Enhancement Of Available Transfer Capability Research Articles

Enhancement of available transfer capability using TCSC with hybridized model: Combining lion and moth flame algorithms

AbstractThe practical computations of enhancing available transfer capability (ATC) are evolving in the recent times. Most of the presently available techniques for enhancing ATC are being implemented; however, in many cases, they do not consider the impact of communications taking place in between the “power transfers, loop flows, non‐linearities, operating policies, and most importantly voltage collapse blackouts,” respectively. Thus, the current research work aims to introduce a new hybrid method to solve the chaos in ATC in power system. The thyristor‐controlled series compensation (TCSC) that belongs to series flexible alternating current transmission system device is utilized for enhancing ATC. The introduced algorithm is termed as Lion Updated Moth Flame Optimization (LU‐MFO) to select the corresponding line for TCSC device to be connected.

Available Transfer Capability Enhancement in Deregulated Power System through TLBO Optimised TCSC

Rapid industrial development and innovations in technology bring about the menace of congestion in deregulated power systems (DPS). The transmission lines are continuously working under a stressed condition with reduced power transfer capacity. In this situation, the power losses and voltage deviations at the load buses are increased and hence reduce the system stability. To mitigate congestion, improving available transfer capability (ATC) of the transmission system is one of the most feasible and practical solution. This paper focuses on the implementation of Thyristor Controlled Series capacitor (TCSC) to mitigate congestion by enhancing ATC and via reducing power losses. AC Power Transfer Distribution Factor (ACPTDF) is applied to calculate ATC and to find the location of TCSC. To optimize the TCSC parameter (reactance), a Teaching Learning Based Optimization (TLBO) is proposed in the present work. The proposed optimization is validated on the IEEE 30 Bus system. The results are validated by matching with the results obtained through standard grey wolf optimization (GWO) and particle swarm optimization (PSO) techniques. The results show that despite two antagonistic objectives of ATC enhancement and power loss reduction, TLBO outperformed the other optimization techniques under different contingency conditions. The overall ATC of the IEEE 30 Bus system for the bilateral transactions is enhanced by 11.86%. Further active and reactive power losses are reduced by 16.7% and 29.6% for DPS.

Optimal Setting of Thyristor Controlled Series Compensator with Brain Storm Optimization Algorithms for Available Transfer Capability Enhancement

Applications of Flexible AC Transmission Systems (FACTS) devices for enhancement of Available Transfer Capability (ATC) is gaining attention due to economic and technical limits of the conventional methods involving physical network expansions. FACTS allocation which is sine-qua-non to its performance is a major problem and it is being addressed in recent time with heuristic algorithms. Brain Storm Optimization Algorithms (BSOA) is a new heuristic and predicting optimization algorithms which revolutionizes human brainstorming process. BSOA is engaged for the optimum setting of FACTS devices for enhancement of ATC of a deregulated electrical power system network in this study. ATC enhancement, bus voltage deviation minimization and real power loss regulation are formulated into multi-objective problems for FACTS allocation purposes. Thyristor Controlled Series Capacitor (TCSC) is considered for simulation and analyses because of its fitness for active power control among other usefulness. ATC values are obtained for both normal and N-1-line outage contingency cases and these values are enhanced for different bilateral and multilateral power transactions. IEEE 30 Bus system is used for demonstration of the effectiveness of this approach in a Matlab software environment. Obtained enhanced ATC values for different transactions during normal evaluation cases are then compared with enhanced ATC values obtained with Particle Swarm Optimization (PSO) set TCSC technique under same trading. BSO behaved much like PSO throughout the achievements of other set objectives but performed better in ATC enhancement with 27.12 MW and 5.24 MW increase above enhanced ATC values achieved by the latter. The comparative of set objectives values relative to that obtained with PSO methods depict suitability and advantages of BSOA technique.

