Etap Knowledge Base: Tie-pd Loops

ETAP Knowledge Base

Tie-PD Loops Description: The system contains one or more tie-PD loops Category:

Short Circuit

Type:

Error

Keywords:

One or more tie-PD loops

Calculation Warning: The system contains one or more tie-PD loops and the fault current through the PDs cannot be determined. The short-circuit contributions through these PDs will not be reported. System Description:

This document is confidential and proprietary to Operation Technology, Inc. and may not be reproduced, published or disclosed to others without the written authorization of Operation Technology, Inc., 17 Goodyear, Suite 100, Irvine, CA 92618, USA. © 2010 by Operation Technology, Inc. All Rights Reserved.

© Operation Technology, Inc.

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Tie-PD Loops The calculation warning you get is caused if you have a situation as shown above. This is a simple case when you have more than one Tie PD forming a loop in case of a wheeling system. The program is warning you that it determined the contribution from Bus 2 to Bus 1 as 0.575 kA but cannot calculate the current flowing through each PD (CB1 and CB2), as it does not know the current split in this case. Therefore even though the sum total is 25.1 + 0.575 = 25.7 kA, the 0.575 kA is not reported in the output report. The total on Bus 1 however will be reported as the correct number 25.7kA. Therefore, this does not impact the calculation accuracy or reported totals, but is only missing the reported contribution from Bus 2 to Bus 1.

This document is confidential and proprietary to Operation Technology, Inc. and may not be reproduced, published or disclosed to others without the written authorization of Operation Technology, Inc., 17 Goodyear, Suite 100, Irvine, CA 92618, USA. © 2010 by Operation Technology, Inc. All Rights Reserved.

© Operation Technology, Inc.

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