Abstract
The unified power flow controller (UPFC) is a powerful power flow and reactive compensation FACTS controller. It consists of two voltage source converters connected back-to-back with a common DC bus. One of the VSC converters is shunt connected to the AC power system. It is equivalent to a STATCOM, which injects a current into the power system at the point of connection (POC). The other is what is referred to as a Static Synchronous Series Compensator (SSSC), which injects a voltage in series with the transmission line. The injected series voltage can be at any angle with respect to the line current. The injected currents have two parts. First, when the two converters share the same DC bus capacitor, the real power part, which is in phase with the line voltage, delivers or absorbs real power into/from the line. The real power also compensates for the losses in the UPFC. Second, the reactive part, which is in quadrature with the line voltage, emulates an inductive reactance or a capacitive reactance at the point of connection. That is, in an UPFC, the STATCOM can regulate the shunt reactive power at the line connection and also inject or absorb real power to control the DC bus capacitor voltage, thereby facilitating real power transfer between the two converters.
The first installed UPFCs were built with the use of relatively slow switching gate turn-off (GTO) thyristor devices, which were switched at fundamental frequency. This arrangement required the use of harmonically neutralized voltage-sourced converters (HN-VSC) to achieve harmonic cancellation and eliminate or reduce the need for harmonic filters. Currently built VSCs use Modular Multilevel Converters (MMC) that use insulated gate bipolar transistors (IGBTs), which enable design of higher voltage converter valves that eliminate the need for parallel connection of converter modules.
The chapter also provides information about two variations of the UPFC, the Static Synchronous Series Compensator (SSSC) and the Interline Power Flow Controller (IPFC).
This is a preview of subscription content, log in via an institution.
Notes
- 1.
While controlling the receiving-end reactive power demand might be feasible for short AC lines, it would not be applicable to long AC lines.
- 2.
If 2 2-level converters are phase shifted by 30°, the combination produces 12-pulse harmonics. To achieve 24-pulse operations with 2-level converters requires a second set of 12-pulse converters with a phase shift of 15°, that is, the 30° phase shift split in half.
- 3.
If any breaker pole opens at one end of the line, there will be no path for current injection into the circuit in which a breaker pole is opened. In that case, there is an ampere-turns unbalance in the leg of the delta winding that is connected to the open line phase and the winding has to saturate before zero-sequence current will flow in the delta winding.
- 4.
The zero-sequence currents will be short-circuited through the delta winding for as long as currents can be induced in the AC line. However, if single-pole trip-reclose is used for the line or when one end of the line opens up, the path for zero-sequence current flow is broken.
- 5.
The power semiconductor technologies are still evolving. So it is not impossible for new types of GTO devices to emerge based on wide bandgap devices (e.g., the silicon carbide technology).
- 6.
The overload rating might be limited to 15–30% unless higher-power devices are used for the system.
References
Ainsworth, J.D., Davies, M, Fitz, P.J., Owens, K.E., Trainer, D.R..: Static Var Compensator (STATCOM) based on single-phase chain circuit converters; IEE Proceedings On-line No. 19982032, 1998
Allebrod, S., Hamerski, R., Marquardt, R.: New transformerless, scalable modular multilevel converters for HVDC-transmission, IEEE Power Electronics Specialist Conference, PESC2008, June 2008
An, T., Powell, M.T., Thanawala, H.L., Jenkins, N.: Assessment of two different STATCOM configurations for FACTS applications in power systems; POWERCON’98. 1998 International Conference on Power System Technology. Proceedings (Cat. No.98EX151), vol. 1, pp. 307–312, 1998
Ängquist, L.: Synchronous voltage reversal control of thyristor controlled series capacitor. Ph.D. thesis, Royal Institute of Technology, Stockholm (2002)
Bian, J., Ramey, D.G., Nelson, R.J., Edris, A.: A study of equipment sizes and constraints for a unified power flow controller. IEEE Trans. Power Delivery. 12(3), 1385 (1997)
CIGRE TB 51.: Load Flow Control in High Voltage Power Systems Using FACTS Controllers; section 3.4.8, CIGRE Technical Brochure 51, Jan 1996
CIGRE TB 144.: Static Synchronous Compensator (STATCOM); CIGRE Technical Brochure 144, Aug 2000
CIGRE TB 145, Modeling of Power Electronics Equipment (FACTS) in Load Flow and Stability Programs, CIGRE Technical Brochure. 145, (1999)
CIGRE TB 160.: Unified Power Flow Controller (UPFC); CIGRE Technical Brochure 160, Aug 2000
CIGRE TB 269.: VSC Transmission, CIGRE Technical Brochure 269, Apr 2005
CIGRE TB 371.: Static Synchronous Series Compensator, CIGRE Technical Brochure 371, Feb 2009
CIGRE TB 504.: Voltage and VAr Support in System Operation, CIGRE Technical Brochure 504, Aug 2012
EPRI: Convertible Static Compensator (CSC) for New York Power Authority; EPRI Final Report 1001809, Dec 2003. https://www.epri.com/#/pages/product/000000000001001809/?lang=en-US
