• Journal of the Korean Society of Safety
• /
• v.33 no.2
• /
• pp.21-27
• /
• 2018

The expansion and stable operation of electric power facilities are important factors with development of industrial facilities in modern society. In high-voltage equipment such as GIS, the insulation characteristics may be deterioated by environment-friendly gas adaption and miniaturization. There is also the possibility of accidents due to insulation breakdown due to the deterioration of power facilities. Therefore, it is necessary to extend the diagnosis system to continuously monitor the danger signals of these power equipment and to prevent accidents. Most of the internal defects in the GIS system are conductive particles, floating electrode defects, protrusion defects, and the like. In this case, a partial discharge phenomenon is accompanied. These partial discharge signals occur irregularly and various noise signals are included in the field, so it is difficult to evaluate the reliability in the development of the diagnostic system. In this paper, a study was made on equipment capable of generating a partial discharge simulated signal that can be adjusted in size and frequency to be applied to a diagnostic device by electromagnetic wave detection method. The PD simulated pulse generator consists of a user interface module, a high-voltage charging module, a pulse forming circuit, a voltage sensor and an embedded controller. In order to simulate the partial discharge phenomenon similar to the actual GIS, a discharge cell was designed and fabricated. The application of the prototype pulse generator to the commercialized PD diagnosis module confirmed that it can be used to evaluate the performance of the diagnostic device. It can be used for the development of GIS diagnosis system and performance verification for reliability evaluation.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.2290-2295
• /
• 2005

In this paper, it is developed simulator system of 3 D.O.F parallel robot for educate of expertness. This simulator system is composed of three parts ? 3 D.O.F parallel robot, controller (hardware) and software. First, basic structure of the robot is 3 active rotary actuator that small geared step motor with fixed base. An input-link is connected to this actuator, and this input-link can connect two ball joints. Thus, two couplers can be connected to the input-link as a pair. An end-plate, which is jointed by a ball joint, can be connected to the opposite side of the coupler. A sub-link is produced and installed to the internal spring, and then this sub-link is connected to the upper and bottom side of the coupler in order to prevent a certain bending or deformation of the two couplers. The robot has the maximum diameter of 230 mm, 10 kg of weight (include the table), and maximum height of 300 mm. Hardware for control of the robot is composed of computer, micro controller, pulse generator, and motor driver. The PC used in the controller sends commands to the controller, and transform signals input by the user to the coordinate value of the robot by substituting it into equations of kinematics and inverse kinematics. A controller transfer the coordinate value calculated in the PC to a pulse generator by transforming it into signals. A pulse generator analyzes commands, which include the information received from the micro controller. A motor driver transfer the pulse received from the pulse generator to a step motor, and protects against the over-load of the motor Finally, software is a learning purposed control program, which presents the principle of a robot operation and actual implementation. The benefit of this program is that easy for a novice to use. Developed robot simulator system can be practically applied to understand the principle of parallel mechanism, motors, sensor, and various other parts.

• Nuclear Engineering and Technology
• /
• v.46 no.3
• /
• pp.387-394
• /
• 2014

A Slowing Down Time Spectrometer (SDTS) system is a highly efficient technique for isotopic nuclear material content analysis. SDTS technology has been used to analyze spent nuclear fuel and the pyro-processing of spent fuel. SDTS requires an external neutron source to induce the isotopic fissile fission. A high intensity neutron source is required to ensure a high for a good fissile fission. The electron linear accelerator system was selected to generate proper source neutrons efficiently. As a first step, the electron generator of an 80-keV electron gun was manufactured. In order to produce the high beam power from electron linear accelerator, a proper beam current is required form the electron generator. In this study, the beam current was measured by evaluating the performance of the electron generator. The beam current was determined by five parameters: high voltage at the electron gun, cathode voltage, pulse width, pulse amplitude, and bias voltage at the grid. From the experimental results under optimal conditions, the high voltage was determined to be 80 kV, the pulse width was 500 ns, and the cathode voltage was from 4.2 V to 4.6 V. The beam current was measured as 1.9 A at maximum. These results satisfy the beam current required for the operation of an electron linear accelerator.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.201.2-201.2
• /
• 2016

The triggered vacuum switch (TVS) is widely used as a high power switch in the field of pulsed power application. TVS can produce current of higher than 100 kA within a microsecond after being triggered. A triggering high voltage pulse generator supplies a high voltage signal to the trigger system to initiate the discharge between a trigger pin and one of main electrode. The trigger system, which consists of a tungsten trigger electrode and cylindrical ceramic insulator around it, is normally installed at the center of main cathode electrode. The discharging characteristics of the trigger system strongly depend on the geometry, electrode material, vacuum pressure and so on. In addition, we especially will focus on the developing a triggering pulse generator, which can vary not only value of voltage but also pulse duration, because its properties gives pivot influences on the TVS discharge. To verify such effects, we made a 3.3 kJ TVS set-up initially. Thus we will discuss some of prominent results from 3.3 kJ TVS system. In parallel we will show on the design of 300 kJ TVS system for the high current in the future.

