• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.6
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• pp.592-597
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• 2019

A conventional method to improve transient stability in power system is the use of reactive power compensation devices such as STATCOM and SVC. However, this traditional method cannot prevent a rapid voltage collapse brought on by motors stalling due to system fault. On the other hand, ESS(Energy Storage System) provides fast-acting, flexible reactive and active power control. The fast active power compensation with energy storage system plays a significant role in transient stability enhancement after a major fault of power system. In this paper, transient stability enhancement method by using energy storage system is proposed for the power system including a dynamic load such as large motor. The effectiveness of energy storage system compared to conventional devices in enhancing transient stability of power system is presented. The results of simulations show that the simultaneous injection of active and reactive power can enhance more effectively transient stability.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.375-378
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• 2003

This paper presents a study on the power factor improvement of the Wind turbine Generation System(WTGS) at Haeng-won wind farm in Jeju Island. Vestas WTGS named V47 as a model system is selected in this paper, and has 660 kW Power ratings. In this system, power factor correction is controlled by the conventional method with power condenor bank. So, model system at Haeng-won wind farm has very low power factor in the area of low wind speed, which is from 4 m/s to 6 m/s. This is caused by the power factor correction using power condenser bank To improve the power factor in the area of low wind speed, we used the static var compensator(SVC) using current controlled PWM power converter by IGBT switching device. finally, to verify the profosed method, the results of computer simulation using Psim program are presented to support the discussion.

• International Journal of Control, Automation, and Systems
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• v.3 no.spc2
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• pp.322-333
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• 2005

This paper proposes a combination of the Thyristor Controlled Series Capacitor (TCSC) and Static Var Compensator (SVC) installation for enhancing the damping performance of a power system. The developed scheme employs a damping controller which coordinates measurement signals with control signals to control the TCSC and SVC. The coordinated control method is based on the application of projective controls. Controller performance over a range of operating conditions is investigated through simulation studies on a single-machine infinite-bus power system. The linear analysis and nonlinear simulation results show that the proposed controller can significantly improve the damping performance of the power system and hence, increase its power transfer capabilities. In this paper, a current injection model of TCSC is developed and incorporated in the transmission system model. By using equivalent injected currents at terminal buses to simulate a TCSC no modification of the bus admittance matrix is required at each iteration.

• Journal of information and communication convergence engineering
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• v.7 no.2
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• pp.209-214
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• 2009

The employment of the induction generator is preferable in the natural energy utilization by the minimum maintenance and the mechanical robustness, Another merit is also expected when it is connected to the power network system, because constant-voltage and constant frequency (CVCF) power generation is easily realized in spite of the variation of the rotor speed. However the induction generator needs much amount of the reactive power that reduces power factor in the primary side. The improvement of power factor in the primary side requires large VAR compensator, this point is solved, the merit of the induction machine as a main generator will become more established. This paper proposes a novel approach where the secondary is controlled by a PWM inverter not only to get CVCF power but also to improve the primary power factor. Basically the inverter is controlled so that the field current is supplied from the secondary side in this approach. The required capacity of the inverter is small, because only the slip power is controlled in the secondary side. In the experimental system where the sea wave torque simulator is used, the power factor is well improved by the microcomputer controlled PWM inverter.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.51 no.2
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• pp.60-67
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• 2002

This paper presents a control approach for designing a self tuning fuzzy controller for a synchronous generator excitation and SVC system. A combination of thyristor-controlled reactors and fixed capacitors (TCR-FC) type SVC is recognized as having the most flexible control and high speed response, which has been widely utilized in power systems, is considered and designed to improve the response of a synchronous generator, as well as controlling the system voltage. The proposed parameter self tuning algorithm of fuzzy controller is based on the steepest decent method using two direction vectors which make error between inference values of fuzzy controller and output values of the specially selected PSS reduce steepestly. Using input-output data pair obtained from PSS, the parameters in antecedent part and in consequent part of fuzzy inference rules are learned and tuned automatically using the proposed steepest decent method. The related simulation results show that the proposed fuzzy controller is more powerful than the conventional ones.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.226-228
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• 2002