Fardanesh B., Henderson M., Gyugyi L., Lam B., Adapa R., Shperling B., Zelingher S., Schauder C., Mountford J., Edris A.: Convertible Static Compensator Application to the New York Transmission System, CIGRE Session Paper 14–103 (1998)
Fortescue, C.L.: Method of symmetrical co-ordinates applied to the solution of polyphase networks; (PDF). AIEE Trans. 37(part II), 1027–1140 (1918)
Grund, C.E., Pollard, E.M., Patel, H.S., Nilsson, S.L.: Power modulation controls for HVDV systems; Cigre paper 14-03, 1984
Gyugyi, L.: Unified power-flow control concept for flexible AC transmission systems; IEE Proceedings C - Generation, Transmission and Distribution. 139(4), (1992)
Gyugyi, L., Schauder, C.D., Williams, S.L., Torgerson, D.R., Rietman, T.R., Edris, A.: The unified power flow controller: a new approach to power transmission control. IEEE Trans. Power Delivery. 10(2), 1085–1097 (1995)
Gyugyi, L., Schauder, C.D., Sen, K.K.: Static synchronous series compensator: a solid-state approach to the series compensation of transmission lines. IEEE Trans. Power Delivery. PWRD-12(1), 406–417 (1997)
Gyugyi, L., Sen, K.K., Schauder, C.D.: The interline power flow controller concept: a new approach to power flow management in transmission systems. IEEE Trans. Power Delivery. 14(3), 1115–1123 (1999)
Heathcote, M.J.: Phase shifting transformers and quadrature boosters, Section 7.5 pages 7010-710. In: The J & P Transformer Book, Thirteens Edition, Elsevier, Ltd, 2007. https://www.elsevier.com/books/j-and-p-transformer-book/heathcote/978-0-7506-8164-3
Holmes, D.G., Lipo, T.A.: Pulse Width Modulation for Power Converters. IEEE Press and A, Wiley (2003)
Jacobson, B., Karlsson, P., Asplund, G., Harnefors, L., Jonsson, T.: VSC-HVDC transmission with cascaded two level converters, Cigre paper B4-110, Cigre 2010
Mohan, N., Undeland, T.M., Robbins, W.P.: Gate turn-off thyristors, chapter 24. In: Power Electronics Converters, Applications and Design, 2nd edn, pp. 613–625. Wiley, New York (1995a)
Mohan, N., Undeland, T.M., Robbins, W.P.: Insulated gate bipolar transistors, chapter 25. In: Power Electronics Converters, Applications and Design, 2nd edn, pp. 626–640. Wiley, New York (1995b)
Nam, T., Kim, H., Kim, S., Son, G.T., Chung, Y.H., Park, J.W., Kim, C.K., Hur, K.: Trade-off strategies in designing capacitor voltage balancing schemes for modular multilevel converter HVDC. J. Electr. Eng. Technol. 11, 1921–1718 (2016). https://doi.org/10.5370/JEET.2016.11.3.1921
Oates, C., Davidson, C.: 2011. A comparison of two methods of estimating losses in the modular multi-level converter; EPE 2011 – Birmingham. ISBN: 9789075815153
Renz, B.A., Keri, A.J.F., Mehraban, A.S., Kessinger, J.P., Schauder, C.D., Gyugyi, L., Kovalsky, L.J., Edris, A.A.: World’s first unified power flow controller on the AEP system; CIGRE paper 14-107, 1998
Schauder, C., Gernhardt, N., Stacey, E., Lemak, T., Gyugyi, L., Cease, T.W., Edris, A.: Development of a +/− 100 MVAR static condenser for voltage control of transmission systems. IEEE Trans. Power Delivery. 10(3), 1486–1496 (1995)
Schauder, C., Gernhardt, N., Stacey, E., Lemak, T., Gyugyi, L., Cease, T.W., Edris, A., Wilhelm, M.: TVA TATACOM project: design, installation, and commissioning. CIGRE 1996 Paper: 14–106
Schettler, F., Huang, H., Christl, N.: HVDC transmission systems using voltage sourced converters: design and application. Conference Proceedings, IEEE Summer Meeting 2000, Paper No. 2000 SM-260, vol. 2, pp. 716–720
Sen, K.: SSSC – static synchronous series compensator: theory, modeling, and applications. IEEE Trans. Power Delivery. 13(1), 241–246 (1998)
Sen, K., Keri, J.F.: UPFC comparison of field results and digital simulation results of voltage sourced-converter based FACTS controllers. IEEE Trans. Power Delivery. 18(1), 300–306 (2003)
Sen, K.K., Stacey, E.J.: UPFC-unified power flow controller: theory, modeling, and applications; IEEE Transactions on Power Delivery; IEEE Transactions on Power Delivery. 13(4), (1998)
Zhou, X., Wang, H., Aggarwal, R.K., Beaumont, P.: Performance evaluation of a distance relay as applied to a transmission system with UPFC. IEEE Trans. Power Delivery. 21(3), 1137–1147 (2006)
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2020 Springer Nature Switzerland AG 2019
About this entry
Cite this entry
Adapa, R., Nilsson, S., Andersen, B., Yang, Y. (2020). Technical Description of the Unified Power Flow Controller (UPFC) and Its Potential Variations. In: Nilsson, S. (eds) Flexible AC Transmission Systems . CIGRE Green Books. Springer, Cham. https://doi.org/10.1007/978-3-319-71926-9_10-2
Download citation
DOI: https://doi.org/10.1007/978-3-319-71926-9_10-2
Received:
Accepted:
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-319-71926-9
Online ISBN: 978-3-319-71926-9
eBook Packages: Springer Reference EnergyReference Module Computer Science and Engineering
Publish with us
Chapter history
-
Latest
Technical Description of the Unified Power Flow Controller (UPFC) and Its Potential Variations- Published:
- 11 March 2020
DOI: https://doi.org/10.1007/978-3-319-71926-9_10-2
-
Original
Technical Description of the Unified Power Flow Controller (UPFC) and Its Potential Variations- Published:
- 10 January 2020
DOI: https://doi.org/10.1007/978-3-319-71926-9_10-1