• Proceedings of the KIEE Conference
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• 1999.11b
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• pp.200-202
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• 1999

This paper describes the optimization problem of real power rescheduling and present an algorithm based linear programming for studying the load-shedding and generation reallocation problem when a portion of the transmission system is disabled and at power flow solution cannot be obtained for the overload of some lines. And in case initial is infeasible, solution could not be converge. So this paper gives an algorithm being lie infeasible quantities within limit. The paper describes a LP-based algorithm to obtain the solution in power dispatch related to overload situations in power system and it is easily extened under various objective. The optimization procedures is based in linear programming with bounded variables and use the multi-segment curve method for a objective function and the validity of the algorithm is verified with two examples : 10-bus system and 57-bus system.

• Proceedings of the KIEE Conference
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• 2001.11b
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• pp.167-169
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• 2001

This paper introduces the principal pool rules of the wholesale power market scheduled to be commissioned in January 2003 in Korea. The pool rules includes electricity trading procedures such as bidding, determining and publishing of forecasted market price, and 5 minute unconstrained dispatch scheduling for generation/market price, which are required for settlement after dispatching and should be conformed by KPX and participants in the market. Detailed procedures of the rules are under development and additional provisions for stable market operation are under discussion.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.20 no.43
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• pp.127-137
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• 1997

This paper proposes a heuristic method for job shop scheduling with alternative machines. Our heuristic suggests two machine-selecting rules and two priority dispatching rules for modifying existent ones considering alternative machines, and then it extends existing nondelay/active job shop schedule generation. This heuristic provides good criteria(rules) in the selection of a proper machine among those performing a specific operation and for the dispatch of an operation to a selected machine and thus these rules permit the efficient job shop scheduling with alternative machines. The performances of our two machine-selecting rules in addition to the two priority dispatching rules, applied together with the existing 17 rules, are experimented and evaluated, respectively.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.12
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• pp.575-580
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• 2000

Switching of the transmission lines(T/L) is one of the ways for suppressing the short circuit capacity. This paper presents the extended optimal power flow(OPF) to the problem of selecting the T/Ls to be open. The constraints of the short circuit currents within limits are added to the inequalities of OPF. Also, the overload on the other lines due to switching of T/Ls is avoided by the linearized inequalities. The number of the open lines can be minimized by incorporating into the objective function of OPF in order to maintain reliability. The method of an effective calculation of the extended OPF is also proposed in this paper, which makes the two parts decoupled. The one concerning the generation dispatch is solved in the first place by the conventional method. Secondly, the other concerning the line-switching is optimized by the proposed formulation.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.1
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• pp.1-5
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• 2001

In this paper, a new method for calculating the penalty factors of all generators including the slack bus is presented. A simple transposition of the angle reference, from the conventional slack bus to another bus where no generation exists, enables the derivation of the loss sensitivity of the slack bus. Penalty factors are obtained without any physical assumption through a simple substitution of the bus loss sensitivities. Penalty factors calculated by proposed method are not dependent on reference bus and can also be directly substituted into the general ELD equation for computing the optimal dispatch. Equations for loss sensitivities, Penalty factors and ELD are calculated simultaneously in normal power flow computation. A case study on a test system has proved the effectiveness of the proposed' angle reference transposition' method.

• Journal of Electrical Engineering and Technology
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• v.2 no.2
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• pp.152-156
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• 2007

This paper proposes a method for real-time control of both capacitors and ULTC in a distribution system to reduce the total power loss and to improve the voltage profile over the course of a day. The multi-stage consists of the off-line stage to determine dispatch schedule based on a load forecast and the on-line stage generates the time and control sequences at each sampling time. It is then determined whether one of the control actions in the control sequence is performed at the present sampling time. The proposed method is presented for a typical radial distribution system with a single ULTC and capacitors.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.204-207
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• 1998

This paper presents a software development technique for EMS applications. The definite client-server configuration is proposed and EMS software package is developed. The developed EMS software package consists of AGC(Automatic Generation Control). Economic Dispatch. State Estimator. Contingency Analysis Simulator and Database Applications. In order to integrate each of the developed modules, EMS Network Server is developed. The proposed package is tested with a sample system. It is expected that the developed package can be easily applicable to the practical system.

• Proceedings of the KIEE Conference
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• 2004.11b
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• pp.201-203
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• 2004

본 논문에서는 먼저 유효전력 시장과 무효전력 시장을 분리하여 운영한다는 가정하에서 발전기의 무효전력 생산을 위한 최적의 전압값을 산정하고자 한다. 유효전력 시장에서 경제 급전(Economic Dispatch)을 통해 발전기의 유효전력 생산 비용을 최소화시키는 최적의 유효전력량 결정원리를 응용하여, 무효전력 시장에서의 발전기의 무효전력 생산 비용을 최소화시키는 최적의 발전기 전압 profile을 결정하는 무효전력시장 구축 알고리즘을 제시한다. 이 알고리즘에는 기본적으로 주효전력-전압의 조류방정식과 목적함수로서 무효진력 비용의 최소화 문제, 그리고 부하측 전압과 관련된 부등식제약조건의 선형화 문제 등이 포함된다. 이렇게 산출된 발전전압에 의한 무효전력의 가격은 실제 전압제어에 의한 가격산정이라는 측면에서 그 의미를 찾아볼 수가 있다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.7
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• pp.809-815
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• 2018

Distributed generations (DGs) using renewable energy resources in power systems have been widely integrated, and many of these DGs have intermittency. DGs can significantly affect the overall voltage profile of the system through the reactive power control for a voltage support. Therefore, in the planning stage of the optimal operation and dispatch of voltage regulation devices, DGs' hosting capacity with the reactive power control scheme should be considered. In this paper, we model the IEEE 34-bus test feeder, including all essential equipment. An optimization method is utilized to determine the optimal siting and operation of the voltage regulation devices in the presence of DGs with reactive power control scheme. Finally, we compare the optimal results of the each case to analyze the relationship among the hosting capacity of the DGs and voltage regulation devices operation.

• Journal of Electrical Engineering and Technology
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• v.8 no.6
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• pp.1261-1268
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• 2013

This study proposes a voltage and reactive coordinative control strategy with distributed generator (DG) in a distribution power system. The aim is to determine the optimum dispatch schedules for an on-load tap changer (OLTC), distributed generator settings and all shunt capacitor switching on the load and DG generation profile in a day. The proposed method minimizes the real power losses and improves the voltage profile using squared deviations of bus voltages. The results indicate that the proposed method reduces the real losses and voltage fluctuations and improve receiving power factor. This paper proposes coordinated voltage and reactive power control methods that adjust optimal control values of capacitor banks, OLTC, and the AVR of DGs by using a voltage sensitivity factor (VSF) and dynamic programming (DP) with branch-and-bound (B&B) method. To avoid the computational burden, we try to limit the possible states to 24 stages by using a flexible searching space at each stage. Finally, we will show the effectiveness of the proposed method by using operational cost of real power losses and voltage deviation factor as evaluation index for a whole day in a power system with distributed generators.