Transmission Line Dynamic Thermal Ratings 1

[SidiropoulosM]

The thermal capability of a transmission line depends on the physical characteristics of the conductor and on a complex combination of environmental parameters. Electric utilities have generally applied static (or "fixed&quot ratings, based on a set of conservative assumptions. Dynamic ratings, on the other hand, are based on current weather conditions and allow, in most cases, higher line loadings. They are based on the monitoring of the conductor tension or conductor sag. I am currently studying the application of such a system on a 115 kv line. Any field or operational experience with dynamic ratings would be greatly appreciated.

 

[stevenal]

Can you dynamically monitor vegetation growth also? Any extra capacity is lost when the circuit is open.

 

[jbartos]

Suggestion: There may be other aspects beside the wheather to consider. Visit

http://www.nrcce.wvu.edu/special/electricity/appendix5a.htm

http://www.elect.mrt.ac.lk/Increasing_power_1999.pdf

http://www.cat-1.com/files/papers/CIGRE/2000/ApplicatnofRTRatngs.pdf

etc. for more info

 

[e93ktlee]

A simplied way will be to model the line as a heat balance system where the heat generated (internal resistance & solar absorption) equals the heat loss (via convection & radiation). Model it in a integration formula.

 

[SidiropoulosM]

Thank you all for your input. Our problem is not how to model the line but getting field data from others who have used dynamic thermal monitoring.

Thanks again. Michael Sidiropoulos
Transmission Planning Engineer

 

[jbartos]

Suggestion: Visit

http://images.tdworldexpo.com/files/1104/OUT6 - Seppa Paper.ppt

etc. for more info

 

[jghrist]

See:

1 Ambient temperature corrected dynamic transmission line ratings at two PG&E locations
Steeley, W.J.; Norris, B.L.; Deb, A.K.;
Power Delivery, IEEE Transactions on , Volume: 6 Issue: 3 , Jul 1991
Page(s): 1234 -1242

2 Real-time monitoring and dynamic thermal rating of power transmission circuits
Douglass, D.A.; Edris, A.-A.;
Power Delivery, IEEE Transactions on , Volume: 11 Issue: 3 , Jul 1996
Page(s): 1407 -1418

3 Field studies of dynamic thermal rating methods for overhead lines
Douglass, D.A.; Edris, A.-A.;
Transmission and Distribution Conference, 1999 IEEE , Volume: 2 , 11-16 Apr 1999
Page(s): 842 -851 vol.2

4 Prospects for dynamic transmission circuit ratings
Holbert, K.E.; Heydt, G.T.;
Circuits and Systems, 2001. ISCAS 2001. The 2001 IEEE International Symposium on , Volume: 3 , 6-9 May 2001
Page(s): 205 -208 vol. 2

5 An experimental evaluation of a thermal line uprating by conductor temperature and weather monitoring
Callahan, P.M.; Douglass, D.A.;
Power Delivery, IEEE Transactions on , Volume: 3 Issue: 4 , Oct 1988
Page(s): 1960 -1967

6 Economic evaluation of dynamic thermal rating by adaptive forecasting
Hall, J.F.; Deb, A.K.;
Power Delivery, IEEE Transactions on , Volume: 3 Issue: 4 , Oct 1988
Page(s): 2048 -2055

7 Dynamic thermal rating of critical lines-a study of real-time interface requirements
Henke, R.K.; Sciacca, S.C.;
IEEE Computer Applications in Power , Volume: 2 Issue: 3 , Jul 1989
Page(s): 46 -51

8 Field application of a dynamic thermal circuit rating method
Douglass, D.A.; Edris, A.A.; Pritchard, G.A.;
Power Delivery, IEEE Transactions on , Volume: 12 Issue: 2 , Apr 1997
Page(s): 823 -831