A REVIEW OF PROBABILISTIC APPROACHES FOR AVAILABLE TRANSFER CAPABILITY CALCULATION (original) (raw)
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Risk-based available transfer capability assessment including nondispatchable wind generation
International Transactions on Electrical Energy Systems, 2014
With the prevalence of large-scale renewable energy in remote areas, it is necessary to appraise the ability of the network to provide access to this clean energy. Available transfer capability (ATC) is a key measure for the potency of electricity markets to facilitate trading and promote competition by accommodating additional energy transactions. This paper investigates the impact of nondispatchable wind energy on the ATC using a risk-based approach. Because of the uncertainties ingrained in wind turbine generator energy output, as determined by the variability of wind speed, a probabilistic wind model is considered using Weibull density function. Continuation power flow is exploited to evaluate the ATC corresponding to maximum system loading, subject to network and equipment constraints, whereas the cumulative probabilistic risk is computed to capture the risk associated with the ATC. The proposed approach is implemented on the modified Institute of Electrical and Electronics Engineers 30 bus system. Results of the different risk levels related to the ATC can provide useful information to system operators for granting firm or interruptible transactions to market participants subject to economic merits. Copyright
Deterministic approach Available Transfer Capability (ATC) calculation methods
2016
With the new strategy of deregulation electrical power systems, Available Transfer Capability (ATC) is significant indicator. This paper debate for deterministic methods to compute ATC. Concepts and calculation approaches of Optimal Power Flow (OPF), Continuation Power Flow (CPF) and Power Transfer Distribution Factors (PTDF) has been presented. Cons and prons of each with simulated results are presented using IEEE 30 -bus test systems without any contingences proposed, the results shows efficient results with high performance accuracy
IJCRT - International Journal of Creative Research Thoughts (IJCRT), 2021
Available transfer capability (ATC) is a metric in power systems that determines the maximum amount of incremental power that can be transferred between two parts (usually seller and buyer) of the underlying power system without crossing any system thresholds. It is evaluated using 3 major metrics; i.e.; total transfer capability (TTC), transmission reliability margin (TRM) and existing transmission commitments. In order to determine these parameters, various methods are proposed by researchers, some of these methods are applicable to large scale grids, while others work effectively for small-to-medium grid deployments. In order to deploy a customized grid with effective ATC calculations, it is recommended that power system designers must select an optimum combination of these methods. For instance, Single Linear Step (SL) approach uses present state system information along with sensitivities embodied in the power transfer distribution factors (PTDF) and line outage distribution factors (LODF) in order to determine ATC values. The SL method is applicable only for small-scale power distribution systems, but can be extended via Iterated Linear Step (IL) method to incorporate controller changes for large scale systems. As system complexity increases, it becomes difficult to select the best method out of the given methods for ATC calculations. In order to reduce this complexity, the underlying text reviews different ATC calculation methods, and compares their statistical performance. Using this study, power system designers can identify most suited methods for their system deployment, and thus save time and cost for testing out different method.
An innovative probabilistic methodology for net transfer capacity evaluation
2015 IEEE Eindhoven PowerTech, 2015
In the context of transmission system planning, research proposes methods to assess the effect of uncertainties of power system operating condition due to forecasting errors of intermittent generation and loads. In particular probabilistic power flow methods are illustrated to calculate the probability distributions of the voltages and the branch currents, starting from the distributions of power injections/absorptions. These uncertainties play a key role in the operational planning of power systems, as certain configurations of load and intermittent generation can cause security problems. This paper aims to propose a probabilistic methodology to assess Net Transfer Capacity (NTC) among network areas, which quantifies forecast error uncertainties by applying the Point Estimate Method (PEM) combined with Third Order Polynomial Normal (TPN) Transformation. This approach is compared with a conventional NTC assessment technique and has been validated against Monte-Carlo benchmark on an IEEE test system.
Available Transfer Capability Calculation Methods: A Review
2014
Intimation of available transfer capability (ATC) by Independent System Operator is important issue in a deregulated power markets. ATC is the prime important indication for all companies, IPPs, retailers, transmitters, distributors and customers, for participation in the trading of electrical powers. ATC indicates remaining transfer capability over and above already committed use in a competitive electricity markets for its commercial use. This paper review the literature related to ATC calculation in a deregulated electricity markets.
Dynamic available transfer capability computation using a hybrid approach
Iet Generation Transmission & Distribution, 2008
In a restructured electricity market, accurate evaluation of available transfer capability (ATC) with dynamic constraints is a challenging task. An approach to determine dynamic ATC, utilising the benefits of a direct method as well as time-domain simulation method, has been developed. Structure-preserving energy function model, which retains the topology of the network, along with transient stability limit, has been used to compute dynamic ATC for bilateral as well as multilateral transactions in an electricity market. Constant impedance as well as composite models for real power loads have been considered. A new contingency severity index, which takes into account the impact of transactions on the severity of the contingencies, has been proposed to reduce the list of credible contingencies to be considered in determining the ATC. To demonstrate the effectiveness of the proposed method, it has been tested on 10-machine, 39-bus New England system and a practical 60-machine, 246-bus Indian system.
