主动配电网中无功功率全局协调控制策略

发布时间：2018-01-31 01:27

本文关键词： 主动配电网无功控制策略电压恢复全局优化　出处：《北京交通大学》2017年硕士论文　论文类型：学位论文

【摘要】：为了满足分布式电源(distributed generator,DG)高接入率及高控制要求的需要,主动配电网可通过灵活多变的网架结构和多种类型分布式电源、可控负荷等的协调控制实现大规模可再生能源并网。大规模DG接入配电网,可以提高清洁能源的比重,但其固有的间歇性、波动性和不确定性将影响配电网的运行,带来包括电能质量、电压控制及稳定性等问题。基于以上背景,本文深入开展主动配电网无功特性以及控制策略的研究,对于更好的接纳DG,实现对配电网的主动控制,提高系统的稳定运行水平具有重要的意义。本文在针对主动配电网不同的运行工况制定了不同的无功控制策略,通过控制策略的协调配合,使主动配电网在不同时间尺度和不同空间位置达到全局无功最优分配,主要工作内容如下:(1)定量分析了 DG并网对配电网的影响。采用牛顿-拉夫逊法作为潮流计算方法并在Matlab中进行仿真分析,从DG的容量、位置和功率因数三个方面分析了 DG接入对配电网电压以及网络损耗的影响。通过分析结果,提出了分布式电源接入配电网的相关建议。(2)针对系统正常运行情况制定对传统调压设备的控制策略。以有载调压变压器(On-load Tap Changer,OLTC)分接头和电容器组作为优化变量建立数学模型,选取了网损最小、电压偏差最小和综合考虑网损和电压偏差最小这三种优化目标分别进行分析,并采用遗传优化算法进行求解,使系统工作在最优潮流状态。(3)针对系统因为外界环境变化而造成的电压波动制定了基于灵敏度分析的无功电压控制策略。通过计算配电网电压—无功灵敏度值来寻求无功调节的最优方案,使调压更具目的性,发挥DG和SVG的快速无功调节能力实现电压恢复。(4)针对系统电压发生较大波动的情况制定分区电压调节策略。当网络中的DG和SVG的无功出力无法完成电压恢复时,启动电容器组和OLTC分接头进行调压,根据调压设备的最小调节单元引起的电压改变量将网络进行调压区域的划分,并制定了调压顺序规则,将调压装置的相互影响作用降到最小,避免了无效调压。(5)在以上三种调压策略的基础上制定无功全局协调控制策略,根据各种无功调节装置的各自特点,分别将其纳入至不同的控制环节中,通过以上三种控制策略的相互协调配合,使主动配电网在不同空间位置和不同时间尺度上达到无功分配全局优化。
[Abstract]:In order to meet the needs of high access rate and high control requirements of distributed power generation distributed generator (DGG). Active distribution network can realize large-scale renewable energy grid connection through flexible and changeable network structure and coordinated control of various types of distributed power generation and controllable load. Large scale DG can be connected to distribution network. Can increase the proportion of clean energy, but its inherent intermittent, volatility and uncertainty will affect the operation of distribution networks, including power quality, voltage control and stability issues. In this paper, the reactive power characteristics and control strategy of the active distribution network are deeply studied, so as to better accept DGs and realize the active control of the distribution network. It is of great significance to improve the stable operation level of the system. In this paper, different reactive power control strategies are formulated for different operating conditions of the active distribution network, through the coordination of control strategies. The active distribution network can achieve the global optimal reactive power allocation in different time scales and different space positions. The main work is as follows: (1) the influence of DG on distribution network is analyzed quantitatively. Newton-Raphson method is used as the power flow calculation method and simulated in Matlab, and the capacity of DG is analyzed. The influence of DG access on distribution network voltage and network loss is analyzed from three aspects of position and power factor. This paper puts forward the relevant suggestions of distributed power generation access to distribution network. (2) to make the control strategy of traditional voltage regulating equipment according to the normal operation of the system, and to use the on-load voltage regulating transformer (. On-load Tap Changer. The mathematical model of OLTC tap and capacitor bank is established as the optimization variable. The three optimization objectives, namely, minimum network loss, minimum voltage deviation and comprehensive consideration of network loss and minimum voltage deviation, are selected for analysis respectively. Genetic optimization algorithm is used to solve the problem. Make the system work in the optimal power flow state. A reactive power and voltage control strategy based on sensitivity analysis is developed for the voltage fluctuation caused by the external environment. The optimal scheme of reactive power regulation is obtained by calculating the voltage-reactive sensitivity value of the distribution network. Make pressure regulation more purposeful. Exert DG and SVG's fast reactive power regulation ability to realize voltage recovery. When the reactive power of DG and SVG in the network can not complete the voltage recovery, a voltage regulation strategy is developed for the voltage fluctuation of the system. Start the capacitor bank and OLTC tap to adjust the voltage, according to the voltage change caused by the minimum regulating unit of the voltage regulator, divide the network voltage regulation area, and establish the regulation of voltage regulation sequence. The interaction of voltage regulator is minimized to avoid the ineffective voltage regulation. 5) based on the above three voltage regulation strategies, the reactive power global coordinated control strategy is formulated, according to the respective characteristics of various reactive power regulation devices. Through the coordination and coordination of the above three control strategies, the active distribution network can achieve the global optimization of reactive power distribution in different space positions and different time scales.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM714.3;TM744

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