Main Supply Conductor question

[Knobhead]

Last time I used one of my master keys was fault finding on a 660V single phase 2.6MVA supply.

Before that I was paralleling 1.6MVA transformers. I’d only just started with the company and was asked if there was a way of defeating the locked key system! As I said my keys are locked in a chest at home.
Close the Bus Section ACB at the same time another guy has his finger on one of the incomer ACB’s trip.
Shout CLOSED
He shouts OPEN.
If it took 2 seconds we were slow!

Yes it’s dangerous (we were exceeding the maximum fault current 50 KA) but at times needs must, RoB2 will tell you how long it takes to go through a kiln controlled shut down, what took 2 seconds would have resulted in two days down time!

Time to hold my hand up. I’m a rotten barsteward!
I closed the BS after I’d checked the feeder currents.
My mate opened the incomer under near 700A load.
If it had gone wrong, he would have copped the full blast!

I’m a rotten barsteward?

I’ve been next to a 3.3KV 1600A ACB when it opened under fault. I needed new underepants!

 

[Knobhead]

I have never seen a room lit like the arc in a 3.3 KV ACB opening under fault!
It is f***ing frightening!

A brilliant blue flash, then everything goes quiet the plant has shut down!
Then it’s think time. Open feeder 1 close BS 1-2 in three 11KV substations! All back and running within ½ an hour!



The brilliant blue flash!
I hold more qualification in photography as I was sponsored by Kodak and Bowens for 10 years.
I couldn’t light a room like that bloody ACB opening!

 

[Hants-Spark]

Tony - Sounds like you've had some fun (is that the right word) in your day, we have a 3.3 & 11KV ring at our place, I've been there when its popped but never within the switchroom itself, a cable fault twice in the same place, joiners didnt have a good day I suspect. Tried to close as fault was unknown to start with but just fired straight through. Out come the diggers

 

[Knobhead]

It wasn’t fun!

I was ---- scared closing the ACB! It would hold, then trip when the system was on light load?

It took me damn near 6 moths to track the fault down. A faulty OLTC unit was causing a 15% voltage rise at the weekends.

 

[Bobster]

I've been in a sub for 2hours with me jamming main contactor for the kiln main drive before.

As you know leaving a hot kiln not turning for longer than 15-20 min starts causing real problems.

 

[Bobster]

And my I really don't like castell key systems. I've always thought anybody with half a brain would figure how to make one.

I've always stuck to fortress systems where I can. Even then I've never had but have seen master keys for fortress systems.

 

[Knobhead]

I've been in a sub for 2hours with me jamming main contactor for the kiln main drive before.

As you know leaving a hot kiln not turning for longer than 15-20 min starts causing real problems.

Bent like a banana!

You wouldn’t believe 1000T of steel and refractory could bend, it does!

 

[Knobhead]

And my I really don't like castell key systems. I've always thought anybody with half a brain would figure how to make one.

I've always stuck to fortress systems where I can. Even then I've never had but have seen master keys for fortress systems.

Simple reason, you can’t get a Fortress Master Key.

I’ve got Castell Master Keys. I made them. As said they are locked away in one of my big tool chests.

They are bloody dangerous! Under no circumstances will anyone else ever get their hands on them. I would be responsible!

 

[Hants-Spark]

Reading the last few threads, it appears masters are obtainable for both Fortress & Castell key systems, a major flaw for both manufactures by the sounds of it. Maybe one system is better than the other but they both serve a purpose, safety, these systems are then complimented by a robust control management system to ensure accidents are prevented. Everyone goes to work happy and leaves work even happier.

 

[brookster]

Reading the last few threads, it appears masters are obtainable for both Fortress & Castell key systems, a major flaw for both manufactures by the sounds of it. Maybe one system is better than the other but they both serve a purpose, safety, these systems are then complimented by a robust control management system to ensure accidents are prevented. Everyone goes to work happy and leaves work even happier.

I don't know about that , not sure I have read and signed the risk assessment for a happiness so until I have I will remain a grumpy bast**d!