基于改进蚁群算法的电网无功补偿优化控制研究

电力系统无功功率补偿控制是个综合非线性问题,利用改进蚁群算法建立以电网电压畸变为约束条件、以电压和无功综合满意度达标为目标函数的无功优化综合数学模型。结合IEEE 14系统,对基于改进蚁群算法无功优化配置方案进行了仿真分析。结果表明,利用改进蚁群算法建立的无功补偿模型能够精确地进行电网无功功率的补偿,是无功优化控制的一种理想模型,具有一定的科学研究价值。     

基于粒子群算法的变电站电压无功综合控制

变电站电压无功综合控制的作用是在负荷和电压波动情况下向用户提供合格的电能,降低网损。近年来已开发出许多电压无功综合控制优化算法。根据负荷预测,全局规划,寻求最优控制策略,是较先进的一种方法。文章阐述在负荷预测精度不断提高的基础上,如何建立变电站电压无功控制的求解模型,利用改进的粒子群算法求取变电站电压无功最优控制策略。对实例的计算结果表明,利用该算法得出的控制策略与传统方法相比控制效果更优,且能提高系统的安全性和经济性。     

基于负荷预测的变电站电压无功综合控制策略

目前的变电站电压无功综合控制方法对短期负荷波动的适应性差,为解决该问题,提出了一种变电站电压无功综合控制策略数学模型。该算法模型由启动判据、利用超短期负荷预测结果对控制量的修正算法、动作判据和区域配合算法几个数学模型构成,给出了这些模型的数学表达式和这些数学模型怎样与基于前一工作日和节假日负荷的超短期负荷预测结果相结合来实现地区变电站的电压无功综合控制的方法,并采用该算法研制设备的变电站的运行结果证实了该算法模型的正确性与优越性。     

基于分级分区的地区电网无功电压闭环控制系统

采用两级无功电压控制策略相结合的体系实现无功电压闭环控制。"区域级"无功电压控制将电网划分为若干具有辐射状结构的无功电压控制区域,以各分区为单位,采用等值递推和最优匹配注入流算法的交叉迭代方法来实现。"厂站级"无功电压控制利用改进的九区图法实现,并在"区域级"无功电压控制策略无法实施时启动。现场控制实例和仿真算例表明,算法实用、鲁棒性好,形成的控制策略合理有效,优化控制效果明显。     

基于改进型纵横交叉算法的电力系统无功规划优化

<正>将纵横交叉(CSO)算法应用到电力系统无功规划优化问题,并对CSO算法进行改进。运用混沌映射产生分布均匀的初始解,引进纵交叉微算子,并将量子粒子群算法搜索机制与CSO结合,增加算法的搜索能力。利用电压稳定裕度指标,找寻系统电压稳定性较薄弱节点,将其作为无功规划节点,并将综合规划费用和电压稳定裕度指标写入目标函数,追寻综合规划费用最低的同时提高电压稳定性。通过IEEE-30节点系统的仿真,验证了该规划方法和算法的有     

三目标混合骨干粒子群算法的电力系统无功优化

电力系统无功优化通常以降低有功网损和减小电压偏移为目标,建立了综合考虑有功网损和电压偏移最小及电压稳定裕度最大的三目标无功优化模型。首次引入混合骨干粒子群算法用于解决电力系统无功优化问题。该算法利用关于粒子个体极值和全局极值的高斯分布对粒子位置进行更新,再通过K-均值聚类的方式,引入单纯形法对有代表性的粒子进行单纯形搜索,使算法既能够具备较强的全局搜索能力,又能够提高收敛速度和精度。将该算法和其他算法应用于IEEE-14节点系统中进行无功优化,通过数据的计算和比较,结果验证了该模型和算法用于解决多目标电力系统无功优化问题的优越性和实用性。     

基于分级分区的地区电网无功电压闭环控制系统

采用两级无功电压控制策略相结合的体系实现无功电压闭环控制."区域级"无功电压控制将电网划分为若干具有辐射状结构的无功电压控制区域,以各分区为单位,采用等值递推和最优匹配注入流算法的交叉迭代方法来实现."厂站级"无功电压控制利用改进的九区图法实现,并在"区域级"无功电压控制策略无法实施时启动.现场控制实例和仿真算例表明,算法实用、鲁棒性好,形成的控制策略合理有效,优化控制效果明显.     

