• Journal of Electrical Engineering and Technology
• /
• 제2권1호
• /
• pp.29-34
• /
• 2007

The input and output impedances in a low voltage distribution system is one of the most important matters for power line communication because from the viewpoint of communication, the attenuation characteristic of the high frequency signals is greatly caused by impedance mismatch during sending and receiving. The frequency range is from 1MHz to 30MHz. Therefore, this paper investigates the input and output impedances in order to understand the characteristic of high frequency signals in the low voltage distribution system between a pole transformer and an end user. For power line communication, the model of Korea's low voltage distribution system is proposed in a residential area and then the low voltage distribution system is set up in a laboratory. In the low voltage distribution system, S parameters are measured by using a network analyzer. Finally, input and output impedances are calculated using S parameters.

• 전기학회논문지P
• /
• 제63권3호
• /
• pp.163-168
• /
• 2014

In this paper, when photovoltaic systems are connected to distribution system, most effective capacity and location of PV system are studied considering customer interruption costs of power distribution system. The reliability model of PV system considering the duration of sunshine, the model of time-varying load and Roy Billinton test system (bus2 model) are used. To simulate the effects of PV system, various cases are selected; (1) base case which is no connection of PV system to power distribution system when faults are occurred, (2) 3MW case which is 3[MW] connection of PV system (3) 4[MW] case, and (4) 20[MW] case which is 20[MW] connection of PV system to the bus of power distribution system. The capacity limit of connected PV system is settled to 14[MW] for all cases except case 4. The reliability and customer interruption costs for residential, general, industrial, and educational customer is evaluated.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1993년도 하계학술대회 논문집 A
• /
• pp.96-98
• /
• 1993

In accordance with increase of electrical power demanded, more efficient supervisory control of distribution system is required. This study contains development of MMI(man-machine-interface) system with GUI(graphic-user-interface), for the automatic power distribution system. The main function of MMI system are to edit network of power distribution, to view network, to warnning a breakdown and to management of data base for network. The GUI function of MMI system enables more efficient management of power distribution system.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2006년도 제37회 하계학술대회 논문집 A
• /
• pp.204-205
• /
• 2006

This paper describes the protective ability of lightning arrestor in combined distribution system with power cable. To evaluate the protective ability, change of arrestor and grounding location are considered. On the other hand, arrestor developed by Cooper Power Systems for underground power cable system, is considered to evaluate surge protective ability as in underground system, when arrestor occurs failure has overhead line. The result shows that lightning arrestor in combined distribution system with power cable protect effectively when failure at arrestor in overhead line. On the other hand, arrestor developed by Cooper Power Systems for underground power cable system, is considered to evaluate surge protective ability in underground distribution system, when arrestor of overhead line has failure. The result shows that lightning arrestor installed in underground cable can effectively protected cables from surge when arrestor of overhead line has failure. And also even though grounding locations are decreased, it is revealed that protective ability is nearly similar.

• 전기학회논문지
• /
• 제58권8호
• /
• pp.1472-1478
• /
• 2009

The domestic power distribution system is operating in an open loop mode; however, it already has a loop structure. Power distribution systems must be changed for bi-directions power supply for smart networks due to a changing of paradigm in electric power industry. The simplest bi-directions distribution networks can make it closing of normally open switch. However, bi-directions power supply is very difficulty to be operated and there are many parts which it must study. This paper presented various models that are able to change a radial system for loop structures. Further, we compared the reliability index for each model by evaluating the amount of improvement reliability required in radial power distribution system. In addition, we calculated CIC(Customer Interruption Cost) for each model by comparing and analyzing.

