基于最优潮流的广域FACTS控制提高输电能力

讨论了利用最优潮流进行基于广义测量的二次控制问题.研究表明FACTS控制器如不装备广义测量控制则不能充分发挥其控制潜能.提出了可协调和优化控制器设定点,从而增加静态最大负荷能力的新控制策略.此外,对基于远方测量反馈控制的简单方案和基于在线最优的通用方案进行了研究.最后,以一实例定量评估了基于广义测量的FACTS控制的效果.     

具有FACTS设备的输电网络规划

利用改进的遗传算法ＭＡＧＡ进行具有ＦＡＣＴＳ设备的输电网络规划,算例系统的结果表明ＭＡＧＡ适用于解决具有ＦＡＣＴＳ设备的电网规划问题,而且在电网的扩建和改造方面。ＦＡＣＴＳ技术将带来很大的经济效益。     

Coordinated application of FACTS controllers to damp out inter-area oscillations

This paper proposes a systematic analysis and design procedure for simultaneously determining the best locations and input signals of flexible AC transmission system (FACTS) devices in order to damp out inter-area oscillations. First, a modified modal power flow oscillation flow method is developed to determine the nature of the energy exchange over the transmission network in the presence of FACTS devices. With this method, the modal distribution along critical system paths is identified, and the contribution of each machine and network device is computed. Controllability and observability studies are then used to assess the effect of existing FACTS controllers on system damping as well as to identify optimal locations for new devices. The proposed procedure is demonstrated on a 46-machine, 190-bus reduced-order equivalent model of the Mexican interconnected system that includes several static VAR compensators.     

A new dynamic control strategy for power transmission congestion management using series compensation

The growth of electricity market due to increase in demand and infrastructure made the power system more complex. Managing the transmission congestion is one of the main challenges faced by the utilities. To relieve from the bottlenecks, Flexible AC Transmission Systems (FACTS) and Distributed FACTS (D-FACTS) devices can be used in controlling the transmission line power flows. The real power flow control is realized by varying the transmission line impedance. The power flow in transmission line should satisfy inequality constraints to maintain the system in normal state. To achieve this, an algorithm is developed to control the FACTS/D-FACTS devices connected to all the transmission lines of n-bus system. The significant changes required in line impedance which will be deployed by FACTS devices are decided by the algorithm. In this paper, a 5 bus system and a 14 bus system with FACTS devices in all the transmission lines is considered. The transmission lines of the 5 and 14 bus systems are made to be overloaded in different combinations by choosing appropriate loading conditions. The control algorithm is tested on all the overloaded conditions to overcome the congestion. The FACTS devices controlled by the algorithm removes the overloading effect and improve the reliability of the network.     

Optimal placement and parameter setting of SVC and TCSC using PSO to mitigate small signal stability problem

This paper aims to select the optimal location and setting parameters of SVC (Static Var Compensator) and TCSC (Thyristor Controlled Series Compensator) controllers using PSO (Particle Swarm Optimization) to mitigate small signal oscillations in a multimachine power system. Though Power System Stabilizers (PSSs) associated with generators are mandatory requirements for damping of oscillations in the power system, its performance still gets affected by changes in network configurations, load variations, etc. Hence installations of FACTS devices have been suggested in this paper to achieve appreciable damping of system oscillations. However the performance of FACTS devices highly depends upon its parameters and suitable location in the power network. In this paper the PSO based technique is used to investigate this problem in order to improve the small signal stability. An attempt has also been made to compare the performance of the TCSC controller with SVC in mitigating the small signal stability problem. To show the validity of the proposed techniques, simulations are carried out in a multimachine system for two common contingencies, e.g., load increase and transmission line outage. The results of small signal stability analysis have been represented employing eigenvalue as well as time domain response. It has been observed that the TCSC controller is more effective than SVC even during higher loading in mitigating the small signal stability problem.     

基于FACTS的现货市场阻塞解决方法研究

在电力市场环境下,利用柔性交流输电系统FACTS(FlexibleACTransmissionSystem)设备解决网络阻塞问题,获取更大的经济效益已经越来越引起人们的重视。提出基于FACTS的现货市场阻塞解决方法。从安全域的角度分析了引入FACTS控制作用解决阻塞问题的机理,建立了含FACTS控制作用的潮流和最优潮流模型,并用算例进行了分析。研究结果表明,FACTS的控制作用可以有效地解决网络传输阻塞问题,降低购电成本,避免由于网络输电阻塞引起节点电价的震荡。     

Swarm intelligence based algorithms for reactive power planning with Flexible AC transmission system devices

In the proposed work, authors have applied swarm intelligence based algorithms for the effective Co-ordination of Flexible AC transmission system (FACTS) devices with other existing Var sources present in the network. IEEE 30 and IEEE 57 bus systems are taken as standard test systems. SPSO (Simple Particle Swarm Optimization) and other two swarm based intelligence approaches like APSO (Adaptive Particle Swarm Optimization) and EPSO (Evolutionary Particle Swarm Optimization) are used for the optimal setting of the Var sources and FACTS devices. The result obtained with the proposed approach is compared with the result found by the conventional RPP (Reactive power planning) approach where shunt capacitors, transformer tap setting arrangements and reactive generations of generators are used as planning variables. It is observed that reactive power planning with FACTS devices yields much better result in terms of reducing active power loss and total operating cost of the system even considering the investment costs of FACTS devices.     

