Relay Parameter & TCC Setting in SKM 3

[sak3281]

Dear All

Being new user of SKM PTW, I have the following questions for the attached files.

In the attached file named: "VAMP-40 Settings" the relay component editor is shown. The first Parameter is I> (0.1-5 x PA), what PA stands for? The second parameter is " IEC Normal Inv." and in the Settings-1 we see as 0.1. What is 0.1. Is it time in seconds?

In the second attached file named "TCC Settings" we can see Current Multiplier and Time Multiplier. In this case the FLA of the motor was 197.5A and the CT ratio is 1600/5A, so I choosed Current Multiplier = 197.5/1600 = 0.12. Is it correct value of Current Multiplier? How I can calculate time multiplier?

Looking forward for your help. Thanks

 

[dpc]

PA = Primary Amps, I would assume.

The time multiplier is hand-picked by you, not calculated.

The software is simply trying to emulate the available settings in the relays. You should review the instruction booklets for the relays to gain an understanding of how they work and the various settings available.

For software-specific questions, the best resource would be SKM tech support.



David Castor

http://www.cvoes.com

 

[EddyWirbelstrom]

VAMP-40 Relay ( 50/51 )
Open the library by clicking on the library icon ( 6th icon from the left ).
Go CAPTOR > Relays > Electronic and select the relay VAMP 230/245/255 ( for ANSI 50/51 ).
Click on the Trip Curves tab of the library dialog box.

The curve segment I>, (0.1-5 x PA) is for the Long Time Pickup segment which has a setting range of 0.1 to 5 x Primary Amps.

The next curve segment is for the inverse ( IDMT curve) for an IEC Normal Inverse ( also referred to as Standard Inverse ) curve ( as opposed to a IEEE curve ).
Trip time = 0.14 * TMS // ( PSM0.02 -1 )
Where :
• TMS = Time Multiplier Setting ( usually from 0.1 to 1.0, but for the VAMP 0.05 to 20 )
• PSM = Plug Setting Multiplier ( multiple of the Long Time Pickup Current I> ) setting current


I>> = Short-Time-Pickup Current as a multiple of Primary Amps with setting range 0.1 to 20 times Primary Amps.

I>> ( should be t>> ) Definite time delay in seconds.


TCC Settings
The Pickup Calculation ‘’Tap* Primary Amps’’ means that the Io> pickup current will be
Tap setting * CT primary amps. In your case Io> pickup amps = 0.1 * 1600 – 160A.

 

[sak3281]

@EddyWirbelstrom, Sir Thanks alot for the effort and explanation.

If we go to any TCC and select the curve of any relay, right click, click Selected device TCC Settings (see attached Image), there is Time Multiplier and Current Multiplier. What is the importance of this and how we can calculate these both.

How we can utilitze the above explanation given by you. Normally when we add a relay, we double click on it and chnage the settings in component editor for the relay. What is the advantage in doing the settings from library (as explained by you) rather then changing it from component editor.

Waiting for your valueable reply. Thanks

 

[EddyWirbelstrom]

Relay settings are not applied in the library.
I mentioned the library only to show how the relay device was built, and to describe the curve elements.
One only needs to go the library to edit a device, or check how is was built.

Relay settings can only be entered via the Component Editor, or via the Settings tab of the TCC.


TCC Device-Setting Multiplier
The current multiplier is used to offset the curve.
eg.
Assume two identical transformers supply a switchboard.
Assume a fault occurs on the loadside of an outgoing breaker from the switchboard.
The outgoing breaker will experience twice the current of one of the transformer breakers.
When determining grading between the transformer relay and the outgoing circuit breaker, the overcurrent curve for the transformer would have to be offset by a factor of two because it experiences only half the current experienced by the outgoing circuit breaker.
This offset can be achieved by setting the Current Multiplier of the transformer relay to 2.

The preferred way of achieving this offset is to leave the Current Multipler set to 1.0, and to use the 'Branch Fault Current Through Protective Device’ and select the ‘Reference’ relay.
In our above example the reference relay would be the outgoing circuit breaker.
Both transformer relays would automatically be offset by the ratio of current through the outgoing circuit breaker to current through the transformer relays.
This is a very useful facility in situations where there are multiple parallel incomers to a board and one outgoing relay must grade with the multiple parallel incomers, all of which will be offset by the ratio of current through the outgoing breaker to current through each of the incomers.

The Time Multiplier is an extension to the relay Time Multiplier.
I can not imagine a use for it if the relay library is built with the correct Time Multiplier setting range.
Leave the Time Multiplier at 1.0

I can not imagine a use for the Time Adder.
I recommend leaving the Current Multipler at 1.0, Time Multipler at 1.0, and Time adder at 0.0 sec.

The comprehensive manuals at C:\PTW\Doc describe the above in more detail.
Also try the F1 help key which is context sensitive.
You can also check the FAQs at

http://www.skm.com

 

[sak3281]

Thanks alot for detailed explanation.