Health Monitoring of Overhead Power Transmission Line:

User Needs

Vth SAMCO WorkshopVienna

26-27 January, 2004

Dmitri SNEGOVSKI (Mech. Eng., PhD student)Transmission and Distribution of Electrical Energy

University of Liege - Montefiore Institute of Electricity

Belgium

Vth SAMCO Workshop Monitoring of Overhead Power Transmission Line – User Needs

Vienna, 26-27 January, 2004 2 ULG - Montefiore Institute of Electricity

Summary

1. Monitoring Problematics2. Sag & Temperature Monitoring3. Sensible Elements4. Damage Diagnostics5. Wind-Induced Vibrations6. Vibration Measurement7. Conclusions

Vth SAMCO Workshop Monitoring of Overhead Power Transmission Line – User Needs

Vienna, 26-27 January, 2004 3 ULG - Montefiore Institute of Electricity

1. What the User Needs NOT?

New York - August 14, 2003 Black-Out in USA, initiated by increased conductor sag due to overheat

Vth SAMCO Workshop Monitoring of Overhead Power Transmission Line – User Needs

Vienna, 26-27 January, 2004 4 ULG - Montefiore Institute of Electricity

Concerns

Ageing Increasing Power LoadsDeregulation in Power Transmission

Vth SAMCO Workshop Monitoring of Overhead Power Transmission Line – User Needs

Vienna, 26-27 January, 2004 5 ULG - Montefiore Institute of Electricity

Impacts

WindCorrosionContamination

Vth SAMCO Workshop Monitoring of Overhead Power Transmission Line – User Needs

Vienna, 26-27 January, 2004 6 ULG - Montefiore Institute of Electricity

Real-time & Permanent

Nondestructive & Hotline Mounted

Predictive, Secure, Controllable etc.

What kind of monitoring user needs?

Vth SAMCO Workshop Monitoring of Overhead Power Transmission Line – User Needs

Vienna, 26-27 January, 2004 7 ULG - Montefiore Institute of Electricity

> Maintenance > Optimal Power Delivery

Why Real-time & Permanent?

Vth SAMCO Workshop Monitoring of Overhead Power Transmission Line – User Needs

Vienna, 26-27 January, 2004 8 ULG - Montefiore Institute of Electricity

Ageing

Wind-induced motion

> Maintenance > Optimal Power Delivery

Prevent hazards…

Why Real-time & Permanent?

Vth SAMCO Workshop Monitoring of Overhead Power Transmission Line – User Needs

Vienna, 26-27 January, 2004 9 ULG - Montefiore Institute of Electricity

Sag

> Maintenance > Optimal Power Delivery

Why Real-time & Permanent?

Sag and/or Temperature Monitoring

Vth SAMCO Workshop Monitoring of Overhead Power Transmission Line – User Needs

Vienna, 26-27 January, 2004 10 ULG - Montefiore Institute of Electricity

Sag

> Maintenance > Optimal Power Delivery

Sag and/or Temperature Monitoring

Why Real-time & Permanent?

Vth SAMCO Workshop Monitoring of Overhead Power Transmission Line – User Needs

Vienna, 26-27 January, 2004 11 ULG - Montefiore Institute of Electricity

Sag

> Maintenance > Optimal Power Delivery

Sag and/or Temperature Monitoring

Why Real-time & Permanent?

Vth SAMCO Workshop Monitoring of Overhead Power Transmission Line – User Needs

Vienna, 26-27 January, 2004 12 ULG - Montefiore Institute of Electricity

2. Sag monitoring methods

© PTI, Inc.

Vth SAMCO Workshop Monitoring of Overhead Power Transmission Line – User Needs

Vienna, 26-27 January, 2004 13 ULG - Montefiore Institute of Electricity

Load cells for tension monitoring

SDG&E CAT monitor installed on a 230 kV anchor tower.

Direct radio communications are established with the ground station (GS).

GS dumps the data to the post via telephone line.

Tension monitoringCAT monitor

Vth SAMCO Workshop Monitoring of Overhead Power Transmission Line – User Needs

Vienna, 26-27 January, 2004 14 ULG - Montefiore Institute of Electricity

Sag monitoring

TargetCamera

Datalogger & Communications

Meteo (optional)

Sagometer (EDM International, Inc.)

Vth SAMCO Workshop Monitoring of Overhead Power Transmission Line – User Needs

Vienna, 26-27 January, 2004 15 ULG - Montefiore Institute of Electricity

3.OHL Sensible elements

1. Conductors2. Fittings (spacers, insulator chains, …)3. Towers

Vth SAMCO Workshop Monitoring of Overhead Power Transmission Line – User Needs

Vienna, 26-27 January, 2004 16 ULG - Montefiore Institute of Electricity

Conductor damages

Fretting fatigue of second layer of strand (left) or surface failure (right)

Vth SAMCO Workshop Monitoring of Overhead Power Transmission Line – User Needs

Vienna, 26-27 January, 2004 17 ULG - Montefiore Institute of Electricity

Conductor damages

Strand breaking due to corrosion

Vth SAMCO Workshop Monitoring of Overhead Power Transmission Line – User Needs

Vienna, 26-27 January, 2004 18 ULG - Montefiore Institute of Electricity

Conductor damages

Vth SAMCO Workshop Monitoring of Overhead Power Transmission Line – User Needs

Vienna, 26-27 January, 2004 19 ULG - Montefiore Institute of Electricity

Conductor damages

Aeolian vibration-induced damages of conductor - contact with suspension saddle

Vth SAMCO Workshop Monitoring of Overhead Power Transmission Line – User Needs

Vienna, 26-27 January, 2004 20 ULG - Montefiore Institute of Electricity

Aeolian vibration-induced damages of conductor - contact with Aircraft Warning Marker

