• KIEE International Transactions on Power Engineering
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• v.2A no.3
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• pp.89-94
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• 2002

In this paper, a protection system using a Multi-Agent concept for power distribution networks is proposed. Every digital over current relay(OCR) is developed as an agent by adding its own intelligence, self-tuning and communication ability. The main advantage of the Multi-Agent concept is that a group of agents work together to achieve a global goal which is beyond the ability of each individual agent. In order to cope with frequent changes in the network operation condition and faults, an OCR agent, suggested in this paper, is able to detect a fault or a change in the network and find its optimal parameters for protection in an autonomous manner considering information of the whole network obtained by communication between other agents. Through this kind of coordination and information exchanges, not only a local but also a global protective scheme is completed. Simulations in a simple distribution network show the effectiveness of the suggested protection system.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.178-180
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• 2003

Since faults often occur on power system, relay protection has become an important part to protect the equipments of power system efficiently and safely. Database can store the data about the relay protection efficiently, and these data must be shown to users through the web. Proset2000(an overall program system to protect power system) can realize this function in some measure, but it needs to be developed. This paper is about the further development of Proset2000. In this paper, web of Proset2000 is made by ASP programming technology, and users can browse and search the useful data through the web. There are some new functions, such as the summary of setting values, the message board and the management of administrator.

• IE interfaces
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• v.20 no.2
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• pp.186-194
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• 2007

Recent deregulation of Korean electricity industry has made each power generation company pay more attention to maximizing its own profit instead of minimizing the overall system operation cost while guaranteeing system security. Electricity power generation problem is typically defined as the problem of determining both the on and off status and the power generation level of each generator under the given fuel constraints, which has been known as Profit-Based Unit Commitment (PBUC) problem. To solve the PBUC problem, the previous research mostly focused on devising Lagrangian Relaxation (LR) based heuristic algorithms due to the complexity of the problem and the nonlinearity of constraints and objectives. However, these heuristic approaches have been reported as less practical in real world applications since the computational run time is usually quite high and it may take a while to implement the devised heuristic algorithms as software applications. Especially when considering long-term planning problem which spans at least one year, the complexity becomes higher. Therefore, this paper proposes an explicit column generation algorithm using power generation patterns and the proposed algorithm is successfully applied to a Korean power generation company. The proposed scheme has a robust structure so that it is expected to extend general PBUC problems.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.193-195
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• 2002

In this paper, a communication module is proposed to be applied to communication between over current relay (OCR) agents in multi agent protection system. A multi agent system can achieve a global goal beyond the ability of each individual agent by working together, in which it is the prerequisite for each agent to be able to exchange or share information or processing status with other agent. The proposed communication module is purposed to enable not only each agent to bring about its own goal, but also the whole protective system to provide much improved coordinated protection. It is applied to a self adaptive protection system for a distribution network using multi agent concept to show its effectiveness.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.14 no.4
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• pp.305-312
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• 2014

This paper discusses real-time peak shaving algorithms for a large-scale battery energy storage system (BESS). Although several transmission and distribution functions could be implemented for diverse purposes in BESS applications, this paper focuses on a real-time peak shaving algorithm for an energy time shift, considering wind power generation. In a high wind penetration environment, the effective load levels obtained by subtracting the wind generation from the load time series at each long-term cycle time unit are needed for efficient peak shaving. However, errors can exist in the forecast load and wind generation levels, and the real-time peak shaving operation might require a method for wind generation that includes comparatively large forecasting errors. To effectively deal with the errors of wind generation forecasting, this paper proposes a real-time peak shaving algorithm for threshold value-based peak shaving that considers fuzzy wind power generation.

• Journal of Power Electronics
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• v.10 no.1
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• pp.72-78
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• 2010

In this paper the operation of a double-fed wound-rotor induction machine, coupled to a wind turbine, as a generator at sub-synchronous speeds is investigated. A novel approach is used in the analysis, namely, the rotor power flow approach. The conditions necessary for operating the machine as a double-fed induction generator (DFIG) are deduced. Formulae describing the factors affecting the range of sub-synchronous speeds within which generation occurs are deduced. The variations in the magnitude and phase angle of the voltage injected to the rotor circuit as the speed of the machine changes to achieve generation at the widest possible sub-synchronous speed range is presented. Also, the effect of the rotor parameters on the generation range is presented. The analysis proved that the generation range could increase from sub-synchronous to super-synchronous speeds, which increases the amount of energy captured by the wind energy conversion system (WECS) as result of utilizing the power available in the wind at low wind speeds.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.10
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• pp.1718-1726
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• 2010

Utilization of renewable energy is becoming increaingly important from the viewpoints of environmental protection and conservation of fossil fuel. However, the generating power of renewable energy is always fluctuating due to the environmental status. This paper presents a scheme for supervisory control of wind generation system with the energy storage and STATCOM to reduce the power variation. In this paper, we especially concentrate on constant power output control of wind generation system. In order to achieve this purpose, the coordinated control strategy between different types of energy storage system and reactive power compensation device. The proposed control scheme has been validated by PSCAD/EMTDC simulation. As a result, the proposed scheme can handle the power output of wind generation system with a constant value.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.299-301
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• 2003

In this paper, a protection system using Multi-Agent concept for power distribution network is proposed. Multi agent system consist of Feeder agent, OCR(Over Current Relay) agent, Recloser agent and Switch agent. An agent calculates and corrects its parameter by itself through communication with neighboring agents and its own intelligence algorithm. Simulations in a simple distribution network show the effectiveness of the suggested protection system. Multi-Agent System, protection of distribution network, Communication.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.151-153
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• 2003

This paper was studied on using data of the protective relay by Power Quality Monitor. The protective relay will have problem to save data for PQM(Power Qualify Monitoring) analysis because the protective relay memory is limited. So this paper was proposed new data compression of the data was get from the protective relay. The scheme is compared each cycle after DFT(Discrete Fourier Transform). And scheme is verified through simulation of protective relay data was from real distribution system.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.707-710
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• 1996

This paper is to build and develop the generation schedule program to provide a stable power supply and economic operation of power generation system. A practical algorithm is presented for solving the thermal unit commitment problem which is one of very important areas in economic operation of power system. This algorithm is based on priority ordering by the unit generation cost and it is shown that the operation cost of chosen sets of generators is the minimum. The proposed method is proven to be very practical, accurate and efficient in a KEPCO system.