【作者】 文一宇；

【导师】 颜伟；

【作者基本信息】 重庆大学 ， 电气工程， 2011， 硕士

【摘要】 随着现代电力系统的发展,系统的规模不断扩大,网络的结构日趋复杂,环境和经济因素的制约使电力系统的运行情况更加接近极限条件,进而引发安全稳定问题,导致系统崩溃。因此,电力系统的安全稳定问题一直是研究的热点,而其中的静态电压稳定问题也越来越受到关注。目前,切负荷控制被认为是解决电力系统电压稳定性的一种有效的控制措施。但现有的静态电压稳定控制策略都是基于全网信息来形成控制方案,在电网处于临界运行情况下依靠全网信息来进行决策,将造成控制实施的不及时,最终无法达到控制的预期效果。因此,本文以外网等值方法为基础,提出了基于外网等值的区域电网的静态电压稳定分析方法与广域控制模型。以期通过将区域电网的外部网络等值,达到提高区域电网静态电压稳定分析与广域控制效率的目的。本文主要研究内容如下:①以基于单点信息的外网等值方法研究为基础,提出了一种考虑量测数据误差的戴维南等值最小二乘模型,并将此模型与连续潮流结合起来,应用于分析区域电网的静态电压稳定裕度。在所提的戴维南等值模型中,考虑了等值电势相角的变化;而且模型方程中量测量不再视为常数,而是作为待求变量,以期通过最小二乘法滤除量测数据存在的误差。最后通过改造的IEEE14节点系统对所提等值方法的有效性进行了仿真验证。②针对区域电网的特点,基于考虑量测误差的戴维南等值最小二乘模型,提出了一种考虑外网等值的静态电压稳定广域切负荷控制策略。该策略通过戴维南等值方法考虑了外部系统对区域电网的影响;并以负荷增长状态下的潮流等式约束为静态电压稳定约束,较为合理的考虑了静态电压稳定的要求。而后,以等值后网络在负荷增长状态下的潮流等式约束作为静态电压稳定约束条件,建立了区域电网的全二次最小切负荷优化模型,并采用半光滑牛顿法求解。由于策略采用了全二次优化模型,计算过程中海森矩阵只需修正一次,可提高模型求解速度。采用改造的IEEE14节点系统和IEEE30节点系统对所提策略的有效性进行了的仿真验证。更多还原

【Abstract】 With the development of the power technology, the expansion of the system size and the increasing complication of the network structure, power systems are operated more close to their limit conditions under the restriction of environmental and economic factors. And the security and stability problems occur continually which may even cause the system collapse. Consequently, power system stability and security problem has been an important research issue and the static voltage stability problem is paid more and more attention.Load shedding is considered as an effective measure to the voltage stability problem. The existing control strategies are all formulated based on information of the whole network. The implement of control measures may miss the opportunity when power system is operated close to its limit. Then the expected control purpose cannot be achieved. So a method for analyzing the static voltage stability of regional grid and a wide-area control strategy, which is based on external network equivalence method are proposed. The efficiency of static voltage stability analysis and wide-area control should be improved after taking account the external network equivalence method.The main contexts are listed as follows:①A least square Thevenin equivalence model taking account of measurement error is proposed based on the single-bus external network equivalence method, which can not only consider the change of equivalent voltage phase angle, but also filter the measurement error effectively. Continuation power flow method is adopted to analysis the static voltage stability margin based on the proposed equivalence model. Numerical tests on the modified IEEE14 bus system illuminate that static voltage stability is more accuracy with the proposed equivalence model.②A wide-area load shedding strategy based on Thevenin equivalence is proposed according the specialty of regional grids. The proposed strategy takes the effect of external system into account according to the Thevenin equivalence method. The requirement of static voltage stability is considered reasonably by taking the power flow equations with increasing load as static voltage stability constraints. Then a minimizing load shedding optimal model, which is quadratic, is established by considering the power flow equations with load margin as the static voltage stability constraints and the semi-smooth Newton method is used to solve the optimal model. The calculation speed can be increased by using the quadratic model, whose Hiaasen matrix is formed only at the first iteration. The validity and the efficiency of the proposed load shedding strategy are tested in the modified IEEE14 bus system and IEEE30 bus system.更多还原