Available Transfer Capability Determination Research Articles

Appraisal of Available Transfer Capability Determination Methods in Competitive Electricity Market

The existing power market is contentiously promoting sustainability and competitiveness in the electricity industry. It has raised the transmission networks' transfer capacity as an emerging area for researchers. The electricity production units and consumers share the same transmission network. All stakeholders try to generate power from cheaper sources to make more significant profit margins. This situation creates transmission congestion, violation of voltage and thermal limits, and system security threats. The accurate measurement and optimal use of the available transfer capability (ATC) shall resolve this issue up to some extent. Thus, efficient evaluation of ATC is needed to ensure system security, and it provides an open and trending research topic. This article presents a review of the various techniques for ATC determination and provides the characteristics, practices, and features of the methods. This analysis demonstrates the issues of ATC evaluation techniques and provides the research areas to the researchers.

Review of Available Transfer Capability Determination with Grid Connected Hybrid Wind System using Probabilistic Collocation Method

Any distribution system with large integration of renewable energy based dispersed generations exposed to several difficulties clearly appeared while evaluating complex large-scale system Available Transfer Capability (ATC), where it is considered as one of the indices reflecting levels of reliability and security for power systems. This paper presents a review of ATC determination of the hybrid wind connected system using Probabilistic Collocation Method (PCM) under transient stability, voltage constraints. Applications of PCM technique in several electrical fields of power system transient-state evaluation are also debated, compared with Monte Carlo method. The first results shows the vast time saving obtained using PCM, with satisfied accuracy. The main goal of the review is to exploring different available usages of PCM technique and their corresponding suitable so that a reasonably precise and effective PCM algorithm can be determined for the concerned system, the relevant theory is outlined here, and unpretentious examples are applied to illustrate the applicability computation of ATC value implementing PCM method, as well as an example with a more credible power system, are obtainable. The feasibility of the suggested method would be validating through in the IEEE-24 RTS bus system.

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.

Numerical bifurcation and its application in computation of available transfer capability

Numerical bifurcation analysis techniques are very powerful and efficient in physics, biology, engineering, and economics. This paper mainly discusses its application in computation of available transfer capability (ATC) among the specific interface in AC–DC hybrid power grid. Considering the load as a parameter, which implies the load increment at any bus and the specified generation schedule, the saddle node bifurcation and the Hopf bifurcation have been used for static and dynamic ATC determination respectively. The proposed method has been applied to a modified WSCC 9-bus AC–DC power system for the ATC determination. The impact of the method has also been discussed.

Determination of available transfer capability with implication of cascading collapse uncertainty

Available transfer capability (ATC) provides important information for power marketers and planning sectors in restructured power systems. The stochastic nature of power system behaviour, however, made ATC determination a difficult and complicated task. A stochastic framework has been established for ATC calculation with implication of uncertainties in transmission failures, hourly peak loads and system cascading collapse. The proposed ATC calculation framework is based on parametric bootstrap technique which enables generating random samples of system operating condition with uncertainty at a predefined confidence interval. The IEEE RTS-96 network is employed to demonstrate the effectiveness of the proposed framework. The results presented indicate the significant impact of uncertainties on ATC value.

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.

Assessment of oscillatory stability constrained available transfer capability

This paper utilizes a bifurcation approach to compute oscillatory stability constrained available transfer capability (ATC) in an electricity market having bilateral as well as multilateral transactions. Oscillatory instability in non-linear systems can be related to Hopf bifurcation. At the Hopf bifurcation, one pair of the critical eigenvalues of the system Jacobian reaches imaginary axis. A new optimization formulation, including Hopf bifurcation conditions, has been developed in this paper to obtain the dynamic ATC. An oscillatory stability based contingency screening index, which takes into account the impact of transactions on severity of contingency, has been utilized to identify critical contingencies to be considered in determining ATC. The proposed method has been applied for dynamic ATC determination on a 39-bus New England system and a practical 75-bus Indian system considering composite static load as well as dynamic load models.

Available Transfer Capability Determination in the Restructured Electricity Market

Deregulation of the electricity industry throughout the world aims at creating a competitive market to trade electricity, which generates a host of new technical challenges to market participants and power system researchers. For transmission systems, it requires non-discriminatory open access to transmission resources. Therefore, for better transmission services support and full utilization of transmission assets, one of the major challenges is to accurately gauge the transfer capability remaining in the system for further transactions, which is termed the available transfer capability (ATC). It is crucial to develop an appropriate ATC determination methodology that enables one to evaluate the realistic transmission transfer capability by accounting for all related important requirements. This article describes the evaluation of single-area ATC using power transfer distribution factors in a combined economic emission dispatch environment. In addition, multi-area ATC is calculated with the inclusion of participation factors. Simultaneous bilateral and multilateral wheeling transactions have been carried out on IEEE 30-bus and IEEE 118-bus systems for the assessment of the ATC for both normal, line, and generator outage contingencies. The obtained ATC results are compared with the Power World Simulator to justify its accuracy. The solutions obtained are quite encouraging and useful in the present restructuring environment.

