Mechanical Behaviour of Multi-Span Overhead Transmission Lines Under Dynamic Thermal Stress of Conductors Due to Power Flow and Weather Conditions

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Dynamic Thermal Rating (DTR) of overhead transmission lines represents a significant improvement with respect to the traditional criteria used to assess the steady-state ampacity of conductors. In fact DTR uses actual operating conditions of the power line, rather than assumed conservative conditions. This is extremely promising for the secure operation of the power system: with DTR, TSOs can fully exploit the dynamic performances of conductors, i.e. currents significantly higher than the steady-state thermal limits, in the meantime that the system is redispatched. The present paper proposes a novel dynamic model for calculating sags and tensions in a multi-span power line, for purposes of DTR. The model considers not only the mechanical interaction between spans, due to rotation of strings, but also that the temperature of conductors can vary span by span, for different weather conditions. The problem was solved with a fast Newton-Raphson technique, rather than with conventional relaxation methods, in order to comply with the requirements of real-time operation. The developed tool is able to forecast the time trend of conductor temperatures, tensions, sags and clearances at each span, or to indicate which current can be carried for a given time, before a clearance or temperature constraint is violated. A case study compares the results of this novel method with the outcomes of the traditional "ruling span" technique.
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Ampacity; Dynamic Thermal Rating; Overhead Line; Sag; Tension

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Popovic, D.P., An efficient unified methodology for steady-state security assessment of electric power interconnection, (2010) International Review of Electrical Engineering (IREE), 5 (1), pp. 241-249.

Abdullah, M.P., Hassan, M.Y., Hussin, F., Congestion cost allocation base on contribution for pool market, (2011) International Review of Electrical Engineering (IREE), 6 (2), pp. 953-959.

E.Albizu, A.Fernández, J. Mazón, J.Bengoechea, E.Torres, Hardware and software architecture for overhead line rating monitoring, 2001 IEEE PowerTech, Trondheim-Norway, 2011.

J.R.Santos, A.Gomez Exposito, F.Parreno Sanchez, Assessment of conductor thermal models for grid studies, IET Gener. Transm. Distrib. Vol. 1, No. 1, 2007.

R.Adapa, D.A.Douglass, Dynamic Thermal Ratings: Monitors and calculation methods, IEEE PES 2005 Conference and Exposition, Durban-South Africa, July 2005.

J.Heckenbergerová, J.Hošek, Dynamic thermal rating of power transmission lines related to wind energy integration, 11th International Conference on Environment and Electrical Engineering, EEEIC 2012, Venice-Italy, May 2012.

D.A.Douglass, A.Edris, Real-time monitoring and dynamic thermal rating of power transmission circuits, IEEE Transactions on Power Delivery, Vol.11, Issue 3, 1996.

G.Liu, B.Ruan, M.Zhang, A transient model for overhead transmission line dynamic rating based on thermal circuit method, Automation of Electric Power Systems, Vol.36, 2012.

Jiri Hosek, Dynamic thermal rating of power transmission lines and renewable resources, Weather Intelligence for Renewable Energies, COST Workshop, Nice-France, 2011.

T.Krontiris, A.Wasserrab, G.Balzer, Weather-based loading of overhead lines–consideration of conductor’s heat capacity, Conference on Modern Electric Power Systems, Wroclaw, 2010.

P.Pelacchi, D.Poli, The influence of wind generation on power system reliability and the possible use of hydrogen storages, Electric Power System Research, Vol.80 Issue 3, 2010.

Giuntoli, M., Poli, D., A novel mixed-integer linear algorithm to generate unit commitment and dispatching scenarios for reliability test grids, (2011) International Review of Electrical Engineering (IREE), 6 (4), pp. 1971-1982.

M.Giuntoli, D.Poli, On the possible use of probabilistic techniques for purposes of short-term load dispatching, (2013) International Review of Electrical Engineering (IREE), accepted for publication.

M.Giuntoli, P.Pelacchi, D.Poli, On the use of simplified reactive power flow equations for purposes of fast reliability assessment, IEEE EUROCON 2013, Zagreb, Croatia, 1-4 July 2013.

CIGRE, SC 22, WG 12, Thermal behavior of overhead conductors, ELECTRA No.44, October 1992. Revision 2002: ELT_144_3, on

IEEE Standard for Calculating the Current-Temperature of Bare Overhead Conductors, IEEE Std. 738-2006 (Revision of IEEE Standard 738-1993), 2007.

