The receiving Control Area (Load Host) is responsible for initiating confirmation with the delivering Control Area (Generation Host). Final confirmation shall be made no less than 5 minutes prior to implementation of the initial schedule and no less than 5 minutes prior to implementation of any revisions to the initial schedule, unless the changes are necessitated by contingency events. Confirmation means agreement shall be made before either the delivering or receiving Control Area makes any generation changes to implement the interchange schedule.

b. The delivering Control Area will confirm the parameters of each energy transaction with the Generation Entity.

c. The receiving Control Area will confirm the parameters of each energy transaction with the Load Entity.

d. Any change in confirmed energy transactions will be coordinated between the delivering and receiving Control Areas and the ISO. For changes initiated for economic reasons, normal notification lead times will be observed and the changes coordinated through the ISO and the OASIS.

For changes necessitated by contingency events, the Control Areas will take appropriate corrective action immediately and notify the ISO as soon as possible.

e. The ISO will contact the energy transaction requesting entity when consideration of Redispatch is necessary. The requesting entity is responsible for deciding whether Redispatch is to be pursued.

f. For transactions into or out of ERCOT across the HVDC Ties, the ERCOT Control Area will confirm the parameters with the non-ERCOT Control Area

E. INTERCHANGE CLASSIFICATIONS (CONT.)

and with the HVDC Tie operator. Responsibility for transaction scheduling is between the delivering and receiving Control Areas.

NERC Transaction Tags shall be obtained by the ISO for each transaction into or out of ERCOT across the HVDC Ties. There shall be a one-for-one correlation between the transactions on the other side of the HVDC Ties and on the ERCOT side (no aggregation of schedules). The ISO will provide a copy of the NERC Tag(s) to the ERCOT receiving/delivering Control Area.

g. If the delivering or receiving ERCOT Control Area for a HVDC Tie schedule is notified of any curtailments or modifications to that schedule, it must first verify the schedule change with the delivering/receiving Control Area on the other side of the HVDC Tie(s). It must then notify the HVDC Tie operator and then the ISO to be sure that they are informed of the schedule change. Likewise, if the HVDC Tie operator or the ERCOT ISO is notified of any HVDC Tie schedule changes by anyone other than the delivering/receiving ERCOT Control Area, they will immediately contact the ERCOT Control Area to verify and coordinate the change.

h. The ISO will contact the energy transaction requesting entity and the delivering and receiving ERCOT Control Areas and, when appropriate the HVDC Tie operator when issuing transaction curtailment notifications. The ERCOT receiving/delivering Control Area will notify the non-ERCOT Control Area(s) and confirm the needed schedule change(s) with both that Control Area and the HVDC Tie operator.

4. INADVERTENT ENERGY

The hourly difference between a Control Area’s actual net interchange and a Control Area’s scheduled net interchange is classified as inadvertent energy. Unscheduled energy that flows as emergency help, caused by bias, during a frequency disturbance is an example of inadvertent energy.

All inadvertent energy is placed in an Inadvertent Payback Account to be paid back in kind using a transaction designator type I. Inadvertent accounts are not maintained between specific Control Areas, however they must balance to zero within ERCOT. Inadvertent energy is classified as on-peak or off-peak. The clock hours from hour ending 0800 through hour ending 2200 Monday through Saturday shall be considered on-peak while all other hours are off-peak.

a. When the Inadvertent Energy Account of a Control Area exceeds 1000 MWh, the Control Area involved will notify the affected Generation Entities that a request is being made to the ISO to schedule payback to reduce the amount. Control Areas are encouraged to keep the Inadvertent Energy Accounts as low as practical. The payback schedule is between specific Control Areas and

e. Buyer and Seller Obligations

Buyers and sellers of load regulation service may enter into agreements allowing the seller to stop supplying service at any time for any reason. On such occasions, the service provider will automatically revert to any pre-specified backup service supplier and in absence of a backup provider revert to the default provider specified above.

7. Generation-Schedule Imbalance

a. Generation-Schedule Imbalance Definition

Generation-schedule imbalance service compensates for energy mismatches between the scheduled and actual transmission of power between the seller of power and the provider of transmission service in the Generation Host’s Control Area.

b. Operating Applications

This service provides the energy mismatch between what is scheduled, and what is being provided by the seller to the Generation or HVDC Tie Host. These mismatches differ from backup requirements in that they are typically not intended, recognized, or preventable in real time. These mismatches may occur due to factors including, but not limited to, meter calibration errors, telemetry errors, timing errors, governor response, interruption of schedules or HVDC tie trips. This energy differs from inadvertent energy in that the imbalance can only be supplied by the Generation Host or HVDC Tie Host Control Area, not other Control Areas. In cases where the seller and the buyer are in the same Control Area, the energy mismatch will be between the seller and the Generation Host Control Area

c. Requirements

Generation-schedule imbalance service is mandatory and can only be provided by the Generation Host or HVDC Tie Host Control Area (for schedules originating on the SPP side of the HVDC tie). Each Generation Entity must have arrangements with its Generation Host for Generation-Schedule Imbalance service and each Entity scheduling power over the HVDC tie into ERCOT must have arrangements with the HVDC Tie Host Control Area for this service. Typically the amount of service will be determined as the difference between revenue meter readings and energy transaction schedule total amounts for a given period of time.

