• Title, Summary, Keyword: Synchronous Generator

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A comparison of the operating characteristics of the synchronous generator and induction generator applied to the small hydroelectric power plant (소수력에 적용한 동기발전기와 유도발전기의 운전 특성 비교)

  • Kim, Jong-Gyeum;Kim, Young-Kuk
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.63 no.2
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    • pp.55-60
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    • 2014
  • In general, A synchronous generator is higher than the voltage stability of the induction generator. However, induction generator has many advantages rather than a synchronous generator in terms of price and maintenance. So, coverage rate of the induction generator is gradually increasing in small hydroelectric power station rather than 1000kW recently. In order to increase the penetration of induction generator, pre-analysis of the operation of the generator is needed. In this study, we analyzed for the problems that occur when synchronous generator and induction generator of 1500kW is connected to the distribution system.

Performance Improvement of Synchronous Generator using Exciter Control with Field Coils Parameter Estimation Technique (계자코일 파라메터추정 기법을 이용한 동기발전기의 성능개선)

  • Kang, Seong-Hyun;Park, Seong-Mi;Lee, Hwa-Chun;Park, Sung-Jun
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.27 no.4
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    • pp.31-40
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    • 2013
  • This paper proposes a performance improvement of synchronous generator using exciter control with field coils parameter estimation technique. In general, the generator excitation system controller uses the PID controller. When the Field winding impedance changed, the PID gains must be changed. General method is difficult to apply varying capacity of the synchronous generator. The proposed control method determine automatically measure the internal impedance of the synchronous generator's exciter and configure the controller. This method can be applied regardless of the generator capacity. So it is possible to apply a variety of synchronous generator systems. The validity of the proposed algorithm is verified by simulations and experiments.

3D electromagnetic design and electrical characteristics analysis of a 10-MW-class high-temperature superconducting synchronous generator for wind power

  • Kim, J.H.;Park, S.I.;Le, T.D.;Kim, H.M.
    • Progress in Superconductivity and Cryogenics
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    • v.16 no.2
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    • pp.47-53
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    • 2014
  • In this paper, the general electromagnetic design process of a 10-MW-class high-temperature superconducting (HTS) synchronous generator that is intended to be utilized for large scale offshore wind generator is discussed. This paper presents three-dimensional (3D) electromagnetic design proposal and electrical characteristic analysis results of a 10-MW-class HTS synchronous generator for wind power. For more detailed design by reducing the errors of a two-dimensional (2D) design owing to leakage flux in air-gap, we redesign and analyze the 2D conceptual electromagnetic design model of the HTS synchronous generator using 3D finite element analysis (FEA) software. Then electrical characteristics which include the no-load and full-load voltage of generator, harmonic contents of these two load conditions, voltage regulation and losses of generator are analyzed by commercial 3D FEA software.

Application Analysis for Loss of Excitation Relay of Generator Protection (발전기 보호용 계자상실 계전기의 적용 분석)

  • Oh, Yong-Taek;Park, Chul-Won
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.63 no.4
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    • pp.322-326
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    • 2014
  • Recently, the LOE(loss of excitation) incidents are occurred in domestic synchronous generator frequently, the synchronous generator protection system has been much attention for the LOE protection of the incidents that threats synchronous generators and power systems. This paper was showed the characteristics and practices of distance relay that widely used LOE protection relaying in generator. Firstly, the operating characteristics and the impedance locus for LOE of the generator protection were introduced. Even if the conventional simulation program is used for modeling, but it is difficult to implement a LOE modeling and simulation of synchronous generator. So, the LOE relay operation data collected from thermal power plant and nuclear power plant in real fields were analyzed. By reviewing the applications of GE Mho relays, the reliability of LOE for synchronous generator protection in domestic were improved.

A Study on Excitation System for Synchronous Generator using Current Mode Controlled PWM Converter (전류제어형 PWM컨버터를 이용한 동기발전기용 여자시스템에 관한연구)

  • 장수진;류동균;서민성;김준호;원충연;배기훈
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • pp.151-156
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    • 2002
  • The output voltage of Synchronous Generator is regulated constantly by field current control in excitation system. A synchronous generator is equipped with an automatic voltage regulator(AVR), which is responsible for keeping the constant output voltage under normal operating conditions about various levels. High frequency PWM converter (Current Mode Control Buck converter) type excitation system for synchronous generator is able to sustain output voltage level properly when the fault condition happened. This paper deals with the design and evaluation of the excitation system controller for a synchronous generator to improve the steady state and transient stability. The simulation and experimental results show that the proposed excitation system is improve the respons time by the AVR(automatic voltage regulator) of 50kW synchronous generator that is applied the current mode control excitation system.

