Glossary - o
For your convenience, this page contains an alphabetically organized list of terms, definitions and common acronyms used in the electric utility industry.
| A | B | C | D | E | F | G | H | I | J | K | L | M |
| N | O | P | Q | R | S | T | U | V | W | X | Y | Z |
Term/Acronym |
Definition |
| OCN | Operating Condition Notice |
| OOM | Out of Merit Order |
| OOMC | Out of Merit Capacity |
| OOME | Out of Merit Energy |
| Obligation | Total Obligations scheduled by a QSE that are comprised of energy Obligations and Ancillary Services Obligations where:
|
| Off-line | The status of Resources that are not synchronously interconnected to the ERCOT System. |
| On-line | Resources that are synchronously interconnected to the ERCOT System. |
| Operating Condition Notice | The first of four possible levels of communication issued by ERCOT in anticipation of a possible emergency condition detailed in Section 5.6, Emergency and Short Supply Operation. |
| Operating Day | The actual day, including hours ending 0100 to 2400, during which energy is flowing. |
| Operating Guides | Guidelines approved by the ERCOT Board describing the reliability standards for ERCOT. |
| Operating Hour | The current clock hour. |
| Operating Period | A two-hour period comprised of the Operating Hour and the hour preceding the Operating Hour. |
| Operating Plan | A plan developed by ERCOT to operate the ERCOT System in Real Time. |
| Operational Constraint | Anticipated or actual security violation or overload of a transmission element, based on actual network topology. |
| Operational Model | The transmission model based on actual network topology of the ERCOT System. |
| Out of Merit Capacity | Capacity provided by a Resource selected by ERCOT outside the bidding process to resolve a reliability or security event. |
| Out of Merit Energy | Energy provided by a Resource selected by ERCOT outside the bidding process to resolve a reliability or security event. |
| Out of Merit Order (OOM) | The selection of Resources for Ancillary Services that would otherwise not be selected to operate because of their place (or absence) in the bidding process for that service. |
| Outage | Removal of a Facility, or a portion of a Facility, from service to perform maintenance, construction or repair on the Facility for a specified duration. Forced Outage For a Transmission Facility, an Outage initiated by protective relay, or manually in response to an observation by personnel or the System Operator that the condition of equipment could lead to an event, or potential event, that poses a threat to people, equipment, or public safety. For a Generation Resource, an Outage that requires immediate removal (either through controlled or un-controlled actions) of a Resource from service through automated or manual means. This type of Outage usually results from immediate mechanical/electrical/hydraulic control system trips and operator-initiated actions in response to a Resource’s condition. Maintenance Outage Removing Transmission Facility or Resource Facility equipment from service to perform work on specific Facility components that could be postponed briefly. Such work is required to prevent a potential Forced Outage or Forced Derate and cannot be postponed until the next Planned Outage. Such Maintenance Outages are classified as follows:
Any major or minor Transmission Facility or Resource Facility equipment Outage, other than a defined Maintenance Outage, that is planned and scheduled in advance as submitted to ERCOT. |