GE MULTILIN RELAY

[swiminelectricity]

Hi,Folks,

I am still working on SKM TCC DWGs.
The Multilin Settings remains a mystery to me.

On SR-750 setting, it shows: setting1
Inst OC_PU 1.29
O/L PU 2
Ext Inverse 20

On SR469 setting, it shows, setting1
O/L PU 1.15
O/L curves 2
s/c trips 4
s/c delay 500ms


Who is conversant with SKM TCC?

Thank you in advance.

 

[Sanditech]

Have you got the setting software for your mlulilin relays?
If not you can download them from here.

http://www.geindustrial.com/multilin/software/index.htm

When you are in the program for your relay, open a new file and go to page S2 (Settings). There you will find the relevant settings that you can compare with the SKM generic setting termonology you are trying to work with.
I know the 750 relay and the termonology you have been given does not tie into a 750 (O/L Pu is not a 750 setting?)and who would have the Hi set (50)(Inst OC_PU) set below the Lo Set (51) O/L Pu (If thats what it refers to?.
As for Extremeley Inverse 20 This relates to the 51 curve and the 20 must relate to the time multiplier 20mS (if it goes that low).
In a nut shell the SKM terminology has been given is poorly presented to you (as can be seen from your confusion ) and I would seek clarification from the source of that data or from SKM. We all know what assumtions are!!
Hope others may shed some more light on your plight.

The HELP screen on the GE software guides you through the manual if you want clarification on any setting.

SandITech

 

[davidbeach]

SandITech,

In utility distribution feeder protection schemes the 50 element is often (dare I even say usually) set below the 51 element. The 50 element will trip, triggering the first shot of the recloser. Depending on the reclosing scheme, the shot counter will either block the 50 now, or there will be a second shot using the 50 element, then it will be blocked. Subsequent recloser shots will be based on the 51 element tripping the breaker. The initial INST (50) shot(s) are in an effort to let temporary faults clear themselves before any line fuses operate. Once the INST is blocked, the 51 element is set to coordinate with the downstream fuses; allowing any fuse between the breaker and the fault to clear the fault before the breaker operates again.

I have not looked at the SKM library model of that relay (the software is on a different computer), but there is often a problem of trying to use common terminology to describe similar things that different manufacturer's denote differently.

 

[BEPC13]

This is all based on memory so I would still verify it with technical support at SKM. They are usually very helpful.

For the 750
INST OC_PU is the pickup value for the instantaneous 50 element in a multiple of full load amps.

O/L pickup is the pickup level in multiples of full load amps for the 51 element.

EXT INVERSE describes the shape of the curve for the 51 element (ie ANSI Ext Inverse, IEEE Moderately inverse)

The number after EXT INVERSE represents the time dial setting for the 51 element. This adjusts the curve up or down on the TCC. This is similar to electromechanical relays except you have a greater range to select a time dial.

For the 469

O/L PU is the Pick up value for the 51 element in multiples of full load amps. If you read the 469 manual it will tell you this basically disables the O/L curve for amp values below this number. For instance if FLA=100 and O/L PU=1.15 the overload curve will not come into play unless currents exceeds 115A.

O/L Curve 2 describes the curve number selected. In a 469 there are 15 standard curves to select from.

S/C Trip is the pickup value for the 50 element in multiples of Full load amps. For example if FLA is 100 A and S/C Trip is set to 4. That is equall to 400 A.

S/C Delay is the delay of the S/C trip. This can be set to 0 for a true instantaneous trip.