Glossary - r

Term/Acronym

Definition

Conductor/Transformer 2-Hour Rating
The two-hour MVA rating of the conductor or transformer only, excluding substation terminal equipment in series with a conductor or transformer, at the applicable ambient temperature. The conductor or transformer can operate at this rating for two hours without violation of National Electrical Safety Code (NESC) clearances or equipment failure.

Emergency Rating
The two-hour MVA rating of a Transmission Element, including substation terminal equipment in series with a conductor or transformer, at the applicable ambient temperature. The Transmission Element can operate at this rating for two hours without violation of NESC clearances or equipment failure.

15-Minute Rating
The 15-minute MVA rating of a Transmission Element, including substation terminal equipment in series with a conductor or transformer, at the applicable ambient temperature and with a step increase from a prior loading up to 90% of the Normal Rating. The Transmission Element can operate at this rating for 15 minutes, assuming its pre-contingency loading up to 90% of the Normal Rating limit at the applicable ambient temperature, without violation of NESC clearances or equipment failure. This rating takes advantage of the time delay associated with heating of a conductor or transformer following a sudden increase in current.

Normal Rating
The continuous MVA rating of a Transmission Element, including substation terminal equipment in series with a conductor or transformer, at the applicable ambient temperature. The Transmission Element can operate at this rating indefinitely without damage, or violation of NESC clearances.

• Normal Ramp Rate curve;
• Emergency Ramp Rate curve;
• Minimum On-Line time;
• Minimum Off-Line time;
• Hot start time;
• Intermediate start time;
• Cold start time;
• Maximum weekly starts;
• Maximum On-Line time;
• Maximum daily starts;
• Maximum weekly energy;
• Hot-to-intermediate time;
• Intermediate-to-cold time;
• Minimum interruption time;
• Minimum restoration time;
• Maximum weekly deployments;
• Maximum interruption time;
• Maximum daily deployments;
• Minimum notice time; and
• Maximum deployment time.

The evaluation of a proposed transmission project pursuant to the process described in Section 3.11.4, Regional Planning Group Project Review Process.

An Ancillary Service that consists of either Regulation Down Service (Reg-Down) or Regulation Up Service (Reg-Up)

An Ancillary Service that provides capacity that can respond to signals from ERCOT within three to five seconds to respond to changes in system frequency. Such capacity is the amount available below any Base Point but above the LSL of a Generation Resource and may be called on to change output as necessary throughout the range of capacity available to maintain proper system frequency. A Load Resource providing Reg-Down must be able to increase and decrease Load as deployed within its Ancillary Service Schedule for Reg-Down below the Load Resource’s MPC limit.

An Ancillary Service that provides capacity that can respond to signals from ERCOT within three to five seconds to respond to changes in system frequency. Such capacity is the amount available above any Base Point but below the HSL of a Generation Resource and may be called on to change output as necessary throughout the range of capacity available to maintain proper system frequency. A Load Resource providing Reg-Up must be able to increase and decrease Load as deployed within its Ancillary Service Schedule for Reg-Up above the Load Resource’s LPC limit.

1. Arrest frequency decay within the first few seconds of a significant frequency deviation on the ERCOT Transmission Grid using Primary Frequency Response and interruptible Load;
2. After the first few seconds of a significant frequency deviation, help restore frequency to its scheduled value to return the system to normal;
3. Provide energy or continued Load interruption during the implementation of the EEA; and
4. Provide backup regulation.