• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.158-163
• /
• 2005

Competitive electricity markets necessitate equitable methods for allocating transmission usage in order to set transmission usage charges and congestion charges in an unbiased and an open-accessed basis. So in competitive markets it is usually necessary to trace the contribution of each participant to line usage, congestion charges and transmission losses, and then to calculate charges based on these contributions. A UPFC offers flexible power system control, and has the powerful advantage of providing, simultaneously and independently, real-time control of voltage, impedance and phase angle, which are the basic power system parameters on which sys-tem performance depends. Therefore, UPFC can be used efficiently and flexibly to optimize line utilization and increase system capability and to enhance transmission stability and dampen system oscillations. In this paper, a mathematical approach to allocate the contributions of system users and UPFCs to transmission system usage is presented. The paper uses a dc-based load flow modeling of UPFC-inserted transmission lines in which the injection model of the UPFC is used. The relationships presented in the paper showed modified distribution factors that modeled impact of utilizing UPFCs on line flows and system usage. The derived relationships show how bus voltage angles are attributed to each of changes in generation, injections of UPFC, and changes in admittance matrix caused by inserting UPFCs in lines. The relationships derived are applied to two test systems. The results illustrate how transmission usage would be affected when UPFC is utilized. The relationships derived can be adopted for the purpose of allocating usage and payments to users of transmission network and owners of UPFCs used in the network. The relationships can be modified or extended for other control devices.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2009.10a
• /
• pp.86-89
• /
• 2009

In this paper, a broadband power line communication modem and network technology to develop tests with actual characteristics of the underground power line communication channel to be interpreted. Length and structure of the underground distribution line due to underground distribution line to the broadband powerline communication channels to measure the amount of attenuation on the signal generator, spectrum analyzer, such as contactless coupler was used to configure the channel measurement system. Demonstration tests in the test line as a single line by selecting the longest high-voltage lines where the two-channel measurement and signal attenuation on the noise level was measured. Measuring results degrade communication performance can be quite sure that was the presence of impulse noise, long lines, the line length was confirmed by the high-frequency attenuation appears.

• Journal of Advanced Marine Engineering and Technology
• /
• v.40 no.9
• /
• pp.799-804
• /
• 2016

Broadband powerline communication (BPLC) uses distribution lines as a medium for achieving effective bidirectional data communication along with electric current flow. As the material characteristics of power lines are not good at the communication channel, the development of power line communication (PLC) systems for internet, voice, and data services requires measurement-based models of the transfer characteristics of the network suitable for performance analysis by simulation. In this paper, an analytic model describing a complex transfer function is presented to obtain the attenuation and path parameters for a multipath power line model. The calculated results demonstrated frequency-selective fading in multipath channels and signal attenuation with frequency, and were in good agreement with the experimental results. Inductive coupling units are used as couplers for coupling the signal to the power line to avoid physical connections to the distribution line. The inductance of the ferrite core, which depends on the frequency, determines the cut-off frequency of the inductive coupler. Coupling loss can be minimized by increasing the number of windings around the coupler. Coupling efficiency was improved by more than 6 dB with three windings compared to the results obtained with one winding.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.30 no.9
• /
• pp.596-601
• /
• 2017

The advancement and diversification of urban functions has caused an increasing need to improve the reliability of power supplies. The diversification of urban areas causes social disruptions by paralyzing urban functions during power outages. A large power outage occurs in the event of an accident, owing to the subduction of distribution lines. Therefore, in recent years, for the sake of the environment and safety, the safety diagnosis of electric power facilities has become an important issue. In this system, because thermal information changes rapidly during unattended monitoring owing to heat concentration phenomenon due to abnormal load or deterioration, studies have been conducted on the development of a device that can notify the manager at all times.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.412-413
• /
• 2008

