Definition of Terms

It would be interesting if you could reflect these questions back to him for spelling confirmations and answers.

I found a B-harp....

Again thanks for the laugh, I did try finding an aardvark playing a harp with no luck, I wonder if he said "an arc"?? G.A. from me.....

Maybe he meant this kind of harp....

Other worldy sounds of a power line

Is this what was being referred to?

There's a thing called Google, which answers any question one throws at it. It's a good first stop.

Others seem to have pointed to meanings of words you mention, except to A HARP in a serious way.

I cannot help either but to say that it is possibly a slang term or acronym referring to the fact that when transmission lines are first energised, they so not suddenly and cleanly get to the specified AC signal levels immediately.

All electrical circuits have an inductive and capacitive component in them and so delay and some ringing around the target value is likely.

Transformers do not fire up immediately for example. They take from a few to thousands of cycles to saturate and come into equilibrium and generate harmonics in the process.

I could not imagine that other than a pulse of some sort would propagate quickly, but at a finite speed down the line that was being energised.

The term a HARP could, for example, be short for "a Harmonic and Reaction Pulse"

HV transmission lines will make a sound based on their being induced to vibrate at their natural frequency if not dampened. When that happens, it's referred to as a "harp effect". We mostly don't hear it specifically because it's a known phenomenon now and dampening is built in to the transmission towers and supports. Occasionally however the standard dampening doesn't work and weights are added to the wires mid span. I learned this from a friend in the T&D side of the industry after asking him about some weights I observed.

Valve Hall: this is a water cooled array of thyristors hung from roof beams. the valve can weigh 20-30 tonnes. Most valve nowadays are using light to produce an electrical signal. The light being converted to produce electricity via light sensitive semi condictor segments.

The valve cooling water is pure water and is an insulator for the valve and cools the valve when the converter station is under load.Large water purification systems are installed to ensure the water does not conduct while cooling valves.

Valve are hung from the valve hall roof to be earth quake proof.

A Harp. Many names for the phenomenon of seeing a voltage as a blue haze progressing along a conductor when first energised. This is also common on AC lines under certain atmospheric conditions. On DC lines there is a sharp spike in voltage then it settles to the input voltage of say 400-600kV. It can be summed up, (imagined), as a single huge wave approaching a beech and the following waves being the normal flow thereafter.

The voltage must not exceed 1.5 times its normal value and the voltage peak must not last longer than 1second, so to reduce this spike shunt reactors are installed

By "a-harp" he may have been referring to the sound and/or visual effect similar to that produced by an instrument called an aolean harp, a special kind of harp that is literally "played" by the wind.

From the wiki: "The effect can sometimes be observed in overhead utility lines, fast enough to be heard or slow enough to be seen."

These vibrations can become of such magnitude that they can put undue stress on lines, and so you'll see a device called a Stockbridge Damper attached to (typically high-tension) suppress these vibrations.

aeolean, not aolean