Generation providers who operate their production plants with their automatic speed governors in service as required in Operating Guide V and who are properly responding to ERCOT system frequency needs shall not incur Generation-Schedule Imbalance service in the amount of

G. APPLICATION OF ANCILLARY SERVICES (CONT.)

generation produced or absorbed that can be attributed to automatic governor actions.

8. Load-Schedule Imbalance

a. Load-Schedule Imbalance Definition

Load-schedule imbalance service compensates for energy mismatches between the scheduled and actual transmission of power between the buyer of power and the provider of transmission service in the Load Host’s Control Area.

b. Operating Applications

This service provides the energy mismatch between what is scheduled, and what is being received by the buyer from the Load or HVDC Tie Host. These mismatches differ from backup requirements in that they are typically not intended, recognized, or preventable in real time. These mismatches may occur due to factors including, but not limited to, meter calibration errors, telemetry errors, timing errors, load swings, interruption of schedules, or HVDC tie trips. This service differs from inadvertent energy in that the imbalance can only be supplied by the Load Host Control Area, not other Control Areas. This service differs from load following in that load following is used to follow the general trend in load. (Refer to Appendix I.G.1.) In cases where the seller and the buyer are in the same Control Area, the energy mismatch will be between the buyer and the Generation Host Control Area.

c. Requirements

Load-schedule imbalance service is mandatory and can only be provided by the Load Host or HVDC Tie Host Control Area (for transactions terminating on the SPP side of the HVDC tie). Each Load Entity must have arrangements with its Load Host for load-schedule imbalance service and each Entity scheduling power over the HVDC tie out of ERCOT must have arrangements with the HVDC Tie Host Control Area for this service.

9. Scheduled Backup

a. Scheduled Backup Definition

Scheduled backup service consists of scheduling services, capacity and energy required to replace a capacity resource on a planned or scheduled basis.

b. Operating Applications

This is a type of backup energy service which is arranged in advance with the scheduled backup supplier. The most common example occurs.

1. At no time shall the rate of change of load scanned at the slower scan rate cause the ACE of the interconnected Control Areas to change more than either can recover in 15 seconds. This slower scan rate is intended only for unidirectional ties that serve loads that have a slow rate of change such as residential loads. Non-conforming loads such as arc furnaces and other fast changing industrial loads do not qualify for the slower scan rate. Generators or interruptible loads will not qualify for the slower scan rate.
2. The total peak value of all unidirectional interconnects scanned at a rate slower than 4 seconds shall not exceed 5% of the yearly peak load of the Control Area.
3. If an interconnection is scanned at a rate less frequently than once every 4 seconds, both Control Areas must agree.

3. Digital Telemetry

a. Definition

Digital telemetry as covered by this guideline is defined as the transmission of data as a series of discrete signal samplings separated by time intervals.

b. Defined Equipment

This Section shall only apply to the remote field equipment (remote terminal units - RTU). All master station equipment located at central control or dispatching locations is excluded.

c. Equipment Standards

Equipment shall conform to ANSI/IEEE C.37.1. For environmental conditions, equipment shall meet Equipment Group 3 for all remote equipment not located in a central dispatching facility.

d. Dual or Multiple Porting

Concurrent scanning of an RTU through multiple communications ports shall be covered under a separate mutual agreement.

e. Accuracy

Minimum accuracy shall be plus or minus the least significant bit of an 11 bit plus sign A/D converter.

4. Analog Telemetry

Analog telemetry may continue to be used on existing installations, however, on all new installations or complete rebuilds of existing installations, digital telemetry shall be used.

a. Definition

Analog telemetry, as covered by this guideline, is defined as a continuous signal telemetry system employing a frequency shifted tone as the means of communications.

 

Date: Start Time of Reactive Test:

Unit Net Load at Time of Test: MW Temperature at Plant (° F):

Gross Generation MW Auxiliary Load MW

Lagging Power Factor: Max. Reactive Capability

Leading Power Factor: Max. Reactive Capability

Operating Hydrogen Pressure during the Test: LB.

VAR Reading Location: Transmission Bus Voltage at the Time of the Test: kV

Auxiliary Bus Voltage kV