• Proceedings of the KIPE Conference
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• 2014.11a
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• pp.163-164
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• 2014

전력계통은 전력수요의 지속적인 성장에 따라서 전력설비의 추가를 지속적으로 추진하고 있지만, 심해지는 환경문제 등으로 인해 용지 확보에 어려움이 있다. 이로 인해 송전선로 장거리화, 용량부족량 등 전력계통에 여러 가지 복잡한 문제가 야기되는데. 이것은 곧 전력계통의 안정도와 직결된다. 이러한 문제를 효과적이면서 경제적인 해결방법으로 FACT(Flexible AC Transmission System)기술이 주목 받고 있다. FACTS 기기 중 SVC(Static Var Compensator)는 상용운전 중이며, 기존 동기조상기에 비해 저렴하고, 신속 정확한 전압제어를 하는 장점이 있다. SVC는 TCR(Thyristor Controlled Reactor)과 TSC(Thyristor Switched Capacitor), FC(Fixed Capacitor)등 여러 종류의 구성을 가지고 있다. 합성시험회로설비(Synthetic Test Circuit)는 Thyristor로 구성된 TCR, TSC Valve를 실제 운전조건으로 동작시켜 SVC Valve의 신뢰성을 검증하는 설비이다. 특히, TSC Valve는 운전시 초기 과전류가 발생하는 운전특성상 이에 대한 평가기준에 따른 시험을 통해 신뢰성을 반드시 검증하여야 한다. 본 논문에서는 IEC 61954에서 제시하는 시험평가 기준에 의거하여 TSC의 Overcurrent Test를 위한 STC 평가 방법를 기술하고 설계된 TSC 시험을 위한 STC topology와 Simulation으로 검증 방법을 기술한다.

• KIEE International Transactions on Power Engineering
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• v.3A no.1
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• pp.17-26
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• 2003

In this paper, the comparative steady-state operating performance analysis algorithms of the stand-alone single-phase self-excited induction generator (SEIG) is presented on the basis of the two nodal admittance approaches using the per-unit frequency in addition to a new state variable de-fined by the per-unit slip frequency. The main significant features of the proposed operating circuit analysis with the per-unit slip frequency as a state variable are that the fast effective solution could be achieved with the simple mathematical computation effort. The operating performance results in the simulation of the single-phase SEIG evaluated by using the per-unit slip frequency state variable are compared with those obtained by using the per-unit frequency state variable. The comparative operating performance results provide the close agreements between two steady-state analysis performance algorithms based on the electro-mechanical equivalent circuit of the single-phase SEIG. In addition to these, the single-phase static VAR compensator; SVC composed of the thyristor controlled reactor; TCR in parallel with the fixed excitation capacitor; FC and the thyristor switched capacitor; TSC is ap-plied to regulate the generated terminal voltage of the single-phase SEIG loaded by a variable inductive passive load. The fixed gain PI controller is employed to adjust the equivalent variable excitation capacitor capacitance of the single-phase SVC.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.3B no.1
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• pp.10-15
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• 2003

This paper presents the digital computer performance evaluations of the three-phase self-excited induction generator (SEIG) driven by the variable speed prime mover such as the wind turbine using the nodal admittance approach steady-state frequency domain analysis with the experimental results. The three-phase SEIG setup is implemented for small-scale rural renewable energy utilizations. The experimental performance results give a good agreement with those ones obtained from the digital computer simulation. Furthermore, a feedback closed-loop voltage regulation of the three-phase SEIG as a power conditioner which is driven by a variable speed prime mover employing the static VAR compensator (SVC) circuit composed of the thyristor phase controlled reactor (TCR) and the thyristor switched capacitor(TSC) is designed and considered herein for the wind-turbine driven the power conditioner. To validate the effectiveness of the SVC-based voltage regulator of the terminal voltage of the three-phase SEIG, an inductive load parameter disturbances in stand-alone are applied and characterized in this paper. In the stand-alone power utilization system, the terminal voltage response and thyristor triggering angle response of the TCR are plotted graphically. The simulation and the experimental results prove the effectiveness and validity of the proposed SVC which is controlled by the Pl controller in terms of fast response and high performances of the three-phase SEIG driven directly by the rural renewable energy utilization like a variable-speed prime mover.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.51-52
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• 2014

전력계통은 전력수요의 지속적인 성장에 따라서 전력설비의 추가를 지속적으로 추진하고 있지만, 심해지는 환경문제 등으로 인해 용지 확보에 어려움이 있다. 이로 인해 송전선로 장거리화, 용량부족량 등 전력계통에 여러 가지 복잡한 문제가 야기되는데, 이것은 곧 전력계통의 안정도와 직결된다. 이러한 문제를 효과적이면서 경제적인 해결방법으로 FACT(Flexible AC Transmission System)기술이 주목 받고 있다. FACTS 기기 중 SVC(Static Var Compensator)는 상용운전 중이며, 기존 동기조상기에 비해 저렴하고, 신속 정확한 전압제어를 하는 장점이 있다. SVC는 TCR(Thyristor Controlled Reactor)과 TSC(Thyristor Switched Capacitor), FC(Fixed Capacitor)등 여러 종류의 구성을 가질 수 있다. TCR과 TSC는 실제 운전에 앞서 여러 가지 방법으로 검증이 필요하다. 합성 시험회로 설비(Synthetic Test Circuit)는 TCR과 TSC 안에 존재하는 Thyristor Valve의 동작을 실제 동작 조건으로 동작시켜, 동작의 신뢰성을 검증하는 설비이다. 본 논문에서는 TCR의 Operational Test를 위한 STC를 기술하고 있다. 설계된 STC는 PSCAD를 사용하여 검증하였다.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.3B no.1
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• pp.1-9
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• 2003

