• Title/Summary/Keyword: Reactive System

Search Result 2,087, Processing Time 0.028 seconds

Islanding detection algorithm for microgrid considering reactive power (무효전력을 고려한 마이크로그리드의 단독운전 판단 알고리즘)

  • Kang, Yong-Cheol;Jang, Sung-Il;Cha, Sun-Hee;Lee, Byung-Eun;Kim, Yeon-Hee;Lee, Ji-Hoon;Kim, Yong-Guen
    • Proceedings of the KIEE Conference
    • /
    • 2006.07a
    • /
    • pp.236-237
    • /
    • 2006
  • A microgrid is a new type of power system which is formed by the interconnection of small generator to distribution systems. Microgrids are able to supply electric power to their loads independently, which is called with islanding operation, even if they're separated from the power system. As a result, microgrids must be equipped with specific islanding detection schemes for the islanding operation of microgrids. This paper studies an islanding detection method considering reactive power. The proposed method is dealing with the reactive power of the cable which connects between a microgrid and a power system. To show the validity of the proposed method, many islanding operation cases are tested by varying the load conditions of microgrids.

  • PDF

A Study on the Application of STATCOM, SVC to Enhance the Voltage Stability (우리나라 계통의 전압불안정 문제를 개선하기 위한 STATCOM과 SVC의 적용 검토)

  • Lee Sang Ho;Lee Jeong Ho;Oh Tae Kyoo;Kim Tai Ok;Moon Bong Soo
    • Proceedings of the KIEE Conference
    • /
    • summer
    • /
    • pp.129-131
    • /
    • 2004
  • Recent catastrophic failures of power system in various countries highlight the importance of the voltage stability and reactive power operation. Under the emergency situations, dynamic reactive power sources such as STATCOM and SVC play important roles in supporting the system voltage. This paper investigate the stability problem in KEPCO system and suggest the installation of the dynamic reactive Power sources as a countermeasure.

  • PDF

Linear Programming based Optimal Reactive Power Dispatch using Modified Sensitivity Method (수정된 민감도 기법을 이용한 선형계획법 기반의 무효전력 최적배분)

  • Kim, Tae-Kwon;Kim, Byung-Seop;Kim, Min-Soo;Shin, Joong-Rin
    • Proceedings of the KIEE Conference
    • /
    • 2001.07a
    • /
    • pp.190-193
    • /
    • 2001
  • This paper presents a linear programming based Optimal Reactive Power Dispatch (ORPD) problem using modified sensitivity method. The proposed model minimizes the real power losses and improves the voltage profiles in the system with consideration of voltage and reactive power constraints. The method employs modified sensitivity relationships of power systems to establish both the objective function for minimizing the system losses and the system performance sensitivities relating dependent and control variables. The proposed algorithm has been evaluated with the IEEE 6-bus and IEEE 30-bus systems.

  • PDF

Reactive Reserve Based Contingency Constrained Optimal Power Flow for Enhancement of Voltage Stability Margins (전압안정도 여유 향상을 위한 무효예비력 기반 상정사고 제약 최적조류계산)

  • Song, Hwa-Chang;Lee, Byong-Jun;Kwon, Sae-Hyuk;Ajjarapu, Venkataramana
    • Proceedings of the KIEE Conference
    • /
    • 2003.07a
    • /
    • pp.19-23
    • /
    • 2003
  • This paper presents a new concept of reactive reserve based contingency constrained optimal power flow (RCCOPF) for voltage stability enhancement. This concept is based on the fact that increase in reactive reserves is effective for enhancement of voltage stability margins of post-contingent states, in this paper, the proposed algorithm is applied to voltage stability margin of interface flow. Interface flow limit, in the open access environment, can be a main drawback. RCCOPF for enhancement of interface flow margin is composed of two modules, modified continuation power flow (MCPF) and optimal power flow (OPF). These modules art recursively perform ed until satisfying the required margin of interface flow in the given voltage stability criteria.

  • PDF

Development of the Optimum Computational Algorithm for the Real Time Control of Voltage and Reactive Power (전사무효전력간시제어의 최적계산 앨고리즘 개발)

  • Kil-Yeong Song
    • The Transactions of the Korean Institute of Electrical Engineers
    • /
    • v.31 no.10
    • /
    • pp.93-100
    • /
    • 1982
  • This paper presents the optimum computational algorithm for the real time control of system voltage and reactive power on the basis of a improved search method. In particular, special emphasis has been placed on the speed up computation at the first phase, and on the selection of initial state to reduce the transmission losses in the second phase. For the real time control, the new computation is improved and the computation time is very much reduced. And also, this paper discusses the integrated control scheme of system voltage and reactive power from the viewpoint of hierarchical control pattern, and studes the combination of the optimum system operations and controls.