M.Isozaki, N.Iwama, Verification conductors in of forced convective cooling from breeze wind by wind tunnel testing, IEEE/PES Transmission and Distribution Conference and Exhibition 2002, Vol.3 , 2002.

C.Bernauer, H.Bohme, P.Grossmann, Temperature measurement on overhead transmission lines (OHTL) utilizing surface acoustic wave (SAW) sensors, IEEE PES 12th International Conference on Transmission and Distribution Construction, Operation and Live-Line Maintenance (ESMO), Providence-Rhode Island, 2007.

A.Borghetti, M.Bosetti, S.Grillo, A.Morini, M.Paolone, F.Silvestro, A Two-Stage Scheduler of Distributed Energy Resources, IEEE Power Tech Conference, Lausanne, 2007.

S.Grillo, M.Marinelli, S.Massucco, F.Silvestro, Optimal Management Strategy of a Battery-Based Storage System to Improve Renewable Energy Integration in Distribution Networks, IEEE Transactions on Smart Grid, Vol. 3, no.2, 2012.

S.Massucco, A.Pitto, F.Silvestro, A gas turbine model for studies on distributed generation penetration into distribution networks, IEEE Transactions on Power Systems, Vol. 26, no.3, 2011.

R.G.Olsen, K.S.Edwards, A new method for real-time monitoring of high-voltage transmission-line conductor sag, IEEE Transactions on Power Delivery, Vol. 17, No. 4, 2002.

M.Musavi, D.Chamberlain, Q.Li, Overhead conductor dynamic thermal rating measurement and prediction, IEEE Conference on Smart Measurements for Future Grids (SMFG), 2011.

T.O.Seppa, Increasing transmission capacity by real time monitoring, PES Meeting, Vol.2, 2002.

T.O.Seppa, H.W.Adams, D.A.Douglass, N.Coad, A.Edris, P.Olivier, F.R.Thrash, Use of on-line tension monitoring for real-time thermal ratings, ice loads and other environmental effects, CIGRÉ Session, 22-102, Paris-France, 1998.

H.J.Dräger, D.Hussels, R.Puffer, Development and implementation of a monitoring-system to increase the capacity of overhead lines, CIGRÉ Session, B2-101, Paris-France, 2008.

A.Pohl, A Review of wireless SAW sensors, IEEE Ultrasonics, Ferroelectrics, and Frequency Control, Vol.47, No. 2, 2000.

L.M.Keselman, Y.Motlis, Application of the ruling span concept for overhead lines in mountainous terrain, IEEE Transactions on Power Delivery, Vol.13, Issue 4, 1998.

Y.Motlis, J.S. Barrett, G.A.Davidson, D.A.Douglass, P.A.Hall, J.L.Reding, T.O.Seppa, F.R.Thrash, H.B.White, Limitations of the ruling span method for overhead line conductors at high operating temperatures, IEEE Transactions on Power Delivery, Vol.14 , Issue 2, 1999.

M. Landau, Incremental method for sag-tension calculations, Trans.Amer. Inst. Elect. Eng., Vol. 70, 1951.

J.H.Waghorne, V.E.Ogorodnikov, Current carrying capacity of ACSR conductors, Trans. Amer. Inst. Elect. Eng., Vol. 70, 1951.

H.E.House, P.D.Tuttle, Current-carrying capacity of ACSR, Trans. Amer. Inst. Elect. Eng. Part III, Vol. 77, 1959.

P.F.Winkelman, Sag-tension computations and field measurements of bonneville power administration, Trans. Amer. Inst. Elect. Eng. Part III, Power App. Syst., Vol. 78, 1960.

O.Nigol, J.S.Barrett, Characteristics of ACSR conductors at hightemperatures and stresses, IEEE Trans. Power App. Syst., Vol. PAS-100, no. 2, Feb. 1981.

J.S.Barrett, S.Dutta, O.Nigol, A new computer model of ACSRconductors, IEEE Trans. Power App. Syst., Vol. PAS-102, no. 3, 1983.

T.O.Seppa, Factors influencing the accuracy of high temperature sag calculations, IEEE Transactions on Power Delivery, Vol.9, Issue 2, 1994.

A.Alawar, E.J.Bosze, S.R.Nutt, A hybrid numerical method to calculate the sag of composite conductors”, Electric Power System Research, Vol. 76, pp. 389–394, 2006.

