• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.3813-3820
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• 2014

Recently, with the increase in electrical consumption and the unbalanced power demand and supply, the power reserve rate is becoming smaller and the reliability of the power supply is deteriorating. Under this circumstance, a Battery Energy Storage System (BESS) is considered to be an essential countermeasure for demand side management. On the other hand, an economic evaluation is a critical issue for the introduction of a power system because the cost of BESS is quite high. Therefore, this paper presents economic evaluation method for utility use by considering the best mix method and successive approximation method, and an economic evaluation method for customer use by considering the peak shaving function based on the real time price. From a case study on a model power system and educational customer, it was confirmed that the proposed method is a practical tool for the economic analysis of BESS.

• Economic and Environmental Geology
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• v.38 no.6 s.175
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• pp.717-729
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• 2005

Peak cooling load of large buildings is generally greater than their peak heating load. Internal and solar heat gains are used fur selection of adquate equipment in large building in cold winter climate like Canada and even Korea. The cost of geothermal heat exchanger to meet the cooling loads can increase the initial cost of ground source heat pump system to the extend less costly conventional system often chosen. Thermal ice storage system has been used for many years in Korea to reduce chiller capacity and shift Peak electrical time and demand. A distribution system designed to take advantage of heat extracted from the ice, and use of geothermal loop (geothermal heat exchanger) to heat as an alternate heat source and sink is well known to provide many benifits. The use of thermal energy storage (TES) reduces the heat pump capacity and peak cooling load needed in large building by as much as 40 to $60\%$ with less mechanical equipment and less space for mechanical room. Additionally TES can reduce the size and cost of the geothermal loop by 1/3 to 1/4 compared to ground coupled heat pump system that is designed to meet the peak heating and cooling load and also can eliminate difficuties of geothermal loop installation such as space requirements and thermal conditions of soil and rock at the urban area.

• Environmental and Resource Economics Review
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• v.14 no.2
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• pp.519-547
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• 2005

The aim of this study is to analysis how economic welfare lost happens within the present korea seasonal and time period electricity pricing system and find out reasonable electricity price system acceptable during the transitional period of korea electricity industry restructuring To analyze economic welfare lost in the electricity industry, in advance seasonal and time periodic 9 demand curves(summer, spring ＆fall, winter/peak-load time, middle-load time, low-load time) and one market supply curve are made and then using these demand and supply curve, seasonal and time periodic market equilibrium prices is calculated. Finally, comparing these market equilibrium prices with present regulated classified seasonal and time periodic prices, the whole economic welfare lost in the electricity industry is calculated. The result of this study shows that in 2002, the total economic welfare lost in electricity industry is 137,770 million Won and under present price system, the worst welfare lost is happening seasonally in spring ＆ fall, time periodically in the middle-load time. Specifically analyzing the characteristics of welfare lost, especially on the industry customers and service customers which are applied in seasonal and time periodic pricing, for the industry customers, the welfare lost calculated in this class occupies 51% of the total welfare lost in the whole electricity industry and the worst welfare lost is happening seasonally in spring ＆ fall, time periodically in the middle-load time. For service customers, the welfare lost calculated in this class occupies 13% of the total welfare lost in the whole electricity industry and the worst welfare lost is happening seasonally in summer, time periodically in the peak time Finally, this study was made based on the year of 2002 and KEPCO has practiced two times of rate change until now. The result of rate change was positively analyzed in the direction of economic welfare improvement(welfare improvement achieved by 16.3% compared to 2002 result).

• Journal of the Korean Institute of Gas
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• v.15 no.3
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• pp.19-25
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• 2011

Generally, the generation methods of cooling energy are electric air conditioning (EAC) and gas air conditioning (GAC). The EAC system is caused by increasing peak power during summer. Because the electric energy has a characteristic of non-storage, the peak electric load has been issued social problem annually whether the facility to supply is enough or not. Another way to supply cooling energy, GAC system is worked by gas energy. The absorption chiller and gas engine heat pump have been commercialized for cooling. However, the total capacity of GAC is much less than EAC and it almost depends on EAC for small market. This paper described the status of cooling energy consumption in domestic and expected the cooling energy to be consumed by electric and gas energy up to 2024 year. And also the benefit of GAC was analyzed with the case of its expansion and it was aimed to give background to fit the GAC policy.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.588-589
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• 2011

`10. 1. 13일 한파지속에 따른 16년 만에 동계피크가 발생 하였으며, '11. 1. 17일 73,137MW로 2년 년속 동계피크 경신으로 우리나라도 이젠 동계피크 발생국가에 해당된다고 볼 수 있다. 이는 경기회복에 따른 산업용전력의 증가가 동계피크 발생을 견인하였지만 타 에너지원에 비해 전기요금이 저렴하기 때문에 난방연료원이 가스나 가름에서 전기로 지속적으로 전환된 것이 가장 큰 원인이라고 보여 진다. 효과적인 전력수요관리를 위해서는 계약종별별로 부하량과 난방부하량을 측정해서 분석하는 것이 무엇보다 중요하다 하겠다. 그렇지만 실시간으로 계약종별로 부하량 자료를 얻을 수 있는 것은 현재 고압고객의 AMR계량시스템자료가 있으나 이는 고압전체의 85% 대 수준의 자료를 읽어올 뿐 전제 부하를 대변할 수 없으므로 발전단 부하를 계약종별로 적절하게 안분하는 것이 필요하다고 볼 수 있다. 8760시간대별 부하분석을 위해서는 발전단 부하와 배전단부하를 근간으로 고압고객의 원격자동검침(AMR) 자료를 활용하여 최대피크기여도를 분석하여 부하분석을 수행하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.1
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• pp.860-867
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• 2015

