Performance of UPFC on System Behavior Under Fault Conditions
11 Dec 2005-pp 505-509
TL;DR: In this paper, the performance and impact of UPFC on the power system behavior during fault conditions was investigated in a two-machine double line power system with UPFC installed in one of the lines.
Abstract: This paper presents a detailed report of the performance and impact of UPFC on the power system behavior during fault conditions. A two machine — double line power system with UPFC installed in one of the lines is considered for the study. The idea is to observe the capability of the UPFC to maintain the active and reactive power flows in the compensated line (which includes UPFC) and to diminish the fall-off of the bus voltage when there is a grounding fault in the transmission line. Simulink based power system block set is used for numerical simulations. Simulation results indicate notable improvement in the behavior of the overall system with UPFC in upholding the voltage and power flows even under typical line faults by appropriate injection of series voltage into the transmission line at the point of connection. The extent of UPFC capability in maintaining the power flows in the line (Line 1), even under fault condition in an adjacent parallel line (Line 2) is provided. Minimizing the disturbances in voltages, currents and power flows in the fault-affected line (Line 2) are also discussed. Further the results illustrate how the UPFC contributes dynamically to a faster recovery of the system to the pre-fault conditions.
Citations
More filters
TL;DR: Based on single-phase ac-ac converter with controllable phase and amplitude (ACCPA), a three-phase ACCPA without third harmonic trap was proposed for power transmission control in grid by adopting a symmetrical relationship of three phase.
Abstract: Based on single-phase ac–ac converter with controllable phase and amplitude (ACCPA), a three-phase ACCPA without third harmonic trap was proposed for power transmission control in grid by adopting a symmetrical relationship of three phase. The three-phase ACCPA is comprised of two parts, which are used to adjust the phase and amplitude of three-phase output voltage, respectively, and continuously. Its front part is made up of three buck-type ac converters, and the back part is a three-phase boost-type ac converter. The operation principle of three-phase ACCPA, the adjustable ranges of the phase and amplitude of the front part, and the calculation formulas of control parameters under ideal conditions were studied and deduced in detail. Furthermore, the control accuracy of the phase angle was discussed for the three-phase ACCPA with digital control, and then, the method to select close-loop control parameters was obtained. The control strategy of three-phase ACCPA was presented and a prototype was fabricated. The experimental waveforms and testing results verified the correctness of the theoretical analysis and the feasibility of the control strategy.
18 citations
TL;DR: In this article, a novel method for power transmission control-ac-ac converter with controllable phase and amplitude (ACCPA) was proposed, which has two control variables and is able to continuously regulate the phase and the amplitude of its output voltage independently.
Abstract: By adopting the concept of virtual quadrature source (VQS), a novel method for power transmission control-ac-ac converter with controllable phase and amplitude (ACCPA) was proposed, which has two control variables and is able to continuously regulate the phase and the amplitude of its output voltage independently. The operation principle was studied in detail, and the relationship with the optimization of control parameters of ACCPA's two duty ratios was analyzed for regulating the phase and amplitude of its output voltage. The phase is regulated in the front part, and the amplitude is regulated in the back part. For phase regulation, two methods were proposed to select optimal control parameters dynamically. The curves followed by two methods are crossed at the reference phase angle and have the same initial control parameters. It is necessary to adjust two independent control parameters for method 1 and one parameter for method 2. So method 2 is simple, easy to implement and has high control stability in comparison with method 1. The control strategy of ACCPA was presented and a prototype of single-phase ACCPA was manufactured. The experimental results verified the correctness of the theory and the feasibility of the control strategy.
16 citations
24 Jun 2007
TL;DR: In this article, the authors present a bibliography of the journal and conference papers published on FACTS during the year 2005 which were not available at the time of preparation of the bibliography on flexible AC transmission systems for the year 2004-2005, published in three papers in the Proceedings of 2006 IEEE PES General Meeting.
Abstract: This present bibliography paper includes the journal and conference papers published on FACTS during the year 2005 which were not available at the time of preparation of the bibliography on flexible AC transmission systems for the year 2004-2005, published in three papers in the Proceedings of 2006 IEEE PES General Meeting. The year 2006 papers as available until October 2006 are included.
10 citations
TL;DR: Experimental results verified the feasibility of single-phaseπ model ACCPA and the correctness of its theory, and proposed model has a more simplified structure.
Abstract: Based on cascaded ac–ac converter with controllable phase and amplitude (ACCPA), a novel π model ACCPA was proposed for power flow control, whose output voltage phase and amplitude can be regulated, respectively, and simultaneously with respect to the input voltage. Single-phase π model ACCPA comprises a buck-type ac unit, a third harmonic trap and a boost-type ac converter. Compared with single-phase cascaded ACCPA, it has a more simplified structure by dispensing with the LC output filter of the buck-type ac converter, and can adopt the same two-stage duty-cycle modulation. The buck-type ac unit regulates the phase of output voltage and the boost-type ac converter does the amplitude. By utilizing impedance compensation with capacitance in single-phase π model ACCPA, it is effective to counteract or reduce the lag effect which is put on fundamental voltage by line impedance of third harmonic trap and inductance. Three-phase π model ACCPA comprises three buck-type ac units and a three-phase boost-type ac converter, it not only dispenses with three LC output filters, but also does three third harmonic traps, so it has simple structure. Experimental results verified the feasibility of π model ACCPA and the correctness of its theory.
