TPL-003-0b: System Performance Following Loss of Two or More Bulk Electric System Elements

System simulations and associated assessments are needed periodically to ensure  that reliable systems are developed that meet specified performance requirements, with sufficient lead time and continue to be modified or upgraded as necessary to meet present and future System needs.


Effective Date
April 23, 2010

R1. The Planning Authority and Transmission Planner shall each demonstrate through a valid assessment that its portion of the interconnected transmission systems is planned such that the network can be operated to supply projected customer demands and projected Firm (nonrecallable reserved) Transmission Services, at all demand Levels over the range of forecast  system demands, under the contingency conditions as defined in Category C of Table I  (attached). The controlled interruption of customer Demand, the planned removal of  generators, or the Curtailment of firm (non-recallable reserved) power transfers may be  necessary to meet this standard.  To be valid, the Planning Authority and Transmission Planner  assessments shall:

R1.1. Be made annually.

R1.2. Be conducted for near-term (years one through five) and longer-term (years six  through ten) planning horizons.

R1.3. Be supported by a current or past study and/or system simulation testing that  addresses each of the following categories, showing system performance following Category C of Table 1 (multiple contingencies).  The specific elements selected (from each of the following categories) for inclusion in these studies and simulations shall be acceptable to the associated Regional Reliability Organization(s).

R1.3.1. Be performed and evaluated only for those Category C contingencies that  would produce the more severe system results or impacts. The rationale for the contingencies selected for evaluation shall be available as supporting information. An explanation of why the remaining simulations would produce less severe system results shall be available as supporting information.

R1.3.2. Cover critical system conditions and study years as deemed appropriate by the responsible entity.

R1.3.3. Be conducted annually unless changes to system conditions do not warrant  such analyses.

R1.3.4. Be conducted beyond the five-year horizon only as needed to address  identified marginal conditions that may have longer lead-time solutions.

R1.3.5. Have all projected firm transfers modeled.

R1.3.6. Be performed and evaluated for selected demand levels over the range of forecast system demands.

R1.3.7. Demonstrate that System performance meets Table 1 for Category C contingencies.

R1.3.8. Include existing and planned facilities.

R1.3.9. Include Reactive Power resources to ensure that adequate reactive resources  are available to meet System performance.

R1.3.10. Include the effects of existing and planned protection systems, including any  backup or redundant systems.

R1.3.11. Include the effects of existing and planned control devices.

R1.3.12. Include the planned (including maintenance) outage of any bulk electric  equipment (including protection systems or their components) at those Demand levels for which planned (including maintenance) outages are performed.

R1.4. Address any planned upgrades needed to meet the performance requirements of Category C.

R1.5. Consider all contingencies applicable to Category C.

R2. When system simulations indicate an inability of the systems to respond as prescribed in  Reliability Standard TPL-003-0_R1, the Planning Authority and Transmission Planner shall each:

R2.1. Provide a written summary of its plans to achieve the required system performance as  described above throughout the planning horizon:

R2.1.1. Including a schedule for implementation.

R2.1.2. Including a discussion of expected required in-service dates of facilities.

R2.1.3. Consider lead times necessary to implement plans.

R2.2. Review, in subsequent annual assessments, (where sufficient lead time exists), the continuing need for identified system facilities.  Detailed implementation plans are not needed.

R3. The Planning Authority and Transmission Planner shall each document the results of these Reliability Assessments and corrective plans and shall annually provide these to its respective NERC Regional Reliability Organization(s), as required by the Regional Reliability  Organization.

M1. The Planning Authority and Transmission Planner shall have a valid assessment and corrective plans as specified in Reliability Standard TPL-003-0_R1 and TPL-003-0_R2.

M2. The Planning Authority and Transmission Planner shall have evidence it reported documentation of results of its reliability assessments and corrective plans per Reliability Standard TPL-003-0_R3.

TPL-004-0a - Transmission System Standards

TPL-003-0b - Appendix1

TPL-003-0b - Appendix1cont1

TPL-003-0b - Appendix1cont2



TPL-003-0b - Appendix2 TPL-003-0b - Appendix2cont1 TPL-003-0b - Appendix2cont2 TPL-003-0b - Appendix2cont3 TPL-003-0b - Appendix2cont4

TPL-003-0b - Appendix2cont5