• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.6
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• pp.89-99
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• 2008

In this paper proposes a novel tacking algorithm regarding the power loss when operating a tracking system for a rapidly changing insolation to improve the power of PV hacking system. The tracking system of sensor method used in a conventional PV power station is unable to exactly track a sun position when lacking in the intensity of radiation and has the problem is malfunction of tracking system by a rapidly changing climatic. The tracking system of program method spends too much energy on the unnecessary operation of tracking system because that is unable to adapt itself to a outside factor of climatic environment. In case of tracking an azimuth and altitude of the sun in realtime, therefore, the actual PV power is less increasing than the power of tracking system fixed a specific position. To reduce the power loss, this pap proposes a novel control algorithm of the tracking system. Also, this paper is analyzed efficiency of traditional solar tracking method and proposed method, prove validity of proposed algorithm through demonstrable study.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.11
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• pp.532-537
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• 2006

Lightning induced faults accounts for more than 66% at the transmission lines of KEPCO. The lightning causes damages to power system equipments including transmission line, the blackout of electricity and the electro-magnetic interference. Because of this reason, we need the real time lightning information for the optimal operation of power system. And, it is required to obtain and accumulate the lightning current parameters for the insulation design. In 2005, KEPRI constructed a lightning detection network, the KLDNet (i.e. Kepco Lightning Detection & Information System) and launched a lightning information service for KEPCO customers. It is intended to provide data service on the operation of transmission lines and collect lightning-related data, which is the most important factor regulating power system design and operation. The new system will replace LPATS, the old detection system, which has been operating since 1995 and is rapidly failing in terms of both detection performance and location accuracy. The purpose of this paper is to explain the work performed and the results of that work in performing a site survey of several locations. The purpose of the site survey is to find locations acceptable for the installation of a lightning location receiver in support of a Lightning detection system(LDS). A restriction was placed on the surveyed locations, as they must belong to the Korea Electric Power Company. This requirement was made to facilitate the communication needs of the LDS network. Total of 15 sites were evaluated as possible LDS sensor sites. Some of the sites were rejected for physical reasons and therefore no electrical testing was performed. Of the 15 sites, total of 10 sites were considered acceptable and 5 sites were rejected for various reason. In this paper, we would like to explain the site survey and detection efficiency for LDS.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.10
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• pp.5899-5905
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• 2014

Faults in electric power system can be a critical problem for vehicles. The system durability is determined mainly by the durability of their components and operating conditions. Monitoring the conditions of the electric power system may be necessary because it is very difficult to predict precisely when it will fail. Therefore, the aim of this study was to develop a diagnosis system for an electric power system of a vehicle. The alternator voltage, excitation voltage, lamp voltage, battery voltage, and engine rpm from a crank angle sensor are monitored continuously and the system fault can be then detected in real time. NI USB- 9201 DAQ and LabVIEW SW have been used to measure the voltages and analyze the data. Compared to conventional measurements for only each component, an integrated and portable measurement method was developed. In addition to the monitoring the electric power system in real time, the saved data from the measurement also provides valuable information to improve the durability of the components.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.11B
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• pp.655-662
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• 2007

Monitoring systems used at present to operate HVAC(Heating, Ventilation and Air Conditioning) optimally do not have a function that enables to detect faults properly when there are faults of such as operating plants or performance falling, so they are unable to manage faults rapidly and operate optimally. In this paper, we have developed a classified rule-based fault detection system which can be inclusively used in HVAC system of a building by installation of sensor which is composed of HVAC system and required low costs compare to the model based fault detection system which can be used only in a special building or system. In order to experiment this algorithm, it was applied to HVAC system which is installed inside EC(Environment Chamber), verified its own practical effect, and confirmed its own applicability to the related field in the future.

• Journal of Sensor Science and Technology
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• v.5 no.5
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• pp.55-62
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• 1996

This paper describes development of Polarized Stereo Monitoring System (KAERI-PSM) and compares the remote handling performance of KAERI-PSM with that of other monitoring systems, electric shutter type stereo monitoring system and general TV monitoring system. Remote handling performance is evaluated by total time and error number on remote operating experiments. Four kinds of remote handling experiments are carried out through 1) directly 2) general TV 3) electric shutter type monitor, and 4) KAERI-PSM. In these experiments six employees are participated and PUMA robot with force-torque reflectional joystic is used. The result of experiments show that camera angle against object is significant factor in monitoring and stereo monitoring system give more performance benifits in terms of accuracy and speed of remote handling operation than general TV monitoring system. In comparision of the polarized and electric shutter type stereo monitoring system, both have similar accuracy and speed for remote handling operation, but the former is superior in image quality and stability of the performance.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.2
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• pp.147-154
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• 2021

In this paper, the configuration and design of the test equipment are presented to examine the impact of rapid temperature change in cooling-air that may occur during the operation of the fixed wing aircraft Environmental Control System (ECS) on avionic electronic equipment. At the start of the ECS, the temperature of the air supplied by the aircraft ECS may be increased to 5.0℃ per second. In order to ensure operating of the avionic electronic equipment that is mounted on the aircraft and receives cooling-air from the ECS, testing equipment that can implement the cooling-air characteristic test environment is required. During design of test equipment was verified cooling-air rapid rate of temperature change by performing a thermal/flow analysis, performance of the test equipment implemented was verified by applying an avionic electronic equipment.

