【作者】 王洋；

【导师】 江晓东； 李林川；

【作者基本信息】 天津大学 ， 电气工程， 2014， 硕士

【摘要】 随着风电并网技术的不断发展，风电装机容量在电网中的比例越来越高。就中国而言，风力发电采取大规模，高集中开发，并通过远距离，高电压电网进行输送。由于风能预测精度的不足，风能出力随机性和不确定性的特点会对电力系统的影响越来越大。风能的大量接入影响系统的潮流分布和线路传输能力，会对电网的电压稳定性产生一定的影响。对于风电系统来说，电力系统静态电压稳定性不再是确定性问题，而是考虑了风能出力随机性的随机问题。针对这一问题，本文提出了一种考虑风能随机性和不可控性的电压稳定分析方法。1.不再假定风能出力等于预测值。考虑风能预测精度不足，视风能出力为满足某一概率分布的随机变量。利用场景生成技术，通过大量场景近似表示风能出力的随机性。每一种场景代表一种可能的出力情况，并考虑各风电场出力的时空相关性。2.对于基于场景的随机问题，为了提高计算速度，提出了一种高效的‘基于问题的场景消除技术’。与常规的场景消除技术相比，该方法不仅考虑场景之间的统计特性，也考虑了电压稳定问题的具体特性，利用风能出力与负荷裕度的关系进行场景的消除，可快速准确的找到可能引起电压稳定问题的风能出力情况。该方法主要采用了：K-means分群，灵敏度分析，look-ahead方法，连续潮流分析。3.利用改进look-ahead方法，快速得到各风能出力下所对应的负荷裕度，得到负荷裕度的概率分布曲线。根据获得的概率分布曲线图，可直观的分析风能出力随机性对电压稳定的影响情况，得到统计信息。本文考虑了机组无功越限时的电压稳定情况，当机组发生无功越限时，系统不仅可能发生鞍结点分岔，也可能发生结构诱导分岔。更多还原

【Abstract】 With the development of the technology of wind power integration, thepenetration of wind power into power system has been increased drastically. ForChina, the development mode is large-scale and high concentration. And thetransmission of wind power is through the long distance and high voltage network.Because of the forecasting error, the uncertain and random characteristics haveinfluenced the power system. The increasing penetration of wind power will influencethe distribution of power flow and the capacity of transmission, and it will lead to theproblem of voltage stability. For the wind power system, the voltage stability has to beinterpreted as a stochastic problem. In this paper, a method of voltage stabilityanalysis considering the uncertain and random characteristics of wind power has beenproposed.1. Wind power is treated as a stochastic variable which satisfies one probabilitydistribution. Through the scenarios generation method, wind power has beenrepresented by a huge number of scenarios.2. For the scenarios-based stochastic problem, a high effective Problem-dependentscenarios reduction method has been proposed. Compared with the traditionalmethod, the proposed method has taken not only the statistical characteristics ofscenarios but also the problem itself into consideration. Through theproblem-dependent method, the severe scenarios which can lead to voltagecollapse can be found quickly. It is composed of K-means, sensitivity analysis,look-ahead method and continuous power flow method.3. The corresponding load margin of each scenario can be obtained by enhancedlook-ahead method quickly and accurately. Then the probability distribution ofload margin corresponding to the wind power can be obtained. The influence ofwind power on the voltage stability can be got through the distribution.Besides that, the reactive power limit has been taken into considerations. Whenthe system encounters the Q-limit, it may lead to the limit-induced bifurcation whichis more dangerous for the power system.更多还原