• Proceedings of the KIEE Conference
• /
• 1999.07f
• /
• pp.2475-2477
• /
• 1999

This paper describes a simulation model and scaled hardware model to analyze the dynamic performance of Unified Power Flow Controller, which adjust flexibly the active and reactive power flow through the ac transmission line. The design of control system was developed using vector control method. The results of simulation and scaled hardware test show that the developed control system works accurately. And both models are very effective to analyze the dynamic performance of the Unified Power Flow Controller.

• The Journal of Industrial Distribution & Business
• /
• v.8 no.7
• /
• pp.39-49
• /
• 2017

Purpose - There are common factors both in Technology Readiness and Acceptance Model and Technology Paradox Theory which can be put together and made in one unified model. The unified model can provide the following merits. First, the unified model is simple but contains factors of the models. Second, the unified model can clarify the process of technology acceptance of common consumers. Third, the unified model can provide the opportunities to analyze the negative sides of new technology, thus find ways to improve the level of acceptance by general consumers. Research design, data, and methodology - The 450 questionnaires were handed out to people around Seoul and 421 were collected. Except insincere and wrong-marked ones, 402 were used to analyze. SPSS program was used to analyze. Factor analysis, regression analysis was conducted to test the hypotheses. Results - By analyzing sub-factors of both models and binding the common factors in one category, we accomplish one model. And we tested the model by empirical method. The results show that the results from the unified model are almost same as the results from the two models. In other words, the unified model works. Conclusions - Explaining one state of affair by two different method is in some sense distracting attention. By devising a new model including factors of both models, we can explain the affair more straightforward and efficiently. At first the technology acceptance model was devised to explain the technology users in an organization and the following tests and revised models were for the similar purposes. However, as on-lone activities including contracts have been expanded and become important, consumers as the technology uses have emerged as first factor to consider. In accordance models to explain this situation has been suggested. The model suggested in this research is one of the models but it has the following merits. That is, it is simple but has strong explanation power, it can clarify the process of technology acceptance of common consumers by containing negative sides of consumer conception, and thus, it can provide the opportunities to analyze the negative sides of new technology, also find ways to improve the level of acceptance by general consumers.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.50 no.8
• /
• pp.388-394
• /
• 2001

This paper presents how to determine the optimal operating points of Unified Power Flow controllers (UPFC) the line flow control of which can enhance system security level. In order to analyze the effect of these devices on the power system, the decoupled model has been employed as a mathematical model of UPFC for power flow analysis. The security index that indicates the level of congestion of transmission line has been proposed and minimized by iterative method. The sensitivity of objective function for control variables of and UPFC has been derived, and it represents the change in the security index for a given set of changes in real power outputs of UPFC. The proposed algorithm with sensitivity analysis gives the optimal set of operating points of multiple UPECs that reduces the index or increases the security margin and Marquart method has been adopted as an optimization method because of stable convergence. The algorithm is verified by the 10-unit 39-bus New England system that includes multiple FACTS devices. The simulation results show that the power flow congestion can be relieved in normal state and the security margin can be guaranteed even in a fault condition by the cooperative operation of multiple UPECs.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.54 no.9
• /
• pp.422-430
• /
• 2005

This paper describes experimental analysis of UPFC, which is composed of cascaded H-bridge modules and single-phase multi-winding transformers for isolation. The operational characteristic was analyzed through experimental works with a scaled model, and simulation results with PSCAD/EMTDC. The UPFC proposed in this paper can be directly connected to the transmission line without series injection transformers. It has flexibility to expand the operation voltage by increasing the number of H-bridge modules. The analysis results can be utilized to design the actual WFC system applicable for the transmission system.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.55 no.2
• /
• pp.94-102
• /
• 2006

This paper describes experimental analysis of UPQC, which is composed of cascaded H-bridges and single-phase multi-winding transformers. The operational characteristic was analyzed through experimental works with a scaled model, and simulations with PSCAD/EMTDC. The UPQC proposed in this paper can be directly connected to the distribution line without series injection transformers. It has flexibility to expand the operation voltage by increasing the number of H-bridge modules. The analysis results can be utilized to design the actual UPQC system applicable for the actual distribution system.

• Journal of Power Electronics
• /
• v.10 no.1
• /
• pp.91-96
• /
• 2010

In this paper, a simplified control algorithm for a three-phase, four-wire unified power quality conditioner (UPQC) is presented to compensate for supply voltage distortions/unbalance, supply current harmonics, the supply neutral current, the reactive power and the load unbalance as well as to maintain zero voltage regulation (ZVR) at the point of common coupling (PCC). The UPQC is realized by the integration of series and shunt active filters (AFs) sharing a common dc bus capacitor. The shunt AF is realized using a three-phase, four leg voltage source inverter (VSI) and the series AF is realized using a three-phase, three leg VSI. A dynamic model of the UPQC is developed in the MATLAB/SIMULINK environment and the simulation results demonstrating the power quality improvement in the system are presented for different supply and load conditions.

• Proceedings of the KIPE Conference
• /
• 2005.07a
• /
• pp.389-391
• /
• 2005

This paper describes experimental analysis of UPFC, which is composed of cascaded H-bridge modules and single-phase multi-winding transformers for isolation. The operational characteristic was analyzed through experimental works with a scaled model, and simulation results with PSCAD/EMTDC. The UPFC proposed In this paper can be directly connected to the transmission line without series injection transformers. It has flexibility to expand the operation voltage by increasing the number of H-bridge modules. The analysis results can be utilized to design the actual UPFC system applicable for the transmission system.

• Journal of Power Electronics
• /
• v.7 no.4
• /
• pp.286-293
• /
• 2007

This paper proposes a distribution voltage control method when a voltage increase condition occurs due to reverse power flow from the clustered photovoltaic (PV) system. This proposed distribution voltage control is performed a by distribution-unified power flow controller (D-UPFC). D-UPFC consists of a hi-directional ac-ac converter and transformer. It does not use any energy storage component or rectifier circuit, but it directly converts ac to ac. The distribution model and D-UPFC voltage control using the ATP-EMTP program were simulated and the results show the voltage increase control in the distribution system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.21 no.8
• /
• pp.34-43
• /
• 2007

This paper presents a methodology on the AHP(Analytic Hierarchy Process) to calculate unified power quality index which provide an overall assessment of the distribution system performance. To obtain the unified power quality index. we propose the use of the AHP model and consider contingency using Monte Carlo simulation. The proposed method is especially useful and effective for planning. We have applied the proposed method to an actual relatively large system.

• Proceedings of the KIEE Conference
• /
• 2005.07a
• /
• pp.332-334
• /
• 2005

This paper presents a dynamic simulation of the unified power flow controller (UPFC) using a current injection method. Flexible AC Transmission System (FACTS) devices give more flexibility of control for security and economic operation of power systems. Diffculties of modeling UPFC in the conventional dynamic simulation programs arise from the fact that the injected voltage by the series inverter is superimposed on the shunt inverter side voltage. A solution can be a current injection method, in which a serial part of UPFC is converted to a parallel equivalent circuit using source transformation, and two current sources affect each other at every time step. To verify efficiency of this method, the proposed model is applied for the transient analysis of an example power system.