Online estimation of control parameters of FACTS devices for ATC enhancement using artificial neural network

The deregulated electricity sector needs an improvement in the Available Transfer Capability (ATC) towards the maintenance of power network at balanced condition and to utilize the system in effective manner. Independent System Operator (ISO) maintains the ancillary services by ensuring the reliability of the power system. One of the major functions of ancillary service provider is to maintain the voltage and power flow at stable level. To improve the ATC, both the line power flow and bus voltage profile have to be modified and it is taken care by the ISO. The major limiting criterion for ATC is bus voltage profile. It is well known that the device Thyristor Controlled Series Compensation TCSC which is one of the Flexible AC Transmission System (FACTS) devices can modify the line flow by adjusting the line reactance and Static VAR compensator (SVC) can improve the bus voltage profile by injecting reactive power to the bus. In this research, an Artificial Neural Network (ANN) based estimation of control parameter of FACTS devices such as TCSC and SVC for ATC enhancement is used. The proposed approach uses two different ANN network to find the different TCSC and SVC control parameters to improve the ATC values without violating its voltage constraints for real time transactions. The ANN algorithms such as Radial Basis Function (RBF) as well as Back Propagation Algorithm (BPA) were used to find the TCSC and SVC Parameters and the results are compared. The proposed methods are demonstrated through Reliability Test System (RTS) of IEEE 24 bus. The simulation output represents the suitability of the anticipated method for Real Time estimation of FACTS devices control parameter settings for ATC Enhancement.

Enhancement of ATC of micro grid by optimal placement of TCSC

Presently micro grid network are force to operate close to their stability limit due to exponential growth of power demand. Maintaining transmission line parameters within permissible limits during transient is a challenging task. The principal parameters for assessment of instability during transient are Critical Clearing Time (CCT) and Critical Clearing Angle (CCA). The highly developed semiconductor based power thyristor device, enable the power engineer with most versatile Flexible AC transmission System (FACTS) controllers. Thyristor controlled series capacitor (TCSC) provide great strategy for controlling parameter during transient and enhancing stability and Available Transfer Capability (ATC) of transmission lines. In this paper IEEE 14 bus system is considered as the test system. A three phase fault is simulated and the voltages for pre, during and post fault condition are analyzed. The CCA and CCT are calculated by solving swing equation using point by point method. The delta-time curve at different fault clearing time both with and without connecting TCSC are plotted to study behaviour of delta variation and hence to evaluate transient stability.

ATC assessment and enhancement of integrated transmission and distribution system considering the impact of active distribution network

Assessment and enhancement of transmission network capability have been one of the prime interests of power system monitoring, operation and control. Conventionally, the issue of available transfer capability (ATC) assessment has been tackled considering the transmission and distribution networks as segregated entities because they had little or no influence on each other's performance owing to the unidirectional flow of power from the transmission to distribution networks. Now, with increasing interest in smart transmission and distribution in amalgamation with a paradigm shift in sources of generation from centralised to decentralised even at distribution levels mandating the analysis of power grid while inculcating both the hierarchies simultaneously. In this study, a platform for quasi-static operation of power transmission and distribution networks, employing a multi-agent based system has been developed. The developed multi-agent systembased system has been utilised for assessment of ATC considering active distribution network (ADN) whereby Modified IEEE 24 bus system at transmission and Modified IEEE 123 node system at distribution level has been considered as a test system. It has been observed that the presence of ADN considerably affects the ATC of the system.

FACTS Devices Loss Consideration in Placement Approach for Available Transfer Capability Enhancement

This paper incorporates Flexible AC Transmission System (FACTS) device loss with the general loss sensitivity equation for the determination of optimum location for its placement in deregulated power networks, with objectives of Available Transfer Capability (ATC) enhancement, bus voltage improvement and loss reduction. A detailed mathematical model in terms of circuit system parameters is presented based on FACTS loss amalgamation approach. Thyristor Controlled Series Capacitor (TCSC) FACTS device is considered for simulation and analysis because of its capability to control active power among other parameters. The TCSC location is established based on analysis of sensitivity factors obtained from partial derivatives of the resultant loss equations (including FACTS) with respect to control parameters. ATC values are obtained using ACPRDF method and with TCSC in place, these values are enhanced for different bilateral and multilateral power transactions. IEEE 5 Bus system is used for the demonstration of the effectiveness of this approach. Placement with this method resulted into ATC enhancement of more than 60% well above the values obtained when TCSC was placed with thermal limit method. In addition, a substantial bus voltage improvement of up to 3% deviation minimization as well as up to 10% active power loss reduction was recorded with this placement.

