• Journal of Power Electronics
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• v.11 no.1
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• pp.90-96
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• 2011

Congestion management is one of the most challenging aspects in the recently deregulated electricity markets. FACTS devices have been shown to be an efficient alternative to control the flow of power in lines, resulting in increased loadability, lower system loss and a reduced cost of production. In this paper, the application of a static series synchronous compensator (SSSC) for the purpose of congestion management of power systems has been studied. A sensitivity-based analysis method is utilized for effective determination of the SSSC location in an electricity market. The method is topology based and it is independent of the system operation point. A power injection p-model is developed for the SSSC in this study. Numerical results based on the modified IEEE 14 bus system with/without the SSSC demonstrate the feasibility as well as the effectiveness of the SSSC for congestion management in a network. The results obtained when using the SSSC to improve system transfer capability and congestion management is encouraging.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.5
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• pp.302-307
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• 2004

As deregulation of power industry is becoming a reality, there has been an intense interest in the strategic bidding for suppliers to maximize their profits. The profit gained by a supplier is related not only to its energy-price bid curve but also to its submitted operational parameters such as generation capacity, etc. So suppliers are willing to use those strategic parameters that can be manipulated by themselves and are effective to their profit. This paper deals with the competition model with compound strategies: generation capacity and bidding curve. The parameter space is modeled by dividing into the two strategies, so the problem is made up of the four types of sub-game in a two player game. This paper analyzes the global Nash Equilibrium (NE) over the whole divisions by computing the sub-game NEs in some divisions and by deriving the best response curves which have discontinuities in other divisions. The global NE is shown to correspond to the Cournot NE where the quantity variable is realized by a constraints of a generation capacity.

• Proceedings of the KIEE Conference
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• 2005.11b
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• pp.162-164
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• 2005

This paper presents an hour-ahead System Marginal Price (SMP) forecasting framework based on a neural network. Recently, the deregulation in power industries has impacted on the power system operational problems. The bidding strategy of market participants in energy market is highly dependent on the short-term price levels. Therefore, short-term SMP forecasting is a very important issue to market participants to maximize their profits. and to market operator who may wish to operate the electricity market in a stable sense. The proposed hybrid neural network is composed of tow parts. First part of this scheme is pattern classification to input data using Kohonen Self-Organizing Map (SOM) and the second part is SMP forecasting using back-propagation neural network that has three layers. This paper compares the forecasting results using classified input data and unclassified input data. The proposed technique is trained, validated and tested with historical date of Korea Power Exchange (KPX) in 2002.

• KIEE International Transactions on Power Engineering
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• v.5A no.3
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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.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.10
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• pp.1787-1791
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• 2010

This paper presents the survey results of the interruption on domestic customer, especially commercial, with primary focus on the cost are presented. General method utilized in quantifying the benefit of reliability on power system is to estimate the Customer Interruption Cost(CIC) associated with the electric service interruption. According to change the circumstance of electricity market by the deregulation and the introduction of new technology, reliable and accurate CIC is required for estimate the applied plan and technology under the circumstance. This paper presents the commercial customer interruption cost is estimated by the survey conducted by KEPCO in 2009. To collect the customer interruption data for calculation of CIC, the survey is conducted. The survey targeting commercial customer around the branch-offices under twelve regional headquarters of KEPCO was carried out.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.10
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• pp.1792-1796
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• 2010

In this paper, the survey results of the interruption on domestic residential customer with primary focus on the cost are presented. General method utilized in quantifying the benefit of reliability on power system is to estimate the Customer Interruption Cost(CIC) associated with the electric service interruption. According to change the circumstance of electricity market by the deregulation and the introduction of new technology, reliable and accurate CIC is required for estimate the applied plan and technology under the circumstance. This paper presents the residential customer interruption cost is estimated by the survey conducted by KEPCO in 2009. To collect the customer interruption data for calculation of CIC, the survey is conducted. The survey targeting residential customer around the branch-offices under twelve regional headquarters of KEPCO was carried out.

• Journal of Electrical Engineering and Technology
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• v.4 no.1
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• pp.49-54
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• 2009

One of the major challenges confronting a multiservice electric utility is the establishment of the right prices for its services. The key objectives of particular pricing schemes are reasonableness of company earnings, economic efficiency, the responsiveness of supply and of the allocation of sources to the desires of consumers, and maintenance of some degree of competition. This paper proposes a value-based pricing mechanism amenable to the current deregulation situation in electricity market allowing service differentiation. The proposed pricing mechanism can be implemented in a nodal auction model, and can also be applied to direct load control.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.54-56
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• 2003

With the advancement of superconductor materials, especially in HTC YBCO(Gen II), the feasibility of SMES in power systems become much higher than previous days application[1]. Also, with the de-regulation of electricity market, it is indispensable to have a proper estimation of power quality index and power quality cost calcluation mechanism to stabilize highly industrialized society and to vitalize the investment for electric power system. This paper suggests a comprehensive algorithm[2] to determine the policy of SMES investment with the PQ Indices[3] based on aggregated load CBEMA curve reflecting the voltage characteristics such as volatge sags and interruptions which make electric load in unstable operation.

• International Journal of Fluid Machinery and Systems
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• v.9 no.2
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• pp.182-193
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• 2016

Introduction of intermittent electricity production systems like wind and solar power to electricity market together with the deregulation of electricity markets resulted in numerous start/stops, load variations and off-design operation of water turbines. Hydraulic turbines suffer from the varying loads exerted on their stationary and rotating parts during load variations since they are not designed for such operating conditions. Investigations on part load operation of single regulated turbines, i.e., Francis and propeller, proved the formation of a rotating vortex rope (RVR) in the draft tube. The RVR induces pressure pulsations in the axial and rotating directions called plunging and rotating modes, respectively. This results in oscillating forces with two different frequencies on the runner blades, bearings and other rotating parts of the turbine. This study investigates the effect of transient operations on the pressure fluctuations exerted on the runner and mechanism of the RVR formation/mitigation. Draft tube and runner blades of the Porjus U9 model, a Kaplan turbine, were equipped with pressure sensors for this purpose. The model was run in off-cam mode during different load variations. The results showed that the transients between the best efficiency point and the high load occurs in a smooth way. However, during transitions to the part load a RVR forms in the draft tube which induces high level of fluctuations with two frequencies on the runner; plunging and rotating mode. Formation of the RVR during the load rejections coincides with sudden pressure change on the runner while its mitigation occurs in a smooth way.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.877-887
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• 2015

Rapid development of cities with constant increasing load and deregulation in electricity market had forced the transmission lines to operate near their threshold capacity and can easily lead to voltage instability and caused system breakdown. To prevent such catastrophe from happening, accurate readings of voltage stability condition is required so that preventive equipment and operators can execute security procedures to restore system condition to normal. This paper introduced Enhanced Hybrid Particle Swarm Optimization algorithm to estimate the voltage stability condition which utilized Fast Voltage Stability Index (FVSI) to indicate how far or close is the power system network to the collapse point when the reactive load in the system increases because reactive load gives the highest impact to the stability of the system as it varies. Particle Swarm Optimization (PSO) had been combined with the ANN to form the Enhanced Hybrid PSO-ANN (EHPSO-ANN) algorithm that worked accurately as a prediction algorithm. The proposed algorithm reduced serious local minima convergence of ANN but also maintaining the fast convergence speed of PSO. The results show that the hybrid algorithm has greater prediction accuracy than those comparing algorithms. High generalization ability was found in the proposed algorithm.