• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.2251-2252
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• 2008

Recently, voltage sag from sudden increasing loads is also one of the major problems inside the utility network. In order to compensate the voltage sag problem, power compensation device systems could be a good solution method. In case of voltage sag, an energy source is needed to overcome the energy loss caused by the voltage sag. Superconducting Magnetic Energy Storage (SMES) is a very promising source of this energy due to its fast response of charging and discharging time. Before constructing the power electronic delivering system for the SMES, it is necessary to simulate the system to understand its behavior. Nowadays, a lot of devices have been developed to compensate voltage sag such as Dynamic Voltage Restorer (DVR), Distribution Static Compensator (D-STATCOM) and Uninterruptible Power Supply (UPS). In this paper, focus is given only on DVR system which will be simulated by using PSCAD/EMTDC software.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.6
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• pp.626-633
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• 2005

This paper proposes a new 2MVA SSFG(Sag Swell Flicker Generator) injecting voltage by using series inverter. The proposed SSFG composes series inverter, DC capacitor as energy storage, rectifier and voltage clamp circuit. This SSFG is designed to generate typical power disturbances, such as voltage sag/swell, over/under voltage and voltage flicker. Also it is designed to generate unexpected voltage phase jumping waveform by controlling the series inverter. In this paper, three kinds of control methods for the proposed 2MVA SSFG we investigated by PSIM simulation. Also typical voltage sag, swell, flicker waveforms are implemented by adopting effective control method.

• Journal of Energy Engineering
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• v.13 no.1
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• pp.68-74
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• 2004

This paper presents the design of DSTATCOM (Distribution Static Synchronous Compensator) controller. The results are verified by using PSCAD/EMTDC package. The state equation derived by decomposition analysis of DSTATCOM current component is applied to load model and the combined model which considered constraint condition. In case of single line to ground fault, the conventional method of Pl control is compared with LQR control technique. LQR control is shown to be superior in terms of response profile and composition of voltage sag.

• Proceedings of the KIEE Conference
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• 2002.04a
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• pp.116-118
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• 2002

Of all known power quality problems, voltage sags provide the largest reason for concern. Sags occurs more frequently than outages and therefore tend to be more costly for industry as modern technical equipment becomes all the more sensitive to the quality and reliability of supply. Therefore we designed for a new model for Voltage Sag compensator, and we will implement Anti-Windup PI Controller with IP Block.

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.2047-2049
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• 1997

Computers and automatic equipment are very sensitive to the disturbances such as voltage transients, voltage sag, and harmonics. These disturbances cause them to have a malfunction or fault which brings about damages and losses. UPS (uninterruptible power supply) and SPS(stand-by power supply) have been used to provide the required voltage in a critical load without disturbances. However, UPS has appreciable losses due to the operation of the inverter in full rated power at all times. SPS, although whose inverter losses are smaller than those of UPS, transfers disturbances with a short duration to the load, due to the limited reaction time. In this research, a dynamic voltage compensator, which can make up for the weakness of UPS and SPS, is proposed. The operation of the proposed system was verified by a computer simulation. A hardware scaled-model was fabricated and tested to conform the feasibility of the actual system development.

• Journal of IKEEE
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• v.23 no.1
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• pp.99-106
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• 2019

This paper propose a new form of UPQC (Unified Power Quality Compensator) to compensate the current and voltage quality problems of nonlinear loads. The conventional UPQC system consists of a series inverter, a parallel inverter, and a common DC link. A new type of UPQC proposed is a parallel compensator with SVC (Static Var Compensator) added to compensate for the wide compensation range and low DC link voltage. The parallel inverter compensates the reactive power generated by the nonlinear load, and the series inverter compensates the sag and swell generated at the power supply side.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.502-507
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• 2001

This paper proposes a novel detection algorithm of faulted voltages under the unbalanced condition. To quantify the standard of unbalance under the faulted conditions, the 3-phase unbalanced voltages are decomposed into two balanced 3-phase symmetrical components of the positive and negative sequence voltages, which is defined by the magnitude factor (MF) and unbalance factor (MF). It is analyzed that MF and UF values are given as the dc constant values even though unbalance condition. This paper also proposes the control scheme of the instantaneous voltage sag corrector based on this detection algorithm. The validity of the proposed algorithm is verified through the EMTDC simulation and experiments.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.11
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• pp.1947-1954
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• 2007

This paper describes the development of a high-performance single-phase line-interactive Dynamic voltage Restorer, which is composed of an H-bridge inverter and super-capacitors. The operational feasibility was verified through computer simulations with PSCAD/EMTDC software, and experimental works with 3kVA prototype. The developed system can compensates the input voltage sag and interruption within 2ms, in which the maximum allowable duration of voltage interruption is 1.5 seconds. It can be effectively used to compensate the voltage interruption in the sensitive load, such as computer, communication equipment, automation equipment, and medical equipment. The developed system has a simple structure to be easily implemented with commercially available components and to be highly reliable in operation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.10
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• pp.1954-1961
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• 2009

This paper describes the development of a three-phase line-interactive dynamic voltage restorer with hybrid detection method, which is composed of three H-bridge inverter modules and super-capacitors. The operational feasibility was verified through computer simulations with PSCAD/EMTDC software, and experimental works with a 3kVA prototype. The developed system can compensate the input voltage sag and interruption within 2ms. The maximum allowable duration of voltage interruption is about 4 seconds. The developed system can be effectively used to compensate the voltage interruption in the sensitive load, such as computer, communication devices, and automation devices, and medical equipment. The developed system has a simple structure to be easily implemented with commercially available components, and to be highly reliable in operation.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.1070-1072
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• 2001

In recent years, customers and power supplies are interested in power quality. Demands of customers are change from standard quality of distribution power system to various high quality of distribution power system. so, it is necessary to apply power quality compensator, in our project, we develop the power quality compensator of 150kVA which compensates power factor and voltage sag, interruption. it is very frequently occurred power qualify problems[1,2]. As a series and shunt compensator, power quality compensator consists of two inverters with common do link capacitor bank. It compensates the current quality in the shunt part and the voltage qualify in the series part. In this paper we present the design and control algorithm of power quality compensator. As a control algorithm is implemented by digital controller, we consider sample-and-hold of signals. In this simulation, we use EMTDC/PSCAD V3.0 software which can simulate instantaneous voltage and current.