• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 D
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• pp.958-961
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• 1997

This Paper deals with voltage variation and voltage regulation method in power distribution systems including cogeneration facilities. In order to deliver suitable voltages to many customers at the distribution substations. In this paper, an on-line real time modified voltage regulation method is proposed. The result from a case study show that the proposed method can be practical tool for the voltage regulation in distribution systems including cogeneration facilities.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 A
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• pp.253-255
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• 1997

This paper, which is one of the researches to limit high fault-current, treats the application of an inductive High Tc Superconducting Fault Current Limiter(HTSFCL) to distribution systems. In case that the inductive HTSFCL is applied to distribution systems, this paper presented the usefulness and the commercial possibility of it through computer simulation. If the inductive HTSFCL is established in distribution systems, after fault, it limits fault current effectively within a few millisecond, so it contributes to stability of power distribution system. Especially as the system with the HTSFCL is compared with the system without it, the system is improved in stability.

• 한국정보시스템학회지:정보시스템연구
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• 제28권1호
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• pp.133-153
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• 2019

Purpose The purpose of this study is to design a regional electricity planning model rather than the existing single region ones and verify its usefulness. The regional electricity planning model is to determine both electricity distribution among regions and power plant planning at the same time satisfying regional demands and distribution networks. Design/methodology/approach This study made a regional electricity planning model by integrating power plant planning and electricity distribution among regions. The regional electricity planning model is formulated into a linear programming problem, and coded and run using the OSeMOSYS, one of open source energy systems. Findings According to the empirical analysis result, this study confirmed that the regional electricity planning model proposed in this study deducts the unfairness among regions in view of electricity and green house gas. In addition, the model is expected to be used in evaluating and developing the national policies concerning fine dust and/or green house gas.

• Journal of Power Electronics
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• 제13권4호
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• pp.701-711
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• 2013

This paper takes into account the influence of the different impedances of distribution lines on power distribution among inverters when the inverters are paralleled with the droop control method. The impact of distribution lines on the power distribution of inverters can be divided into two aspects. Firstly, since the distributed generators are in low voltage grids, there is resistive impedance in the distribution lines, which will cause control coupling and reduce system stability. The virtual negative resistive impedance of inverters is adopted in this paper to neutralize the resistive element of distribution lines and thus make the distribution line impedance purely inductive. Secondly, after solving the resistive impedance problem, the difference in the inductive impedance value of distribution lines due to the low density of distributed generators will cause an unequal share of reactive power. With regards to this problem, modification is put forward for the droop control strategy to share the reactive power equally. The feasibility of the design is validated by simulation and experimental results.

• 신재생에너지
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• 제10권3호
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• pp.47-54
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• 2014

Recently, BESS is considered as one of essential countermeasure for demand side management. However, an economic evaluation is critical issue for the introduction of power system because the cost of BESS is very high in present stage. Therefor, this paper presents economic evaluation method for customer use case by considering peak shaving function based on the real time price. From the case study on the model power system and educational customer, it is confirmed that the proposed method is a practical tool for the economic analysis of BESS. and analytical approach for the reliability assessment in radially operated distribution systems. The approach can estimate the expected reliability performance of distribution systems by a direct assessment of the configuration of the systems using the reliability indexes such as NDP (Non-Delivery Power) and NDE (Non-Delivery Energy). The indexes can only consider the number and configuration of the load, but can not consider the characteristics of the load which is the one of the most important factor in the investment cost for the distribution systems. Therefore, this paper presents the new performance indexes for the investment of the distribution facilities considering both the expected interruption cost for the load section and the operation characteristics of Energy Storage System. The results from a case study show that the proposed methods can be a practical tool for the reliability management in distribution systems including Energy Storage System.

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

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 A
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• pp.205-207
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• 1993

Distribution planning requires comprehensive knowledge about not only distribution but also transmission/subtransmission system expansion plan. At the same time, distribution planning is very time consuming and a series of routine job which involves a lot of experience and efforts of planning engineers. Since the quality of distribution planning depends upon the ability of planning engineers, the economy of investment should be taken into consideration. The object of this study is to establish a computerized distribution planning system which helps distribution engineers finding a new system expansion plan. It provides the engineers with at optimal system expansion plan which satisfies the condition of both reliability and economy.

• 조명전기설비학회논문지
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• 제19권2호
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• pp.100-106
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• 2005

본 논문에서는 분산형 전원을 포함하는 배전계통을 위한 3상 조류계산 프로그램에 대하여 소개한다. 배전계통의 조류계산을 위하여 각 상간에 존재하는 불평형을 모두 고려할 수 있도록 계통 내 설비들의 모델을 선정하였으며, 전력방정식이나 측정함수 등도 새로 유도하였다. 본 논문을 통해 개발된 조류계산 프로그램은 다양한 크기와 형태의 시험계통에 대해 사례연구를 시행함으로써 알고리즘의 타당성 및 프로그램의 수렴성을 검증하였다.

• Journal of Power Electronics
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• 제18권5호
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• pp.1479-1488
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• 2018

Power packet (PP) distribution system distributes power to different loads that share the same distribution cable in a packetized form. When compared with conventional power systems, a PP distribution system (PPDS) can reduce standby power, eliminate Point-of-Load (PoL) power conversion, and intelligently control the load demand from the source side. Due to the absence of PoL conversion, when multiple power sources at different voltage levels and conditioning requirements jointly send power to various loads at different voltage ratings, the generated voltage has an irregular shape. A large filter at each of the load sides is required to reduce such a large voltage ripple. In this paper, a single-inductor, multiple-input-single-output converter structure based multiple-energy-source mixer is proposed. It combines PP generation, maximum power point tracking (MPPT) of renewable energy sources (RESs) and filtering at the source side. To demonstrate the possible renewable energy integration, a PV panel is used as a power source together with other constant voltage sources. The PV power is approximately tracked using the constant voltage method and it is used for each of the PP generations. The proposed PP distribution system is experimentally verified and it is shown that a conventional PI controller is sufficient for stable system operation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 A
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• pp.555-557
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• 2003

As electric power transmission systems grow to supply the increasing electric power demand, transmission capacity is larger. but that's really difficult to secure the location for power transmission and distribution to user. The high temperature superconducting(HTS) cable is a method to solve this problem. But for applying to real systems, it needs to investigate the effect of HTS cable. The most important things is the investigation of fault condition. the fault on HTS cable include the quench state. When a fault occur in a circuit, three critical parameters(temperature, current density, magnetic field) exist. when one of these parameters exceeds the critical value, the superconducting becomes normal-conducting. f the cooling power is insufficient to recover the superconducting state, the normal-conducting zone expands. In order to solve these problem, this paper present simulate the quench state considering the over-current and over-voltage in the informal circuit and analyze the quench state.