MEDIUM VOLTAGE PROTECTIVE RELAY MODELING - SKM POWER TOOLS

[PE (always learning)]

Hey Everyone,

I'm a little new to medium voltage protective relays and I was needing some help with modeling the proper devices in SKM power tools. I'm working with a M20 Sepam Protective Relay and I'm trying to make sure I choose the right information in SKM power tools. This relay is located inside a MCC that feeds a 450 HP Pump. I have attached a picture of the relay and a picture of my options in the SKM library. Can someone please help me with correctly choosing the right information. Is there a way to tell if this relay is DT (Definitive Time) or IDMT (Inverse Definitive Minimum Time)? Also, I'm assuming that this relay is providing protecting for both phase and ground fault. Is there a trick to modeling these properly in SKM?

Best Regards

 

[ron]

The Sepam M20 is a multifunction relay and can do any or all of.

Of course it can do DT or IDMT. Check Page 37 of this PDF https://download.schneider-electric.com/files?p_Doc_Ref=PCRED301005EN

 

[PE (always learning)]

I guess my question was more along the line of can I tell whether or not this protective relay is specified as DT or IDMT. It seems like the unit can be specified as one or the other but not both. Maybe I'm just getting confused with the selections on SKM.

 

[ron]

SKM can plot any of those library entries because the relay can be programmed for any of those settings.
You can protect the motor in any of those fashions. If it is existing, the only way to know what is in the current setting, is to scroll through.
The best way I've found in SKM to understand the different library entries is to show the motor performance curve, then plot each of the library entries and see which you like and which has adjustments that make sense.

Depending on how you set them, you can use the IDMT as the long time pickup and delay portion of the curve and the DT as the short time pickup part of the curve and make it look like a low voltage breaker overall. Or you can use them with separate characteristics with a gap between and they will look more like a 51 relay curve (IDMT) and a horizontal line (DT) (50).
.