Integrating flexible demand response toward available transfer capability enhancement

Available transfer capability (ATC) has been widely adopted as a crucial measure to guarantee free and reliable power trading. The existing literature generally evaluates the ATC of a power grid considering inelastic load. However, the impacts of responsive load have not yet been systematically explored, which underestimates the ability of demand side resources in ATC enhancement. Therefore, we propose a two-stage ATC evaluation framework in this paper integrating flexible demand response (FDR). In the first stage, i.e., a day-ahead market, a demand side bidding scheme is developed in which electricity users can make flexible choices to participate in demand response (DR) programs according to their preferences. In this paper, FDR is categorized into three typical patterns: (i) deferrable DR, (ii) switchable DR and (iii) adjustable DR. The objective is to minimize the total generation and dispatch costs, while respecting the constraints for FDR, the minimal accommodation of renewable energy, the inter-area power trading, etc. Then based on generation and demand side bidding, a day-ahead unit commitment model is formulated to schedule thermal generators, interchange power and FDR. In the second stage, a real-time ATC evaluation model based on the aforementioned unit commitment results is proposed to quantify the contributions of FDR on ATC enhancement. Case studies based on IEEE 14-bus system and a provincial power grid in China demonstrate that FDR can effectively improve real-time ATC by load shifting and peak shaving, and facilitate the accommodation of renewable energy.

Self-adaptiveness in particle swarm optimisation to enhance available transfer capability using thyristor-controlled series compensation (TCSC)

Available transfer capability (ATC) is one of the challenging criteria under the functioning of the deregulated power system. The high demand for improving ATC is generally met using flexible alternating current transmission system (FACTS) devices in the power system. However, it suffers from serious crisis during determination of the optimal location and compensation stage of FACTS. The present study uses thyristor-controlled series compensation (TCSC) devices in order to compensate for the limitation of FACTS. Further, a novel self-adapted particle swarm optimisation (SAPSO) algorithm is proposed in this study for enhancing ATC. Experiments are carried on three benchmark bus systems such as IEEE 24, IEEE 30 and IEEE 57. Performance and statistical analyses are carried out by comparing the proposed SAPSO with the conventional PSO. Eventually, the study proves the effectiveness of the proposed method in case of ATC enhancement.

ATC enhancement in electricity markets with GUPFC and IPFC – A comparison

Available transfer capability (ATC) needs to be declared well in advance by the system operator to reserve transactions and avoid any congestion in the network. In this paper, an optimal power flow based approach has been utilized for bilateral/multi-transactions deregulated environment to obtain the ATC. The ATC has been obtained with generalized unified power flow controller (GUPFC) and interline power flow controller (IPFC) for intact and line contingency cases. The impact of ZIP load model has been evaluated on the ATC with both the devices. The main contribution of the paper is the comparison of the ATC obtained with. GUPFC and IPFC for intact and contingency cases with constant P,Q load model and ZIP load model. The results have been determined for intact and line contingency cases taking simultaneous as well as single transaction cases. The results obtained are also compared with DC/AC and PTDFs. The proposed method have been applied for IEEE 24 bus RTS.

ATC enhancement by incorporating FACTS devices for deregulating scenario in present power market

The cost based monopolistic power market rules are new fangled by the word deregulation. Trepidations in its conceptualisation and integrated operation in the impending scenario are transmission pricing, congestion management and Available Transfer Capability (ATC). Of this intriguing technical challenge, ATC is the one that needs to be interrogated and dogged to make open access a feasible obsession for private entity participation which is deregulation’s intention. This research work aims at calculating ATC using non iterative, simple, Power Transfer Distribution Factors (PTDF) based methodology, enhancing them using Flexible AC Transmission system (FACTS) devices like Static compensator (STATCOM) and Unified Power Flow Controller (UPFC). A proven alternative to overcome extravagance by erecting new transmission facility is incorporation of FACTS devices in the existing structure that indulge in reactive power compensation. These FACTS devices are modelled using the power flow equations and is placed optimally based on the slope of sensitivity factors. The optimal settings of FACTS devices is obtained by a soft computing technique labelled as Particle Swarm Optimisation (PSO) to enhance the ATC for the assumed bilateral and multilateral power contracts. The voltage and angle of shunt and series FACTS devices are randomly generated as the population of PSO on sample 6 bus and standard IEEE 30 bus systems.