基于协调VQC定值的分层电压无功控制

在基于VQC实现变电站各级电压无功综合控制的基础上,探索县级电网多变电站VQC协调控制。通过通信子系统获取各变电站的开关状态和负荷信息,利用卡尔曼滤波法对次日负荷进行预测,然后使用离散无功优化模型及其扩展内点算法进行全网离散无功优化计算,在有限变压器分接头调整次数和电容器组投切次数约束下得到最优无功和最优电压运行曲线,在此基础上完成县级电网多台VQC定值设定。计算结果验证了所提出的算法的正确性、可靠性以及处理区域电网离散无功优化问题的能力。     

基于动态多种群粒子群算法的低压配电网电压无功优化

粒子群算法已在配电网无功优化领域中得到广泛应用,而基本粒子群算法在求解多约束条件的低压配电网电压无功优化问题时耗时过长。为解决这一问题,提出了利用动态多种群粒子群算法对低压配电网进行电压无功优化方案。动态多种群粒子群算法通过轮盘赌将粒子按照各节点电压合格、各节点无功补偿容量不超过预设值和系统总无功不过补偿这3个约束条件进行动态分组,粒子根据改进的粒子速度位置更新公式飞行搜寻,最后获得满足以上约束条件的电压无功优化问题最优解。本文提出的电压无功优化方案将分散并联电容器组与配电变压器调压相结合,与集中补偿无功方式相比,节点电压偏移程度更小、电网损耗更低。本文应用的约束优化粒子算法与基本粒子群算法相比,运行速度大幅提高,计算结果较为优化。     

地区电网无功电压的综合调节

电压质量对电网稳定及电力设备安全运行具有重大影响,而无功潮流又是影响电压质量的一个重要因素。为了适应高速发展的经济对电能质量日益提高的要求,提高电压无功调节的自动化水平和调节效能成为供电发展的一个主要方向。为此,在滨海地区建立了区域电压无功优化控制系统,利用高效稳定的计算机算法在集控中心集中对电网电压进行综合调节,达到了预期的控制效果,为进一步的应用扩展奠定了良好基础。     

A combined artificial neural network-fuzzy dynamic programmingapproach to reactive power/voltage control in a distribution substation

Reactive power/voltage control in a distribution substation is investigated in this work. The purpose is to determine proper capacitor on/off status and suitable load tap changer (LTC) positions for the 24 hours in the next day. To reach this goal, an artificial neural network (ANN) is designed to reach a preliminary dispatch schedule for the capacitor and LTC. The inputs to the ANN are main transformer real power and reactive power and primary and secondary bus voltages and the outputs are the desired capacitor on/off status and LTC tap positions. The preliminary dispatch schedule is further refined by fuzzy dynamic programming in order to reach the final schedule. To demonstrate the effectiveness of the proposed method, reactive power/voltage control is performed on a distribution substation in Taipei, Taiwan. Results from the example show that a proper dispatch schedule for capacitor and LTC can be reached by the proposed method in a very short period     

Volt/Var control in a distribution system by a fuzzy optimization approach

This paper presents a fuzzy optimization approach for solving the Volt/Var control problem in a distribution system with uncertainties. Wind turbines are being considered in the study distribution system. The main purpose is to find an optimum combination of tap position for the main transformer under load tap changer (ULTC) and on/off status for switched capacitors in a day to minimize the voltage deviation on the secondary bus of the main transformer, reactive power flow through the main transformer and real power loss on feeders. When performing the Volt/Var control problem in conventional methods, the hourly load and wind speed must be forecasted to prevent errors. However, actually there are always errors in these forecasted values. A characteristic feature of the proposed fuzzy optimization approach is that the forecast hourly load and wind speed errors can be taken into account using fuzzy sets. Fuzzy set notations in the load demand, wind speed, voltage deviation on the secondary bus, reactive power flow through the main transformer and total real power loss on feeders are developed to obtain the optimal dispatching schedule under an uncertain environment. To demonstrate the effectiveness of the proposed method, the Volt/Var control problem is performed in a distribution system within the service area of Yunlin District Office of Taiwan Power Company (TPC). The results show that a proper dispatching schedule for ULTC position and capacitor switching operation can be reached using the proposed method.     

