• Journal of the Korean Society of Industry Convergence
• /
• v.20 no.5
• /
• pp.419-424
• /
• 2017

The purpose of this study is to develop a virtual testbed capable of predicting the functional performance of a linear electromagnetic actuator for a high voltage relay in order to reduce its development costs and time. The virtual testbed is defined by a multiphysics coupling approach in order to consider the complex interactions of multi-domains such as the solenoid model of electromagnets, the mass-spring-damper model of mechanical systems, the electric circuit model for an external control unit, and the thermal model for predicting temperature variations. The performances of the existing high voltage relay were estimated by the virtual testbed, and then the effectiveness and validation of the proposed testbed were discussed in comparison with the experimental test results. This study showed that the virtual testbed can be applied in design, optimization, and investigation of high voltage relays.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.53 no.3
• /
• pp.148-151
• /
• 2004

For turn on high pressure sodium vapor lamp, Starting Voltage is very important factor. This starting voltage supply to high pressure sodium vapor lamp as electric discharge lamp, Electric field is producted in electric discharge tube, So accelerative electron collide against vapor atom and second electron is generated, And rapidly the current flow to electric discharge tube. This starting voltage is high voltage and source for melting contact that relay is according as turn on/off high pressure sodium vapor lamp. Consequently, This paper propose that the prevention of melting contact in accordance relay of controller for turn on/off high pressure sodium vapor lamp.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.54 no.9
• /
• pp.437-443
• /
• 2005

This paper deals with an experimental study for Klippon reiay in Cheju-Heanam HVDC system Klippon relay was troubled many times for years, and Klippon relay's fault caused the HVDC system trip. So for several years, these reasons of Klippon relay fault were investigated. The malfunction of Klippon relay in Cheju-Haenam HVDC system has been caused by the incoming of random surge(current source and voltage source). This paper has stu야ed the theoretic리 analysis and experimental study of Klippon relay, and the solutions against the problems were suggested according to their causes. Among the problems, grounding problem was removed by one-point earth connection and by modification of grounding circuit. The effects of inrush current was removed by inserting the blocking diodes by series in Klippon relay circuits. Finally, The over-voltage induced on Klippon relay, by a relay excitation coil, was removed by inserting a free-wheeling diode in Parallel with the excitation coil.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.27 no.5
• /
• pp.81-88
• /
• 2013

A low voltage circuit breaker protects electrical equipments from over current and short faults of system by cutting the power supply. The breaker use a thermal magnetic type trip device from the past. In recent years, electronic type relays are applied due to useful functions and services. The purpose of this development is full digitalizing of relay functions of a low voltage breaker. It includes separation of current sensor from current transformer, digital signal processing, high speed relaying, and voltage measuring for power meter. The suggestions are tested and implemented by making prototype and testing its all relay functions.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.969-974
• /
• 2003

A simple and cost-effective method for the electrostatic suspension of thin plates like silicon wafers is proposed which is based on a switched voltage control scheme. It operates according to a relay feedback control and deploys only a single high-voltage power supply that can deliver a dc voltage of positive and/or negative polarity. This method possesses the unique feature that no high-voltage amplifiers are needed which leads to a remarkable system simplification relative to conventional methods. It is shown that despite the inherent limit cycle property of the relay feedback based control, an excellent performance in vibration suppression is attained due to the presence of a relatively large squeeze film damping origination from the air between the electrodes and levitated object. Using this scheme, a 4-inch silicon wafer was levitated stably with airgap variation decreasing down to 1 $\mu\textrm{m}$ at an airgap of 100 $\mu\textrm{m}$

• Journal of the Korean Society for Precision Engineering
• /
• v.22 no.10 s.175
• /
• pp.56-64
• /
• 2005

A simple and cost-effective method for the electrostatic suspension of thin plates like silicon wafers is proposed which is based on a switched voltage control scheme. It operates according to a relay feedback control and deploys only a single high-voltage power supply that can deliver a DC voltage of positive and/or negative polarity. This method possesses the unique feature that no high-voltage amplifiers are needed which leads to a remarkable system simplification relative to conventional methods. It is shown that despite the inherent limit cycle property of the relay feedback based control, an excellent performance in vibration suppression is attained due to the presence of a relatively large squeeze film damping origination from the air between the electrodes and levitated object. Using this scheme, a 4-inch silicon wafer was levitated stably with airgap variation decreasing down to $1 {\mu}m$ at an airgap of $100{\mu}m$.

• Proceedings of the KIEE Conference
• /
• 1999.07c
• /
• pp.1437-1439
• /
• 1999

This paper describes test method though low voltage power system implementation for high impedance fault relay test before its operation in real power system. Through this test, relay tested its function and algorithm. In this paper, we will provides test method using low voltage power system and its results.

• Journal of the Korean Society for Precision Engineering
• /
• v.23 no.6 s.183
• /
• pp.104-110
• /
• 2006

A design and control of electrostatic suspension system for flexible objects is presented. A number of electrode pairs of which the number depends on the object flexibility are positioned above the object and the voltages applied to each electrode pair are controlled, independently on the others, on the basis of the gap length. To implement the system with low cost and compactness, switched-voltage control scheme that is based on the relay feedback control is utilized. Relay feedback control method deploys only a single high-voltage power supply that can deliver a DC voltage of positive and/or negative polarity and thus high voltage amplifiers that are costly and bulky are not needed any more. It is shown that despite the inherent limit cycle property of the relay feedback based control, an excellent performance in vibration suppression is attained due to the presence of a relatively large squeeze film damping originating from the electrodes and levitated object. Employing fourteen electrode pairs, a thin aluminum plate with a thickness of 0.1 mm has been suspended at a gap length of 0.75mm.

• Journal of the Korean Society for Precision Engineering
• /
• v.25 no.6
• /
• pp.71-79
• /
• 2008

In the manufacture of flat panel display devices, there is a strong demand for contactless glass panel handling devices that can manipulate a glass panel without contaminating or damaging it. To fulfill this requirement, an electrostatic suspension device far glass panels where the glass panel is supported by electrostatic forces without any mechanical contact is proposed. To implement the system with low cost and compactness, switched-voltage control scheme that is based on the relay feedback control is utilized. Relay feedback control method deploys only a single high-voltage power supply that can deliver a DC voltage of positive and/or negative polarity and thus high voltage amplifiers that are costly and bulky are not needed any more. It is shown that despite the inherent limit cycle property of the relay feedback based control, an excellent performance in vibration suppression is attained due to the presence of a relatively large squeeze film damping originating from the electrodes and levitated object. Using this scheme, a $100{\times}100mm^2$ glass panel was levitated stably with airgap variation decreasing down to $1\;{\mu}m$ at an airgap of $100\;{\mu}m$.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.61 no.1
• /
• pp.23-28
• /
• 2012

The market of domestic Power Plant Generator Protection and Control System (GPCS) is narrow and required the high reliability, and technology. So, it is still operated as turn-key. In recent years, digital relays has evolved into IED can perform the control and monitoring functions without central monitoring based on IEC61850 international standards communications, and attention for advancement of smart grid and ECMS has been increased in South Korea. The increasing attention on multi-function IED, DGPS(digital generator protection system), for internal fault protection of large generator results in starting a national project in South Korea, the IED prototype development for next-generation power units. The voltage restrained overcurrent relay have been used as back-up overcurrent protection for generators. In this paper, voltage restrained overcurrent relay is one of the back-up protective factors in generator protection IED was presented. For evaluation performance of the voltage restrained overcurrent relay, the data of ATPDraw5.7p4 modeling was used.