Optimal sizing of SSSC controllers to minimize transmission loss and a novel model of SSSC to study transient response

In this paper, based on steady-state models of flexible AC transmission system (FACTS) devices, the sizing of static synchronous series compensator (SSSC) controllers in transmission network is formed as an optimization problem. The objective of this problem is to reduce the transmission losses in the network. The optimization problem is solved using particle swarm optimization (PSO) technique. The Newton–Raphson load flow algorithm is modified to consider the insertion of the SSSC devices in the network. Numerical examples, illustrating the effectiveness of the proposed algorithm, are introduced. In addition, a novel model of a three-phase voltage source converter (VSC) that is suitable for series connected FACTS a controller is introduced. The model is verified by simulation using Power System Blockset (PSB) and Simulink software.     

Steady-state optimization in power systems with series FACTS devices

This paper presents an optimization-based methodology to identify key locations in the AC network where placement of a series-connected FACTS device increases the maximum megawatt power transfer the most. The models used for the thyristor-controlled series capacitor (TCSC) and unified power-flow controller (UPFC) include the nonlinear constraints of voltage limitation, zero megawatt active-power exchange, voltage control, and reactive-power exchange. This article describes briefly the steady-state flexible AC transmission systems (FACTS) models and their integration in an existing optimal power-flow (OPF) software package designed and implemented by the authors. A reduced real-life network is used for the case studies. The optimization results help in evaluating the effectiveness of the series FACTS devices in maximizing the network transfer capability and deliver a measure of the FACTS ratings.     

Wavelet entropy based algorithm for fault detection and classification in FACTS compensated transmission line

Distance protection of transmission lines including advanced flexible AC transmission system (FACTS) devices has been a very challenging task. FACTS devices of interest in this paper are static synchronous series compensators (SSSC) and unified power flow controller (UPFC). In this paper, a new algorithm is proposed to detect and classify the fault and identify the fault position in a transmission line with respect to a FACTS device placed in the midpoint of the transmission line. Discrete wavelet transformation and wavelet entropy calculations are used to analyze during fault current and voltage signals of the compensated transmission line. The proposed algorithm is very simple and accurate in fault detection and classification. A variety of fault cases and simulation results are introduced to show the effectiveness of such algorithm.     

Analysis of FACTS devices on Security Constrained Unit Commitment problem

This paper focuses on solving Security Constrained Unit Commitment (SCUC) problem using ABC algorithm incorporating FACTS devices. The objective of the SCUC problem is to obtain the minimum operating cost simultaneously maintaining the security of the system. The SCUC problem is decomposed into Unit Commitment (UC), the master problem and Security-Constrained Economic Dispatch (SCED) as the sub-problem. The existing generation constraints, such as hourly power demand, system reserves, and minimum up/down time limits, ramp up/down limits are included in the SCUC problem formulation. The ability of FACTS devices to control the power flow through designated routes in transmission lines and thereby reducing the overloading of lines are studied. The solution of SCUC problem is also analyzed during a single line outage contingency. The SCUC is carried out incorporating FACTS devices such as SVC, TCSC, STATCOM, SSSC, UPFC and IPFC. The modeling of the FACTS devices within the power system network and finding a suitable location are discussed. The SCUC has been solved and validated on an IEEE 118-bus test system and a practical South Indian 86 bus utility.     

基于TCSC的优化阻塞模型设计与应用研究

针对柔性交流输电装置控制线路潮流的特点,在传统OFF的基础上,将调整网络参数与经济调度方法相结合,研究了计及TCSC的优化阻塞调度模型。求解过程中,把TCSC对系统的调节作用表述成节点附加功率的形式,并将TCSC控制参数纳入变量空间内寻优。IEEE5系统的仿真结果验证了该方法的有效性。     

具有FACTS设备的多目标电网规划

提出了具有灵活交流输电 (FACTS)设备的多目标妥协规划模型 ,综合考虑了FACTS设备对电网规划的经济性和可靠性两方面的影响 ,并采用混合遗传—模拟退火算法求解了该模型。算例结果表明FACTS设备能够提高电网规划的经济性及经济性与可靠性的综合水平 ,并证明了多目标电网规划妥协模型及其解算方法的有效性     

基于电气剖分方法的TCSC成本费用分摊

FACTS装置能有效消除或缓解电力网络阻塞现象,合理有效的成本回收机制的制定能够保证和激励FACTS装置的安装使用。本文基于"论责"原则,提出了一种新的按照源流各方造成阻塞的定量责任大小进行FACTS成本分摊的方法。利用电气剖分方法定量分析输电线路阻塞的成因,并给出相关源流承担阻塞责任的份额关系。在此基础上,将FACTS成本费用根据交易参与者的定量阻塞责任大小进行分摊。最后用改进的IEEE30节点算例对该方法进行了验证,算例结果表明,所提方法能够合理有效地回收FACTS装置的成本。     

