• KIEE International Transactions on Power Engineering
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• 제4A권4호
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• pp.262-267
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• 2004

With the advent of electric power systems moving from a vertically integrated structure to a deregulated environment, calculating reactive power service charges has become a new and challenging theme for market operators. This paper examines various methods for reactive power management adopted throughout various deregulated foreign and domestic markets and then proposes an innovative method to calculate reactive power service charges using a reactive power market in a wholesale electricity market. The reactive power market is operated based on bids from the generating sources and it settles on uniform prices by running the reactive OPF programs of the day-ahead electricity market. The proposed method takes into account recovering not only the costs of installed capacity but also the lost opportunity costs incurred by reducing active power output to increase reactive power production. Based on the result of the reactive OPF program, the generators that produce reactive power within the obligatory range do not make payments whereas the generators producing reactive power beyond the obligatory range receive compensation by the price determined in the market. A numerical sample study is carried out to illustrate the processes and appropriateness of the proposed method.

• Journal of Electrical Engineering and Technology
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• 제4권3호
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• pp.337-345
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• 2009

Deregulation in power industry has made the reactive power ancillary service management a critical task to power system operators from both technical and economic perspectives. Reactive power management in power systems is a complex combinatorial optimization problem involving nonlinear functions with multiple local minima and nonlinear constraints. This paper proposes a practical market-based reactive power ancillary service management scheme to tackle the challenge. In this paper a new model for voltage security and reactive power management is presented. The proposed model minimizes reactive support cost as an economic aspect and insures the voltage security as a technical constraint. For modeling validation study, two optimization algorithm, a genetic algorithm (GA) and particle swarm optimization (PSO) method are used to solve the problem of optimum allocation of reactive power in power systems under open market environment and the results are compared. As a case study, the IEEE-30 bus power system is used. Results show that the algorithm is well competent for optimal allocation of reactive power under practical constraints and price based conditions.

• 대한전기학회논문지:전력기술부문A
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• 제53권1호
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• pp.67-72
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• 2004

This paper addresses the bidding strategies of generating firms in a competitive market where the firms are provided with payment for generating reactive power. Reactive support for voltage control is an integral and critical part of power system operations. Since reactive support is unbundled in a competitive market under open access transmission, it is treated as one of ancillary services. The operation costs and opportunity costs for reactive support are compensated by payment to the firms, hence their bidding strategies will be affected. The opportunity costs are evaluated from the foregone profits of a generator in making sales in real power market by providing reactive support instead of real power. Game theory approach is used to analysis the transaction strategies of real power by the bimatrix method in this paper. Through computing the Nash equilibrium in a sample system, an incentive of a generator for improving the reactive generating capacity is found to be effective and the variations of the profits are analyzed as the demand power factor changes.

• 조명전기설비학회논문지
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• 제20권5호
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• pp.78-84
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• 2006

전력산업이 수직독점적인 구조에서 규제완화의 경쟁체제로 전환됨에 따라 무효전력서비스의 요금산정이 전력시장 운영자에게는 새로운 이슈가 되고 있다. 본 논문은 몇몇의 선진국과 국내에서 채용되는 무효전력서비스에 대한 요금산정방법을 검토하고, 무효전력시장을 이용하는 새로운 요금산정방법을 제안한다. 무효전력시장은 무효전력 발전원이 제시하는 입찰값을 바탕으로 하루전 전력시장 후에 무효전력 최적조류계산을 거쳐 단일가격으로 결정된다. 제안하는 방법은 무효전력 설치용량에 대한 투자비뿐만 아니라 무효전력 생산량을 늘리기 위해 발전기가 줄이게 되는 유효전력에 대한 기회비용을 함께 고려하고 있다. 26모선 모델계통에서의 사례연구를 통하여 제안하는 방법의 효용성을 입증하고 있다.

