• 제목/요약/키워드: Power Distribution System

검색결과 3,018건 처리시간 0.033초

Complementary Power Control of the Bipolar-type Low Voltage DC Distribution System

  • Byeon, Gilsung;Hwang, Chul-Sang;Jeon, Jin-Hong;Kim, Seul-Ki;Kim, Jong-Yul;Kim, Kisuk;Ko, Bokyung;Kim, Eung-Sang
    • Journal of Electrical Engineering and Technology
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    • 제10권3호
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    • pp.786-794
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    • 2015
  • In this paper, a new power control strategy for the bipolar-type low voltage direct current (LVDC) distribution system is being proposed. The dc distribution system is considered as an innovative system according to the increase of dc loads and dc output type distribution energy resources (DERs) such as photovoltaic (PV) systems and energy storage systems (ESS). Since the dc distribution system has many advantages such as feasible connection of DERs, reduction of conversion losses between dc output sources and loads, no reactive power issues, it is very suitable solution for new type buildings and residences interfaced with DERs and ESSs. In the bipolar-type, if it has each grid-interfaced converter, both sides (upper, lower-side) can be operated individually or collectively. A complementary power control strategy using two ESSs in both sides for effective and reliable operation is proposed in this paper. Detailed power control methods of the host controller and local controllers are described. To verify the performances of the proposed control strategy, simulation analysis using PSCAD/EMTDC is being performed where the results show that the proposed strategy provides efficient operations and can be applied to the bipolar-type dc distribution system.

A Strategy for Balanced Power Regulation of Energy Storage Systems in a Distribution System during Closed-Loop Operation

  • Han, Yoon-Tak;Oh, Joon-Seok;Cha, Jae-Hun;An, Jae-Yun;Hyun, Seung-Yoon;Lee, Jong-Kwan;Seo, In-Yong;Kim, Jae-Eon
    • Journal of Electrical Engineering and Technology
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    • 제12권6호
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    • pp.2208-2218
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    • 2017
  • To resolve overload in a distribution system, a distribution system operator (DSO) often performs a load transfer using normally open tie points and switches in the distribution line. During this process, the distribution system is momentarily operated in closed-loop operation. A closed-loop current in the distribution system can cause a power failure due to excess breaking current in the circuit breakers and reclosers. Therefore, it is necessary to calculate the closed-loop current exactly. However, if there are a large number of distributed generation (DG) systems in the distribution system, such as energy storage systems (ESS), they might obstruct the closed-loop operation based on bidirectional power flow. For quick and precise operation of a closed-loop system, the ESS has to regulate the power generation while satisfying closed-loop operation in the worst cases. We propose a strategy for balanced power regulation of an ESS. Simulations were carried out using PSCAD/EMTDC, and the results were compared with calculation results.

배전계통에 연계된 전지전력저장시스템의 유.무효전력 제어 (Active and Reactive Power Control of the Battery Energy Storage System interconnected with Power Distribution System)

  • 김재철;문선호;최준호;김응상
    • 조명전기설비학회논문지
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    • 제13권4호
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    • pp.127-133
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    • 1999
  • 본 논문은 배전계통에 전지전력저장시스템(Battery Energy Storage System: BESS)를 연계하여 운전하는 경우 BESS의 유.무효전력 제어에 대하여 연구하였다. BESS을 배전계통에 연계하는 경우, 이의 유.무효전력 출력을 제어함으로써 배전계통에 일정 전력을 공급, 첨두 부하를 삭감하고 전압을 보상할 수 있다. 본 논문에서는 배전계통과 전지전력저장시스템을 등가 모델링 하였고 전지전력저장시스템의 유.무효 전력제어를 위한 전력 조류 방정식을 제시하였다. 본 논문에서는 BESS의 유.무효전력을 제어하기 위하여 $P-\delta$와 Q-V 제어를 사용하였고 이를 입증하기 위하여 BESS의 유.무효전력 제어를 PSCAD/EMTDC 프로그램을 이용하여 시뮬레이션 하였다.

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Single-Inductor, Multiple-Input-Single-Output Converter Based Energy Mixer for Power Packet Distribution System

  • Reza, C.M.F.S.;Lu, Dylan Dah-Chuan;Qin, Ling;Qi, Jian
    • 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.