This paper deals with the nodal admittance approach steady-state frequency domain analysis of the three-phase self-excited induction generator (SEIG) driven by the variable speed prime mover as the wind turbine. The steady-state performance analysis of this power conditioner designed for the renewable energy is based on the principle of equating the input mechanical power of the three-phase SEIG to the output mechanical power of the variable speed prime mover mentioned above. Us-ing the approximate frequency domain based equivalent circuit of the three-phase SEIG. The main features of the present algorithm of the steady-state performance analysis of the three-phase SEIG treated here are that the variable speed prime mover characteristics are included in the approximate equivalent circuit of the three-phase SEIG under the condition of the speed changes of the prime mover without complex computations processes. Furthermore, a feedback closed-loop voltage regulation of the three-phase SEIG as a power conditioner which is driven by variable speed prime movers such as the wind turbine(WT) employing the static VAR compensator(SVC) circuit composed of the thyristor phase controlled reactor(TCR) and the thyristor switched capacitor(TSC) controlled by the PI controller is designed and considered for wind-turbine driving power conditioner.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.355-356
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• 2015

LS산전은 전기적 트리거 방식의 사이리스터(electrical-triggered thyristor)를 이용한 Static Var Compensator(이하 SVC) 개발에 성공했다. 개발된 SVC는 ${\pm}100MVar$ 급으로 과전압에 대한 자체 보호 기능을 내장하고 있으며 LS산전표준과 IEC 규격에 따라 성능이 검증되었다. 본 논문에서는 SVC 시스템의 핵심 구성품인 Thyristor Controlled Reactor (이하 TCR) / Thyristor Switched Capacitor (이하 TSC) Valve 개발 시험의 일부로 진행한 절연 시험에 대해 상세히 소개하고자 한다.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.45 no.1
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• pp.67-73
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• 1996

Subsynchronous resonance(SSR) causes a torsional shaft torque on the generator. Damages resulting from the uncontrolled SSR have resulted in the breakdown in the shaft and costs for replacement power. This paper is to determine the feasibility of controlling SSR by the fast modulation of series compensation capacitors. The presence of subsynchronous currents in the system was detected by a subsynchronous relay which was modeled by the transient analysis of control systems(TACS) in electromagnetic transients program (EMTP). The capacitor segments were switched by bi-directional thyristor switches. These were modeled into EMTP. The strategy to switch the capacitors were modeled as a closed loop system. The paper proves that effective control of SSR can be obtained only by the detuning of the system and the removal or blocking of subsynchronous energy from the system. (author). refs., figs., tabs.

• Journal of Power Electronics
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• v.3 no.3
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• pp.185-196
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• 2003

In this paper, the single-phase static VAR compensator (SVC) is applied to regulate and stabilize the generated terminal voltage of the single-phase self-excited induction generator (single-phase SEIG) driven by a variable-speed prime mover (VSPM) under the conditions of the independent inductive load variations and the prime mover speed changes The conventional fixed gain PI controller-based feedback control scheme is employed to adjust the equivalent capacitance of the single-phase SVC composed of the fixed excitation capacitor FC in parallel with the thyristor switched capacitor TSC and the thyristor controlled reactor TCR The feedback closed-loop terminal voltage responses in the single-phase SEIG coupled by a VSPM with different inductive passive load disturbances using the single-phase SVC with the PI controller are considered and discussed herem. A VSPM coupled the single-phase SEIG prototype setup is established. Its experimental results are illustrated as compared with its simulation ones and give good agreements with the digital simulation results for the single-phase SEIG driven by a VSPM, which is based on the SVC voltage regulation feedback control scheme.

• 전기의세계
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• v.24 no.1
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• pp.55-62
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• 1975

A single-phase induction motor with it's stator winding splitted into two series windings, of which the terminals of one winding is switched pulsationally by a thyristor type ON-OFF device so that the motor may operate as a pulsational shaded-pole motor, can modulate current waveforms of it's two series windings. In view of current waveform modulation method, a single-phase single-winding motor operates as a two-phase induction motor with asymmetrical axis windings where the starting torque can be obtained effectively without an auxiliary capacitor attached and it's running speed controlled by shifting phase between current waveforms differently. Equivalent circuit for analysis is modified from a double revolving field equivalent circuit of a single-phase induction motor with asymmetrical windings whose angle is 45.deg.C elet. degrees. Analysis and test results show that ON-OFF action of the pulsational shaded-pole winding has the same effect of a series capacitor, and then at heavy loads this motor operates with a small amonut of the input current than that having the fixed shaded-pole winding.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.434-436
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• 1995

This paper was to determine the feasibility of controlling subsynchronous resonance(SSR) by the fast modulation of series compensation capacitors. The presence of subsynchronous currents in the system was detected by a subsynchronous relay which was modeled by the transient analysis of control systems (TACS) in the electromagnetic transients program (EMTP). The capacitor segments were switched by bi-directional thyristor swtiches. The paper proved that effective control of SSR can be obtained only by the detuning of the system and the removal or blocking of subsynchronous energy from the system.