• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.6
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• pp.1086-1090
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• 2011

This paper presents a method to evaluate generation rescheduling priority using transient energy margin sensitivity for power system operation. A change in any of the functional parameters obviously causes a change in the energy margin. Especially the energy margin sensitivity is evaluated for change with respect to generation. For a given contingency, the energy margin is computed and the respective sensitivities are also computed. It is possible to rank the sensitivities and thereby determine the generators which will affect the energy margin most and hence affect the stability (instability) of the system. The sign of the sensitivity indicates the direction of change in generation for a given change in energy margin.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.8
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• pp.1467-1472
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• 2011

This paper presents an optimal operation of microgrid systems and considering a tie-lines capacities that concerned each grid. The microgrid system consists of a wind turbine, a diesel generator, and a fuel cell. An one day load profile and wind resource for wind turbine generator were used for the study. For the grid interconnection, tie-line capacities were applied as constraints. The capacity constraints of tie-lines in production cost analysis are very important issues in the operation and planning of microgrid. In optimization, the Harmony Search (HS) algorithm is used for solving the problem of microgrid system operation which a various generation resources are available to meet the customer load demand with minimum operating cost. The application of HS algorithm to optimal operation of microgrid proves its effectiveness to determine optimally the generating resources without any differences of load mismatch.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.7
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• pp.1287-1293
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• 2009

This paper presents an application of Harmony Search (HM) meta-heuristic optimization algorithm for optimal operation of microgrid system. The microgrid system considered in this paper consists of a wind turbine, a diesel generator, and a fuel cell. An one day load profile which divided 20 minute data and wind resource for wind turbine generator were used for the study. In optimization, the HS algorithm is used for solving the problem of microgrid system operation which a various generation resources are available to meet the customer load demand with minimum operating cost. The application of HS algorithm to optimal operation of microgrid proves its effectiveness to determine optimally the generating resources without any differences of load mismatch and having its nature of fast convergency time as compared to other optimization method.

• Proceedings of the KIEE Conference
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• 2007.11b
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• pp.207-209
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• 2007

For proper application of the superconducting fault current limiter(SFCL), the prior investigation of fundamental characteristics and its effects to the distribution systems are needed. The Current limiting behavior of SFCL is dominated by quenching and recovery characteristics. So, we have developed an EMTP/ATPDraw model of resistive type SCFL using MODELS language. The operating characteristics and current limiting behaviors of SFCL in distribution systems have been simulated and investigated.

• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.345-347
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• 2008

Available transfer capability(ATC) is an important indicator of the usable amount of transmission capacity accessible by several parties for commercial trading in power transaction activities. This paper deals with an application of optimization technique for available transfer capability(ATC) calculation and analyzes the results of ATC by using several variables of optimal power flow. The method proposed is applied to the modified IEEE 14 buses model system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.10
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• pp.1265-1270
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• 2018

One of the ways to improve the stability of power facilities used in power systems is to use power surge arresters and to protect against transient overvoltages and surges in normal operation. Also it is important to reduce the impact of lightning strikes because lightning can create overvoltage in the grid of the wind turbine and affect power quality. So This paper analyzes the effects of overvoltage and adjacent turbines due to single strike and multi strike to ground impedance changes when the surge arrester is deteriorated in a wind power farm.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.1
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• pp.146-153
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• 2004

This paper presents the method for the placement and operation of dispersed generator systems(DGs) using fuzzy goal programming in distribution systems. For the placement and operation of DGs the problem is formulated with reduction of search spaces and flexibility of system situations. Especially, the original objective function and constraints are transformed by fuzzy goal programming to evaluate their imprecise nature for the criterion of power loss minimization, the number or total capacity of DGs and the bus voltage deviation, and then solve the problem using genetic algorithm.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.412-413
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• 2011

This paper presents a new generation rescheduling approach for preventive control of power systems, which can optimally reallocate power generations for unstable contingencies. The transient stability constraints used in the optimal rescheduling model are described by energy margin sensitivity. Especially the energy margin sensitivity is evaluated for change with respect to generation. For a given contingency, the energy margin is computed and the respective sensitivities are also computed.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.606-607
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• 2011

전력계통의 부하를 모델링하기 위해서는 부하 모델 구조의 선정과 부하모델 구조의 파라미터를 추정하는 방법이 필요하다. 부하 모델의 구조는 ZIP모델을 사용하고, 부하 모델의 파라미터를 추정하는 방법으로는 Levenberg-Marquardt방법을 사용하여 한국전력공사 변전소이차 측에서 측정된 실측 데이터를 이용하여 부하를 모델링하였다. 또한 모델링된 부하의 대표파라미터를 선정하고 대표파라미터를 실제 계통에 적용하였을 때의 오차를 분석하였다.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.241_242
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• 2009

This paper presents a method to assess total transfer capability (TTC) by using energy function. To get the critical energy, the potential energy boundary surface(PEBS) method which is one of the transient energy function(TEF) method is used. TTC assessment is to calculate TTC by using the repeated power flow (RPF) method. It is seen that energy margin can be use to assess available transfer capability(ATC).