Attached are two images of a 345KV manual disconnect.

This is one of two parallel paths through which flows a total of 1250MW. (You can calculate the total current from that if you want).

(This is the generator bay in a breaker and a half scheme.)

First reading waS 64c rise in a 7.5 mph wind.

Second reading two days later approx 10C rise in a 2.5 mph wind.

The total loading has not changed. Division of load between the two parallel paths is unknown (I assume it splits based on impedance of the two paths).

How serious would you view this? What do you make of the fact that it has gone down? What would you consider the risks would be if switching was done that opened the parallel path to put all the load through this hotspot?

Thx

This message has been edited. Last edited by: electricpete,

Y601_Disconnect.ppt (416 Kb, 95 downloads)

E-Pete
One thing I noticed is the two are at different angles which can make a difference.

64C is very significant. The drop could be due to a couple of things (the angle as the other poster mentioned) also if there has been a fusing (welding) in the connection the resistance may have dropped as well. Also was the disconnect been operated and how long has it been since the last operation?

I would definitely keep an eye on it.

Pete,

I agree with BWC, we had a similar problem on a 13.4kV switch. Our IR tech trended it for weeks since the entire facility would have to shut down to separate this switch. DeltaT's all over the place. It did not want to move when it came time to pull it but once it moved, it moved free. Getting it started apparently took some heft. He also recorded a substantial increase in deltaT just before the shutdown [about 75F but this one is much smaller & lighter than yours]. Still, Wouldn't have lasted much longer. Slightly loose hinge/pivot bolt allowed a reduced contact pressure >>Poor internal contact...zzzzzZZZZT.

Dana

PS.
In that light I've attached a short clip...you may have seen it already but it's neat just the same

LugoSWR-1.mpeg (1,559 Kb, 54 downloads) Ooh-Hot!