This paper presents a new control approach for designing a coordinated controller for static VAR compensator system. A SVC constructed by a Fixed Capacitor and a Thyristor Controlled Reactor is designed and implemented to improve the damping of a synchronous generator, as well as controlling the system voltage. A design of linear quadratic controller based on optimal controller depends on choosing weighting matrices. A coordinated optimal controller is achieved by minimizing a quadratic performance index using dynamic programming techniques. The selection of weighting matrices is usually carried out by trial and error which is not a trivial problem. We proposed a efficient method using GA of finding weighting matrices for optimal control law. Thus, we prove the usefulness of proposed method to improve the stability of single machine-infinite bus with SVC system.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.83-84
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• 2008

Voltage fluctuation, also known as flicker, is a power quality problem caused by nonlinear loads like electric arc furnace. Since it is interpreted as a variation of the supplied electrical energy, it causes the residential customers to feel much annoyed visually through the lamps. Due to the statistical nature of IEC (International Electrotechnical Commission) short-term flicker severity index, Pst, it is not feasible to pre-evaluate the flicker level using the transient power system simulators such as Sim Power System in Matlab/Simulink. So this paper presents not only how to design the Matlab/Simulink IEC flickermeter to yield the Pst value, which considering electric distribution environments of South Korea, but also how to mitigate the voltage flicker at the Point of Common Coupling (PCC). In order to achieve this, the flicker mitigation efficiencies of various compensating devices, such as Static Var Compensator (SVC), STATCOM will be applied and compared. The simulated result demonstrates which compensating equipment is the most efficient method to mitigate the flicker phenomenon.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.408-409
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• 2015

한국전력공사에서는 2015년 4월말 기준 808개의 변전소를 운전 중에 있다. 변압기 용량으로 보면 299,734MVA에 달하고 있으며, 매년 증가하는 전력수요에 맞추어 신규 변전소 건설과 더불어 변전설비가 계속하여 확충되고 있다. 또한, 계절별 및 시간대별 부하변동에 따른 변전소 모선의 전압변동에 대응하기 위하여 Sh.C(Shunt Condenser), Sh.R(Shunt Reactor), SVC(Static Var Compensator) 등 다양한 무효전력보상 및 조절 설비들이 지속적으로 설치되고 있다. 이들 무효전력보상 설비들은 주로 변전소 모선에 전용 차단기를 통하여 연결되어 운전되고 있으며, 전용 차단기는 매일 시간대별 부하변동에 대응하여 개폐빈도가 많은 다빈도 차단기로서 잦은 개폐조작에 따른 내구성이 필요하며 변전소 모선전압을 기준전압 범위 이내로 안정적으로 유지하기 위한 신뢰성이 요구되고 있다. 본 논문에서는 345kV Sh.R 개폐용 동일유형의 345kV 50kA 1점절 다빈도 차단기에서 차단조작시 발생한 차단부 절연파괴 고장의 원인을 분석하고 재발방지를 위한 대책에 대하여 논하였다.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.10 no.5
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• pp.101-107
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• 1996

This paper proposed the voltage compensation analysis method in distribution system by EMTP. SVC (Static Var Compensator) of the thyristor controlled reactor type is used for compensation system. EMTP(E1ectr-o Magnetic Transient Program) model of SVC is proposed to analysis the voltage improvement characteristics at the high voltage system bus. It is composed with three parts ; rms detector, voltage regulator and gate pulse generator. The control signal of TCR is determined by rms value which was measured in system. As the result of EMTP simulation, all of the SVC characteristics like TCR current, firing pulse and bus voltage is very reliable. This method could be used to analysis the planning and the operation of compensation system in the large scale factory.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.5
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• pp.760-768
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• 2016

Recently, as one of the policies for carbon free operation method of independent power system replacing diesel generator with renewable energy such as wind power and photovoltaic(PV) system has been presented. Therefore, this paper proposes an operation algorithm and modeling of independent power system by considering CVCF(constant voltage constant frequency) ESS(energy storage system) for constant frequency and voltage, LC(load control) ESS for demand and supply balancing and SVC(static var compensator) for reactive power compensation. From the simulation results based on the various operation scenario, it is confirmed that proposed operation algorithm and modeling may contribute stable operation and carbon free in independent power system.