Conductor damages

Vth SAMCO Workshop Monitoring of Overhead Power Transmission Line – User Needs

Vienna, 26-27 January, 2004 21 ULG - Montefiore Institute of Electricity

Tower Damages

Aeolian vibrationGalloping

Vth SAMCO Workshop Monitoring of Overhead Power Transmission Line – User Needs

Vienna, 26-27 January, 2004 22 ULG - Montefiore Institute of Electricity

Other:

Spacers, spacer dampersVibration dampersInsulatorsAircraft warning markersetc.

Twin bundle spacer damper

Stockbridge damper

Insulator chain

Vth SAMCO Workshop Monitoring of Overhead Power Transmission Line – User Needs

Vienna, 26-27 January, 2004 23 ULG - Montefiore Institute of Electricity

4. Damage Diagnostic Methods

Corona Discharge-based (CM)Electro-magnetic Acoustic (EMAT)Space potential probes (EPRI project)

Vth SAMCO Workshop Monitoring of Overhead Power Transmission Line – User Needs

Vienna, 26-27 January, 2004 24 ULG - Montefiore Institute of Electricity

EMAT (Electro Magnetic Acoustic Transducer)Colorado School of Mines, U.S.A.

Damage Diagnostic

Vth SAMCO Workshop Monitoring of Overhead Power Transmission Line – User Needs

Vienna, 26-27 January, 2004 25 ULG - Montefiore Institute of Electricity

+ Can be used on live (hot) conductors

+ Allows detecting minor defects

- Time-limited

EMAT(Electro Magnetic Acoustic Transducer)

Vth SAMCO Workshop Monitoring of Overhead Power Transmission Line – User Needs

Vienna, 26-27 January, 2004 26 ULG - Montefiore Institute of Electricity

5. Diagnose the Wind - Induced Vibrations

• UnavoidableTurbulence-induced

• Necessary to minimize:GallopingWake-induced vibrationsAeolian vibrations

Vth SAMCO Workshop Monitoring of Overhead Power Transmission Line – User Needs

Vienna, 26-27 January, 2004 27 ULG - Montefiore Institute of Electricity

Aeolian Vibration

Oscillation Amplitude

~ 1 D

Vth SAMCO Workshop Monitoring of Overhead Power Transmission Line – User Needs

Vienna, 26-27 January, 2004 28 ULG - Montefiore Institute of Electricity

Wake-Induced Vibration

γ z− &

xV &−

DFLF

rV

ZF

XFx&z&

Wind

Vth SAMCO Workshop Monitoring of Overhead Power Transmission Line – User Needs

Vienna, 26-27 January, 2004 29 ULG - Montefiore Institute of Electricity

Turbulence-Induced Buffeting

-16

-14

-12

-10

-84 6 8 10 12 14 16 18

Y, m

Z, m ASTERAERO-Z

4035 302520151050

10.00 14.00 18.00 22.00 02.00 06.00Time (Hrs)

Vth SAMCO Workshop Monitoring of Overhead Power Transmission Line – User Needs

Vienna, 26-27 January, 2004 30 ULG - Montefiore Institute of Electricity

Galloping

0LD

C Cy

∂+ <

∂

Wind Ice

Vth SAMCO Workshop Monitoring of Overhead Power Transmission Line – User Needs

Vienna, 26-27 January, 2004 31 ULG - Montefiore Institute of Electricity

6. Vibration Measurement

Existing measuring devices

SEFAG vibration recorder (Conductor diameter: about 0.03 m)

Vth SAMCO Workshop Monitoring of Overhead Power Transmission Line – User Needs

Vienna, 26-27 January, 2004 32 ULG - Montefiore Institute of Electricity

Heavy weight (more than 5 kg) - > conductor fatigue

High cost (~10000 €) Limited Autonomy

Vibration Measurement

Impossible to detect reliably the large amplitude at mid-spanHigher frequencies cannot be recorded.

Vth SAMCO Workshop Monitoring of Overhead Power Transmission Line – User Needs

Vienna, 26-27 January, 2004 33 ULG - Montefiore Institute of Electricity

7. Conclusions?

Health Monitoring of Overhead Transmission Lines is of increasing importance

Tension & sag monitoring is more elaborated but still a competitive field

OHL conductor vibration monitoring devices have limitations (cost, monitoring period)

Diagnostic of damages and hazards in OHL needs both « Artificial Intelligence » and hardware tools.

Vth SAMCO Workshop Monitoring of Overhead Power Transmission Line – User Needs

Vienna, 26-27 January, 2004 34 ULG - Montefiore Institute of Electricity

The most challenging studies…

Vth SAMCO Workshop Monitoring of Overhead Power Transmission Line – User Needs

Vienna, 26-27 January, 2004 35 ULG - Montefiore Institute of Electricity

…are the worst garnished!

Vth SAMCO Workshop Monitoring of Overhead Power Transmission Line – User Needs

Vienna, 26-27 January, 2004 36 ULG - Montefiore Institute of Electricity

Jean-Louis Lilien

Lilien@montefiore.ulg.ac.be

Dmitri Snegovskisnegovsk@montefiore.ulg.ac.be

tel.(04) 366-26-30