• 전기학회논문지
• /
• 제65권5호
• /
• pp.753-759
• /
• 2016

Power automation system to operate power distribution systems can be distinguished by distribution SCADA with remote monitoring and control; and distribution automation system with basic functions such as service restoration to the distribution SCADA; and distribution management system which is operated by various applications in order to enhance distribution system operation performance based on the distribution automation system. In the technological change, a technical boundary of information technology (IT) and operation technology (OT) is being blurred by that new concepts such as interoperability. In addtion, IT/OT convergence has been proposed by the improvement of ICT and power system technology. At the viewpoint, advanced distribution management system (ADMS) to have the new concepts and to increase distribution system operation efficiency through global information and functions from the other systems has been proposed. In order to implement the ADMS, IT and OT have to be employed together on the ADMS; and the concept-based IT/OT convergence concept has been presented. Therefore, this paper introduces ADMS and IT/OT convergence and proposes a design of IT/OT convergence based ADMS system design with configurations and functions.

• Journal of Electrical Engineering and Technology
• /
• 제2권2호
• /
• pp.201-207
• /
• 2007

As the power industry moves towards open competition, there has been a need for methodology to evaluate distribution power system reliability by using customer interruption costs, particularly in power supply zones under the competitive electricity market. This paper presents an algorithm to evaluate system average interruption duration index, expected energy not supplied, and system outage cost taking into consideration failure rate of the distribution facility and industrial customer interruption cost. Also, to apply this algorithm to evaluate system outage cost presented in this paper, the distribution arrangement of a dual supply system consisting of mostly high voltage customers in an industrial complex in Korea is used as a sample case study. Finally, evaluation results of system interruption cost, system average interruption duration index, and expected energy not supplied in the sample industrial complex area are shown in detail.

• Journal of Power Electronics
• /
• 제7권4호
• /
• pp.286-293
• /
• 2007

This paper proposes a distribution voltage control method when a voltage increase condition occurs due to reverse power flow from the clustered photovoltaic (PV) system. This proposed distribution voltage control is performed a by distribution-unified power flow controller (D-UPFC). D-UPFC consists of a hi-directional ac-ac converter and transformer. It does not use any energy storage component or rectifier circuit, but it directly converts ac to ac. The distribution model and D-UPFC voltage control using the ATP-EMTP program were simulated and the results show the voltage increase control in the distribution system.

• 전기학회논문지
• /
• 제60권1호
• /
• pp.20-25
• /
• 2011

This paper analyzed the application of Superconducting Fault Current Limiter (SFCL) on 22.9 [kV] bus tie in a power distribution system. Commonly, the parallel operations of power main transformers offer a lot of merits. However, when a fault occurs in the parallel operation of power main transformer, the fault currents might exceed the interruption capacity of existing protective devices. To resolve this problem, thus, the SFCL has been studied as the fascinating device. In case that, Particularly, the SFCL could be installed to parallel operation of various power main transformers in power distribution system of the Korea Electric Power Corporation (KEPCO) on 22.9 [kV] bus tie, the effect of the resistance of SFCL could reduce the increased fault currents and meet the interruption capacity of existing protective devices by them. Therefore, we analyzed the effect of application and proposed the proper impedance of the R-type SFCL on 22.9 [kV] bus tie in a power distribution system using PSCAD/EMTDC.

• 전기학회논문지P
• /
• 제62권4호
• /
• pp.210-215
• /
• 2013

This paper analyze the bus voltage sags in the power distribution system with a small scale cogeneration system when the superconducting fault current limiter was introduced. Among the solutions to decrease the short-circuit current considering the locations of the small scale cogeneration system, the superconducting fault current limiter (SFCL) has been announced as one of the promising methods to reduce the fault current because the installation of the small scale cogeneration system which increases the short-circuit current. According to the application locations of the small scale cogeneration system in a power distribution system, it has caused the variations of voltage sag and duration which depends on the change of the short-circuit current, which can make the operation of the protective device deviate from its original set value when the fault occurs. To investigate the voltage sag when a SFCL was applied into a power distribution system where the small scale cogeneration system was introduced into various locations, the SFCL, small scale cogeneration system, and power system are modeled using PSCAD/EMTDC. In this paper, the effects on voltage sags are assessed when the SFCL is installed in power distribution system with various locations of the small scale cogeneration system.