5 citations
21 Mar 2012
TL;DR: In this article, the effect of an UPFC on the transient stability of two-machine systems was analyzed using MATLAB-SIMULINK, and it was found that the critical clearing time of the system has increased after the inclusion of UPFC.
Abstract: The aim of this paper is to analyze the effect of an Unified Power Flow Controller (UPFC) on transient stability of two-machine system. The performance of the systems is simulated by using MATLAB-SIMULINK. It has been found that the critical clearing time of the system has increased after inclusion of an UPFC. Hence, the transient stability of the system has been enhanced.
3 citations
References
More filters
17 Sep 1991
TL;DR: The advanced static VAr compensator (ASVC) as mentioned in this paper is based on the principle that a self-commutating static inverter can be connected between three-phase AC power lines and an energy storage device, such as an inductor or capacitor, and controlled to draw mainly reactive current from the lines.
Abstract: The advanced static VAr compensator (ASVC) is based on the principle that a self-commutating static inverter can be connected between three-phase AC power lines and an energy-storage device, such as an inductor or capacitor, and controlled to draw mainly reactive current from the lines. This capability is analogous to that of the rotating synchronous condenser and it can be used in a similar way for the dynamic compensation of power transmission systems, providing voltage support, increased transient stability, and improved damping. The authors present a simplified mathematical model of the ASVC that has made it possible to derive the transfer functions needed for control system synthesis. The resulting control system designs are briefly outlined and further analysis is presented to show the behaviour of the ASVC when the line voltage is unbalanced or distorted. The analysis is based on a vectorial transformation of variables, first described by R.H. Park (1928) for AC machine analysis, and later, using complex numbers, by W.V. Lyon (1954) in the theory of instantaneous symmetrical components.
1,039 citations
TL;DR: In this paper, the authors proposed a unified power flow controller (UPFC) that is able to control both the transmitted real power and, independently, the reactive power flows at the sending-and the receiving-end of the transmission line.
Abstract: This paper shows that the unified power flow controller (UPFC) is able to control both the transmitted real power and, independently, the reactive power flows at the sending- and the receiving-end of the transmission line. The unique capabilities of the UPFC in multiple line compensation are integrated into a generalized power flow controller that is able to maintain prescribed, and independently controllable, real power and reactive power flow in the line. The paper describes the basic concepts of the proposed generalized P and Q controller and compares it to the more conventional, but related power flow controllers, such as the thyristor-controlled series capacitor and thyristor-controlled phase angle regulator. The paper also presents results of computer simulations showing the performance of the UPFC under different system conditions. >
997 citations
01 Jul 1993
TL;DR: In this paper, two fundamentally different types of invertor can be used for this purpose, one providing control of output voltage magnitude and phase angle, and the other having only phase angle control.
Abstract: The advanced static Var compensator (now widely known as the static condenser or STATCON) uses a high power self-commutating inverter to draw reactive current from a transmission line. Two fundamentally different types of invertor can be used for this purpose, one providing control of output voltage magnitude and phase angle, and the other having only phase angle control. For each of these types, the governing equations are derived, and frequency domain analysis is used to obtain the relevant transfer functions for control system synthesis. Further analysis is provided to determine the response of the STATCON to negative sequence and harmonic voltage components on the transmission line. The results are illustrated with measured waveforms obtained from a scaled analogue model of an 80 MVAr STATCON.<
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974 citations
01 Jan 1996
TL;DR: In this paper, a unified power flow controller (UPFC) is proposed to control real and reactive power flow in a transmission line by a pair of back-to-back power electronic inverters.
Abstract: The real and reactive power flow in a transmission line can be controlled by a pair of back to back power electronic inverters. This configuration is called a unified power flow controller (UPFC). Operation of a UPFC using a control strategy which is based on d-q axis theory is presented by simulation and experimental laboratory results. A new cross-coupling control strategy is also presented which has an improved performance.
75 citations
23 Jun 1996
TL;DR: In this article, the performance of a unified power flow controller (UPFC) with four different controllers is evaluated through simulation and implementation in an experimental laboratory model, and it is found that the cross-coupling and robust H/spl infin/ controllers have the best performance when the exact value of the power transmission parameters are unknown.
Abstract: The performance of a unified power flow controller (UPFC) with four different controllers is evaluated through simulation and implementation in an experimental laboratory model. The controllers which were investigated are the PI controller, PI controller with decoupling, cross-coupling controller and robust H/spl infin/ controller. It is found that the cross-coupling and robust H/spl infin/ controllers have the best performance when the exact value of the power transmission parameters are unknown.
67 citations
"Performance of UPFC on System Behav..." refers background or methods in this paper
...Fig. 2 .Per-phase equivalent circuit forthepowersystem with...
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...Thusthepossible cases forinvestigation arelisted asfollows: CaseAl:twomachine - double line system (System A)with LGfault inline 2 . CaseBI:twomachine -double line system andUPFC(SystemB)withLGfault inline 2 CaseA2:twomachine - double line system (System A)with LLLGfault inline 2 CaseB2:Twomachine -double line system andUPFC (System B)withLLLGfault inline 2 Thefault affected line hastwofaults -F]occurring atreceiving endandF2atsending end....
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...Fig. 2 represents theperphase equivalent circuit ofaUPFC [2]....
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...al. [ 2 ]. Theprinciple ofthis control strategy istoconvert themeasured three phase currents andvoltages into d-qvalues and thentocalculate thecurrent references fromdesired power references andmeasured voltages fromEqs(1)to(4)....
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...Thepowerflow control isthen realized byusing controllers toforce thelinecurrents to follow their references [ 2 ]....
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