Active and Reactive Power Compensator for Wind Power System with Squirrel-Cage Induction Generator (농형유도 풍력발전시스템을 위한 유.무효전력보상장치)

  • Yang, Seung-Chul;Ju, Young-Ah;Han, Byung-Moon
    • Proceedings of the KIPE Conference
    • /
    • 2008.10a
    • /
    • pp.48-50
    • /
    • 2008
  • A wind power system with squirrel-cage induction generator has irregular change of output power according to the sudden change of wind speed. This paper describes the development of a active and reactive power compensator, which is composed of a 3-phase inverter and a bidirectional DC/DC converter with super-capacitor. The operational characteristic was analyzed through simulations with PSCAD/EMTDC and experimental works with a scaled model. The developed system can continuously compensate the active power change with energy storage and the reactive power change with 3-phase inverter.

  • PDF

Evaluation of Generator's Reactive Power in Deregulated Electricity Market (전력시장 체제에서 발전기 무효전력 출력의 가치 평가에 관한 연구)

  • Na, Chun-Su;Park, Jong-Keun;Han, Tae-Kyung;Kim, Mun-Kyeom;Kim, Do-Han;Lee, Sang-Ho;Lee, Sang-Sung
    • Proceedings of the KIEE Conference
    • /
    • 2005.07a
    • /
    • pp.869-871
    • /
    • 2005
  • As deregulated electricity markets are being implemented in different countries, the remuneration of reactive power which contribute to ancillary services is one of the key issues, so it is necessary to evaluate the generator's reactive. In this paper, we focus on the evaluation of reactive power which contributes to reactive power balance. The idea is that the main usages of the reactive power of generator can be divided into two components. First one is physically required amounts for transmitting the real power and the second one is the amounts contributed to support the system, that is, to maintain the voltage profiles. In this paper, the second component is used to evaluate the effective amounts of the reactive power contributed to ancillary service.

  • PDF

The Characteristics of the STATCOM System operated by SVPWM (SVPWM 방식의 STATCOM 시스템 동작 특성)

  • Lee, Hwa-Su;Kim, Yong-Heon;Lee, Eun-Woong;Lee, Dong-Ju
    • Proceedings of the KIEE Conference
    • /
    • 2003.10b
    • /
    • pp.69-71
    • /
    • 2003
  • STATCOM which is connected the load parallel with capacitor, is the reactive power compensation device. In this paper, we study the principle of reactive power compensation with STATCOM system. And then we confirmed the function of STATCOM system to be fabricated by our lab, being measured and analyzed the output voltage and current

  • PDF

Superconducting Magnetic Energy Storage (SMES) Control Models for the Improvement of Power System Stability (계통안정도 개선을 위한 SMES 제어모델에 관한 연구)

  • Ham, Wan-Kyun;Kim, Jung-Hoon
    • Proceedings of the KIEE Conference
    • /
    • 2005.07a
    • /
    • pp.501-503
    • /
    • 2005
  • Superconducting Magnetic Energy Storage (SMES) can inject or absorb real and reactive power to or from a power system at a very fast rate on a repetitive basis. These characteristics make the application of SMES ideal for transmission grid control and stability enhancement. The purpose of this paper is to introduce the SMES model and scheme to control the active and reactive power through the power electronic device.

  • PDF

무효전력 최적제어에 의한 전력손실의 최소화

  • Lee, Hyeong-Gwan
    • ETRI Journal
    • /
    • v.6 no.4
    • /
    • pp.31-36
    • /
    • 1984
  • This paper presents an efficient method for real power loss minimization and for improvements in voltage profiles. This method is accomplished by optimal control of reactive power in the system. The problem is formulated as an optimization problem, suitable for solution by linear programming technique. After establishing the objective function for minimizing the system losses with the help of linearised sensitivity relationships of control variables, i. e., the transformer tap position, generator terminal voltages and switchable reactive power sources. The linear programming technique is used to determine the optimal adjustments to the above variables, simultaneously satisfying the constraints. The proposed algorithm has been tested on a sample system and the result is presented and discussed.

  • PDF