This paper presents a control method for energy cost saving in the water reuse pumping system. An optimize horizon switching strategy is proposed to implement an pump control. And Particle Swarm Optimization (PSO) algorithm is used to solve optimal problems in each time step. Energy costs are calculated for electricity on both TOU in the light, heavy, and maximum load time period and peak charges. The control method in water reuse pumping systems is determined to reduce the TOU cost. The simulation results show a energy cost saving for water reuse pumping systems.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.2
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• pp.317-324
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• 2007

Most conventional hybrid systems using renewable energy sources have been applied for stand-alone operation, but Utility-interface may be an useful and viable option for hybrid systems. Grid-connected operation may have benefits such as reduced losses in power system distribution, utility support in demand side management, and peak load shaving. This paper addresses power control and dynamic performance of a grid-connected PV/wind/BESS hybrid system. At all times the PV way and the wind turbine are individually controlled to generate the maximum energy from given weather conditions. The battery energy storage system (BESS) charges or discharges the battery depending on energy gap between grid invertger generation and production from the PV and wind system. The BESS should be also controlled without too frequently repeated shifts in operation mode, charging or discharging. The grid inverter regulates the generated power injection into the grid. Different control schemes of the grid inverter are presented for different operation modes, which include normal operation, power dispatching, and power smoothing. Simulation results demonstrate that the effectiveness of the proposed power control schemes for the grid-interactive hybrid system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.8
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• pp.15-20
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• 2010

This paper shows a reasonable diversity factor, that was made by the systematic and statistical way considering actual conditions, such as investigated contract power and peak power for the last 5 years of each customer for 20 Lease Apartment. In this paper, it is necessary to analyze the key features and general trend from the investigated data. It made an analysis of the feature parameters, such as average, standard deviation, median, maximum, minimun and thus it was carried out by the linear and nonlinear regression analysis. The standards of demand, diversity, and load density are necessary to create the design of a transformer capacity that is seldom presented in terms for academic study.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.672-678
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• 2020

The parallel-feeding operation of an AC traction power supply system has the advantages of extending the power supply section and increasing the power supply capacity by reducing the voltage drop and peak demand caused by a train operation load. On the other hand, the parallel-feeding operation is restricted because of the circulating power flow induced from the phase difference between substations. Moreover, the power supply capacity is limited because of the unbalanced substation load depending on the trainload distribution, which can be changed by the train operation along the railway track. This paper suggests a Thyristor-controlled Phase Angle Regulator (TCPAR) to reduce the circulating power flow and the unbalanced substation load, which depends on the phase difference and the trainload distribution and provides a feasibility study. A dedicated control model of TCPAR is also provided, which uses substation power supplies as the input to control the circulating power flow and an unbalanced substation load depending on the phase difference and the trainload distribution. Simulation studies using PSCAD/EMTDC shows that the proposed TCPAR control model can reduce the circulating power flow and the unbalanced substation load depending on the phase difference and the trainload distribution. The proposed TCPAR can extend the parallel-feeding operation of an AC traction power system and increase the power supply capacity.

• Journal of the Korean Institute of Intelligent Systems
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• v.9 no.4
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• pp.420-425
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• 1999

The maximum demand controller is an electrical equipment installed at the consumer side of power system for monitoring the electrical energy consumed during every integrating period and preventing the target maximum demand (MD) being exceeded by disconnecting sheddable loads. By avoiding the peak loads and spreading the energy requirement the controller contributes to maximizing the utility factor of the generator systems. It results in not only saving the energy but also reducing the budget for constructing the natural base facilities by keeping thc number of generating plants ~ninimumT. he conventional MD controllers often bring about the large number of control actions during the every inteyating period and/or undesirable loaddisconnecting operations during the beginning stage of the integrating period. These make the users aviod the MD controllers. In this paper. fuzzy control technique is used to get around the disadvantages of the conventional MD control system. The proposed MD controller consists of the predictor module and the fuzzy MD control module. The proposed forecasting method uses the SOFM neural network model, differently from time series analysis, and thus it has inherent advantages of neural network such as parallel processing, generalization and robustness. The MD fuzzy controller determines the sensitivity of control action based on the time closed to the end of the integrating period and the urgency of the load interrupting action along the predicted demand reaching the target. The experimental results show that the proposed method has more accurate forecastinglcontrol performance than the previous methods.