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D.C. Municipal Regulations (Last Updated: September 13, 2017) |
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Title 15. PUBLIC UTILITIES AND CABLE TELEVISION |
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Chapter 15-5. FUEL ADJUSTMENT CLAUSE AUDIT AND REVIEW PROGRAM |
Section 15-523. MONTHLY REPORTS
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523.1All monthly reports under this chapter shall be filed no later than forty-five (45) days after the close of the monthly reporting period, unless otherwise specified in this chapter.
APPENDIX 5-1
Definitions of Power Plant Performance Indices1
The following are definitions of performance indices to be used in complying with the Commission's FAC Audit and Review Program:
The fraction of time that a plant is available for operation is called Operating Availability (OA). This parameter is defined by:
OA =
AH × 100
(1)
PH
where
AH = service hours + reserve shutdown hours. Service hours is the number of hours a unit was in the in-service state. Reserve shutdown hours is the number of hours a unit was in the economy shutdown state, and
PH = the number of hours in the period measurement. A unit is not considered "available" when it is forced out of service or is down for planned maintenance. The number of service hours includes the number of hours that a plant operates at rated capacity and at derated capacity due to planned or unplanned partial outages. The operating availability measures the percentage of time that a unit is capable of producing power at any power level.
In order to account for the effects of partial outages in the measurement of availability, the parameter Equivalent Availability (EA) has been defined. This parameter is defined by:
EA =
AH - (EFOH + ESOH) × 100
(2)
PH
Where
EFOH=
Forced Partial Outage Hours Size of Reduction in MW
MDC
ESOH=
Scheduled Partial Outage Hours × Size of Reduction in MW
MDC
and
1Sources:
(1)National Regulatory Research Institute, Recommendations For Regulatory Actions To Promote Power Plant Productivity Improvements (Columbus, Ohio: NRRI, August 1979); pp. 8-11.
(2)Institute of Electrical and Electronics Engineers, IEEE Trial-use Standard Definitions For Use In Reporting Electrical Generating Unit Reliability, Availability and Productivity (New York, New York.: IEEE, December 1980).
MDC = Maximum dependable capacity in MW.
The equivalent availability is a measure of the unit's true ability to produce power since it takes into account partial outages. This index is important since it is possible to have a unit with one hundred percent (100%) availability but with less than one hundred percent (100%) equivalent availability. Operating availability can be used to indicate the percentage of time the unit is fully out of service. When compared to operating availability, equivalent availability can be used to indicate the additional loss in production capability due to partial outages.
The Capacity Factor is a measure of the actual output (MWh) of a unit within a specified time period relative to its potential output.
The Capacity Factor (CF) is defined by:
CF =
Total Gross Generation in MWh × 100
(3)
(PH) × (MDC)
The "Total Gross Generation," equation (3), can be affected by factors other than forced or scheduled outages. The factors include economy dispatch and regulatory deratings. If there is no economy dispatch (base-loaded plants) and no deratings other than those due to forced or scheduled partial outages, then the capacity factor approaches the equivalent availability.
The Heat Rate is a measure of the thermal efficiency of a generating unit. It is defined by:
Heat Rate (BTU/kWh) =
(BTU Fuel) × (Heat Input)
(4)
kWh Output
The Heat Rate represents the fuel-heat input required to generate a kWh and deliver the generated power to the transmission line leaving the station. The heat rate is inversely proportional to the unit's efficiency.
A parameter used to express a plant's total unavailability due to full forced outages (i.e., unscheduled outages) is the Forced Outage Rate.
This parameter is defined as:
FOR =
FOH × 100
(5)
SH+FOH
where
FOH = Full forced outage hours, and
SH = Service hours.
or
FOF(Forced Outage Factor) =
FOH × 100
(5A)
PH
where
PH = Period hours.
Partial forced outages are taken into account by defining an Equivalent Forced Outage Rate. This parameter is defined as:
EFOR =
FOH + EFOH × 100
(6)
FOH+SH
or
EFOF Equivalent Forced Outage Factor) =
FOH + EFOH × 100
(6A)
PH
A parameter is used to express a plant's unavailability due to scheduled outages planned well in advance is the Planned Outage Rate (POR).
This parameter is defined by:
POR =
POH × 100
(7)
PH
where
POH = planned outage hours, or the numbers of hours a unit was in the planned outage state'.
A parameter used to express a plant's unavailability due to maintenance outages is the Maintenance Outage Rate (Class 4 outage)
This parameter is defined by:
MDR =
MOH × 100
(8)
PH
where
MOH = maintenance outage hours.
2 Unplanned outage hours (UOH) are the number of hours a unit is in the unplanned outage state. IEEE identifies five (5) unplanned outage classes. These are:
Class 1 Unplanned Outage (Immediate). An outage that requires immediate removal from the available state or prevents a unit from being placed in service if off line. A starting failure shall be signed as a Class 1 unplanned outage.
Class 2 Unplanned Outage (Delayed). An outage that does not require immediate removal from the available state but requires that a unit be removed from the available state within six (6) hours.
Class 3 Unplanned Outage (Postponed). An outage that can be postponed beyond six (6) hours but requires that a unit be removed from the available state before the end of the next week-end.
Class 4 Unplanned Outage (Deferred). An outage that will allow a unit outage to be deferred beyond the end of the next week-end but which requires that a unit be removed from the available state before the next planned outage.
Class 5 Unplanned Outage (Extended). An outage that is the extension (for any reason except startup failure) of a planned outage beyond its predetermined duration.
IEEE Trial-Use Standard Definitions For Use In Reporting Electric Generating Unit Reliability, Availability, and Productivity), Institute of Electrical and Electronics Engineers: New York, New York, 1980; p.8.