Location Of Flexible AC Transmission System Devices Research Articles

Optimal sizing and placement of STATCOM, TCSC and UPFC using a novel hybrid genetic algorithm-improved particle swarm optimization

The increase in global power demand has caused most of today's power networks to become overloaded especially in Sub-Saharan Africa. The increased load demand can be met through expansion of existing generation and transmission system. However, construction of new power infrastructure is limited by financing and technical constraints. Thus, power networks have been left to operate at overload conditions with high power losses and many power quality (PQ) problems. Flexible AC Transmission System (FACTS) devices can improve the power transfer capability of the existing transmission networks without the need of constructing new power infrastructure. In this paper, a multi-objective function comprising of minimization of power loss (PL), voltage deviation (VD) and operational cost (OC) was formulated and solved using a novel algorithm. A novel Genetic Algorithm-Improved Particle Swarm Optimization (GA-IPSO) technique is proposed in this paper for optimization of size and location of FACTS devices. Static Synchronous Compensator (STATCOM), Thyristor Controlled Series Capacitor (TCSC) and Unified Power Flow Controller (UPFC) are the three FACTS devices considered. The proposed technique was validated using IEEE-33 Bus Test System, which is a popular benchmark Radial Distribution System (RDS). The three FACTS devices were optimized separately and also in a combined manner. Under the separate optimization, the size and location of individual FACTS devices were optimized. For combined optimization, the sizes and locations of more than one device were optimized in the same test system. For separate optimization, UPFC produced the best results by reducing the active power losses by 38.44 % and OC from $1.59×105 to $ 1.15×105. Under the combined optimization, combination of TCSC, STATCOM and UPFC gave better results by achieving active power loss reduction of 56.09 % and reducing OC from $1.59×105 to $ 1.03×105. Comparison of GA-IPSO technique with other algorithms such as Particle Swarm Optimization (PSO), Genetic Algorithm (GA), Improved Grey Wolf Optimization (IGWO) and Differential Evolution Algorithm (DEA) showed that the proposed hybrid technique was superior and more efficient in solving the FACTS optimization problem.

Transmission impedance control impacts on carbon emissions and renewable energy curtailment

Increased levels of renewable energy penetration have created new congestion patterns in recent years. Since the grid is not designed for the new patterns, the operators may need to curtail renewable energy to maintain transmission flows within acceptable limits. Transmission line impedance control, using flexible ac transmission system (FACTS) devices, has been proposed as an approach to relieve congestion in transmission systems and enhance renewable energy utilization. In this paper, we conduct a comprehensive study to provide insights on FACTS implementation’s impact on renewable energy integration and carbon emission reduction. The study considers variations in renewable energy penetration level, system loading patterns, location of renewable generation, and location of FACTS devices. Furthermore, generation mix data from prominent regional transmission organizations (RTO) are used to achieve more realistic results. Simulations studies are carried out on a modified RTS-96 system with a two-stage stochastic unit commitment model. The results show that, even though impedance control is effective in cost reduction, it has limitations in facilitating renewable energy integration in systems with prominent cheap fossil fuel power plants.

Considering FACTS in Optimal Transmission Expansion Planning

The expansion of power transmission systems is an important part of the expansion of power systems that requires enormous investment costs. Since the construction of new transmission lines is very expensive, it is necessary to choose the most efficient expansion plan that ensures system security with a minimal number of new lines. In this paper, the role of Flexible AC Transmission System (FACTS) devices in the effective operation and expansion planning of transmission systems is examined. Effort was taken to implement a method based on sensitivity analysis to select the optimal number and location of FACTS devices, lines and other elements of the transmission system. Using this method, the transmission expansion plan for a 9 and a 39 bus power system was performed with and without the presence of FACTS with the use of DPL environment in Digsilent software 15.1. Results show that the use of these devices reduces the need for new transmission lines and minimizes the investment cost.

A Multi-objective Hybrid Heuristic Approach for Optimal Setting of FACTS Devices in Power System Operation

<p>Improvement of power system performance in terms of increased voltage profile and decreased transmission loss is becoming one of the challenging tasks to the system operators under open access environment. Apart from traditional power flow controlling devices, use of Flexible AC Transmission System (FACTS) devices can give an attractive solution for the operation and control of deregulated power system. The type, size, location and number of FACTS devices are to be optimized appropriately in order to get the targeted benefits. In this paper, two FACTS devices, Thyristor Controller Phase Shift Transformer (TCPST) and Interline Power Flow Controller (IPFC) are selected to obtain the required performance such as improvement of voltage profile and loss minimization. To search the optimal location and optimal rating of the selected FACTS devices, a hybrid algorithm which formulated with Particle Swarm Optimization (PSO) and Gravitational Search Algorithm (GSA) is proposed. At the first step, the optimization problem is solved for finding the optimal location of FACTS devices using PSO with an objective of voltage profile maximization and later GSA is implemented to optimize their parameters with an objective of transmission loss minimization. The proposed method is implemented on IEEE 30-bus test system and from the simulation results it can be proved that this technique is well suited for real-time application. </p><p align="center"><strong><br /></strong></p>

Techno-economical benefits of optimal location of SVC for congestion management

This research paper deals with the congestion of transmission lines in deregulated electricity market and thus, suggesting an optimal power flow framework to solve the problem. In this research paper, a model has been designed that help decongest using re-dispatch method and then calculate the taxes. In order to reduce taxes, it considers the installation of flexible AC transmission systems (FACTS) devices in the transmission network. The optimal location of FACTS devices can be recognised by the bus on which maximum tax is imposed. The IEEE 30-bus system is used to simulate the market and illustrate the proposed method. The simulation is done in MATLAB. The results show that when SVC is included, the amount of re-dispatched power reduces significantly, resulting in an optimal operating point closer to that dictated by the market settlement. Secondly, the results prove that SVC is a viable option for congestion management, from technical as well as economical points of view.

