Sang-Bong Choi

Evaluation of the customer interruption cost taking into consideration macro economic approach in Korea

This paper presents assessment of the customer interruption cost with a macro economic evaluation of Korean customers. The customer interruption cost is considered as one of the most useful indices to plan optimal power system facilities. This paper reviews methodology and factor to determine interruption cost and evaluates the customer interruption cost and ratio to the average revenues per electric energy sold for the public, service agriculture, fishery, mining, manufacturing and residential sectors by customer type for 5 years.

A Survey on Interruption Costs of Korean Industrial Customers

An approach is often used to estimate the reliability value to determine consumers economic losses resulting from service interruptions. The quantitative estimation of interruption costs are important and meaningful work. Further the restructuring of the electric industries worldwide, most of the electric utilities and consumers have to consider the two important elements such as supply reliability and quality while calculating the related costs and the contract to sell or purchase electricity because it takes costs to keep the two elements at their higher level. Especially, the interruption or the supply reliability will have the influence on the bilateral contract between the suppliers and customers as a key point to determine the price of electric power in the competitive electric market. The increasing use of electrical and electronic machines day-by-day the electrical power supply system and the environment on the process of generation to consumption of electricity also are being changed. In other words both suppliers and consumers of electricity are required to be responsible for their interruption costs since the monetary losses are resulted from the service interruptions. This paper addresses the analysis of interruption costs and the studies made through the direct interview with Korean industrial customers for the period of two years. It is conducted to evaluate the direct and short duration interruption costs resulting from local random electrical supply interruptions. The cost is evaluated by providing a designed questionnaire focused on the experience or the preparative actions which consumers predicted they would take. In the first phase, authors made a survey on all types of industry with 176 industrial customers and evaluated them as per standard industry classification (SIC). In that case, the evaluation data obtained are not so reasonable, because the number of sampled industries was small and the sampled industries were surveyed by being divided into 18 types. So, in the second phase the authors concentrated on only 4 types of 302 industries who have many and large sensitive loads to the short duration interruption

Development of criteria and calculation of Korean industrial customer interruption costs

This paper presents the results of direct interview survey of Korean industrial customers conducted to evaluate the direct, short-term impacts and costs resulting from local random electrical supply interruptions. The cost is evaluated using the questionnaires authors designed, which are mainly on the experience or preparatory actions consumers predicted they would take. Economic evaluation of reliability that traditionally takes into account duration and frequency of interruption does not accurately reflect the lost value or economic impacts of industrial customer, especially large size, caused by any kind of interruption. So, to imply the substantial difference in costs incurred by different customer group, the authors apply the international standards, i.e. IEC, IEEE, of the recent classification of interruption to reflect the difference of interruption characteristics on the questionnaires for the analysis of the interruption cost.

Assessment of interruption costs for commercial customers in Korea

This paper presents assessment of the interruption costs for commercial customer in Korea with customer survey methodology. When various research results are examined, assessment of direct interruption cost is much more simple. Especially, in the case of commercial customers, it is known that the assessment of direct interruption cost is more useful. Accordingly, this paper selected the customer survey method to assess the interruption cost for commercial customer in Korea considering interruption and customer characteristic.

Development of New Monitoring System for Power Quality Management in Korea

This paper presents the status of power quality and outlines the development of a new power quality monitoring system based on the experience of a series of authors researches and field measurements for industrial customers in Korea. It also proposes the functions of the monitoring device and the efficient analysis method based on the Korean electrical act and international standards on power quality. Finally, the authors suggest some countermeasures for advancing the power quality to cope with the competitive electric power market and customers needs after restructuring of electric power industry in Korea

A power quality monitoring system for the efficient competitive electricity market in Korea

This paper analyzes the present status of power quality and outlines the development of a monitoring system of power quality based on the experience of a series of authors researches and field measurements for industrial customers in Korea. It also proposes the functions of the monitoring device and the efficient analysis method based on the Korean electrical act and international quality standards. Finally, the authors suggest some countermeasures for advancing the power quality to cope with the competitive electric power market and customers needs after restructuring of electric power industry according to KEPCO (Korea Electric Power Corporation)s plan, which is to be completely separated by distribution system in near future in Korea.

Analysis on the longitudinal temperature and derating factor of power cables surrounding dissimilar soil materials region

The permissible current-carrying capability of power cables has been calculated on the basis of installing in the homogeneous materials as the same thermal resistivity. But, in case of installing power cables surrounding dissimilar soil thermal properties, the gradient of temperature will be occurred not only the radial heat flow but also longitudinal heat flow along the power cables. So there are many problems at calculating the permissible current-carrying capability in convenient method. This paper presents the heat model and algorithms of the longitudinal heat flow along power cables to analyze the temperature distribution and the derating factor of the permissible current-carrying capability of power cables. The algorithm is derived from two dimension Fouriers law and energy balance equation using heat conduction equation of heat transfer. The analysis of derating factor of the permissible current-carrying capability of power cables is derived from the algorithm and equation proposed by IEC 60287. The proposed heat model and algorithm are programmed to analyze the hotspot of power cables using the graphical user interface technique. This program is of great use to reasonably calculate the permissible current-carrying capability of power cables and to operate underground power systems in more stable and reliable.

Development of the real-time soil thermal property analyzer using CDMA

This paper introduces the real-time soil thermal property analyzer and temperature measurement system (STP) which is combined with radio telecommunication techniques. To measure the thermal parameters in real-time, the radio telecommunication technique uses the personal communication service (PCS) which is commercialized in Korea for the first time in the world by CDMA technology. The soil thermal property analyzer has an ability of measuring thermal resistivity, thermal diffusivity and thermal stability. To estimate the soil thermal properties, curve fitting algorithms by means of the least square method are used. Also, TCP/IP protocol and MTM are used to communicate a control center with the real-time STP installed at multiple locations along routes of the underground power cables under examination.