2705 West Lake Drive

Taylor, Texas 76574

Ratings Usage Whitepaper

Version 1.0

John Moseley

7/30/2010

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Revision History

Revision / Comments / Date / Author
1.0 / Initial Version / 7/30/2010 / John Moseley

Background

Due to the design of downstream systems, the following are two sets of ratings structures that the NMMS must currently support.

  1. Measurements for storing Ratings
  2. Hierarchy
  3. Equipment {TransformerWindings, ACLineSegments, SeriesCompensator}
  4. Terminal (near = True)
  5. Analog (forNetwork= T , PositiveFlowIn = T)
  6. AnalogLimitSet
  7. AnalogLimit (LimitType = Normal)
  8. AnalogLimit (LimitType = TwoHr)
  9. AnalogLimit (LimitType = FifteenMinute)
  10. Analog (forNetwork= T , PositiveFlowIn = F)
  11. AnalogLimitSet
  12. AnalogLimit (LimitType = Normal)
  13. AnalogLimit (LimitType = TwoHr)
  14. AnalogLimit (LimitType = FifteenMinute)
  15. Terminal (near = False)
  16. Analog (forNetwork= T , PositiveFlowIn = T)
  17. AnalogLimitSet
  18. AnalogLimit (LimitType = Normal)
  19. AnalogLimit (LimitType = TwoHr)
  20. AnalogLimit (LimitType = FifteenMinute)
  21. Analog (forNetwork= T , PositiveFlowIn = F)
  22. AnalogLimitSets
  23. AnalogLimit (LimitType = Normal)
  24. AnalogLimit (LimitType = TwoHr)
  25. AnalogLimit (LimitType = FifteenMinute)
  26. Model Requirements
  27. Atleast one among a.i.1.a and a.i.1.b must be defined at Terminal (near = True)
  28. Atleast one among a.i.2.a and a.i.2.b must be defined at Terminal (near = False)
  1. Consumption(Downstream system that reads this data)
  2. MMS
  3. Utilizes a conservative approach and stores Minimum value for each limit type (Normal, TwoHour, FifteenMinute). i.e.

Normal_Limit = MIN(a.i.1.a.1.1, a.i.1.b.1.1, a.i.2.a.1.1, a.i.2.b.1.1)

TwoHr_Limit = MIN(a.i.1.a.1.2, a.i.1.b.1.2, a.i.2.a.1.2, a.i.2.b.1.2)

FifteenMin_Limit = MIN(a.i.1.a.1.3, a.i.1.b.1.3, a.i.2.a.1.3, a.i.2.b.1.3)

  1. These limits are used as default static limits of the equipment for powerflow studies. (Default i.e. no limit is transferred from EMS to MMS).
  1. EMS
  2. Stored in Netmom with the expectation that all values for the same limit type will be the same i.e.

Normal_Limit = a.i.1.a.1.1 = a.i.1.b.1.1 = a.i.2.a.1.1 = a.i.2.b.1.1

TwoHr_Limit = a.i.1.a.1.2 = a.i.1.b.1.2 = a.i.2.a.1.2 = a.i.2.b.1.2

FifteenMin_Limit = a.i.1.a.1.3 = a.i.1.b.1.3 = a.i.2.a.1.3 = a.i.2.b.1.3

  1. Used as equipment limits when power flow-like studies are run in an environment devoid of realtime telemetery and dynamic limits-override (STNET-type environments) .
  1. OwnerShareRatings for storing Ratings
  2. Hierarchy
  3. Equipment {TransformerWindings, ACLineSegments, SeriesCompensator}
  4. OwnerShareRating (RatedBy = TDSP)
  5. Rating (RatingType = Static)
  6. AnalogLimit (LimitType = Normal)
  7. AnalogLimit (LimitType = TwoHr)
  8. AnalogLimit (LimitType = FifteenMinute)
  9. AnalogLimit (LimitType = Conductor)
  10. Rating (RatingType = Dynamic, activateValue = [20, 25,…, 115,120])
  11. AnalogLimit (LimitType = Normal)
  12. AnalogLimit (LimitType = TwoHr)
  13. AnalogLimit (LimitType = FifteenMinute)
  1. Model Requirements
  2. A single StaticRating (a.i.1.a) must always be defined for an equipment.
  3. 20 temperature-based DynamicRatings must be present when the equipment is dynamically rated.
  4. Mutliple sets of OwnerShareRatings (a.i.1) may be defined when a dynamically rated equipment is jointly rated.
  1. Consumption(Downstream system that reads this data)
  2. Planning
  3. Equipment/Branch limits.
  4. ConductorRating is considered as the third limit.
  5. EMS
  6. For each dynamically rated equipment, all ratings defined under a.i.1 are stored on a per owner basis.
  7. Effective equipment limit is derived from this set for an effective Temperature definition and utilized in power flow studies (RTNET and STNET type environment can use these).

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