• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.27 no.6
• /
• pp.75-81
• /
• 2013

In this paper, protection coordination between residual current devices and surge protective devices in low-voltage consumer's distribution systems are presented. In the case that a surge protrctive device(SPD) is located on the load side of an residual current device(RCD), when the surge is injected from the source side of the RCD, most of injected surge currents are split into the RCD and the protection coordination between the SPD and RCD is improper, three of 6 specimens experience unintended operation due to test impulse currents. Also when the surges is injected from the load side, a lot of the surge currents is split into the SPD, but a half of test specimens causes nuisance trip. Coordination between SPD and RCD is not valid. When installing SPD, it is important to select SPD after due consideration of the protection voltage level of metal oxide varistor embedded in RCD. It is expected that the results obtained from this work could be useful to improve the protection effects of SPD in low-voltage distribution systems.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2000.07a
• /
• pp.128-131
• /
• 2000

The main objective of this paper is to design and test a new type of polymer ZnO surge arrester for DC power system of railroad vehicles. The rated voltage is 1500V direct current. The main research works are focused on structure design by finite element method, rating voltage, temporary over voltage and studies of characteristics of polymeric surge arrester.

• Proceedings of the KIPE Conference
• /
• 2001.07a
• /
• pp.197-200
• /
• 2001

This paper presents a PWM buck AC-AC converter with instantaneous compensation for input voltage sag and surge. The presented converter use commercial IGBT modules and its output voltage is regulated so as to remain constant AC output voltage. The feedforward control technique is also proposed to establish instantaneous duty level change whereby stable output voltage will be retained. This paper show the characteristics and control algorithm of the converter through various PSPICE simulations.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.27 no.2
• /
• pp.29-35
• /
• 2013

For the purpose of designing and applying optimum surge protection, one of the essential points is to take into account the energy coordination between cascaded surge protective devices(SPDs) and it is important to obtain an acceptable sharing of the energy stress between two cascaded SPDs. In this paper, in case of two voltage-limiting SPDs connected in parallel, the amount of splitting impulse current and energy that flow through each SPDs is investigated as a function of the protective distance. As a result, the energetic coordination between cascaded SPDs is strongly dependent on the voltage protection level of SPDs and the protective distance. It was confirmed that the sharing of the energy between two cascaded SPDs and the limited voltage levels are appropriate when the voltage protection levels of both upstream and downstream SPDs are the same.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.26 no.4
• /
• pp.28-34
• /
• 2012

Installing surge protection devices for a low-voltage system is important to ensure the survival of electric or electronic devices and systems. If surge protection devices (SPD) are installed without consideration of the concept of lightning protection zones, the equipment to be protected might be damaged despite the correct energy coordination of SPDs. This damage is induced by the reflection phenomena on the cable connecting an external SPD and the load protected. These reflection phenomena depend on the characteristics of the output of the external SPD, the input of the loads, and the cables between the load and the external SPD. Therefore, the SPD has an effective protection distance under the condition of the specific load and the specific voltage protection level of SPD. In this paper, PSCAD/EMTDC software is used to simulate the residual voltage characteristics of SPD Entering the low-voltage device. And by applying a certain voltage level, the effective protection distances of SPD were analyzed according to the each load and length of connecting cable, and the effectiveness of SPD were verified.

• Proceedings of the KIEE Conference
• /
• 2004.11b
• /
• pp.63-65
• /
• 2004

The recent advancement in the power electronic technique has increased the use of induction motor fed by inverter using high-frequency switching devices. Also the tendency is toward larger size and higher voltage. Therefore, The IGBT (Insulated-Gate Bipolar Transistor) that is high switching frequency element has been using increase. But, The switching surge voltage was occurred by high switching frequency of inverter has appeared a voltage doubling in the motor input terminal due to mismatching of cable characteristic impedance and motor characteristic impedance. Actually, The Switching surge voltage became the major cause to occur the insulation failure by serious voltage stress in the stator winding of induction motor. The short during rise time of switching surge and cable length is increased, the maximum transient voltage seen at the motor terminals increases. In this paper, Analyzed switching surge transient voltage of power cable pulling is used EMTP(Electromagnetic Transient Program) at the induction motor terminal and in cable.

• Journal of Advanced Marine Engineering and Technology
• /
• v.21 no.4
• /
• pp.387-392
• /
• 1997

This paper describes a combination surge generator for carrying out performance tests on the surge protection circuits of shipboard electrical systems. Pspice simulations were performed to decide the values of the parts required and to analyze the characteristics of the generator circuitry. The surge generator fabricated can produce four of the most common surge test waveforms : the O.5i/S/100kHz Ringwave, the 1.2/50$\mu$S voltage, the 8/20$\mu$S current, and the lO/lOOOi/S voltage wave¬forms specified in ANSI Std. C62. Source impedances of the surge generator are 12$\Omega$ in the O.5$\mu$S/100kHz mode, O.5$\Omega$ in the 1.2/50$\mu$S and 8/20$\mu$S mode, and 40$\Omega$in the l0/1000$\mu$S mode, and are determined by the ratio of the maxi¬mum open - circuit voltage to the maximum short - circuit current. Experimental results show that the surge generator provides most of the outputs required for the testing of the surge protection circuits on shipboard electrical systems.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.05c
• /
• pp.156-159
• /
• 2002

This paper presents an experimental study of the surge response characteristics for the primary winding of a pole transformer and ultimately aims at devising countermeasures against the surge in operating transformer. After applying the impulse voltage to the primary of the 30 kVA pole transformer with single bushing, the voltage waveforms were measured at each tap lead and compared with one another. As a result, the voltage peak of the surge propagating in the primary was decreased in magnitude at a constant rate and somewhat delayed compared to the peak of the applied surge as the tap leads were getting closer to the grounding terminal. The voltage measured at the secondary was not delayed in time, different from that at the primary, and it was about 1/6 according to the turn ratio.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.43 no.5
• /
• pp.761-769
• /
• 1994

VCB (Vacuum Circuit Breaker), with the strong arc extinction capability in switching the source of an induction motor, occurs the severe switching surge voltage which can cause the breakdown or the deterioration of motor insulation. Therefore, a method which reduces surge voltage across motor windings is necessary. So, it is analyzed that fast-rise-time surges resulting from VCB switching operations give rise to severe voltage stress on turn insulation. Additionally, the switching surge simulation algorithms using EMTP are developed, and C, R values of surge suppressor minimizing the steep-fronted stress in winding insulation surges are calculated.

• Proceedings of the KIEE Conference
• /
• 2001.10a
• /
• pp.285-288
• /
• 2001

The Railway Signalling Equipment's transformation to Micro-electronic has been caused to the decrease of its introspection against a surge voltage. So, there has been many tries to protect the railway signalling equipment from a surge voltage by using of a various surge protector. In this study, we are trying to draw up the protective plan to prevent this weakness on introspection by analyzing the electric characteristic on such a surge protector and reviewing the way on distributing wires in signalling room.