低压配电网三相不平衡治理的研究

发布时间：2018-08-21 13:57

【摘要】：随着智能电网的高速发展,对低压配电网络的电能质量和降低损耗提出了更高的要求,而三相负载不平衡是影响它们的重要因素。如果不采用合理高效的手段治理配电网中的三相不平衡,可能就会影响整个电力系统安全稳定的运行。因此,低压配电网中三相不平衡问题成为人们研究的热点。通常对于低压网段三相负荷不平衡的治理,常用的是无功补偿装置和智能换相开关。虽然两者均能达到治理的目的,但前者由于其较高的成本和较大的体积使其不利于在市场中广泛的应用,而后者大都是基于机械触点开关来进行换相,会对供电质量产生较大的影响。因此,本文设计了全电容补偿的无功补偿方案和固态智能换相开关两种三相不平衡治理方案,具体工作主要包括:1.介绍了无功补偿和相间负荷调整的应用发展现状,总结了两种三相不平衡度的计算方法,分析了三相不平衡对配电变压器、输电线路、发电机等带来的危害,概述了电力相关部门常采用的解决三相不平衡的措施。2.从无功补偿角度,分析了无功补偿原理和三相功率平衡化现象。通过分析典型单相负荷的不平衡补偿,进而引出了基于理想补偿网络的三相负荷补偿模型,并对该模型进行仿真分析。接着针对理想补偿网络中存在的不足,设计了矢量分析的补偿策略,并推得了其数学模型。3.以矢量分析补偿策略为基础,设计了基于全电容的编组复合开关无功补偿方案。针对该方案中与补偿电容值相关的基波电流有功和无功分量检测问题,设计了空间矢量变换的电流检测方法。通过对方案进行仿真分析,验证了其可行性。4.最后从负荷相序调整角度,设计了基于固态智能换相开关的三相不平衡治理方案。通过对固态智能换相开关进行仿真,验证了其在换相过程中电压中断时间大大的缩短。接着详细的介绍了该治理方案中各个主要功能模块和最优换相策略的获得过程,同时建立了三相不平衡优化模型,并采用加速粒子群智能优化算法对模型求解。通过实验仿真分析,验证了所建立的模型和求解方法的可行性。
[Abstract]:With the rapid development of smart grid, the power quality and loss reduction of low-voltage distribution network are required higher, and three-phase load imbalance is an important factor affecting them. If we do not use reasonable and efficient means to control the three-phase imbalance in the distribution network, it may affect the safe and stable operation of the whole power system. Therefore, the problem of three-phase imbalance in low-voltage distribution network has become a hot topic. Reactive power compensator and intelligent commutation switch are commonly used for the treatment of unbalanced three-phase load in low voltage network. Although both can achieve the goal of governance, the former, because of its high cost and large volume, is not conducive to its wide application in the market, while the latter is mostly based on mechanical contact switches for commutation. Will have a greater impact on the quality of power supply. Therefore, the reactive power compensation scheme of full capacitance compensation and the two three phase imbalance control schemes of solid state intelligent commutation switch are designed in this paper. The main work includes: 1. This paper introduces the application and development of reactive power compensation and interphase load adjustment, summarizes two calculation methods of three-phase unbalance, analyzes the harm of three-phase unbalance to distribution transformer, transmission line, generator, etc. The measures to solve the three-phase imbalance commonly adopted by power-related departments. 2. 2. From the angle of reactive power compensation, the principle of reactive power compensation and the phenomenon of three-phase power balance are analyzed. By analyzing the unbalanced compensation of typical single-phase load, a three-phase load compensation model based on ideal compensation network is proposed, and the model is simulated and analyzed. Then, the compensation strategy of vector analysis is designed for the deficiency of ideal compensation network, and its mathematical model. 3. Based on the compensation strategy of vector analysis, the reactive power compensation scheme of marshalling compound switch based on full capacitance is designed. In order to detect the active and reactive components of the fundamental current which is related to the compensation capacitance, a space vector transform (SVT) current detection method is designed. The feasibility of the method is verified by simulation and analysis. Finally, from the point of view of load phase sequence adjustment, a three phase imbalance control scheme based on solid state intelligent commutation switch is designed. Through the simulation of the solid-state intelligent commutation switch, it is verified that the voltage interruption time is greatly shortened during the commutation process. Then the process of obtaining the main function modules and the optimal commutation strategy is introduced in detail. At the same time, the three-phase unbalanced optimization model is established, and the accelerated particle swarm optimization algorithm is used to solve the model. The feasibility of the established model and the solving method are verified by simulation.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM732

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