• Journal of Advanced Marine Engineering and Technology
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• v.26 no.3
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• pp.313-319
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• 2002

Since the oil crisis in 1970, a great deal of effort has been made to develop automatic electric load sharing systems as a part of the efforts to save energy. A large scale electric generating system composes more than two generators whose characteristics may be different. When such a system is operated individually or in parallel, the lagrange multiplier's method has difficulty in achieving optimal load distribution because generators usually have the limitations of the operating range with inequality constraints. Therefore, a suitable operating mode of generators has to be decided according to the selection of the generators to meet electric power requirements at the minimum cost. In this study, a method which solves the optimal electric load distribution problem using the dynamic programming technique is proposed. This study also shows that the dynamic programming method has an advantage in dealing with the optimal load distribution problem under the limitations of the operating range with inequality constraints including generator operation mode. In this study, generator operating cost curve of second order equation by shop trial test results of diesel generators are used. The results indicate that the proposed method can be applied to the ship's electric generating system.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2448-2450
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• 2002

In recent years, it has been a worldwide trend that many power utilities gave their attention to develop and operate their power plants, substation and distribution systems. Following this trend, KEPCO(Korea Electric Power Corporation) has developed many electric automation systems with various communication networks. It has been natural that the automation systems are just focused on to remote devices when they come to be designed. But, we have to shirt the focus to the automation system itself. There are many problems in maintenance and integration of the automation systems. When an automation system can't control some remote devices, there is no way to get why and which part(Master, Network, Master-side Modem or Remote-side modem, Remote Device, etc.) of the system has problems. Moreover the system just directly links to another automation system. If the system has to link many systems, it needs the linker per each systems. So, we need a new concept to resolve that problems, and develop the Intelligent and Integrated Gateway(IIG) for the automation systems for easy maintenance and integration.

• KEPCO Journal on Electric Power and Energy
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• v.2 no.2
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• pp.245-251
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• 2016

Despite the exponential throughput improvement in mobile communications systems, their ability to satisfy requirements of state-of-the-art and future applications of advanced metering infrastructure (AMI) is still under investigation. Challenges are mainly due to the inadequacy of third generation partnership project (3GPP) networks to support large amounts of devices simultaneously, while the number of AMI end-devices and the frequency of their data transmission increase with new AMI-based applications. In this introductory survey, innovative and future AMI applications and their communication requirements are first reviewed. Then, we identify challenges of 3GPP long term evolution (LTE) in enabling future AMI applications. More importantly, the latest improvements to LTE-A standard release 12 and 13 are reviewed and analyzed with regards to their potential to improve the quality of LTE-enabled AMI. It is found that 3GPP enhancements on machine type communications (MTC) standards will significantly enhance AMI communications. Beyond MTC specifications, non-MTC-specific enhancements such as carrier aggregation and multi-connectivity for user equipment will also contribute greatly to improving reliability and availability of AMI devices. The paper's focus is towards improved backhaul support for innovative and future AMI applications, beyond traditional automatic meter reading.

• Proceedings of the KIEE Conference
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• 2008.09a
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• pp.9-11
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• 2008

Lightning has been identified as one of the leading causes of outages on transmission and distribution systems. To protect the transmission and distribution line from lightning, the transmission lightning arrestor can be the effective facility on the power system. This paper will discuss Gapped type Arresters application results by analysing effects of lightning arrestors on transmission and distribution line.

• KEPCO Journal on Electric Power and Energy
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• v.1 no.1
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• pp.47-54
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• 2015

The most important function in distribution automation system (DAS) is the service restoration. KEPCO's current service restoration provides a very effective restoration service. However, it has been developed without the consideration of unexpected abnormal conditions that may occur while processing the sequence of switching operations. The objective of this paper is to provide practical service restoration schemes under consideration of abnormal conditions. The proposed service restoration schemes have been integrated to a branch office (B/O) in KEPCO. The proposed method strongly supports the conventional service restoration and adds to its value.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.422_423
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• 2009

DNP 3.0 is the most widely used data communication protocol for electric power control systems. KEPCO(Korea Electric Power Corporation) also uses DNP 3.0 as a data transmission protocol for the DAS(Distribution Automation System) and the SCADA system of the transmmission system. But DNP 3.0 is one of the oldest industrial standard having many restrictions and there are many considerations for optimal design of DNP 3.0 network for the Distribution Automation System.

• Transactions on Electrical and Electronic Materials
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• v.18 no.5
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• pp.303-309
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• 2017

The flexible AC transmission system (FACTS) provides a new advanced technology solution to improve the flexibility, controllability, and stability of a power system. The unified power flow controller (UPFC) is outstanding for regulating power flow in the FACTS; it can control the real power, reactive power, and node voltage of distribution networks. This paper investigates the performance of the UPFC for power flow control with a series of step changes in rapid succession in a power system steady state and the response of the UPFC to distribution network faults and islanding mode. Simulation was carried out using the MATLAB's simulink sim power systems toolbox. The results, which were carried out on a 5-bus test system and a 4-bus multi-machine electric power system, show clearly the effectiveness and viability of UPFC in rapid response and independent control of the real and reactive power flows and oscillation damping [6].

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.1
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• pp.1-6
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• 2002

This paper proposes an advanced reclosing scheme to improve power quality in power distribution systems. When a fault occurs in distribution system, the proposed schema determines the number of reclosing shots and its intervals according to the magnitude of fault current. Thus, an advanced reclosing scheme takes account of the power quality problem in customer\`s and the damage in electric facilities. To verify the effectiveness of the proposed scheme, a numerical simulation that calculates various indices to consider the reliability and the other effects on electric facility, in carried out with actual field data.

• Proceedings of the KSR Conference
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• 1999.11a
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• pp.344-351
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• 1999

The safe operation of electro railways is greatly dependant on its protective systems. The system so-called Fault Protection Wire(FW) is now widely adapted to protect in AT feeding systems. It is connected between the feeder and trolley circuit to return the fault current to autotransfonmers at substation. This paper computed the distribution of fault currents at FW in the system and also evaluated the safety from electric shock when ground fault or flashover occur in the feeding system. The results show FW is useful to protect power supply network from fault in electric railways

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.5
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• pp.238-246
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• 2002

Utilities are trying to install the equipment of high quality to avoid deterioration of supply reliability. In addition, many sectionalizing switches which can decrease the total outage value for a fault are installed for the same reason. Therefore, utilities are interested in stun dards and criteria for installing switches to optimize the total cost on distribution systems. The affect of sectionalizing switches installed on distribution feeder is gradually decreased because the failure rate on distribution feeder is decreased. Also the automation for distribution systems is widely applied for the efficient operation. Therefore, the renewal for installation standards of sectionalizing switches Is required to reflect the current operation situation. The variable data is used to consider the KEPCO's real situation of distribution feeder as follows; the feeder capacity, connecting rate, feeder length, failure rate of distribution feeder, the failure rate of switches, perception time of feeder fault, the restoration time for a faulted section, the transfer time to other feeders, and the switching time. In this study, We propose equations which can determine the number of sectionalizing switches for minimizing the outage and switch installation cost.