Available Transfer Capability Optimisation Using Evolutionary Programming

In a deregulated electric power industry, transmission providers are required to rapidly produce commercially viable information of available transfer capability (ATC) so that such information can help power marketers, sellers and buyers in planning, operation and reserving transmission services. ATC is a measure of the additional amount of power transfer that may flow across the interface, over and above the base case flows without jeopardizing power system security. This paper presents the ATC determination using the evolutionary programming (EP) technique using modified Gaussian formulation. The proposed EP technique has the ability in providing accurate ATC results and the computation burden caused by the AC power flow solutions are significantly reduced. The outages of critical line that adversely affect the amount of ATC are determined by performing the line contingency ranking and selection. ATC determinations have been made on the case study of Malaysian system. Comparison in terms of accuracy and computation time in estimating the ATC are made by considering the three methods which are the EP using modified Gaussian formulation (EPMG), EP using standard Gaussian formulation (EPSG) and the recursive AC power flow solution (RACPF).

Available Transfer Capability Optimisation Using Evolutionary Programming

In a deregulated electric power industry, transmission providers are required to rapidly produce commercially viable information of available transfer capability (ATC) so that such information can help power marketers, sellers and buyers in planning, operation and reserving transmission services. ATC is a measure of the additional amount of power transfer that may flow across the interface, over and above the base case flows without jeopardizing power system security. This paper presents the ATC determination using the evolutionary programming (EP) technique using modified Gaussian formulation. The proposed EP technique has the ability in providing accurate ATC results and the computation burden caused by the AC power flow solutions are significantly reduced. The outages of critical line that adversely affect the amount of ATC are determined by performing the line contingency ranking and selection. ATC determinations have been made on the case study of Malaysian system. Comparison in terms of accuracy and computation time in estimating the ATC are made by considering the three methods which are the EP using modified Gaussian formulation (EPMG), EP using standard Gaussian formulation (EPSG) and the recursive AC power flow solution (RACPF).

Dynamic voltage stability constrained ATC calculation by a QSS approach

The evaluation of Available Transfer Capability (ATC) in deregulated power system should take into account thermal limits, transient, steady-state and dynamic angle stability as well as the voltage stability limit. The consideration of voltage stability in the determination of ATC, however, was not well researched before. On the other hand, under the power market environment, voltage instability becomes a more important consideration in many countries in recent years, especially when following a large disturbance in a heavily stressed power system over long distances. A new ATC determination scheme using Quasi-steady-state (QSS) approximation is proposed in this paper and implemented on a test system. The performance of the QSS approximation is also compared with the Full-Time-Scale (FTS) simulation. From the results, it is shown that the proposed scheme can evaluate ATC with dynamic voltage stability constraints accurately and the calculation speed is accelerated considerably to meet the real-time requirement.

Available Transfer Capability Determination Using Power Transfer Distribution Factors

Electric power industries throughout the world have been restructured to introduce competition among the market participants and bring several competitive opportunities. A fair competition needs open access and non-discriminatory operation of the transmission network. Open access to the transmission system places an emphasis on the intensive use of the interconnected network reliably, which requires knowledge of the network capability. Available Transfer Capability (ATC) is a measure of the remaining power transfer capability of the transmission network for further transactions. This paper describes the assessment of ATC using AC Power transfer distribution factors (ACPTDFs) in combined economic emission dispatch (CEED) environment. The ACPTDFs are derived using sensitivity based approach for the system intact case and utilized to check the line flow limits during ATC determination. The obtained ATC results are compared with Newton Raphson Load Flow method (NRLF) to justify its accuracy. Simultaneous bilateral and multilateral wheeling transactions have been carried out on IEEE 6, 30 and 118 bus systems for the assessment of ATC. The solutions obtained are quite encouraging and useful in the present restructuring environment.

Available Transfer Capability (ATC) Determination in a Competitive Electricity Market Using AC Distribution Factors

This article presents the development of a simple and non-iterative method to calculate available transfer capability (ATC) for a transmission system using a new set of distribution factors. Sets of power transfer distribution factors and voltage distribution factors have been obtained using the sensitivity based approach for system intact, as well as contingency cases, and utilized to check line flow limits and voltage limits during ATC determination. The accuracy of these distribution factors have been established with respect to full NRLF results and ATC results have been obtained for bilateral and multilateral transactions on IEEE 24-bus Reliability Test System (RTS) system and a 75-bus Indian system network.

A Novel Method for ATC Computations in a Large-Scale Power System

In a restructured power system, it is the responsibility of the independent system operator (ISO) to control the power transactions and avoid overloading of the transmission lines beyond their thermal loading megavolt-ampere (MVA) limits. For this, ISO has to update periodically a real-time index termed available transfer capability (ATC). The methods reported to date for ATC determination are unable to cater to either the accuracy or the online CPU time requirements when the system is a large one. This paper proposes a novel method with the full details for determining ATC in a large power system from only three input variables through fuzzy modeling. The method is validated through extensive simulation tests on the standard IEEE 24-bus reliability test system (RTS), and comparison with an ac load flow-based conventional method using the same array of transactions, base cases, and generation/line outages.

Available transfer capability assessment in a competitive electricity market using a bifurcation approach

An application of bifurcation criteria is proposed for available transfer capability (ATC) determination in a competitive power market having bilateral as well as multilateral transactions. The Hopf bifurcation limit has been considered for determination of the dynamic ATC. The saddle node bifurcation and bus voltage limits have been used for static ATC determination. The proposed method has been applied for ATC determination on a 39-bus New England system and a 68-bus system having static loads as well as in the presence of induction motor loads. The impact of SVC placement in the system for the enhancement of ATC has also been studied.