• 대한전기학회논문지
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• 제39권3호
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• pp.223-231
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• 1990

Optimal Power Flow (OPF) solution by the Newton's method provides a reliable and robust method to classical OPF problems. The major challenge in algorithm development is to identify the binding inequalities efficiently. This paper proposes a simple strategy to identify the binding set. From the mechanism of penalty shifting with soft penalty in trial iteration, an active binding set is identidied automatically. This paper also suggests a technique to solve the linear system whose coefficients are presented in the matrix from. This implementation is highly efficient for sparsity programming. Case studies for 3, 5, 14, 118 bus and practical TPC-190, KEPCO-306 bus systems are performed as well.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 A
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• pp.194-196
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• 2001

This paper presents a hybrid algorithm for solving security constrained OPF in interconnected power systems, which is based on the combined application of evolutionary programming (EP) and sequential quadratic programming (SQP). The objective functions are the minimization of generation fuel costs and system power losses. In OPF considering security, the outages are selected by contingency ranking method. The control variables are the active power of the generating units, the voltage magnitude of the generator, transformer tap settings and SVC setting. The state variables are the bus voltage magnitude, the reactive power of the generating unit, line flows and the tie line flow. The method proposed is applied to the modified IEEE 14buses model system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 C
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• pp.1046-1048
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• 1999

This Paper compares two mathematical decomposition coordination methods to implementing the distributed optimal Power flow(OPF) using the regional decomposition: the Auxiliary Problem Principle(APP) and the Alternating Direction Method(ADM), a variant of the conventional Augmented Lagrangian approach. A case study was performed with IEEE 50-bus system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1990년도 하계학술대회 논문집
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• pp.139-142
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• 1990

This paper presents a new approach to optimal power flow (OPF) problem using conjugate gradient method, using this method. We can obtain initial feasible solution and lagrangian multiplier without calculation of matrix inversion.Test experiment shows a desiriable result and a stable convergence characteristic.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.347-349
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• 2000

Under an open transmission access, the generation dispatch is determined by the bidding process of market participants. Congestion occurs when the dispatch would result in the violation of operational constraints. Congestion problem is formulated and solved by OPF(optimal power flow) calculation. The objective functions in OPF are given as quadratic cost functions or piecewise linear functions of bidding functions. In this study, the optimization technique of generation dispatch is presented for the combination of two types of quadratic and linear cost functions.

• Journal of Advanced Marine Engineering and Technology
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• 제28권5호
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• pp.801-810
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• 2004

The Primal-Dual Interior-Point (PDIP) method is currently one of the fastest emerging topics in optimization. This method has become an effective solution algorithm for large scale nonlinear optimization problems. such as the electric Optimal Power Flow (OPF) and natural gas and electricity OPF. This study describes major theoretical developments of the PDIP method as well as practical issues related to implementation of the method. A simple quadratic problem with linear equality and inequality constraints

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전력기술부문
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• pp.190-193
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• 2004

Optimal Power Flow (OPF) is becoming more and more important in the deregulation environment of power pool and there is an urgent need of faster solution technique for on-line application. So this paper presents parallel genetic algorithm-tap search for the solution of the OPF. The control variables modeled unit active power outputs, generator-bus voltage magnitudes and transformer-tap settings. A number of functional operating constraints, such as branch flow limits, load bus boltage magnitude limits and generator reactive capabilities are included as penalties in the fitness function. In parallel GA-TS, GA operators are executed for each process. If best fitness of the GA is not changed for several generations, TS operators are executed for the upper three populations to enhance the local searching capabilities. With migration operation, best string of each node is transferred to the neighboring node after predetermined iterations are executed. For parallel computing, we developed a PC-cluster system consisting of 8 PCs. Each PC employs the 2 GHz Pentium IV CPU and is connected with others through ethernet switch based fast ethernet. To show the usefulness of the proposed method, developed algorithm has been tested and compared on an IEEE 30-bus system in the reference paper. From the simulation results, we can find that the proposed algorithm is efficient for the OPF.

• 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.

• 에너지공학
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• 제24권1호
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• pp.123-131
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• 2015

스마트그리드는 저탄소 녹색성장의 선도 프로젝트로 추진하는 핵심과제로 전력산업의 환경변화에 적응하고 에너지이용 효율을 제고하기 위한 새로운 전력시스템이다. 현 전력계통은 폐쇄적인 EMS(Energy Management System)를 기반으로 운영되어 최소한의 보안강도가 보장되었지만, 스마트그리드 하에서는 개방형 통신망과 연계되면서 기존의 사이버 보안 위협들이 전력시스템으로 유입된다. 또한 EMS와 같은 제어시스템은 실시간 특성이 강하게 요구되며, 높은 수준의 가용성(낮은 고장 빈도와 신속한 복구)이 필요하다. 즉, EMS의 사이버 위협은 IT시스템에 비해 보다 복잡하고 치명적인 요인이 된다. 본 논문에서 갈수록 증대하고 있는 스마트그리드 보안 측면의 문제들을 정의하고, 피상적으로 머물던 스마트그리드의 사이버 위험 문제를 물리적 전력계통과 연계하고 모델링하여 수치로 산출할 수 있는 정량화 방법론을 제시하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
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• pp.268-270
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• 2005

전력계통을 계획, 운영, 검토, 해석하는데 있어서 가장 필요한 OPF(Optimal Power Flow)는 현재 다방면에서 새로운 알고리즘과 많은 수리적 방법을 통하여 접근하고 있다. 이들의 기반이 되는 조류계산은 많은 신뢰성들을 얻었지만, 현재 실무자 중심으로 구성되고 직접적으로 적절한 발전배분 상태를 계산하는 부분에서는 일부 한계성이 나타나고 있다. 이에 대해서 계속된 반복계산에 의한 최적의 계통 발전 배분상태에 근접한 값을 제시할 수 있는 프로그램을 PSS/E의 IPLAN을 통하여 개발하였다.