• 전기의세계
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• v.17 no.3
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• pp.57-61
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• 1968

Limitation to Peterson coil grounded operation of 154KV system began to develop with the growth of system as to voltage and system cost. Therefore, 154KV system is going to be grounded solidly from November this year. This study shows the insulation coordination of solidly ground system, such as the selection of a suitable lightening arrester, determination of transmission line insulation and Basic Insulation Level of station equipment.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.5
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• pp.847-853
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• 2010

This paper describes switching surge analysis for reclosing decision in 345kV combined transmission line with XLPE power cable. Reclosing operation should be decided based on the detailed technical analysis in combined transmission line because this line includes power cable section which is week on insulation. Insulation of power cable can be breakdown at the week point in case of reclosing moment. Therefore the detailed analysis has to be carried out by considering several conditions such as length ratio of power cable section, arrestor, inserting resistance, charging rate, grounding resistance, etc.. On the other hand sheath voltage on IJ(Insulated Joint) is analyzed to check dangerous condition on cable cover. Analysis is performed by EMTP/ATP. Analysis results show that reclosing can be operated as the single line-to-ground fault occurs on overhead line in 345kV combined transmission line, if the inserting resistance is considered before the operation of main circuit breaker.

• Earthquakes and Structures
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• v.19 no.6
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• pp.445-457
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• 2020

An ultra-high voltage (UHV) transmission system has the advantages of low circuitry loss, high bulk capacity and long-distance transmission capabilities over conventional transmission systems, but it is easier for this system to cross fault rupture zones and become damaged during earthquakes. This paper experimentally and numerically investigates the seismic responses and collapse failure of a UHV transmission tower-line system crossing a fault. A 1:25 reduced-scale model is constructed and tested by using shaking tables to evaluate the influence of the forward-directivity and fling-step effects on the responses of suspension-type towers. Furthermore, the collapse failure tests of the system under specific cross-fault scenarios are carried out. The corresponding finite element (FE) model is established in ABAQUS software and verified based on the Tian-Ma-Qu material model. The results reveal that the seismic responses of the transmission system under the cross-fault scenario are larger than those under the near-fault scenario, and the permanent ground displacements in the fling-step ground motions tend to magnify the seismic responses of the fault-crossing transmission system. The critical collapse peak ground acceleration (PGA), failure mode and weak position determined by the model experiment and numerical simulation are in relatively good agreement. The sequential failure of the members in Segments 4 and 5 leads to the collapse of the entire model, whereas other segments basically remain in the intact state.

• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.229-232
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• 1988

Induced voltage causing disturbances on the communication lines of electric train is dealt with when the AT power supply system is employed. In the paper we obtain an algorithm to calculate the induced voltages on the communication lines in the AT system and an algorithm for the induced current in case of the accident that the line falls to the ground. These algorithms are developed to a package of computer programs and their validity was checked on a simulated system.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.11a
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• pp.297-299
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• 2004

In multi-ground distribution system, overhead ground wire and neutral wire are parallel connected to offer the electrical power energy and protect damage of lightning strokes. Therefore a case where the two wires become single wire, the power company can get the benefit such as installation cost saving and line fault protection by simplify of distribution line. In this paper we describe the result of impulse test in both system ; one is the present power system the other is unified power system parallel connected overhead ground wire and neutral wire. As a result of this impulse test, the present power system get lower impulse voltage than the unified power system.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.8
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• pp.1111-1116
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• 2011

Power distribution systems onboard vessels are typically configured without any live line connected to hulls for earthing purpose, where the line to hull voltages are affected and deformed depending on the impedances consisting of insulation resistances and distributed capacitances between power lines and hull. An insulation fault at power lines causes the line to hull voltages to increase to a higher level which brings more possibilities to electric shock and deterioration of insulation material. This study focuses on how to configure a module which enables to continuously monitor the voltages between power line and hull based on the vector diagram by analyzing the neutral point of 3 phase voltages and the algorithm for plotting method on the PC monitors.

• Proceedings of the KIEE Conference
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• 2006.10a
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• pp.196-197
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• 2006

An effective method is described for monitoring the ground impedance of intelligent building and power system. Most of grounding system of buildings are interconnected to extensive grounding network of power line, signal and control line, telecommunication line, and etc. Therefore, the residual voltages of power frequency and its harmonics may have an significant influence on the accurate measurement of ground impedance. For eliminating the influence of residual voltage, we developed a test power source for generating the 110[Hz] square wave and used digital filtering method in this research.

• Proceedings of the KIPE Conference
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• 2007.11a
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• pp.112-114
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• 2007

The voltage stress on line-end coil of the stator winding in the induction motor fed by a PWM inverter is analyzed, using the computer model based on multi-conductors transmission line. A method to calculate circuit parameters, especially, capacitance between the turns and ground is proposed. The voltage distributions inside coil at motor terminal depending on dv/dt are investigated through simulation studies.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.05a
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• pp.335-339
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• 1999

This Paper Proposes a circuit system that is capable of rejecting the zero phase voltage produced by a inverter, which transform do-ac power using high speed power semiconductor. It generates a rejecting voltage which has the same amplitude as, but the opposite phase to the zero phase voltage. The rejecting voltage is superimposed on the load line for rejecting of the zero phase voltage through a transformer. Simulation results show that the zero phase voltage applied to the load and ground current are eliminated.

• Proceedings of the KIEE Conference
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• 2000.11a
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• pp.49-51
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• 2000

This paper presents a fault location algorithm for single-phase-to-ground faults on the teed circuit of a parallel transmission line. This algorithm uses only local end voltage and current information. Remote end and fault currents are calculated by using distribution factors. To reduce load current effect, negative sequence current is used. EMTP simulation result have shown effectiveness of the algorithm under various conditions.