HV discrimination

[mjmarkey1979]

Morning chaps.

First post since I relocated to Australia 3 years ago, good to see this resource still going.

Basically my problem is that I need to confirm whether a Schneider VIP300 protection relay (Is =26A) in the HV cubicle of a 1MVA substation will provide discrimination with some upstream 3 x 40A expulsion drop out fuses (no manufacturing data can be sourced for these) on a HV distribution pole that supplies the substation in question and the adjacent warehouse 750kVA substation. Was going to base EDO's on the relevant Australian standard AS 1033-1 characteristics curve.

Now the program I use in-house only offers LV protection studies, it simply comes down to having both time current characteristics on the same logarithmic scale to prove daylight is there between the two. But I'm having problems trying to a source a program that will let me do this for gratis.

Could any of you chaps know of such resources.

Thanks in advance.

 

[Marmite]

For one simple grading calculation you could easily do it manually. The attached Schneider document goes through the steps and gives the curve formulae for the VIP300.
Regards
Marmite

http://schneider-prod.bsky.net/Inte...protection_relay_for_Ringmaster_MGMV5477.pdf/

 

[desrod]

You might want to check the following site:

http://www.sandc.com/support/tools/coordinaide.asp

I used it in the past for simple cases but now I use commercial software (but that one is free and supported by a reliable company).

Daniel Desrosiers