电力系统无功电压调控装置控制策略

扼要地介绍了一种功能和控制策略与传统的变电站电压无功调节控制装置完全不同的电力系统无功电压调节控制装置的应用、控制原理、控制方法以及计算软件,并对漫湾－草铺500kV输电系统进行了基于经济压差（△UJ)的优化无功潮流（OPF）计算分析。只要在同一电压层的每个发电厂和变电站都装上一套装置并正常运行,电力系统就能有最优（或接近最优）无功潮流,达到电压好、线损低和电压稳定储备高的目的。     

基于遗传算法的变电站电压无功综合控制

采用常规方法进行变电站电压无功控制时 ,往往使二次侧电压过于接近边界而导致系统承受负荷波动的能力大大下降 ,成为系统安全运行的隐患。该文在负荷预测的基础上把遗传算法应用于变电站电压无功控制 ,使主变中流过的无功功率及主变二次侧电压偏移最小。首先建立无功电压控制的求解模型 ,针对其计算空间过大的特点 ,引入遗传算法在全局范围内求最优解。对实例计算结果表明 ,所提算法较传统方法能更有效地搜索到最优控制策略 ,并使二次侧电压合格裕度有较大增加     

配电网无功优化的分时段控制策略

为改善电压、降低损耗、简化控制，根据负荷水平及其变化趋势，对已装有补偿电容和在变电站装有有载调压变压器的配电网，提出了分时段优化控制的策略，开发了次日运行中电容器投切和调压变压器变比调节的模型和算法。应用改进的退火选择遗传算法，该算法对于每一负荷时段可得出该段的最优运行方式；计算一天所有负荷段即得出次日电容器投切和调压变压器变化调节的运行表。该模型易于满足电容器投切和变压器调节次数的限制。文中还分析了有载调压变压器调节电网电压水平的作用和变压器铁耗的影响。算例结果表明该算法不但能有效地降低电能损耗，而且控制简单。     

综合动态安全与静态电压稳定的协调预防控制

考虑不同稳定问题的预防控制措施通过控制中心的调度计划施行,共用一个控制通道,它们之间需要进行协调。首先提出了考虑综合安全约束的最优潮流(CSC-OPF)模型来描述协调预防控制问题,给出了该模型的2种应用模式:对当前运行点的最低成本协调预防控制和以提高极限传输功率为目标的最低成本控制。通过将综合安全约束解耦为运行可行性子约束、静态电压稳定子约束和动态安全子约束,将CSC-OPF模型转化为一个线性优化模型并采用连续线性规划方法来求解。通过新英格兰10机39节点系统算例验证了该方法的有效性。     

Fuzzy dynamic programming approach to reactive power/voltagecontrol in a distribution substation

A fuzzy dynamic programming (FDP) approach is proposed for solving the reactive power/voltage control problem in a distribution substation. The main purpose is to improve the voltage profile on the secondary bus and restrain the reactive power flow into a main transformer at the same time. To reach our objectives, the load tap changer (LTC) usually installed in a main transformer is employed to adjust the secondary voltage and the capacitor connected to the secondary bus is employed to compensate the reactive power flow for the load demands. We first forecast the real and reactive power demands of a main transformer and its primary voltages for the next day. With these forecasting data at hand, a fast LTC tap position estimation formula that takes the load models into account is derived to effectively reduce the computational burden for the proposed approach. Practical constraints on bus voltage limits, maximum allowable number switching operations in a day for the LTC and capacitor and the tolerable worst power factor for a main transformer are also considered. To demonstrate the usefulness of the proposed approach, reactive power/voltage control at a distribution substation within the service area of Taipei City District Office of Taiwan Power Company is investigated. It is found that a proper dispatching schedule for the LTC and capacitor can be reached by the proposed approach     

死区时间控制在等离子体电源中的应用

死区时间选择的不合理会使逆变器件产生过高的浪涌电压和电流甚至损坏。针对这一问题提出了动态的零电压延迟控制技术,它监测输入供电电压和负载电流,当逆变器功率管达到期望的零电压开关(zero voltage switching,ZVS)条件时,控制功率开关管,使变换器几乎在整个工作条件下都能实现ZVS,而不需考虑输入电压、输出负载和元器件的容差,实现最佳的导通延迟时间。应用该技术的等离子体高频高压电源在纺织材料中的实际应用结果表明:该技术在进一步提高了电源效率的同时,减小了因不合理的死区时间带来的过高的浪涌电压和电流,改善了纺织材料表面改性涂层的性能。     

A heuristic and algorithmic combined approach for reactive power optimization with time-varying load demand in distribution systems

Reactive power optimization with time-varying load demand in distribution systems is investigated in this paper. The objective of this paper is to determine the proper setting values of capacitor banks and transformer taps for the 24 h in the next day. A heuristic and algorithmic combined approach is proposed in this paper. The approach simplifies the mathematical model of the daily setting values of reactive power/voltage control devices, solves the temporal optimization of each control device by heuristic rules, and then converts the optimization model with time-varying load into the same one as conventional optimization model with constant load. Therefore, the algorithms applied to the conventional optimization model can be easily used to solve the optimization model with time-varying load demand. Results from numerical examples show that a proper dispatch schedule for capacitor banks and transformer taps can be reached by this approach efficiently.