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Under/Overvoltage relay

asked 2014-03-07 08:56:37 -0500

Diz gravatar image

updated 2014-03-07 08:59:25 -0500

Hi Everyone, I am trying to implement Over/Under voltage relay at a bus. The only relay model I can see is VTGDCAT/VTGTPAT in miscellaneous other models but the problem with these model is the breaker time should be same for upper and lower voltage threshold. My question is how to write a python code so that we can have different breaker time for different upper and lower threshold voltage as below ?

V (pu) = 1.1, 1.05, 0.9, 0.7 time(s)= 1, 5, 3, 2
and so on...

Thanks

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@yfing, Thanks for you quick response. When you say each bus do you mean adding three more fictitious buses ? I recall we cannot add same relay more than one in same bus.

Diz gravatar imageDiz ( 2014-03-07 11:18:49 -0500 )edit

You can have same relay being used more than once for the same bus. The value of MINS (below on my answers) has to be unique.

jconto gravatar imagejconto ( 2014-03-07 12:13:57 -0500 )edit

@jconto, Appreciate your response, that helped.

Diz gravatar imageDiz ( 2014-03-10 09:39:23 -0500 )edit

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answered 2014-03-07 11:02:24 -0500

yfwing gravatar image

In your case, I would use four VTGDCAT/VTGTPAT models for each bus. The first two relays are for over voltage relay (i.e., the VL can be set at a very low value). The last two relays are for under voltage relay (i.e., the VU can be set at a very high value). For your particular example, it could be

Model 1: VU = 1.1, VL = 0.2, TP = 1.0, TB = 0.0

Model 2: VU = 1.05, VL = 0.2, TP = 5.0, TB = 0.0

Model 3: VU = 1.5, VL = 0.9, TP = 3.0, TB = 0.0

Model 4: VU = 1.5, VL = 0.7, TP = 2.0, TB = 0.0

TB is an arbitrary number that I put there. You can change it based on your real value.

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Please mention the data for under frequency relay. Thanks in advance

gajendra gravatar imagegajendra ( 2019-04-03 00:28:38 -0500 )edit
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answered 2014-03-07 12:09:59 -0500

jconto gravatar image

You can have different breaker values. The trick is to separate the UV relay definition from the OV by using more than one relay record. The example below is for a VRT relay schema.

/MINS model     M     M+1 M+2  VL   VU    TP    TB  /
1     'VTGTPAT' XXXX  xxx xx   -1   1.3   0.034 0.1 /
2     'VTGTPAT' XXXX  xxx xx   -1   1.2   0.5   0.1 / 
3     'VTGTPAT' XXXX  xxx xx   -1   1.1   5     0.1 / 
4     'VTGTPAT' XXXX  xxx xx  0.1   5     0.15  0.12 / 
5     'VTGTPAT' XXXX  xxx xx  0.9   5     3     0.12 /
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Asked: 2014-03-07 08:56:37 -0500

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Last updated: Mar 07 '14