全桥型MMC与LCC混合直流的故障及潮流反转特性研究

发布时间：2018-06-17 17:30

本文选题：电网换相高压直流输电 + 全桥型模块化多电平换流器　；参考：《华北电力大学(北京)》2014年硕士论文

【摘要】：传统电网换相换流器(Line Commutated Converter,LCC)成本较低、技术较为成熟,但需吸收大量无功功率且存在换相失败的危险;而全桥型模块化多电平换流器(Full Bridge Modular Multilevel Converter,FBMMC)作为最新一代的电压源换流器(Voltage Source Converter,VSC)拓扑,不仅具有有功无功独立调节,可向无源网络供电等优势,还具有不依赖器件串联、运行控制方式灵活以及穿越严重故障能力等优势,但成本相对较高。。论文提出的整流侧为LCC,逆变侧为全桥型MMC(FBMMC)的混合直流输电方式(Hybrid High Voltage Direct Current with FBMMC as Inverter,FBMMC-IH-HVDC)),既兼顾了 LCC的经济性与FBMMC的灵活性和可控性特点,同时比起一般的混合直流输电方式,它还具有故障穿越能力与潮流反转能力。论文针对FBMMC-IH-HVDC系统的数学模型、运行原理、控制策略、故障穿越及潮流反转特性进行了研究,能够为FBMMC-IH-HVDC工程的实施提供一定的理论依据。首先,论文建立了 FBMMC-IH-HVDC系统的数学模型,研究了其系统结构与运行原理,提出了适用于FBMMC-IH-HVDC系统的全桥MMC侧相应的调制策略、子模块触发控制策略、电容均压控制策略、环流抑制控制策略与降损控制策略,并进行了相应的控制器设计。然后,论文对FBMMC-IH-HVDC系统进行了可控性分析,提出了适合于该系统的站级控制策略,并设计了适用于该系统的控制器。针对LCC侧,提出了适用于LCC的控制策略;针对FBMMC侧,建立了相应的dq坐标动态模型,设计FBMMC的基本功能控制器。接着,论文对于FBMMC-IH-HVDC系统故障穿越特性进行了相应的研究。相对于其他混合直流输电方式,FBMMC-IH-HVDC系统不必等到机械开关的交流断路器的反应再去断开线路,可防止故障电流进一步增大和故障范围的进一步扩大,从而大大提高了系统的安全性和可靠性。最后,论文对于FBMMC-IH-HVDC系统潮流反转特性进行了研究。设计了适用于FBMMC-IH-HVDC系统的一种改进潮流反转方法,从而在系统不停电方式的情况下,即可进行潮流的反转,从而可减小潮流反转过程对系统的冲击。
[Abstract]:The traditional commutated converter line commutated converter LCCs have low cost and mature technology, but need to absorb a lot of reactive power and have the risk of commutation failure. As the newest generation voltage source converter, full Bridge Modular multilevel Converter (FBMMC) not only has the advantages of independent regulation of active power and reactive power, but also has the advantages of independent regulation of active power and reactive power, power supply to passive network, and independent series of devices. The operation control mode is flexible and the ability to pass through the serious fault, but the cost is relatively high. Hybrid High Voltage Direct current with FBMMC as Inverter FMMC-IH-HVDC is proposed, which takes into account the economy of LCC and the flexibility and controllability of FBMMC. It also has the ability of fault passing and power flow reversal. In this paper, the mathematical model, operation principle, control strategy, fault passage and power flow reversal characteristics of FBMMC-IH-HVDC system are studied, which can provide some theoretical basis for the implementation of FBMMC-IH-HVDC project. Firstly, the mathematical model of FBMMC-IH-HVDC system is established, the system structure and operation principle are studied, and the corresponding modulation strategy, sub-module trigger control strategy and capacitive voltage sharing control strategy are proposed for FBMMC-IH-HVDC system. The loop suppression control strategy and the loss reduction control strategy are designed and the corresponding controller is designed. Then, the controllability of FBMMC-IH-HVDC system is analyzed, and the station level control strategy suitable for the system is proposed, and the controller suitable for the system is designed. Aiming at the LCC side, the control strategy suitable for LCC is put forward, and the corresponding dynamic model of DQ coordinate is established for the FBMMC side, and the basic functional controller of FBMMC is designed. Then, the fault-passing characteristics of FBMMC-IH-HVDC system are studied. Compared with other hybrid DC transmission modes, FBMMC-IH-HVDC system does not have to wait for the reaction of mechanical switch AC circuit breaker to disconnect the circuit, which can prevent the further increase of fault current and the further expansion of fault range. Thus, the security and reliability of the system are greatly improved. Finally, the power flow inversion characteristics of FBMMC-IH-HVDC system are studied. An improved power flow inversion method is designed for FBMMC-IH-HVDC system, which can reverse the power flow without power failure and reduce the impact of the power flow reversal process on the system.
【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】：2014
【分类号】：TM721.1

【相似文献】