Causes of humming sound in a transmission line (below 220 KV) other than corona effect

[bikashbraghu]

A humming sound (louder, not normal, & as if house-hold meter abnormal sound) heard near one of the 132 kV Transmission line tower, after its operation since 6 years. The transmission line Conductor used is Cardinall with Current Load - max 70 MW. The louder humming sound seems increased from past week, disturbing the nearby resident.

The other arm of the tower hold the other circuit (recently stringed) and currently not energised.

I suppose the effect is not a corona, please suggest what might be the alarming situation to the Power supply system and to the residents nearyby ?

 

[pwrtran]

If it is not corona it might be some mechanical vibration around 60Hz

 

[davidbeach]

I think that the answer is in the question; you added that other circuit. Somehow there is now a resonant tuning that didn't exist before. Is the sound at, or a harmonic of, the power system frequency, or is the frequency unrelated to the power system? The new line could be just right (wrong?) to become an aeolian harp. Dampers or a different line tension may be required.

 

[FPelec]

Adding another circuit could also have worsened electric field and thus corona. The new circuit is currently grounded? Have you tried to unground it (or vice versa to ground it, if it is currenty grounded)?

Si duri puer ingeni videtur,
preconem facias vel architectum.

 

[FPelec]

Sorry, I've realized only now that the voltage level is "only" 132 kV and not 220 kV. At this voltage level corona should not be an issue: most probably the problem is related to aeolian vibrations as davidbeach said.

Si duri puer ingeni videtur,
preconem facias vel architectum.