Static Exciter Field Cables

[CaptElectron]

I was recently told that the field cables for Static Excitation Systems need to be rated for 10 time (10x) the max exciter voltage… is that true?... is it in an IEEE Spec somewhere?

For example, I’m spec’ing a cable a for a static exciter field run that will have 240 V (nominal) and 360 V (max). Do I need a 4 or 5 kV cable?

I’ve looked in my IEEE standards, surfed the websites of cable and exciter manufacturers, and searched on Eng-Tip but to no avail.

Any help will be appreciated.

Thanks,
CaptElectron

 

[BigJohn1]

I'm not an engineer, but if what you say is true we have many, many miswired static exciters. All our exciters, ranging from 50 to 400 volts, are installed with nothing more than ordinary 600V wire, and these are all separately engineered installations.

I'm kind of curious where the 10X transients would be expected to come from...?

-John

 

[mgtrp]

I'm also not used to seeing HV cables for excitation. The field winding would not typically be rated for such high voltages, so why should the cables be?

The crow-bar circuit should stop the worst of the over voltages that might occur.

 

[ScottyUK]

You may have a static exciter with high field forcing capability, so the exciter can push out mucher high voltage and current under transient conditions than the continuous rating of the exciter. Forcing factors of six aren't uncommon, perhaps higher if requried by the TSO. Other than that, I can't imagine why you would need a voltage margin of 10x rating on the cables.


----------------------------------

If we learn from our mistakes I'm getting a great education!

 

[CaptElectron]

Thank you all for the responses. I'm going to look into the field forcing capabilities of the excitation system and I'll post again with what we've decided to do.

 

[edison123]

A new rotor winding of synchronous generators, motors etc. as per standards, has to be tested for 10 times the rated rotor voltage with a minimum of 1.5 KV and a maximum of 4 KV + twice the rated voltage.

This could account for the test level rating of your exciter cable, which is a part of the rotor circuit.

Muthu

http://www.edison.co.in