Optimal Setting of FACTS Devices using Particle Swarm Optimization for ATC Enhancement in Deregulated Power System

Abstract In electricity supply industries, the word deregulation is disassembly of original structure and reassembly into another form for better efficiency, performance and to draw private sector investment. The major concerns in deregulated power market are transmission pricing, congestion management and Available Transfer Capability (ATC) that need to be dogged. Among these intriguing challenges, one that needs to be interrogated to provide assured open access transmission service is ATC. The way of improving ATC is either adding transmission facilities or using various FACTS devices. In this paper, our concern is incorporation of FACTS, a semiconductor based control devices to enhance the ATC of transmission system. Various FACTS devices like STATCOM, SSSC and UPFC are modeled by power flow equations and optimally set the FACTS parameters by particle swarm optimization (PSO) technique in such a way so as to enhance ATC in the deregulated electricity environment. This replaces the audacious job of erecting new transmission system or expanding the existing one. The non iterative, simple and fast Power Transfer Distribution Factors (PTDF) based sensitivity method is adopted to determine and enhance ATC on sample six bus system to prove the feasibility of ATC enhancement for bilateral and multilateral transactions.

Available transfer capability enhancement with FACTS using Cat Swarm Optimization

Abstract Determination and enhancement of Available Transfer Capability (ATC) are important issues in deregulated operation of power systems. This paper investigates the use of FACTS devices, such as SVC and TCSC, to maximize power transfer transactions during normal and contingency situations. ATC is computed using Continuation Power Flow (CPF) method considering both the thermal limits and voltage profile. Cat Swarm Optimization (CSO) is used as an optimization tool to determine the location and controlling parameters of SVC and TCSC. The suggested methodology is tested on IEEE 14-bus system and also on IEEE 24-bus reliability test system for normal and different contingency cases.

Impact of STATCOM Control Parameters on Available Transfer Capability Enhancement in Energy Markets

Abstract Flexible AC Transmission Systems devices are becoming the imperative part of the transmission system network for power transfer enhancement. In this work, the impact of Static Compensator parameters has been analyzed for available transfer capability (ATC) enhancement. The main contribution of the paper is: (i) impact of STATCOM on the ATC determination for bilateral and multi-transactions (ii) Comparison of ATC values obtained in three different scenarios of STATCOM control parameters variations (iii) comparison of results without and with STATCOM controller parameters for the ATC enhancement. The study has been conducted on IEEE 24 bus Reliability Test System.

Optimal Location of the Facts Devices using the Sensitivity Approach for the Enhancement of ATC and Voltage Profile in Deregulated Power System

The need for the enhancement of the Transfer Capability in a deregulated power system is very essential in the power market. Available Transfer capability (ATC), and Total Transfer capability (TTC), enhancement ensures to increase the Transfer capability in a power system. Improvement of the TTC and ATC depends upon the placement of the FACTS device; sensitivity approach is used to locate the optimal location to place FACTS device. However enhancement of ATC and TTC with voltage analysis is very essential, this helps us to estimate the security of the system which is very crucial when the performance of the system is the major criteria. Repeated power flow program is used to calculate the voltage constrained ATC and TTC. Transfer capability and voltage analysis proposed in this paper are simulated in the power world simulator software.

