FPL TRMID

Revision 4

Effective Date 8/12/2013

FPL Transmission Reliability Margin Implementation Document

Revision History

Rev / Changes / Author / Approver / Date
0 / Initial Draft / JCR/DAMc / DAMc / 3/24/11
1 / Modifications to section 2 B. Minor changes elsewhere. / AJA/DAMc / DAMc / 1/11/12
2 / Modification to sections 2A, 2B, and 2D / MT/DAMc / DAMc / 7/16/2012
3 / Specified application of L10 TRM to all horizons. Clarifying language to how TRM is calculated / DAMc / DAMc / 4/12/2013
4 / Removed TRM for FPL export to southern / BMB / DAMc / 8/9/2013


Transmission Reliability Margin Implementation Document (TRMID)

I.  Introduction

A.  Background

Florida Power and Light (FPL), as a Transmission Operator, applies a Transmission Reliability Margin (TRM) to its transmission paths as permitted by the NERC MOD standards (MOD-008 and MOD-028).

B.  Purpose

This document serves as FPL’s TRMID and explains the methodology utilized by FPL to calculate and use TRM for its transmission system operations.

II.  TRM Calculation (MOD-008 R1, R2)

A.  General

FPL uses variation in generation dispatch components of uncertainty for individual ATC paths. This component is applied to all time intervals.

FPL’s paths involving the Southern sub-region have a contractual as well as a physical limitation. The application of TRM on paths where Southern is the point of receipt is described in section B of this document.

B.  TRM Components (Mod-008 R1.1, R1.2)

FPL uses the following components in its TRM calculation.

Variation in Generation Dispatch (Critical Unit Offline)

This component of TRM is meant to reflect the uncertainty in generation dispatch; specifically forced or unplanned outages of a unit that has a significant impact on Available Transfer Capability.

The generation uncertainty component of TRM is developed from the FRCC Transmission Working group topology model used for the TTC calculations. The First Contingency Incremental Transfer Capability (FCITC) is determined for all paths assuming all generating units are available and dispatched economically or as required for local area protection as specified by the individual TOPs (according to MOD-28 R6.1 & R6.2). New FCITC are then developed assuming that individual generating units critical to the transfer are unavailable. The TRM per path is the difference between the lowest FCITC with a critical unit off and the FCITC established when the unit was dispatched.

This component of TRM is used on all posted ATC paths. The calculations are done on an individual path basis so the allocation is 100% on that path. This TRM is released as non-firm for all horizons.

Variation in Generation Dispatch (L10) applied to Southern Allocation

The TTC on FPL’s Southern paths is the lower of FPL’s contractual allocation or the calculated TTC limit for the specific path. For the calculated TTC specific path limit the TRM component described above is applied. For the contractual import allocation a TRM based on the L10 control performance metric (BAL-001-0.1a R2) is used. This TRM applies only to the contractual allocation and only on paths where Southern is the point of receipt. This TRM is described in further detail in the “TTC Methodology for the Southern Interface”. This contractual TRM is applied in the scheduling, operating and planning horizons and is released as non-firm in all horizons.

C.  TRM Use and Calculation Frequencies (MOD-008 R1.3, R4)

Same Day and Real-Time (Scheduling Horizon)

The TRM applied is the Variations in Generation Dispatch component based on a critical unit offline (Even though no hourly firm transmission is offer).

Day-Ahead and Pre-Schedule (Operating Horizon)

For the above horizon, the TRM applied is the Variations in Generation Dispatch component based on a critical unit offline.

Beyond Day-Ahead and Pre-Schedule up to Thirteen Months (Planning Horizon)

The TRM applied is the Variations in Generation Dispatch component based on a critical unit offline.

Calculation Frequencies

The two Variations in Generation Dispatch components of TRM are calculated by FPL once per year.

D.  TRM Communication (MOD-008 R3, R5)

FPL functions as a Transmission Service Provider and Transmission Planner as well as a Transmission Operator. It communicates its TRM values through the posting of these values to the online reservation evaluation software to which the above entities have access.

This TRMID is posted on FPL’s public OASIS website, the site for FRCC Operating Entities, and will be provided, along with any underlying documentation, within 30 days of a written request by any of the following entities: Transmission Service Providers, Reliability Coordinators, Planning Coordinators, Transmission Planners, and Transmission Operators.

FRCC Operating Entities Posting Area- BAs/TOPs

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