• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.9
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• pp.445-452
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• 2001

Two switching signal patterns are proposed to prevent short circuit of PWM ac choppers. The voltage detection method and the current detection method are proposed to execute two switching signal patterns. In the voltage detection method, the dead-time has to be inserted to the switching signals after polarity of input voltage is checked by voltage transducer at input side. In the current detection method, the direction of load current is checked by current transducer at output side, and the dead-time delay is not considered. Controlling circuit built by current detection method is simple because the dead-time delay is considered. The experimental results are presented to prevent short circuit of ac chopper safely.

• Progress in Superconductivity and Cryogenics
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• v.6 no.2
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• pp.25-28
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• 2004

Three-phase inductive superconducting fault current limiter (SFCL) with DC reactor rated on 6.6 $KV_{rms}/200 A_{rms}$ has been developed in Korea. This system consists of one DC reactor, AC/DC power converter, and a three-phase transformer, which is called magnetic core reactor (MCR). This paper deals with the short-circuit analysis of the SFCL. The DC reactor was the HTS solenoid coil whose inductance was 84mH. The power converter was performed as the dual-mode operation for dividing voltage between the rectifying devices. The short-term normal operation (1 see) and short-circuit tests (2∼3 cycles) of this SFCL were performed successfully. In regular short-circuit test, the fault current was limited as 30% of rated short-circuit current at 2 cycles after the fault. The experimental results have a very similar tendency to the simulation results. Using the technique for the fault detection and SCR firing control, the fault current limiting rate of the SFCL was improved. From this research, the parameters for design and manufacture of large-scale SFCL were obtained.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.6
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• pp.287-292
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• 2001

This paper deals with the configuration, operating principles, systematic calculation method of parameter and optimization method of test circuit for parallel current injection method, series voltage injection method and hybrid synthetic test method as the method for performance test of circuit breaker with extra high interrupting capacity. The test method depicted above is applied to short-circuit making and breaking test (operating sequence :Os CdOs, Od-CdOs) and out-of-phase tests(operating sequence :Os, CdOs) for performance test of the newly-developed 420kV, 50kA and 800kV 50kV puffer-type gas circuit-breaker according to IEC 60056 and IEC 60427. The testing results, evaluation of equivalence for test and analyzed results are also presented in this paper.

• Proceedings of the KIEE Conference
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• summer
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• pp.554-556
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• 2004

Testing capacity of KERI synthetic short-circuit testing facilities has been upgraded to fulfill the requirements up to 550kV 63kA, 1-break circuit breaker ratings. Specially the current capacity was increased 50kA to 63kA and the full type test of 362kV 63kA circuit breaker(1-break) was firstly completed in domestic. UP to now, domestic manufacturers have depended on the foreign testing laboratory for performance verification of newly designed products. This paper introduces the summary of the increased short-circuit testing facilities, the testing techniques and its results for the making and breaking performance of 362kV, 63kA circuit breaker which was Performed according to IEEE C37.06(1999) used in North America.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.800-804
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• 2005

Load flow and short circuit fault transients of a power distribution system with wind turbines as dispersed generation units is presented. Usage of renewable energies such as wind is already a small part of total installed power system in medium and low voltage networks. In this paper, a radial power distribution system with wind turbines is simulated using DIgSILENT PowerFactory software for their influence on load flow and short circuit fault transients. Short fault occurring in dispersed generation systems causes some problems for the system and costumers such as fault level increase or the problems of sudden fluctuations in the current, voltage, power and torque of the double fed induction machine utilized in the wind turbines which have been studied and investigated.

• 제어로봇시스템학회:학술대회논문집
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• 1999.10a
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• pp.281-283
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• 1999

This topic presents an inductor short turn testing. From the rudimentary principles, the quality factor(Q) decreases due to inductor short turn. Frequency response varies because of the variation of circuit inductance and resistance. In general, short turn circuit testing is performed by comparing the ratio of an inductance and resistance of inductor in that particular circuit. An alternative method can be done by considering the response of second order circuit which can give both dynamic and static testing, whereas static testing give an error results not more than 2 turns. For dynamic testing, the result is more accurate, which can test fur the short turn number form 1 turn onward.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.685-686
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• 2006

The excitation system of 500MVA short-circuit generator is very important because of operation of various condition, for example, (over) load switching, short-time current, short-circuit current, etc. This paper introduces a feature of excitation system of 500MVA short-circuit facilities and the function and construction of each part.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.989-990
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• 2007

The excitation system of 500 MVA short-circuit generator is very important because of operation of various condition, for example, (over) load switching, short-time withstand current, short-circuit making and breaking current, etc. This paper introduces a feature of excitation system of 500MVA short-circuit generator and the function and construction.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.05a
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• pp.433-436
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• 2007

This paper analyzes how to calculate the three phase short-circuit currents for ac electrical system and select the high & low voltage circuit breaker based on IEC60609, IEC60056 and IEC60947-2 standards. We proposed the multiplying factor considering system time constant and circuit breaker rating to select circuit breaker accurately.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.10
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• pp.176-180
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• 2007

In the case that an overcurrent flows through in electrical wire due to short-circuit or overload, the wire can be fused, thereby causing an electrical fire. In the present article the characteristics of the fusing current of an electrical wire have been studied to discriminate between short-circuit and overload. In the experiment the fusing time was measured as the currents determined by Preece's equation were supplied to bare wires of various diameter. As the results of experiment, the measured fusing currents well satisfied the Onderdonk's equation. By comparing the measured results and the short current the IEC recommends, it is shown that the variable to determine the short current for a bare copper wire, k is appoximately 300. The fusing current of an electrical wire which becomes a short circuit within 5sec can be expressed as a function of diameter based on the value of k. Consequently, the equation for the fusing current provides a criterion to discriminate between short-circuit and overload.