Two-Point Estimate Method for Quantifying Transfer Capability Uncertainty
IEEE Transactions on Power Systems, 2005
A two-point estimate method is proposed in this paper to assess the power transfer capability uncertainty. This paper assumes that the uncertainty of the line parameters and bus injections involved in transfer capability calculations can be estimated or measured and shows how to estimate the corresponding uncertainty in the transfer capability. Instead of using a large number of simulations as required in the Monte Carlo approach, for a system with uncertain parameters, the two-point estimate method uses 2 calculations of transfer capability to quantify the uncertainty. The proposed method uses a numerical method to calculate the moments of the transfer capability. The moments are then used in the probability distribution fitting. Using the obtained transfer capability uncertainty information and a desired level of reliability, an adequate transmission reliability margin can be determined for each transmission service. The proposed method can be used directly with a deterministic computer program and it does not require derivatives of the transfer capability. Test results of the proposed method are compared with those obtained from the Monte Carlo simulations and a truncated Taylor series expansion method. Index Terms-Point estimate method, transfer capability, transmission reliability margin, uncertainty. NOMENCLATURE Uncertain parameters. Transfer capability. Coefficient of variation. th moment of. Safety margin. Reliability margin. Uncertainty of transfer capability. Probability distribution of safety margin. Probability distribution of uncertain parameter. Nonlinear transfer capability function. Weighting of the concentration. Reliability index.
Available transfer capability calculation methods: A comprehensive review
International Transactions on Electrical Energy Systems, 2019
The ceaseless efforts by power system industries to promote sustainable and competitive electric power market structure in the deregulated environment have given rise to enormous research in the area of transfer capability of transmission networks. Due to high demand for electricity, transmission components are stressed to operate close to their operating limits, and this leads to a decrease in transmission efficiency. To address this issue, efficient evaluation of available transfer capability (ATC) is crucial for system planning, operation, and control. Several approaches have been proposed for ATC computation. Surprisingly, a comprehensive literature review on ATC computation is yet to be efficiently presented. Researchers have been able to come up with fast algorithms, but most of these algorithms are not accurate, and the presented accurate techniques are not fast enough for online applications. This paper presents a comprehensive review of the different approaches for ATC determination. It provides the concepts, methods, and the features of the ATC. For each technique, the state of the art of the several contributions made by researchers has been highlighted. This review reveals that there are issues regarding ATC calculation methods that need attention: the development of fast and accurate algorithm incorporating system dynamics and system uncertainties in ATC determination. Additionally, efforts on the incorporation of renewable energy generation in the ATC evaluation need to be intensified. This review will serve as one in all for researchers as well as a guide for the entrants in this field. KEYWORDS artificial intelligence, available transfer capability, dc power flow, optimal power flow, repetitive power flow 1 | INTRODUCTION Power system industry restructuring, known as deregulation, targeted at controlling the existing monopoly structure by introducing competition at different levels of utilities attracts non-governmental participation in the power system investment and control. The deregulated structure consequently improves the power marketing operations, 1 system's efficiency, and efficient customer service deliveries. In return, the power marketing activities have mitigated the
Probabilistic transfer capability assessment in a deregulated environment
Proceedings of the 33rd Annual Hawaii International Conference on System Sciences
A methodology for available (simultaneous) transfer capability (ATC) analysis based on a probabilistic approach is presented. It is postulated that the system is operated by an ISO. The traditional concept of "area" is extended to include a utility, an individual IPP, a large customer, etc. All areas are divided into three groups: (a) study area or area under the ISO control, (b) transfer participating areas, and (c) external areas which have no direct transactions or they have fixed transactions with the study area. A performance index based contingency selection procedure is applied within the study and transfer participating areas to rank those contingencies that will affect simultaneous transfer capability. The contingency ranking order is utilized by a variation of the Wind Chime diagram to selected contingencies that are then evaluated by an optimal power flow algorithm. Subsequently, the probability distribution of simultaneous transfer capability is computed based on the electric load, circuit and unit outage Markov models. The 24x3 bus IEEE RTS is utilized to evaluate the proposed method. The performance of the proposed method is also demonstrated on an actual large scale system (2182 bus, 8 area system).
Available Transfer Capability Influence on Energy Portfolio
This paper presents an approach to deal with the spatial basis risk for energy transactions. The concepts of hydrothermal coordination are described especially because it has a crucial effect in Brazil, where 92% of the power generation comes from hydropower. The spot market prices are derived from an optimization program, which performs the hydrothermal coordination. The volatility of the prices is high and this is stressed when the transmission constraints are considered. The probabilistic nature of the available transfer capability (ATC) needs to be incorporated to the risk and return assessment. So, a combined approach between the price forecasts due to hydrological uncertainties and the probabilistic ATC is developed. Probabilistic density functions are built to help the analysis of energy portfolios, i.e., to help in the decision-making process about long or short-term contracts. Example with the Brazilian electrical system is used to clarify the concepts presented in this paper.