I.Albizu, A.J.Mazon, I.Zamora, Flexible strain-tension calculation method for gap-type overhead conductors, IEEE Trans. Power Del., Vol. 24, no. 3, Jul. 2009.

J.S.Barrett, Y.Motlis, Allowable tension levels for overhead-line conductors, Proc. Inst. Elect. Eng., Gen., Transm. Distrib., Vol. 148, pp. 54–59, 2001.

A.K.Deb, Powerline Ampacity System: Theory, Modeling, and Applications. Boca Raton, 2000.

A.Alawar, E.J.Bosze, S.R.Nutt, A composite core conductor for low sag at high temperatures, IEEE Trans. Power Del., Vol. 20, no.3, pp. 2193–2199, Jul. 2005.

H.W.Adams, Steel supported aluminium conductors (SSAC) for overhead transmission lines, IEEE Trans. Power App. Syst., Vol. PAS-93, no. 5, pp. 1700–1705, Sep. 1974.

I.Zamora, A.J.Mazon, P.Eguia, R.Criado, C.Alonso, J.Iglesias, J.R.Saenz, High-temperature conductors: A solution in the uprating of overhead transmission lines, Proc. IEEE Power Tech, Porto, Portugal, 2001.

A.G.Exposito, J.R.Santos, P.Cruz Romero, Planning and operational issues arising from the widespread use of HTLS conductors, IEEE Trans. Power Syst., Vol. 22, no. 4, pp. 1446–1455, Nov. 2007.

Albizu, I., Mazon, A.J., Fernandez, E., A method for the sag-tension calculation in electrical overhead lines, (2011) International Review of Electrical Engineering (IREE), 6 (3), pp. 1380-1389.

Jahangiri, T., Zavvari, M., Masouminia, V., Effects of catenary, compaction and phase conductor arrangement of double circuit lines on ROW width using calculations and FEM, (2012) International Review of Electrical Engineering (IREE), 7 (4), pp. 4980-4991.

M.Keshavarzian, C.H.Priebe, Sag and tension calculations for overhead transmission lines at high temperatures-modified ruling span method, IEEE Transactions on Power Delivery, Vol.15, 2000.

K.Kopsidas, S.M.Rowland, B.A.Boumecid, Holistic Method for Conductor Ampacity and Sag Computation on an OHL Structure, IEEE Transactions on Power Delivery, Vol.27, Issue 3, July 2012.

M.Giuntoli, D.Poli, Optimized thermal and electrical scheduling of a Large Scale Virtual Power Plant in the presence of energy storages, IEEE Transactions on Smart Grid, Vol.4 Issue 2, 2013.

Giglioli, R., Poli, D., Small-scale biomass-fired cogeneration, pellet production or district heating: New criteria for selecting the most profitable solution, (2013) International Review on Modelling and Simulations (IREMOS), 6 (3), pp. 782-794.

M.Brenna, M.C.Falvo, F.Foiadelli, L.Martirano, F.Massaro, D.Poli, A.Vaccaro, Challenges in Energy Systems for the Smart-Cities of the Future, 2012 IEEE International Energy Conference and Exhibition, ENERGYCON 2012, Florence.

S.Barsali, R.Giglioli, D.Poli, M.Sforna, R.Salvati, R.Zaottini, The restoration of an electric power system: international survey and possible innovative enhancements for the Italian system, Electric Power System Research, Vol.78 Issue 2, 2008.

T.P.Harley, A direct method for sag-tension calculations, Trans.Amer. Inst. Elect. Eng. Power App. Syst., Vol. 72, 1953.

D.Irony, G.Shklarski, S.Toledo, Parallel and fully recursive multifrontal supernodal sparse Cholesky, Springer Verlag Berlin, 2002.

Jumaat, S.A., Musirin, I., Othman, M.M., Moklis, H., Comparison of FACTS device installation in power transmission system, (2012) International Review on Modelling and Simulations (IREMOS), 5 (4), pp. 1679-1689.

Rao, N.L.S., Govinda Rao, G., Sivanagaraju, S., An extension to the theory of the transmission lines, (2012) International Review on Modelling and Simulations (IREMOS), 5 (5), pp. 2348-2354.

Jahromi, M.Z., Rahmanian, M., Fadaeinedjad, R., Rashidinejad, M., A novel security-considered transmission and generation expansion planning using game theory and ANN, (2012) International Review on Modelling and Simulations (IREMOS), 5 (1), pp. 394-402.


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