Optimal power flow by BAT search algorithm for generation reallocation with unified power flow controller

Optimal power flow with generation reallocation is a suitable method for better utilization of the existing system. In recent years, Flexible AC Transmission System (FACTS) devices, have led to the development of controllers that provide controllability and flexibility for power transmission. Out of the FACTS devices unified power flow controller (UPFC) is a versatile device, capable of controlling the power system parameters like voltage magnitude, phase angle and line impedance individually or simultaneously. The main aim of this paper is to minimize real power losses in a power system using BAT search algorithm without and with the presence of UPFC. Minimization of real power losses is done by considering the power generated by generator buses, voltage magnitudes at generator buses and reactive power injection from reactive power compensators. The proposed BAT algorithm based Optimal Power Flow (OPF) has been tested on a 5 bus test system and modified IEEE 30 bus system without and with UPFC. The results of the system with and without UPFC are compared in terms of active power losses in the transmission line using BAT algorithm. The obtained results are also compared with Genetic algorithm (GA).     

统一潮流控制器系统串联变压器保护设计

串联变压器是统一潮流控制器(UPFC)系统的重要组成部分。其原边绕组直接串入电力系统,变压器设备特性和运行方式同常规电力变压器有很大不同,需要提供专用的保护方案。文中从串联变压器的特性和运行方式出发,提出了串联变压器保护需要考虑的特殊问题。针对其特殊性提出了完整的串联变压器保护配置方案,并给出了适用于串联变压器的专用保护判据。最后使用实际工程参数建立实时数字仿真(RTDS)模型。仿真结果表明,文中理论分析正确,所提出的保护方案和判据可靠有效。     

Performance Evaluation of Power Oscillation Damping Controller—Firefly Algorithm Based Parameter Tuning

This paper presents the performance evaluation of power oscillation damping controller based on firefly algorithm (FA) parameter tuning. The power system stabilizer (PSS), unified power flow controller (UPFC), and static synchronous series compensator (SSSC) are tuned with FA by minimizing integral time multiplied by absolute error (ITAE) as an objective function. An integrated multi-stage linear quadratic regulator – power oscillation damping UPFC/SSSC has been proposed with precise tuning of control parameters which results in overall states' oscillation damping as compared to other classical methods. It has been observed that the proposed control structure damps the oscillations adequately and is modular in design methodology. The sample power system comprising six areas has been considered to demonstrate the effectiveness of the concept. The software has been developed based on the proposed work by the authors and the MATLAB code has been generated in R2009b version. The states' inter-relation which has been shown with eigenvalues reflects a better regulation and the step response is also validated.     

Knowledge domain states mapping concept for controller tuning in an interconnected power network

This paper presents novel power system stabilizers (PSS) tuning approach with particles swarm optimization (PSO) driven knowledge domain states mapping for multi area power system. Tuning of PSS parameters has been done by PSO technique offline at different operating conditions as load dynamics change. The objective function for PSS parameters tuning is integral time multiplied by absolute error (ITAE). The sets of tuned parameters at different operating conditions thus obtained are termed as knowledge domain. The process is viewed as knowledge domain mapping. The dynamical system response has been linked with states, and if there is any violation from desired limits, control action is initiated and thus retuned control parameters obtained straight away from the respective knowledge domain helps to provide quick response and precise damping of signals of interest. Proposed concept also demonstrates that if one controller (PSS) fails to stabilize the system at certain operating condition then another controller (UPFC) connected in the system acts as supplementary controller in automation which assists PSS functioning and thus entire system operation improves by way of modulating the signal dynamics at interface points which quickly damps oscillations. The system study has been performed on a sample six area power systems comprising of UPFC connected between area two and three and PSS to all areas. The proposed concept demonstrates auto tuning of PSS for quick oscillation damping as the operating conditions change and also under situations of PSS failure due to relatively larger perturbation, UPFC acts as supplementary controller by assisting the entire system PSS to recover ensuring stability.     

电力市场条件下的UPFC安装地点的综合定量化评价研究

电力市场的运营在给电力系统和社会带来巨大经济效益的同时,也对电力系统稳定运行提出了更高的要求。UPFC是解决电力系统稳定运行的有效技术之一。在考虑到UPFC安装后紧急控制有效程度,本文提出了评价UPFC安装地点的效果指标;同时,提出了稳态潮流控制下的UPFC安装地点评价指标;在此基础上,分析了在电力市场下的UPFC安装...     

统一潮流控制器稳态性能研究

总结含统一潮流控制器(unified power flow controller,UPFC)的系统潮流计算方法,在此基础上设计一个能与传统PQ潮流算法结合的UPFC潮流计算模型,将潮流计算结果与UPFC的稳态模型相结合,分析控制目标值与系统控制量、电气量的关系.提出一种用中间控制变量代替直接控制方式的潮流控制策略,仿真...     

双级矩阵变换器在统一潮流控制器中的应用研究

根据统一潮流控制器的基本原理,结合双级矩阵变换器的优越电气性能,研究采用双级矩阵变换器实现统一潮流控制器的方案。对统一潮流控制器建立两相同步旋转dq坐标系下的控制动态模型,解决如何利用逆变级变换器注入电网的电压的d、q轴分量控制线路潮流;提出对逆变级变换器采用三环解耦控制,从而提高了系统的动态响应能力和稳定性;分析了双级矩阵变换器的拓扑结构及其双空间矢量控制策略和换流特点。构建了基于双极矩阵变换器的统一潮流控制器的仿真实验系统模型。     

基于Tabu搜索方法的UPFC潮流优化研究

将Tabu搜索方法用于含有统一潮流控制器(UPFC)的电力系统潮流优化控制,建立了以各线路有功传输功率平衡及各PQ节点电压平衡为优化目标的数学模型,应用Tabu搜索方法的思想,通过14节点算例进行含UPFC的潮流优化控制计算,并对结果进行比较分析,得到了含有统一潮流控制器的潮流优化控制策略.     

一种基于自适应遗传算法的统一潮流控制器

提出一种自适应遗传算法的智能控制策略,并将其应用于统一潮流控制器的多变量控制中.对3个通用的标准测试函数进行了优化,将其测试结果与简单遗传算法进行了比较.仿真结果表明:自适应机制提高了算法的搜索性能,与传统PI控制相比具有更强的动态性和鲁棒性。     

考虑投资收益比的UPFC选址与定容算法优化

为提高在已有输配电网络加装统一潮流控制器的经济收益,对统一潮流控制器的选址与定容算法进行优化。以有功潮流性能指数结合电压稳定性指标确定统一潮流控制器的最优安装位置,以经济收益为目标建立统一潮流控制器安装容量与经济收益的函数方程,采用粒子群算法对其求解计算,通过绘制曲线分析得出统一潮流控制器的最优安装容量和最高经济收益。在IEEE14节点系统中与遗传算法进行比较验证,证实了该方法的高效性。