• Proceedings of the KIEE Conference
• /
• 1996.07c
• /
• pp.1864-1866
• /
• 1996

Grounding is the art of making an electrical connection to the earth. In order to protect man, electrical and/or electric equipments from the lightning strokes, all the energy of lightning strokes must be diverted via a safe path to earth. It is essential to the transient grounding resistance against lightning strokes. In this paper, measurements and analyses of grounding surge impedance have been investigated. For measurements of grounding surge impedance the pulse generator was designed and fabricated. The pulse generator has rise time of 22.4 ns and pulse duration of $8\;{\mu}s$. The transient grounding resistance has been measuring by injecting low power and step current between the earthing system under test and a remote reference earth and measuring the potential rise caused by this current. As a result, the transient grounding resistance against lightning surge in the short time domain is much higher than steady state grounding resistance.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.240.2-240.2
• /
• 2014

Characteristics of pulse-discharged plasma in liquid and its biological applications to proteins are investigated by making use of high voltage Marx generator. The Marx generator has been consisted of 5 stages, where each charging capacitor is $0.5{\mu}F$ to generate a high voltage pulse with rising time of $1{\mu}s$. We have applied an input voltage of 6 kV to the each capacitor of $0.5{\mu}F$. The high voltage pulsed plasma has been generated inside a polycarbonate tube by a single-shot operation, where the breakdown voltage is measured to be 7 kV, current of 1.2 kA, and pulse width of ${\sim}1{\mu}s$ between the two electrodes of anode-cathode made of stainless steel, which are immersed into the liquids. For the investigation of the influence of pulsed plasma on biomolcules, we have focused on the amino acids, DNA, proteins, cell and cholesterol.

• Journal of Power Electronics
• /
• v.13 no.4
• /
• pp.619-625
• /
• 2013

Switched mode power supplies (SMPS) are power electronic circuits extensively used in a wide range of applications. High frequency switching operation of SMPS causes electromagnetic emissions and has the potential to interfere with system operation, which in turn has an impact on system performance. This makes electromagnetic compatibility (EMC) an important concern. In this paper, a new and simple spread spectrum technique is proposed by modulating chaotic pulse position modulation (CPPM) and pulse width modulation (PWM). The resulting CPWM is implemented to reduce the conducted EMI in SMPS. The proposed method is found to be effective in reducing conduction EMI. The effectiveness and simplicity of the proposed method on spreading those dominating frequencies is compared to the EMI mitigation technique using an external chaotic generator. Finally, the levels of conductive EMI with standard PWM, CPWM with an external chaos generator and the proposed method are experimentally verified to comply with the CISPR 22A regulations. The results confirm the effectiveness of the proposed method.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.34 no.11
• /
• pp.1631-1636
• /
• 2010

In this study, we demonstrate a nano-scale lithograph obtained on localized (100) silicon (p-type) surface using by modified AFM (Atomic force microscope) apparatuses and by adopting controlling methods. AFM-based experimental apparatuses are connected to a customized pulse generator that supplies electricity between the conductive tip and the silicon surface, while maintaining a constant humidity throughout the lithography process. The pulse durations are controlled according to various experimental conditions. The electrochemical reaction induced by the pulses occurs in the gap between the conductive tip and silicon surface and result in the formation of nanoscale oxide particles. Oxide particles with various heights and widths can be created by AFM surface modification; the size of the oxide particle depends on the pulse durations and the applied electrical conditions under a humid environment.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.58 no.1
• /
• pp.20-26
• /
• 2009

In this paper, the switching mode conversion type pulse charger by fly-back converter method for lead battery of the solar cell generator equipment is proposed. And we propose the control circuit and design method of insulated switching mode convert type pulse charger by fly-back convert method in the lead battery. The proposed system can minimize the current consumption by digital pulse. Also the proposed system can generate the constant 10[KHz] frequency, transmit the signal with main control system in the power control system. And it supervises the state of lead battery using one chip micro processor. The proposed the switching mode conversion type pulse charger by the fly-back converter method can charge fast and stabilize lead battery with nominal value 12[V], 20[AH]. Also we propose the design procedure of the power control circuit for turn ratio of fly-back inductor and determining method of values such as the charging current, bulk current, partial current, over current value and fixed charging voltage. The experiment results for the voltage and current wave for partial, bulk, over and fixed charging period show the good charging effect and performance. And the PCB and internal coupling diagram of the switching mode conversion type pulse charger by fly-back converter method is presented.

• Journal of Sensor Science and Technology
• /
• v.22 no.1
• /
• pp.84-88
• /
• 2013

In this paper, the low price signal generator with capability of frequency high-resolution and variable sync pulse has implemented. It fulfils well the requirements for SS-OCT of the frequency resolution less than 1Hz, frequency stability of ${\leq}{\pm}0.5Hz$/10 min and variable sync pulse output timing. Through its performance test applied to wavelength swept laser, 120 nm sweeping range and 10 mW average optical power were obtained. This shows that the realized sine-wave generator can replace the commercial high cost and high performance signal generators employed by current SS-OCT systems.