• Proceedings of the KIEE Conference
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• 1999.07c
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• pp.1496-1498
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• 1999

The line charging is becoming larger due to the expansion of underground cable and extra high voltage lines. It causes reactive power surplus at light load condition which may force generators to operate reluctantly in the under excited mode. This paper proposes the pratical criteria and methodolgy for the shunt reactor planning while suppressing generator's under excited operation.

• Proceedings of the KIEE Conference
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• 1998.07e
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• pp.1647-1649
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• 1998

This paper describes the power frequency voltage and its countermeasure when a 765 kV transmission line is directly connected to a 345 kV line and operated at 345 kV voltage. The summary of this result is as follows : The western route of 765 kV transmission line doesn't need any countermeasure to reduce the power frequency voltage at the receiving end. The eastern route of 765 kV transmission needs 100 Mvar(3 phase) capacity of shunt reactor at the receiving end to reduce the power frequency voltage. The use of shunt reactors in the 765 kV transmission lines has unexpected problems, one of which is induction of high voltages on a de-energized circuit of two parallel lines. This paper examined the problem of resonance on two parallel transmission circuits in one routes.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1219-1221
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• 2005

We improved quench properties of a superconducting fault current limiter(SFCL) components based on YBCO thin films. This consists of three components with nearly identical properties and one with slightly difference properties. The units were connected in series and first of parallel to increase the current and voltage ratings. It have caused significantly imbalanced power distribution. The imbalance remarkably improved by connecting a shunt reactor to the SFCL component in parallel.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.4
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• pp.880-884
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• 2011

The matrix-type superconducting fault current limiter (MSFCL) consists of the trigger and current-limiting parts. The trigger part with reactors connected in parallel improves the quenching characteristics by applying the external magnetic field into the superconducting units. The current-limiting part with superconducting units connected in parallel and shunt reactors connected in series limit the fault current when the fault occurs. We developed the integrated reactor with the trigger and the current-limiting parts to apply high external magnetic field into the superconducting units. This was composed of a superconducting unit for the trigger part and two superconducting units for the current-limiting parts. We confirmed that the external magnetic field generated in the MSFCL with an integrated reactor was larger than that of the MSFCL with the separated reactors. So the differences of voltages generated between superconducting units were decreased in the difference according to the increment of the applied voltage. The whole magnitude of the SFCL was reduced because the volume of an integrated reactor could be reduced by one-third than that of the separated reactors. We confirmed that the critical behavior between the superconducting units in the MSFCL with an integrated reactor was more improved than that of the MSFCL with the separated reactors.

• Proceedings of the KIEE Conference
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• 1990.11a
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• pp.210-213
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• 1990

This paper presents the countermeasure to present the main transformer of distribution substation from deteriorating and failing due to repeated magnetic force of the transformer winding by ground fault current in 22.9kV multi grounded distribution system. The Winding strength to the short circuit current is designed to be endurable to the stress of over current. But this design is related to the manufactures. In this paper we examine the application of shunt reactor to the neutral point of the low side of the transformer to reduce fault current due to the fault in the distribution lines we have analysed the fault characteristics of the system and calculated the optimum ohmic values of the neutral reactor.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.3
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• pp.538-546
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• 2007

A new 3-phase line-interactive UPS(Uninterruptible Power Supply) system with parallel-series active power-line conditioning capability using AC line reactor and two four-leg PWM VSCs(Voltage Source Converters) was introduced recently. In this paper, the strategy of voltage control in suggested UPS system is explained. The objective of proposed voltage controllers in parallel(shunt) and series PWM VSC is to guarantee satisfactory characteristics in steady state and transient state. Therefore the experimental results to prototype UPS system having power rating of 60kVA is shown to prove the verification of voltage control strategy.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.9
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• pp.1540-1548
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• 2010

KEPCO proposes enhanced voltage management system that is a coordinate voltage control system between the hierarchical voltage control system and the slow voltage control system. It has been installing in Jeju island. VMS consists of a master controller, CVC (Continuous Voltage Controller) and DVC (Discrete Voltage Controller). CVC consists of main controller, FDMU (Field Data Measurement Unit) and several RPDs (Reactive Power Dispatcher). CVC has a control scheme with AVRs of generator to maintain the voltage of a pilot bus in a power system, DVC has a control scheme with static reactive power sources, like a shunt capacitor, a shunt reactor, ULTC and so on, to maintain the reactive power reserve of a power system and a master controller is executed to recover reactive power margin of a power system through coordinated control between CVC and DVC.

• Journal of IKEEE
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• v.18 no.3
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• pp.313-319
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• 2014

The objectives of power system operations are to preserve system stability and reliability as well as to supply proper electric power. For an activation of these objectives, voltage and reactive power should be considered. There are a number of types about reactive power sources, and an insertion of shunt capacitor banks are one of the method to support bus voltage adjacent. This paper includes the design procedure to determine the hybrid type capacitor bank configurations on power system to improve stability and reliability. This procedure includes the capacitor bank capacity calculation, reactor type selection, and reactor capacity calculation. The total capacity calculation of capacitor bank is based on the reactive power margin which is calculated through system studies such as, contingency analysis and Q-V analysis. In the second step, the reactor type and its capacity can be determined through the harmonic analysis. This paper shows that the harmonics are decreased by the proposed hybrid type capacitor bank, especially 5th and 7th harmonics.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1400-1407
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• 2015

This paper deals with methodology to control an automatic substation system. The control system can predict the power system condition by a voltage stability index (VSI). The strategies in this paper is called as Voltage-Reactive Power Control (VRPC), which regulates an abnormal voltage of a target substation by using coordination between tap changers and shunt capacitor/reactor. This method is efficient for better voltage profile. The monitoring substation includes whole of substations around the contingency event. The control quantities of the monitoring substations are decided by the calculation of the VSI, called as a Z-index. Case studies with BC Hydro-Quebec system are presented to illustrate this approach using real-time simulator.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.131-133
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• 2008

최근 전력계통 분야에서는 IEC에서 제정한 변전소 자동화용 국제 규격 프로토콜인 IEC 61850을 적용한 시스템의 도입 및 적용이 활발하게 이루어지고 있다. 이러한 추세에 맞추어 변전소 내 많은 전력기기들의 IEC 61850 프로토콜을 탑재가 요구되고 있으며, 본 연구에서는 변전소 내 조상설비 중 IEC 61850 프로토콜을 적용한 분로리액터 보호용 IED의 설계, 제작, 시험을 통하여 변전자동화 가능성을 확인하였다.