• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.820-822
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• 1996

This paper proposes a method for seeking the scheme of substation restoration by using genetic algorithm. Genetic algorithm (GA), first introduced by John Holland, is becoming an important tool in machine learning and function optimization. GA is a searching or optimization algorithm based on Darwinian biological evolution principle. As a test system, we assume a simple substation system and for the transformer fault, the result is obtained.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.9
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• pp.44-49
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• 2011

Due to increase of fault current, various superconducting fault current limiter (SFCL) are researched. We studied a power distribution system with SFCL. Along the way, we knew characteristics of fault current according to a distance from substation to fault point. Fault current is reduced by distance`s increase from substation. Also, SFCL.s effects are decreased by distance too. Therefore, we analyzed the fault current by a distance from substation to fault point when a SFCL was applied into a power distribution system. We simulated using a PSCAD/EMTDC.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.57 no.3
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• pp.302-310
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• 2008

In order to evaluate the nominal rating of breakers in distribution system due to the increased capacity and operating conditions of power transformers in 154 kV substation, the fault currents in distribution system were calculated by the conventional method and simulations of PSCAD/EMTDC program. Consequently, under the condition of the parallel operation of transformers, the fault currents exceed the nominal current of the breakers in some areas. Without NGR at the secondary neutral of the transformer, the current of single line-to-ground fault was bigger than that of 3-phase fault. Therefore, the results clearly show that the measures to limit the fault currents in distribution system are needed when the increased capacity of power transformers is introduced into 154 kV substation.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.12
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• pp.637-644
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• 2004

This paper proposes an expert system with the knowledge learning capability which can enhance the safety and effectiveness of substation operation in the automated substation as well as existing substation by inferring multiple events such as main transformer fault, busbar fault and main transformer work schedule under multiple inference mode and multiple objective mode and by considering totally the switch status and the main transformer operating constraints. Especially inference mode includes the local minimum tree search method and pattern recognition method to enhance the performance of real-time bus reconfiguration strategy. The inference engine of the expert system consists of intuitive inferencing part and logical inferencing part. The intuitive inferencing part offers the control strategy corresponding to the event which is most similar to the real event by searching based on a minimum distance classification method of pattern recognition methods. On the other hand, logical inferencing part makes real-time control strategy using real-time mode(best-first search method) when the intuitive inferencing is failed. Also, it builds up a knowledge base or appends a new knowledge to the knowledge base using pattern learning function. The expert system has main transformer fault, main transformer maintenance work and bus fault processing function. It is implemented as computer language, Visual C++ which has a dynamic programming function for implementing of inference engine and a MFC function for implementing of MMI. Finally, it's accuracy and effectiveness is proved by several event simulation works for a typical substation.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.5
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• pp.86-93
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• 2010

This paper presents the guideline for enhancing the reliability and availability of SAS with IEC 61850 based IEDs in real power system. The IEC 61850 standard communication networks and systems allow utilities to consider new designs for substations applicable both new substation and refurbishments. The existing solutions are based on hardwired interface between the primary substation equipment and the secondary protection, monitoring, control and recording devices. All over the world, lots of projects at different stages of realization have been reported during the last year leading to a rapid maturation of the associated technologies. At present, IEC 61850 is becoming a popular communication standard for the substation automation system.

• Journal of the Korean Society of Industry Convergence
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• v.14 no.3
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• pp.121-125
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• 2011

EMTP-RV is the very powerful program to analyze the dynamic operation of the power system. To use this package in the large complex power system, it is very important to simplify the power system to simple equivalent network. In our study the 100 MVA STATCOM is placed at 345kV "MIGUM" which is the one of the 345kV substations of the Korean Electric Power System that is consist of more than 1000-bus. MIGUM substation is connected with 7 separated transmission lines to main Korean Electric power system. We developed a new method to simplify the network except the substation that we want to analysis. The power system outside the 345kV substation is modeled into the equivalent network. The loop network outside the substation can be modeled to simplified Thevenin equivalent network. The proposed method is applied to IEEE-14 Reliability Test System and the results shows the effectiveness of the method.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.1
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• pp.14-19
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• 2008

In order to verify a substation automation system based on IEC 61850, Korea Electric Power Research Institute under the project related to SAS has constructed IED testing system, which consists of HMI, IED(Intelligent Electronic Device), network equipment, V/I generator, and performed a various of communication tests such as the interoperability test between two IEDs made by other vendors. The test was proceeded based on SCL(Substation Configuration Description Language). This paper presents ways and procedures to simulate those tests and solutions to clear up SCL based engineering problems and compatibility among the individual manufacture tools.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2352-2354
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• 1999

The purpose of substation grounding system is to provide reference potential with power system and protect field workers from electrical shock resulted from unsymetrical power system faults. For this purpose, grounding grid should be designed to maintain max, touch voltage under safety criteria in fault conditions. It is difficult, however, to design a safe grounding grid at very resistive or narrow area. This paper describes an example of substation grounding grid design procedures in such areas with very severe design conditions. By using grounding conductors, which is located close to earth surface, earth surface potential could be controlled effectively, so that maximum touch voltages is to be maintained under safety criteria.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.59-61
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• 2003

This paper demonstrates an analysis of harmonics at the high speed railway substation and proved on this countermeasure using the PSCAD/EMTDC simulation tool. First, high speed railway feeding system is composed using PSCAD/EMTDC electrical railway feeding system model in advance. Second, This paper applications line capacitance values as feeder-trolley, trolley-rail and feeder-rail to analysis harmonics more accuracy in advance did not application. This capacitance values calculate using the EMTP(Electro Magnetic Transient Program). Third, the tractions are arranged in the section that substation supplies power, and this paper take the simulation each case(fractions composition amount) to see harmonic propagation from traction to substation. As a result, generated harmonics at traction can confirmed that harmonics did not reduce at utility source. This harmonics have an influence on bulk power system. Finally, this paper introduces the methods of harmonics effect minimum. This paper proved harmonics reduce effect through the passive filters application.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.12
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• pp.28-36
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• 2012

Augmentation of existing EHV substations located in hilly terrain and at high altitude require many different considerations as compared to substations located in plain areas and at lower altitude. Owing to high altitude and steep terrain, meticulous engineering and preparations are required, considering the actual available space at the existing substation. Historical fault events too must be considered to enhance reliability and performance of the substation equipment. This paper proposes ways to augment the existing 2 banks of 20MVA, 220/66kV power transformers ($3{\times}6.67MVA$, single-phase) to $2{\times}50$/63MVA, 220/66kV power transformers to meet continuously increasing demand of the capital city over the next 20 years. Upgrading and augmentation of existing substations, especially the main transformers and associated equipment, require replacement with minimum or no disturbance to the existing power supply system. Considerations should also be made during engineering and design, the operational flexibilities, maintenance aspects, future expandability and value addition, in terms of reliability and space usage of the existing substation.