• Journal of Electrical Engineering and Technology
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• v.6 no.3
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• pp.293-301
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• 2011

This paper presents a novel theoretical method based on power analysis to obtain voltage reference values for an inverter-based compensator. This type of compensator, which is installed in parallel with the load, is usually referred to as the active filter. The proposed method is tailored to design the compensator in such a way that it can simultaneously balance the asymmetric load, as well as correct the power factor of the supply side. For clarity, a static compensator is first considered and a recursive algorithm is utilized to calculate the reactance values. The algorithm is then extended to calculate voltage reference values when the compensator is inverter based. It is evident that the compensator would be asymmetric since the load is unbalanced. The salient feature associated with the proposed method is that the circuit representation of system load is not required and that the load is recognized just by its active and reactive consumptions. Hence, the type and connection of load do not matter. The validity and performance of the new approach are analyzed via a numerical example, and the obtained results are thoroughly discussed.

• Proceedings of the KIEE Conference
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• 2001.11b
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• pp.83-87
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• 2001

This work deals with the compensation of the impact of highly varying loads on the power system using a static var compensator(SVC). Highly varying loads is properly modelled via deterministic approach using PSCAD/EMTDC. Also, the procedure to determine a suitable capacity of the compensator is proposed. Finally, the new online index to quantify the harmonic distortion is introduced.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.380-382
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• 2001

This paper deals with the compensation of the impact of highly varying loads on the power system using a static var compensator (SVC). A procedure to determine a suitable capacity of the compensator is proposed, and it is implemented using PSCAD/EMTDC. The proposed method is applied to a test system to illustrate its capabilities.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.128-129
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• 2013

본 논문에서는 전기로 부하에서 발생하는 무효전력 성분과 역상분 전류를 보상하기 위한 STATCOM(STATic synchronous COMpensator)을 Cascaded Multilevel Converter(CMC)로 구성하는 경우 역상분 전류 보상시에 발생하는 직류전압의 불평형을 보상하기 위한 방법을 제안하고, 이를 시뮬레이터를 통해 검증하였다.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.767-769
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• 1993

A multilevel PWM voltage source inverter, especially five-level one, is introduced to obtain a static var compensator(SVC) as a large scale power, source. In this paper, the three phase SVC is modeled using circuit DQ transformation and completely analyzed. Finally, through the experimental results from 5-kVA SVC, the validity of the analyses and the feasibility of the SVC system are shown for high power applications.

• KIEE International Transactions on Power Engineering
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• v.3A no.3
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• pp.161-167
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• 2003

This paper presents a study performed to investigate the steady-state operational strategies of UPFCs in the Jeollanam-Do system in Korea. The objective of the study was to determine the UPFC operating points under normal and contingency conditions. The study consists of developing load flow models to simulate different load levels with and without UPFCs in the system, assessing the effectiveness of UPFCs by contingency analysis, and introducing optimal corrective actions for removing voltage problems caused by contingencies. The paper describes analytical tools, models and approach. It also includes analysis and discussion of the study results. The paper contributes to the area of transmission operational studies with FACTS applications.

• International Journal of Control, Automation, and Systems
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• v.5 no.4
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• pp.364-371
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• 2007

In this paper, we describe the synthesis of robust and non-fragile $H^{\infty}$ state feedback controllers for linear systems with affine parameter uncertainties, as well as a static state feedback controller with poly topic uncertainty. The sufficient condition of controller existence, the design method of robust and non-fragile $H^{\infty}$ static state feedback controller with fuzzy compensator, and the region of controllers that satisfies non-fragility are presented. We show that the resulting controller guarantees the asymptotic stability and disturbance attenuation of the closed loop system in spite of controller gain variations within a resulted polytopic region.

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.2010-2012
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• 1997

A cascade multilevel voltage source inverter is introduced to apply the advanced static var compensator(ASVC) for large scale power application. This cascade M-level inverter consists of (M-1)/2 single-phase full bridges. This inverter is suitable to the flexible ac transmission systems(FACTS) including SVC, series compensation and phase shifting. It can solve the problems of conventional transformer -based multipulse inverters and multilevel diode-clamped inverters. From the simulation results, the validity of ASVC with cascade multilevel inverter is shown for high power application.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.561-565
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• 2001

This paper proposes a new switching scheme of a static var compensator(SVC) with cascade multilevel inverter which employs H-bridge inverter(HBI). To improve the un­balanced problem of the DC capacitor voltages, the rotated switching scheme of fundamental frequency is newly used. The optimized fundamental switching pattern with low switching frequency is adapted to be suitable for high application. The selective harmonic elimination method(SHEM) allows to keep the total harmonic distortion(THD) low in the output voltage of multilevel inverter. The SVC system is modeled using the d-q transform which calculates the instantaneous reactive power. This model is used to design a controller and analyze the SVC system. Simulated and experimental results are also presented and discussed to validate the proposed schemes.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.718-722
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• 2001

This paper proposes an SSSC based on multi-bridge inverters in PWM scheme. The proposed system consists of 6 H-bridge inverter modules per phase. The dynamic characteristic of proposed system was analyzed by simulation with EMTP codes, assuming that the SSSC is inserted in the 154-kV transmission line of one-machine-infinite-bus power system. The feasibility of hardware implementation was verified through experimental works with a scaled-model. The proposed system can be directly inserted in the transmission line without coupling transformers, and has flexibility in expanding the operation voltage by increasing the number of H-bridges.