• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2004.11a
• /
• pp.297-299
• /
• 2004

In multi-ground distribution system, overhead ground wire and neutral wire are parallel connected to offer the electrical power energy and protect damage of lightning strokes. Therefore a case where the two wires become single wire, the power company can get the benefit such as installation cost saving and line fault protection by simplify of distribution line. In this paper we describe the result of impulse test in both system ; one is the present power system the other is unified power system parallel connected overhead ground wire and neutral wire. As a result of this impulse test, the present power system get lower impulse voltage than the unified power system.

• Journal of Electrical Engineering and Technology
• /
• v.8 no.5
• /
• pp.1212-1220
• /
• 2013

In general, for a large power system like DC distribution system for buildings, several power converters are modularized for parallel operation. However, in parallel operation, inconsistency of parameters in each module causes circulating current in the whole system. Circulating current is directly related to loss, and, therefore, it is most important for the safety of the power system to supply the suitable current to each module. This paper proposes a control method to reduce circulating current caused during parallel operation. Accordingly, the validity of parallel operation system including response characteristics and normal state was verified by simulation and experiment result.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.56 no.3
• /
• pp.123-128
• /
• 2007

Hydro power supplies no pollution energy, mainly induction generator has been applied at the small capacity power station. The generating power of small hydro-electric power station connects on the 22.9kV distribution system or low voltage system in the case of three-phase four-wire supply system. There are side effects of various kinds in the 3-three phase 4-wire distribution system mixing 1-phase load and 3-phase load. This system generates the voltage unbalance by unbalanced load operating condition. They have various serious effects on generator and connection system. In this paper, we analyzed what kind of operation characteristic are happened in the induction generator by customer load variation at the 3-three phase 4-wire distribution system.

• Proceedings of the KIEE Conference
• /
• 1989.07a
• /
• pp.265-269
• /
• 1989

Computerized to techniques have been applied to outage call processing system for rapid restoration of power to customers. This paper presents computer aided outage call processing system called '123' system, which has been in operation since 1987. And, also describes its origins, design conception to be considered and its operation effects. From a positive point of view, it shows the functions needs to be added and some problems to be improved. Additionally, it describes the integrated system which has functions of detecting distribution failure, locating failure position by logical computer processing, and although ADS (Automatic Distribution System) has yet to be built up, the primary purpose of the system is to improve service to the customer by means of rapid restoration of electricity outage.

• Proceedings of the KIEE Conference
• /
• 2002.07a
• /
• pp.533-535
• /
• 2002

In Korea, power requirement has been increasing. But the large generation unit is hardly installed because of economic and environment problem. Therefore, the concern of dispersed generation system(DGS) is growing. The power distribution system is generally operated with radial type. The protection system is composed of one directive source. But power distribution system inserted DGS changes it to two directive source system. Therefore, the insertion of DGS has the problem of protection coordination. In this paper, we argue fault current affected by interconnected DGS. We analyze fault current flow affected by DGS placement. Then, we find protective coordination problem. Consequently, we study advance point for protection scheme of power system interconnected DGS.

• Proceedings of the KIEE Conference
• /
• 2002.07a
• /
• pp.133-135
• /
• 2002

It is raised for methodology to evaluate power system reliability using interruption cost which is converted customer loss due to interruption into cost according to power industry is rushed into competition appearance. This paper presents algorithms to evaluate reliability of distribution power system taking into consideration customer interruption cost. Customer interruption cost is considered as one of the valuable index to estimate reliability of the distribution power system from customer situation. Also. this paper estimate evaluation results regarding the reliability of distribution power system using a sample model system. Finally, evaluation results of unserved energy and system interruption cost based on customer interruption cost are shown in detail.

• Proceedings of the IEEK Conference
• /
• 2008.06a
• /
• pp.1085-1086
• /
• 2008

An error prediction system (EPS) for a power distribution system can predict an out-of-order state based on gathered data from the system. This paper describes a software structure of an EPS that is equipped with various sensors. The software analyzes the gathered data from sensors and predict error symptoms using statistical methods. The EPS system is installed on a real power distribution system.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.30 no.3
• /
• pp.117-126
• /
• 2007

It has been a major issue to repair the broken system quickly for improvement of productivity and utilization. Generally, high utilization of system requires the high amount of spare parts in inventory and inventory cost. Therefore, it is necessary to determine the proper amount of inventory with regard to utilization of system. This study designs a methodology for determining the proper amount of inventory level in a two-echelon spare parts distribution system. The requirements are to satisfy proper customer demands at a distribution center and to maintain over the utilization of the whole system at customers. This methodology minimizes total inventory investment at a distribution center and customers.

• Journal of Electrical Engineering and Technology
• /
• v.13 no.2
• /
• pp.540-549
• /
• 2018

This paper proposes the method of active distribution network expansion planning considering distributed generation integration and distribution network reconfiguration. The distribution network reconfiguration is taken as the expansion planning alternative with zero investment cost of the branches. During the process of the reconfiguration in expansion planning, all the branches are taken as the alternative branches. The objective is to minimize the total costs of the distribution network in the planning period. The expansion alternatives such as active management, new lines, new substations, substation expansion and Distributed Generation (DG) installation are considered. Distribution network reconfiguration is a complex mixed-integer nonlinear programming problem, with integration of DGs and active managements, the active distribution network expansion planning considering distribution network reconfiguration becomes much more complex. This paper converts the dual-level expansion model to Second-Order Cone Programming (SOCP) model, which can be solved with commercial solver GUROBI. The proposed model and method are tested on the modified IEEE 33-bus system and Portugal 54-bus system.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.66 no.3
• /
• pp.500-506
• /
• 2017

In 2014, ISO 55000s has been enacted and the power plant asset management is becoming a hot issue for all over the world. The asset management system is being developed as a combination of CBM(Condition Based Maintenance) and RCM(Reliability Centered Maintenance). Therefore, the research on the calculation of the failure rate which is the most basic index of RCM is actively carried out. The failure rate calculation has been going on for a long time, and the most widely used probability distribution is the Weibull distribution. In the Weibull distribution, the failure rate function is determined in three types according to the value of the shape parameter. However, the Weibull distribution has a limitation that it is difficult to apply it when the trend of failure rate changes-such as bathtub curves. In this paper, the failure rate is calculated using the mixture Weibull distribution which can appropriately express the change of the shape of the failure rate. Based on these results, we propose the necessity and validity of applying mixture Weibull distribution.