Project 2009-14
Interpretation − TPL-002-0 − PacifiCorp

Status:
The interpretation was approved by the NERC Board of Trustees on November 5, 2009.

Summary:

The request asks to clarify the following: Does TPL-002-0 R1.3.10 require that all elements that are expected to be removed from service through normal operation of the protection systems be removed in simulations?  Is a Category B disturbance limited to faults with normal clearing where the protection system operates as designed in the time expected with proper functioning of the protection system(s) or do Category B disturbances extend to protection system misoperations and failures? Does TPL-002-0 R1.3.10 require that planning for Category B contingencies assume a contingency that results in something other than a normal clearing event even though the TPL-002-0 Table I - Category B matrix uses the phrase "SLG or 3-Phase Fault, with Normal Clearing"?

Purpose/Industry Need:
In accordance with the Reliability Standards Development Procedure, the interpretation must be posted for a 30-day pre-ballot review, and then balloted.  There is no public comment period for an interpretation.  Balloting will be conducted following the same method used for balloting standards.  If the interpretation is approved by its ballot pool, then the interpretation will be appended to the standard and will become effective when adopted by the NERC Board of Trustees and approved by the applicable regulatory authorities.  The interpretation will remain appended to the standard until the standard is revised through the normal standards development process.  When the standard is revised, the clarifications provided by the interpretation will be incorporated into the revised standard.