A proposal for investment recovery of FACTS devices in deregulated electricity markets

The paper presents a methodology to quantify the benefits, in terms of monetary values, of FACTS devices when used in deregulated electricity market for congestion management. The proposed methodology is used in the proposal for investment recovery of FACTS devices. Despite the long history of development and mature technology, the practical installations of FACTS devices are still limited. The main reasons for few installations are high investment cost and lack of viable measures to quantify the long list of benefits offered by FACTS device. In this respect, the methodology proposed in the paper provides a promising solution. The proposed methodology is based on establishing pricing schemes with and without FACTS devices using OPF formulation. The volume of market with FACTS devices and the increase in surplus due to them forms the basis of quantifying their benefits. The pricing scheme does not destroy the incentive effect in short run and also makes possible the provision of merchant FACTS. The proposed concept was tested and validated with TCSC in five-bus test system. Result shows that, when TCSC is used to relieve congestion in the system and the investment on TCSC can be recovered.     

柔性交流输电系统（FACTS）的研究与前景

本文综述了近几年来在国际和国内开展柔性交流辅、电系统（ＦＡＣＴＳ）的研究状况，以及它的发展前景。柔性交流输电系统的发展紧紧依赖于大功率、高性能的电力电子元件的开发与生产。采用柔性交流输电系统可以使电网由基本不可控变成可控，从而大大地提高了现有输电线路的传输能力，并且还具有许多其它的经济效益。柔性交流输电系统的引入同时将给电力系统的控制带来新的课题。     

Representation of FACTS devices in power system economic dispatch

The main idea behind FACTS (flexible AC transmission system) is to use network parameters as controls to direct flow, thus eliminating problems caused by unwanted loop or parallel flows. The authors present a methodology for the representation of FACTS device such as phase shifters and series compensations in optimal power flow models. The proposed approach is based on, mathematical decomposition and network compensation, techniques. It is possible to incorporate existing optimal power flow algorithms, thus taking advantage of accumulated experience in optimization methods and reducing software development costs. A case study with a Brazilian-derived system is presented     

Determination of IPFC operating constraints in power flow analysis

In recent years, the Flexible AC Transmission System (FACTS) controllers have been widely used to enhance the controllability, security and flexibility in power transmission networks. Interline power flow controller (IPFC) is a versatile member of FACTS devices that can be used to control the power flow in multiple lines in network. Modeling of IPFC with handling its operating constraints is an important issue to determine the practical capabilities of this device. This paper presents a simple modeling with strategies for handling all operating constrains of IPFC in Newton–Raphson (NR) load flow algorithm. The various operating constraints such as; the injected series voltages, injected line currents passing through the converters and exchanged powers among the series converters are investigated. The developed IPFC model with these constraints is validated using standard IEEE 30-bus and IEEE 118-bus test systems.     

Minimization of voltage sag induced financial losses in distribution systems using FACTS devices

Voltage sag can have significant economic consequences for different types of industries. Flexible AC Transmission System (FACTS) is originally developed for transmission networks but similar ideas are now starting to be applied in distribution systems. FACTS devices have become popular as a cost effective solution for the protection of sensitive loads from voltage sag. This paper presents the modeling of FACTS devices to minimize the voltage sag induced financial losses. The overall system financial losses due to voltage sag could be significantly reduced depending on the type of FACTS devices used. The short circuit analysis approach is used to incorporate the effect of these devices on financial losses. Voltage sag produced by balanced and unbalanced short circuits is analyzed by means of an analytical approach using system impedance matrix (Z_Bus) which incorporates FACTS devices. Two types of FACTS devices, which are most often used in practical applications, are considered in this study: Distribution Static Compensator (D-STATCOM) and Static VAR Compensator (SVC). Case studies based on a real Indian distribution system are used to illustrate the modeling method and the effectiveness of these devices in minimization of financial losses.     

Allocation of multi-type FACTS devices using multi-objective genetic algorithm approach for power system reinforcement

This paper presents a novel approach to find optimum locations and capacity of flexible alternating current transmission systems (FACTS) devices in a power system using a multi-objective optimization function. Thyristor controlled series compensator (TCSC) and static var compensator (SVC) are the utilized FACTS devices. Our objectives are: active power loss reduction, new introduced FACTS devices cost reduction, voltage deviation reduction, and increase on the robustness of the security margin against voltage collapse. The operational and controlling constraints, as well as load constraints, are considered in the optimum allocation. A multi-objective genetic algorithm (MOGA) is used to approach the Pareto-optimal front (non-dominated) solutions. In addition, the estimated annual load profile has been utilized in a sequential quadratic programming (SQP) optimization sub-problem to the optimum siting and sizing of FACTS devices. IEEE 14-bus Network is selected to validate the performance and effectiveness of the proposed method.