Voltage Stability Improvement By Using FACTS Elements With Economic Consideration

In last two decades due to increasing power demand power systems are operated to their maximum operation conditions. It will cause to any problems that one of these is voltage instability. To overcome this problem Flexible AC Transmission Systems(FACTS) have been used in power systems. The FACTS devices improves system stability, reduce losses and power generation cost. Best location of FACTS devices will help to maintain bus voltages at desired level, reduce cost of these devices and improve voltage stability margins. This paper presents the methods to location and rating of FACTS devices are optimized with using weighted coefficients method and Sterength Paretto Evolutionary Algorithm(SPEA).Thyristor controlled series capacitor(TCSC)and Static Var Compensator(SVC)are also considered in this paper.

CONGESTION MANAGEMENT BY OPTIMAL ALLOCATION OF FACTS CONTROLLERS USING HYBRID FISH BEE OPTIMIZATION

The role of Independent System Operator (ISO) in the restructured power industry includes system control, capacity planning, transmission tariff and congestion management; the challenging task being minimizing the congestion. One of the popular techniques used to alleviate congestion is using Flexible AC Transmission Systems (FACTS) devices. The power system generally operates near its rated capacity in deregulated market because of intensive usage of transmission grids. So, the major issues that need to be addressed are improving the voltage profile and reducing the power loss in the electrical network. Motivation: The location of FACTS devices can improve the power flow in the line, maintain the bus profile and reduce the losses. However locating the ideal location is a NP problem. This study presents a novel heuristic method to determine the types of FACTS devices and its optimal location in a power system without violating the thermal and voltage limits. Power flow sensitivity index to find the optimal location of UPFC is suggested in this study. A hybrid fish bee swarm optimization is proposed which is based on Artificial Bee Colony (ABC) and Fish School Search (FSS) methods. This proposed algorithm is tested based on IEEE 30 bus system and line performances are studied.

OPTIMAL PLACEMENT OF FLEXIBLE ALTERNATING CURRENT TRANSMISSION SYSTEM (FACTS) DEVICES FOR STATIC VOLTAGE STABILITY ENHANCEMENT

This Voltage stability problems increasing day by day because of demand increase. It is very important to analyze the power system with respect to voltage stability. Location of FACTS devices is important for the enhancement of voltage stability. This paper investigates the voltage stability analysis of 14 bus systems by optimally locating Flexible AC Transmission System (FACTS) devices. Shunt and series FACTS controllers are introduced in the weakest bus and its effectiveness is assessed by comparing voltage profile and loading margins enhancement. It is shown that best location for static voltage stability margin is the “weakest bus” of the system. Continuation power flow (CPF) is done with PSAT (power system stability analysis Toolbox).

Reactive Power Loss Sensitivity Approach in Placing FACTS Devices and UPFC

In this paper, a simple placement technique of Flexible AC Transmission System (FACTS) devices and Unified Power Flow Controller (UPFC) is proposed for loading margin enhancement. Reactive-power loss sensitivity approach is proposed to identify the weakest line of the system and to narrow down the appropriate site of FACTS device. The combination of Reactive-power loss sensitivity and Tangent Vector is proposed to find the appropriate location of UPFC. Proper modeling of FACTS devices, including DC side, is used to accurately capture their behaviors when they are operating at limits. The proposed placement approach may be useful for utilities who wish to find appropriate location of FACTS devices and UPFC regarding to loading margin enhancement.

Selection of optimal number and location of thyristor-controlled phase shifters using genetic based algorithms

In recent years, major structural changes were introduced to the power sector all over the world. As a consequence, transmission expansion activities must be implemented to upgrade the utilities' power delivery systems. Some application of flexible AC transmission system (FACTS) technologies to existing high-voltage power systems has proved that the use of FACTS technology may be a cost-effective option for power delivery system enhancements. Undoubtedly, FACTS devices can minimise costly capital investments, but selecting the appropriate number and placement of these devices can be a challenge. To face this challenge, the paper deals with a methodology, based on a genetic algorithm, to identify the optimal number and location of FACTS devices in an assigned power-system network for maximising system capabilities, the social surplus and to satisfy contractual requirements in an open power market. In order to validate the usefulness of the approach suggested herein, a case study using the IEEE 30-busbar power system is presented and discussed.

Allocation of FACTS devices in hydrothermal systems

This work presents a methodology to represent and analyze the influence of FACTS (flexible AC transmission systems) devices on the multiperiod economic dispatch problem. Two FACTS devices are represented: the series compensator and the phase shifter. The aim is to find the best location of FACTS devices in order to minimize the expected thermal generation costs and the investments on these devices in a prespecified time interval. The methodology handles the operational interdependence between cascade hydro plants which characterize the hydrothermal coordination problem. Transmission losses and circuit capacity variation are also taken into consideration. The approach is tested in a small system and to the system of the southern region of Brazil in order to illustrate the application of the algorithm. Some wheeling transactions are also introduced to investigate their influence on the FACTS location. The results show the robustness of the approach while highlighting the main problems which need be investigated.