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Research on the Power Sharing Control and Stability of VSGs

  • Xie, Dong;Zang, Da-Jin;Gao, Peng;Wang, Jun-Jia
    • Journal of Power Electronics
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    • v.17 no.2
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    • pp.542-550
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    • 2017
  • Aiming at the deficiencies of power sharing control performances when a traditional droop control is adopted for microgrid inverters, this paper proposes a microgrid inverter power sharing control strategy based on a virtual synchronous generator. This control method simulates the electromechanical transient characteristics of a synchronous generator in a power system by an ontology algorithm and the control laws of a synchronous generator by control over the speed governor and excitation regulator. As a result, that the microgrid system is able to effectively retain the stability of the voltage and frequency, and the power sharing precision of the microgrid inverter is improved. Based on an analysis of stability of a microgrid system controlled by a virtual synchronous generator, design thoughts are provided for further improvement of the power sharing precision of inverters. The simulation results shows that when the virtual synchronous generator based control strategy was adopted, the power sharing performances of microgrid inverters are improved more obviously than those using the droop control strategy.

A Study on the Detection of Asynchronous State of the Synchronous Generator

  • Choi, Hyung-Joo;Lee, Heung-Ho
    • Journal of international Conference on Electrical Machines and Systems
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    • v.2 no.4
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    • pp.405-412
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    • 2013
  • This paper includes new protection concepts and practices to avoid mechanical damage of three-phase transformer by asynchronous operation of synchronous generator. this failure is often caused just after synchronous generator was connected to the grid because of a malfunction of the controller or misconnections of the synchronous devices. The results of the studies on the analyzing the phenomenon of asynchronous operation experienced in Korea and rapidly detecting asynchronous state are descrived.

Development of Inter-Turn Short Circuits Sensor for Rotor Winding of Synchronous Generator (발전기 회전자의 층간단락 감지기 개발)

  • Nam, Jong-Ha;Lee, Seung-Hak;Choe, Gyu-Ha
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.51 no.6
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    • pp.307-312
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    • 2002
  • Inter-turn short circuits can have significant effects on a generator and its performance. The Inter-turn short circuits sensor for synchronous generator's field winding has been developed. The sensor, installed in the generator air-gap, senses the slot leakage flux of field winding and produces a voltage waveform proportional to the rate of change of the flux. For identification of reliability for sensor, a shorted- turn test was performed at the Seoinchon combined cycle power plant on gas turbine generator and stim turbine generator. This sensor will be used as a detecting of Inter-turn short circuits for synchronous generator's field winding.

Parallel Operation Characteristics of Utility Interactive Photovoltaic System and Revolving Field Type Synchronous Generator (계통연계 태양광발전시스템과 회전계자형 동기발전기의 병렬운전 특성)

  • Ryu, Yeon-Soo;Yoo, Wang-Jin;Lee, Checl-Gyu;Moon, Jong-Beom
    • 한국태양에너지학회:학술대회논문집
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    • pp.43-48
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    • 2008
  • Through simulations and field experiment on A.C. parallel operation of both Utility Interactive Photovoltaic System and Diesel Engine Revolving Field Type Synchronous Generator, following factors have been found. First, the inverter should be operated in three modes of frequency(mode.1: ${\pm}$0.3Hz, mode.2: ${\pm}$1Hz, mode.3: ${\pm}$2Hz) as default, considering properties of operating Synchronous Generator. Second, as a result of supplying 13.5kW of residual power, it has been found that Synchronous Generator takes the power input only as reactive power, because it was electrically stable with frequency of 60.14Hz and high voltage of 222.3V even when power factor was -0.94. Besides, it was mechanically stable, too, because the quake, noise, and temperature of Synchronous Generator in this case were 7.5mm/s, 97dB, and $6^{\circ}C$ respectively, which were lower than normal load connection of 145.6kW; 11.03mm/s. Thus, load share of Revolving Field Type Synchronous Generator reduces according to the supply of Photovoltaic System to the load power. In this experiment, 200kW of Synchronous Generator and 40kW of Photovoltaic System were operated in parallel. The load share was 20% in maximum. and 11.1lit/hr of fuel was saved.

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Analysis for Voltage Fluctuation and Power Flow at the Grid-Connected Time of Squirrel-Cage Induction Generator (농형 유도발전기의 계통 연계시 전압 변동 및 전력 흐름 분석)

  • Kim, Jong-Gyeum
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.28 no.6
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    • pp.45-51
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    • 2014
  • Synchronous generators and induction generators are mainly used in hydroelectric power generation. Synchronous generator is mainly applied to large hydroelectric plants but induction generator is applied to the small hydro power plants. Stability of induction generator is slightly less than the synchronous generator. However, induction generator has many advantages rather than a synchronous generator in terms of price and maintenance. So Induction generator is used primarily in small hydroelectric power station less than 1,000kW recently. Squirrel cage induction generator generates a high inrush current at the grid-connection. This high inrush current causes a voltage drop on the grid. In order to reduce the voltage drop and to analyze the power flow, the analysis for operating characteristics of the induction generator should be reviewed in advance. In this study, we analyzed the voltage drop and power flow analysis when a 1500kW induction generator is connected to the grid. The voltage drop is slightly higher than the acceptable range of distributed power supply voltage and the power flow of the generator is performed well.