Enhancement of ATC by Optimal Allocation of TCSC and SVC by Using Genetic Algorithm

This paper proposes Improving of ATC is an important issue in the current de-regulated environment of power systems. The Available Transfer Capability (ATC) of a transmission network is the unutilized transfer capabilities of a transmission network for the transfer of power for further commercial activity, over and above already committed usage. Power transactions between a specific seller bus/area and a buyer bus/area can be committed only when sufficient ATC is available. Transmission system operators (TSOs) are encouraged to use the existing facilities more effectively to enhance the ATC margin. Heavily loaded circuits and buses with relatively low voltages can limit ATC usually. It is well known that FACTS technology can control voltage magnitude, phase angle and circuit reactance. Using these devices may redistribute the load flow, regulating bus voltages. Therefore, it is worthwhile to investigate the impact of FACTS controllers on the ATC. In this thesis focuses on the evaluation of the impact of TCSC and SVC as FACTS devices on ATC and its enhancement during with and without line outage cases. In a competitive (deregulated) power market, optimal the location of these devices and their control can significantly affect the operation of the system and will be very important for ISO.

ATC determination with FACTS devices using PTDFs approach for multi-transactions in competitive electricity markets

Available transfer capability (ATC) is an important indicator for accommodating further transactions over and above already existing commitments. With flexible AC transmission system (FACTS) deployment in a system for better utilization, the ATC information quantification is essential. ATC enhancement with these devices can play an important role in an efficient and secure operation of competitive markets. The main objective of the paper is: (i) power transfer distribution factors determination with FACTS devices, (ii) ATC determination for bilateral/multi-lateral transactions based on PTDFs with FACTS devices, (iii) optimal location of FACTS devices based on power flow sensitivity corresponding to transactions, and (iv) comparison of ATC obtained with DC PTDF based approach. The results have been determined for intact and line contingency cases without and with FACTS devices. The proposed method have been tested on IEEE 24 bus RTS.

Enhancement of ATC with FACTS devices using Real-code Genetic Algorithm

Determination and enhancement of Available Transfer Capability (ATC) are important issues in deregulated operation of power systems. This paper investigates the use of FACTs devices, like SVC and TCSC, to maximize power transfer transactions during normal and contingency situations. ATC is computed using Continuation Power Flow (CPF) method considering both thermal limits and voltage profile. Real-code Genetic Algorithm (RGA) is used as an optimization tool to determine the location and controlling parameters of SVC and TCSC. The suggested methodology is tested on IEEE 14-bus system and also on IEEE 24-bus reliability test system for normal and different contingency cases.

Comparison of UPFC and SEN Transformer for ATC enhancement in restructured electricity markets

Available transfer capability (ATC) is an important indicator of remaining transfer capability in the transmission network for its commercial use in a competitive electricity market. In this paper, an optimal power flow based approach has been proposed for multi-transactions deregulated environment. The ATC has been obtained with unified power flow controller (UPFC) and Sen Transformer (ST) for intact and line contingency cases. The impact of ZIP load model has been evaluated on ATC with both devices. The main contribution of the paper is the comparison of ATC obtained with UPFC and Sen Transformer for intact and contingency cases with constant P,Q load model and also taking impact of ZIP load model. The results have been determined for intact and line contingency cases taking simultaneous as well as single transaction cases. The results have also been obtained with DC/AC PTDFs method for comparison. The proposed method have been applied for IEEE 24 bus RTS.

Implementation of FACTS Device for Enhancement of ATC Using PTDF

In this paper an attempt has been made to determine Available Transfer Capability (ATC) with the FACTS device i.e. TCSC. The methods for ATC evaluation are developed considering system thermal limits constraints based on MVA loading of the system. Power Transfer Distribution Factors (PTDF) are used to determine the maximum ATC that may be available across the system in a certain direction without violating line thermal limits. ATC traditionally uses linear methods capable of predicting distances based on thermal limits. However, these methods do not consider bus voltages and static collapse. Most of the studies relating ATC involve contingencies and multi-pattern scenarios that often can only be performed in reasonable time with the use of linear methods. In this paper, a new approach is proposed that first determines the Reactive Power Flows using the exact circle equation for the transmission line complex flow, and then evaluates ATC using active power distribution factors. The effectiveness of proposed method is successfully demonstrated on IEEE 30-Bus system.