A Study on Lightning Overvoltage Characteristics of Grounding Systems in Underground Distribution Power Cables

  • Jung, Chae-Kyun;Jung, Yeon-Ha;Kang, Ji-Won
    • Journal of Electrical Engineering and Technology
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    • 제9권2호
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    • pp.628-634
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    • 2014
  • This paper investigates the transient characteristics of grounding systems used in under-ground distribution power cables. Recently, two kinds of grounding system are used for underground distribution cables in Korea. The first one is conventional multi-point grounding system, the other is newly proposed non-bundled common grounding system. The non-bundled common grounding system has an advantage the decreasing the power loss due to decrease of the shield circulation current. In this paper, the lightning overvoltage induced in neutral wire (in case of non-bundled common grounding system, overvoltage between opened neural wires and grounding in each phase) of these two kinds of grounding systems are estimated and compared by field tests and EMTP simulations. The EMTP simulation methods are firstly verified by comparison of measurement and simulation. Finally, the insulation level against lightning is expected by EMTP simulation results using verified model.

Multy-agent system을 애용한 배전계통 최적 보호시스템 연구 (A study on An Optimal Protection System for Power Distribution Networks by Applying Multi-Agent System)

  • 정광호;민병운;이승재;최면송;강상희
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2003년도 하계학술대회 논문집 A
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    • pp.299-301
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    • 2003
  • In this paper, a protection system using Multi-Agent concept for power distribution network is proposed. Multi agent system consist of Feeder agent, OCR(Over Current Relay) agent, Recloser agent and Switch agent. An agent calculates and corrects its parameter by itself through communication with neighboring agents and its own intelligence algorithm. Simulations in a simple distribution network show the effectiveness of the suggested protection system. Multi-Agent System, protection of distribution network, Communication.

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Cyber Threat and a Mitigation Method for the Power Systems in the Smart Grid

  • Kim, Myongsoo;Kim, Younghyun;Jeon, Kyungseok
    • Journal of Electrical Engineering and Technology
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    • 제9권3호
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    • pp.1043-1050
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    • 2014
  • Obsolescent control systems for power systems are evolving into intelligent systems and connecting with smart devices to give intelligence to the power systems. As networks of the control system are growing, vulnerability is also increasing. The communication network of distribution areas in the power system connects closely to vulnerable environments. Many cyber-attacks have been founded in the power system, and they could be more critical as the power system becomes more intelligent. From these environment, new communication network architecture and mitigation method against cyber-attacks are needed. Availability and Fault Tree analysis used to show that the proposed system enhances performance of current control systems.

배전계통 적정전압 유지를 위한 유효 무효전력 협조제어 (Real and Reactive power coordination control of Distributed Generation System for Distribution Voltage Regulation)

  • 김태응;김재언
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2000년도 하계학술대회 논문집 A
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    • pp.153-155
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    • 2000
  • This paper reveals some correlations between LDC voltage control method and the output of DGS, and also presents a method for determining the amounts of real, reactive Power of DGS for proper voltage regulation of power distribution system with LDC. Proposed method has been applied to a 22.9 kV class power distribution system, and those results show that the distribution system voltage profile is improved.

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IT접지방식의 보호를 위한 활선절연저항 감시기 (Protective Insulation Monitoring Device in IT Earth Systems)

  • 김용중;김효성
    • 전력전자학회논문지
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    • 제20권3호
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    • pp.209-213
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    • 2015
  • With the increasing popularity of renewable generation systems and the advancement of power electronics, DC distribution systems have recently received considerable research attention. DC distribution has numerous advantages, including reliability, power quality, and efficiency. Owing to these advantages, DC distribution has been applied to data centers and power quality-sensitive electronic load conditions. Because grounding electrodes in DC are much more susceptible to corrosion than in AC, the IT system defined in IEC Standard 60364 may be a good candidate for an earthing method for DC distribution systems. In addition, IEC Standard 61557 specifies the requirements for insulation monitoring devices (IMD) for protection of the IT system, which continuously monitors the insulation resistances between the power lines and the earth. This paper discusses the development and evaluation of IMD to promote the reliability of distribution systems and increase safety of humans and facilities.

Characteristic Impedances in Low-Voltage Distribution Systems for Power Line Communication

  • Kim, Young-Sung;Kim, Jae-Chul
    • 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.