• Proceedings of the KIEE Conference
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• 2009.04a
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• pp.169-171
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• 2009

In recent years, environmental concerns have been raised on the use of poorly biodegradable fluids in electrical apparatus in regions where spills from leaks and equipment failure could contaminate the surroundings. For development of the environmental-friendly pole transformer using vegetable oil, we discussed the insulation construction of the transformer and the dielectric characteristics of the Nomex insulation paper in vegetable oil. Based on the experimental data, the insulation of the transformer is designed.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.2 no.3
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• pp.61-71
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• 2003

This paper suggests a wireless diagnostic technique using SMS (Short Message Service) of mobile telecommunication network for pole transformer. The temperature and current of pole transformer are acquired and the average and standard deviation are transmitted using SMS of mobile telecommunication network when transformer is overloaded The algorithm and protocol is design to fit the wireless diagnostic technique. By using the wireless method, the weak point of accessability can overcome. It is possible to manage, control, and monitor many transformers with just one server.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.12
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• pp.1154-1159
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• 2006

The mold transformers have been widely used in underground substations of large building and have some advantages when compared with oil-transformer. Those advantages are low fire risk, environmental compatibility, compact size and high reliability. The mold transformer is generally known to have cooling duct between low voltage and high voltage coil. To achieve better compact structure and low loss, mold transformers made by one body molding method has been developed. Nevertheless, such kinds of transformer need better cooling method because heat radiation between each winding is still of problem. The life of transformer is significantly dependent on the thermal behavior in windings. Many designers have calculated temperature distribution in transformers and hot spot point by finite element method(FEM) to analyze winding temperature rise. In this paper, the temperature distribution analysis of 100 kVA pole mold transformer for power distribution were investigated by FEM program and the thermal analysis results were compared with temperature rise test.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05c
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• pp.156-159
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• 2002

This paper presents an experimental study of the surge response characteristics for the primary winding of a pole transformer and ultimately aims at devising countermeasures against the surge in operating transformer. After applying the impulse voltage to the primary of the 30 kVA pole transformer with single bushing, the voltage waveforms were measured at each tap lead and compared with one another. As a result, the voltage peak of the surge propagating in the primary was decreased in magnitude at a constant rate and somewhat delayed compared to the peak of the applied surge as the tap leads were getting closer to the grounding terminal. The voltage measured at the secondary was not delayed in time, different from that at the primary, and it was about 1/6 according to the turn ratio.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.9
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• pp.108-113
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• 2013

Change of supply voltage, customer load, output of distributed generation, etc cause voltage change in distribution system. OLTC and SVR are usually used to supply normal voltage at customer. But usage of these devices is inefficient and uneconomical in certain circumstances. To solve this problem, new pole transformer which has automatic tap changer is developed. The transformer changes tap when voltage changes. And it has latch switch and reactor for supplying power without outage. To verify normal operation of tap changer, test is conducted. SVR and 50kVA load is used for test.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.780-782
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• 2001

The mold transformer has anti-burnt and possibility of small size contrary to oil-immersed transformer. The mold transformer has generally cooling duct between low voltage coil and high voltage coil and also made by one body molding for small size and low loss. In this paper, the temperature distribution of designed 50kVA pole mold transformer for power distribution is investigated by FEM program. The designed transformer is also manufactured and temperature rise test is carried out.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.387-390
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• 2000

The life of transformer is significantly dependent on the thermal behavior in windings. To analyse winding temperature rise, many transformer designer have calculated temperature distribution and hot spot point by finite element method(FEM). Recently, numerical analyses of transformer are studied for optimum design, that is electric field analysis, magnetic field, potential vibration, thermal distribution and thermal stress. Therefore design time and design cost are decreased by numerical analysis. In this paper, the temperature distribution and thermal stress analysis of 50kVA pole cast resin transformer for power distribution are investigated by FEM program. The temperature change according to load rates of transformer also have been investigated. We have carried out temperature rise test and test results are compared with simulation data.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.2
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• pp.237-244
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• 2016

This paper, presents the characteristics of electromagnetic fields radiated from a pole-transformer. The cylindrical cavity is used to measure electromagnetic fields radiated from a pole-transformer when partial discharge occures inside the pole-transformer. The theoretical analysis is conducted by a finite difference time domain (FDTD) method. As a result, frequency characteristics of the radiated electromagnetic waves emitted from the inside the cavity to the outside through the 1st and 2nd bushings could be observed for the configuration of the cylindrical cavity with a radiation window. The frequency characteristics of electromagnetic field are also studied according to the enclosure structure of the cylindrical cavity. To verify the theoretical analysis, computed results are compared to experimental results.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.1
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• pp.20-27
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• 2001

In this paper, we propose a method for estimating the peak load of pole-transformer in summer season considering the degree of cooling load possession in customer. The cooling load of customer is selected as the most reliable parameter of peak load in summer season. The proposed estimation method is restricted to the aspect of load management for pole-transformer. The main concept of proposed method is that the error of peak load estimation using load regression equation reduces with considering the degree of cooling load possession in customer. We propose an index for estimation of cooling load possession in each customer. The proposed index is defined as cooling load possession in customer (CLPC) and obtained from the increment of monthly electric energy. The membership function for deciding the uncertainty of cooling load possession in customer is used. The database of pole-transformer in Korea Electric Power Corporation (KEPCO) is used for case studies. Through the case studies, we verify that the proposed method reduces the error of peak load estimation than the conventional method in domestic.

• Proceedings of the KIEE Conference
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• 2001.11a
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• pp.245-247
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• 2001

In this paper, the temperature distribution and thermal stress analysis of 50kVA pole mold transformer for power distribution are investigated by FEM program. The temperature rise test of designed mold transformer is carried out and test result is analyzed compare to simulation data.