015, when the Xiluodu and Nuozhadu DC projects are put into operation, the Southern Power Grid will form a more complex multi-DC landing point system during the 12th Five-Year Plan period. Some serious faults may cause commutative failure of the eight-circuit DC inverter at the receiving end of Southern Power Grid. The commutation failure characteristics and power recovery characteristics of the multi-circuit DC inverter are very important for the safe and stable operation of the receiving power network. Therefore, it is necessary to study the DC commutation failure and recovery characteristics through the detailed electromagnetic transient modeling of multi-DC drop point system. In this paper, the mechanism of commutation failure and the main factors influencing the process of commutation failure and power recovery are analyzed firstly, and the voltage variation of inverter side commutation bus is studied by using PSCAD / EMTDC simulation software, taking Nuozhadu 卤800kV UHV DC project as an example. The effect of inverter side AC system strength and low voltage current limiting control (VDCOL) on commutation failure and power recovery characteristics. In order to solve the problem that the accurate initial steady-state of electromagnetic transient simulation of large-scale AC / DC power network is difficult to determine, an EMTDC fast modeling and debugging method is proposed, which transforms the modeling problem of large power grid into a small power grid through the idea of zoning modeling and debugging. The efficiency and accuracy of modeling are greatly improved. In this paper, the dynamic equivalence of the 2015 level annual Fengda planning method data after the "two Dudu" DC operation in Southern Power Grid has been carried out. Using the above method, the electromagnetic transient simulation model of PSCAD / EMTDC for large AC / DC power grid with all 8 times DC detailed model and 500 kV main grid is established. A detailed EMTDC simulation analysis on the commutation failure characteristics of multi-DC drop point system in Southern Power Grid in 2015 is carried out. Through fault scanning of the main 500kV station at the receiving end, the stations that may cause multiple DC commutation failures are determined. The response characteristics and recovery process of each DC under typical fault of DC inverter station are analyzed. Finally, the effect of 卤200Mvar static synchronous compensator (+ 200Mvar) on commutation failure and recovery characteristics of 500kV northern suburb station, water station and kapok station of Southern Power Grid is simulated.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM721.1

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