가공배전선로는 야외에 시설되어 하계의 태풍 및 동계의 설해와 같은 자연재해에 상시 노출됨에 따라 지지물 절손 피해가 발생할 우려가 높다. 따라서 직선으로 시설되는 전주가 절손되지 않도록 설계지역의 기상조건을 감안하여 전주강도가 충분한지 여부를 검토하여야 한다. 그러나 현업에 종사하는 설계원들이 어떠한 방법으로 전주강도를 검토하는지에 대한 이해가 부족한 실정이다. 따라서 본 고에서는 전주강도 계산과 관련하여 연구된 이론을 설명하였고, 그 이론을 바탕으로 장경간개소와 표준경간에 설치되는 전주에 대한 설계방안을 연구한 결과를 사례를 통해서 설명하였다. 본 고에서 제시한 방법에 따라 설계를 시행한다면 직선으로 시공되는 전주들의 강도가 태풍 및 설해에 대비하여 충분히 확보됨에 따라 재해 시에도 이로 인한 전주 절손 피해가 예방될 수 있을 것으로 기대되며, 또한 전기고장 예방을 통한 고품질 전력확보에도 기여할 것으로 기대된다.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.2224-2225
• /
• 2008

가공배전선로는 야외에 시설됨에 따라 태풍과 같은 자연재해로 인한 전기고장 및 설비피해가 발생하기 쉽다. 그러나 이와 관련한 연구들이 이론적인 부분에만 치우쳐 장경간 가공배전선로의 설계 시 어떤 순서로 무엇을 검토해야하는지 알기가 어려웠다. 따라서 본 고에서는 장경간 가공배전선로 설계시 전선종류, 장주형태, 완철간 수직이격거리 및 지지물 길이를 결정하는 방법에 대하여 연구한 결과를 사례를 통해 설명하였다. 본 고에서 제시한 방법에 따라 설계를 시행한다면 장경간 가공배전선의 선간단락고장을 예방할 수 있을 뿐만 아니라, 홍수 시에도 수면으로부터 충분한 지상고 유지를 위하 고장 및 설비피해를 예방할 수 있을 것으로 기대된다.

• International Journal of Safety
• /
• v.7 no.1
• /
• pp.21-25
• /
• 2008

The occurrence of a corona is that electrical discharge due to the heterogeneity that occurs when an electrical field is concentrated in an electrode due to a cusp formed on said electrode. Wire treatment at the end of a 154kV dead end clamp for end users accelerates the occurrence of corona, which in turn leads to power loss and noise. In this study, the characteristics of the corona which occurs between porcelain insulators and support clamps of overhead lines used in l54kV power receiving facilities for end users were investigated. The corona, which cannot be identified by one common method, was measured utilizing a UV image camera. A risk assessment for fire damage and its status was suggested. The stress distribution of the electrical field by length of bare wire was suggested by means of the finite element method (FEMLAB). As a result, it was found to affect a porcelain insulators. These results can be utilized for the enhancement of clamp installation and safety in power facilities.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.57 no.9
• /
• pp.1522-1530
• /
• 2008

This paper presents a discrete wavelet analysis based algorithm to address the fault impedance calculation under transient state in radial power distribution networks. The fault impedances have been derived under different fault conditions. Furthermore, a recursive fault distance estimation method is proposed utilizing the measured fault impedance and power line parameters. The proposed scheme can resolve the errors caused by the non-homogeneous power lines, the presence of lateral loads since, the fault impedance will always be updated with the recursive form. For the verification of the proposed scheme, a filed test has been peformed with varying fault resistances in the 22.9(kV) radial system. Power meters and fault locators were installed at the substation. It was figured out that the performance of the discrete wavelet and the recursive scheme are very good even for high fault resistance condition.

• Proceedings of the KIEE Conference
• /
• 2001.11b
• /
• pp.142-145
• /
• 2001

Recently transmission and distribution power facilities have been often damaged severely by fire which broke out around the facilities in forest. It causes a power failure and thus gives an economic losses to both the public and the power utilities. Sometimes the fire can happen by an electrical accident such as the electrical short circuit or the ground short circuit. In this paper, trend of breaking out the fire has been investigated and an countermeasure against the economic losses due to the fire has been studied.

• Proceedings of the KIEE Conference
• /
• 1999.07e
• /
• pp.2314-2316
• /
• 1999

This study describes the results of aging characteristics of polymer insulators through the tracking wheel test. In order to evaluate the reliability of polymer insulators, 4 polymer insulators which used in the field were selected. Electrical tests such as power frequency voltage test, steep-front impulse voltage test were performed after tracking wheel test. Chemical structure and contact angle were measured for investigating an aging characteristics. Although some changes have occurred on the surface of insulator, there are no critical changes between new and tracking wheel tested insulator.