• Journal of Sensor Science and Technology
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• v.12 no.1
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• pp.34-43
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• 2003

In this study, we implemented the measurement of pH, $pO_2$, $pCO_2$ of the arterial blood on a portable blood gas analysis system. This system is consist of two parts of hardware and software. The hardware part is divided into a fluidic mechanism and an electronic circuit unit. The system program is composed of operating, washing, correcting, and measuring routines. Both of 1-point and 2-point calibration schemes were used to enhance the accuracy of the measurement. In order to evaluate the performance of the developed system, we measured and performed statistical analysis on the characteristics of the sensing electrode response. As a result, coefficient variation was within 1.12, and maximum error was within 1.298%. We confirmed development possibility of portable blood gas analyzer.

• Journal of the Korea Institute of Military Science and Technology
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• v.23 no.6
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• pp.639-649
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• 2020

Air data systems measure airspeed, pressure altitude, angle of attack and angle of sideslip. These measurements are essential for operating flight control laws to ensure safe flights. Since the loss or corruption of air data measurements is considered as catastrophic, a high level of operational reliability needs to be achieved for air data systems. In the case of unmanned air vehicles, failure of any of air data sensors is more critical due to the absence of onboard pilot decision aid. This paper presents design of a dual redundancy air data system and the integration process for an unmanned air vehicle. The proposed dual-redundant architecture is based on two independent air data probes and redundancy management by central processing in two independent flight control computers. Starting from unit testing of single air data sensor, details are provided of system level tests used to meet overall requirements. Test results from system integration demonstrate the efficiency of the proposed process.

• Journal of Internet Computing and Services
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• v.12 no.2
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• pp.135-147
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• 2011

As the number of elderly people living alone has been increasing in the recent years, systems for their safety have been required, and some related services or pilot systems have been operating. These systems provide the monitoring service for the activities of the elderly people living alone with indoor location tracking technology using the various sensors. However, most systems provide services on expensive infrastructure such as attached tags and mobile devices. In this point, this paper attempts to suggest a system based on low cost sensors to collect event data in home environment. And a main characteristic of the system is that people can monitor the results of provided services through web browser in real time and the system can provide related context information to guardians and health care managers through SMS of mobile phone.

• Journal of Power Electronics
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• v.5 no.3
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• pp.233-239
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• 2005

In this paper, a new conceptual circuit configuration of a 3-phase voltage source, soft switching AC-DC-AC converter using an IGBT module, which has one ARCPL circuit and one ARDCL circuit, is presented. In actuality, the ARCPL circuit is applied in the 3-phase voltage source rectifier side, and the ARDCL circuit is in the inverter side. And more, each power semiconductor device has a novel clamp snubber circuit, which can save the power semiconductor device from voltage and current across each power device. The proposed soft switching circuits have only two active power semiconductor devices. These ARCPL and ARDCL circuits consist of fewer parts than the conventional soft switching circuit. Furthermore, the proposed 3-phase voltage source soft switching AC-DC-AC power conversion system needs no additional sensor for complete soft switching as compared with the conventional 3-phase voltage source AC-DC-AC power conversion system. In addition to this, these soft switching circuits operate only once in one sampling term. Therefore, the power conversion efficiency of the proposed AC-DC-AC converter system will get higher than a conventional soft switching converter system because of the reduced ARCPL and ARDCL circuit losses. The operation timing and terms for ARDCL and ARCPL circuits are calculated and controlled by the smoothing DC capacitor voltage and the output AC current. Using this control, the loss of the soft switching circuits are reduced owing to reduced resonant inductor current in ARCPL and ARDCL circuits as compared with the conventional controlled soft switching power conversion system. The operating performances of proposed soft switching AC-DC-AC converter treated here are evaluated on the basis of experimental results in a 50kVA setup in this paper. As a result of experiment on the 50kVA system, it was confirmed that the proposed circuit could reduce conduction noise below 10 MHz and improve the conversion efficiency from 88. 5% to 90.5%, when compared with the hard switching circuit.