• KIEE International Transactions on Power Engineering
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• 제5A권3호
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• pp.228-234
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• 2005

This paper presents the evaluation of reactive power pricing through the control of generator voltages under the assumption that the reactive power market has been transformed into the real power market. By applying the concept of economic dispatch, which minimizes the total cost of real power generation to reactive power generation, the algorithm for implementing reactive power pricing is proposed to determine the optimum voltage profiles of generators. It consists of reactive power voltage equation, the objective function that minimizes the total cost of reactive power generation, and linear analysis of inequality constraints in relation to the load voltages. From this algorithm, the total cost of the reactive power generation can be yielded to the minimum value within network constraints as the range of load voltages. This may provide the fair and reasonable price information for reactive power generation in the deregulated electricity market. The proposed algorithm has been tested on the IEEE 14-bus system using MATLAB.

• KIEE International Transactions on Power Engineering
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• 제11A권4호
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• pp.39-44
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• 2001

As electric power systems have been moving from vertically integrated utilities to a deregulated environment, the charging of reactive power management is a new challenging them for market operators. This paper proposes a new methodology to compute the costs of providing reactive power management service in a competitive electrical power market. The proposed formulation, which is basically different from those shown in the literature, consists of two parts. One is to recover investment capital costs of reactive power supporting equipment based on a reactive power flow tracing algorithm. The other is to recover operational costs based on variable spot prices using the optimal power flow algorithm. The charging shapes resulted from the proposed approach exhibit a quite good meaning viewed from a practical sense. It turns out that reactive power charged are mostly due to recovery of capital costs and slightly due to recovery of operational costs. The methods can be useful in providing additional insight into power system operation and can be used to determined tariffs of a reactive power management service.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전력기술부문
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• pp.77-82
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• 2001

As electric power systems have been moving from vertically integrated utilities to a deregulated environment, the charging of reactive power management is a new challenging theme for market operators. This paper proposes a new methodology to compute the costs of providing reactive power management service in a competitive electrical power market. The proposed formulation, which is basically different from those shown in the literature, consists of two parts. One is to recover investment capital costs of reactive power supporting equipment based on a reactive power flow tracing algorithm. The other is to recover operational costs based on variable spot prices using the optimal power flow algorithm. The charging shapes resulted from the proposed approach exhibit a quite good meaning viewed from a practical sense. It turns out that reactive power charges are mostly due to recovery of capital costs and slightly due to recovery of operational costs. The method can be useful in providing additional insight into power system operation and can be used to determine tariffs of a reactive power management service.

• 대한전기학회논문지:전력기술부문A
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• 제52권7호
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• pp.429-436
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• 2003

This paper presents a new approach for evaluating the transmission marginal loss factors (MLFs) considering the reactive power. Generally, MLFs are represented as the sensitivity of transmission losses, which is computed from the change of the generation at reference bus by the change of the load at the arbitrary bus-i. The conventional evaluation method for MLFs uses the only H matrix, which is a part of jacobian matrix. Therefore, the MLFs computed by the existing method, don't consider the effect of the reactive power, although the transmission losses are a function of the reactive power as well as the active power. To compensate the limits of the existing method for evaluating MLFs, the power factor at the bus-i is introduced for reflecting the effect of the reactive power in the evaluation method of the MLFs. Also, MLFs calculated by the developed method are applied to energy spot markets to reflect the impacts of reactive power. This method is tested with the sample system with 5-bus, and analyzed how much MLFs have an effect on the bidding/offer price, market clearing price(MCP), and settlement in the competitive energy spot market. This paper compared the results of MLFs calculated by the existing and proposed method for the IEEE 14-bus system, and the KEPCO system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 A
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• pp.533-535
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• 2001

This paper proposes a methodology to compute the servicing price of reactive power in electrical power market of competitive environment. The result of proposed method is proved by a 6-bus sample test system. In this paper we propose the real-time pricing method assigning to variable charges, the downstream power flow tracing assigning to fixed charges. The reactive power will be active by the proposed method through competitive electrical power market.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 A
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• pp.181-183
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• 1999

As one of ancillary services, voltage support and reactive power service should be compensed properly for its contribution. In this paper, a cost-based reactive power planning is presented. which minimizes the total cost of reactive power support of generators and VAR compensation facility installation. Reactive power support of generator is evaluated by the opportunity costs of reduced energy sale considering the varying SMP(system marginal price) in power market, Gradient projection method is applied to solve this reactive power planning using IEEE14 bus system.