• 제목/요약/키워드: EMTP

검색결과 764건 처리시간 0.023초

제어 가능한 전류원 기반의 인버터를 이용한 실제적 태양광 발전 시스템 모델링 (Modeling of Practical Photovoltaic Generation System using Controllable Current Source based Inverter)

  • 오윤식;조규정;김민성;김지수;강성범;김철환;이유진;고윤태
    • 전기학회논문지
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    • 제65권8호
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    • pp.1340-1346
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    • 2016
  • Utilization of Distributed Generations (DGs) using Renewable Energy Sources (RESs) has been constantly increasing as they provide a lot of environmental, economic merits. In spite of these merits, some problems with respect to voltage profile, protection and its coordination system due to reverse power flow could happen. In order to analyze and solve the problems, accurate modeling of DG systems should be preceded as a fundamental research task. In this paper, we present a PhotoVoltaic (PV) generation system which consists of practical PV cells with series and parallel resistor and an inverter for interconnection with a main distribution system. The inverter is based on controllable current source which is capable of controlling power factors, active and reactive powers within a certain limit related to amount of PV generation. To verify performance of the model, a distribution system based on actual data is modeled by using ElectroMagnetic Transient Program (EMTP) software. Computer simulations according to various conditions are also performed and it is shown from simulation results that the model presented is very effective to study DG-related researches.

최대 전압 강하에 비례하는 무효전류 공급 루프를 이용한 DFIG 풍력단지의 계층전압제어 (Hierarchical Voltage Regulation of a DFIG-based Wind Power Plant Using a Reactive Current Injection Loop with the Maximum Voltage Dip for a Grid Fault)

  • 박건;김진호;강용철
    • 전기학회논문지
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    • 제65권8호
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    • pp.1334-1339
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    • 2016
  • In a power grid that has a high wind power penetration, the fast voltage support of a wind power plant (WPP) during the grid fault is required to stabilize the grid voltage. This paper proposes a voltage control scheme of a doubly-fed induction generator (DFIG)-based WPP that can promptly support the voltage of the point of common coupling (PCC) of a WPP during the grid fault. In the proposed scheme, the WPP and DFIG controllers operate in a voltage control mode. The DFIG controller employs two control loops: a maximum voltage dip-dependent reactive current injection loop and a reactive power to voltage loop. The former injects the reactive power in proportion to the maximum voltage dip; the latter injects the reactive power in proportion to the available reactive power capability of a DFIG. The former improves the performance of the conventional voltage control scheme, which uses the latter only, by increasing the reactive power as a function of the maximum voltage dip. The performance of the proposed scheme was investigated for a 100-MW WPP consisting of 20 units of a 5-MW DFIG under various grid fault scenarios using an EMTP-RV simulator. The simulation results indicate that the proposed scheme promptly supports the PCC voltage during the fault under various fault conditions by increasing the reactive current with the maximum voltage dip.

Positive Offset Mho 계자 상실 계전기 보호 협조 정정에 관한 연구 (A Study on Protective Coordination Setting of Positive Offset Mho Loss of Field Relay)

  • 김광현;박지경;김준혁;김두웅;강성범;김철환;유영식;양정재;고윤태
    • 전기학회논문지
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    • 제65권8호
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    • pp.1326-1333
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    • 2016
  • It is important to clear the fault and prevent resulting in damage to power system. Although the frequency of generator internal fault is relatively low, it can lead to incalculable damage to power system as well as generator. Especially, loss of field on generator can cause the generator to lose synchronism for a short time if it is not removed promptly. Therefore, it is needed to conduct research on loss of field relay for detecting or clearing the loss of field. However, the setting of the relay may vary in generator operator or engineer, and the relay is not coordinated well with other elements associated with loss of field. In this paper, we address specifically the coordination of positive offset mho loss of field relay which is one of the protection schemes for loss of field. Computer simulations are performed by using ElectroMagnetic Transients Program-Restructured Version (EMTP-RV) based on actual data.

히스테리시스 특성을 고려한 측정용 변류기 보상 알고리즘 (Compensating algorithm for a measurement type CT considering hysteresis characteristic of the core)

  • 강용철;정태영;이병은;소순홍;이현웅;이미선;박정호;최현태;장성일;김용균
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2007년도 제38회 하계학술대회
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    • pp.44-45
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    • 2007
  • This paper deals with error compensation in current transformers. Since the exciting current can be considered as the main error source, its evaluation can allow the compensation of its detrimental effects to be obtained. The exciting current required by the transformer in every king of steady state operation can be determined by simply acquiring the secondary current, provided that the examined CT has been preliminarily identified. This paper also proposed a new approach to the model of the exciting branch. The exciting branch can be divided into a non-linear core loss resistor, and a non-linear magnetizing inductor whose flux and current characteristic is not the same as the characteristic shown by the joined tips of the first quadrant of a family of hysteresis loops. The performance of the proposed algorithm was validated under various conditions using EMTP generated data. Test result show, in all cases an improvement in primary current reproduction accuracy, compared with that achieved using CT's ratio.

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