See Also
The following describes the determination of derived status as it was in version 19. To see derived status as it as of version 20 click here.
Differences exist between planning models and full-topology EMS models when it comes to determining if a device is energized and what the status is of the device.
With planning software and bus-branch models, two distinct fields exist: Status and Online. The Status field is an explicit field that exists to determine if a device is open or closed. This is needed because breakers are not modeled. The Online field indicates if the device is actually energized which will be affected by the status of branches.
With full-topology EMS models, breaker or disconnect status determines the status of other devices, i.e. whether or not they are energized. No explicit status field exists for other devices like generators, loads, lines, transformers, etc. Typically when using a full-topology model in Simulator, the Status of non-switching devices (generators, loads, lines, etc.) will be set to Closed. A hybrid model with only parts of the system modeled with breaker detail can still use the Status field for non-switching devices.
The actual status of a device can be confusing, especially for those accustomed to a planning model. To eliminate confusion, the Derived Status field will be used to indicate the status with which planning model users are accustomed.
Derived Status is determined by the following:
- Status = Open --> Derived Status = Open
- Else
- Search starting at the device terminals traverse branches with Status = Closed looking for closed breakers, generation, or load (switched shunts are excluded here)
- If search successful at all terminals --> Derived Status = Closed
- Else If search successful at FROM end only (if two terminal device) --> Derived Status = Open To
- Else If search successful at TO end only (if two terminal device) --> Derived Status = Open From
- Else --> Derived Status = Open
- Search starting at the device terminals traverse branches with Status = Closed looking for closed breakers, generation, or load (switched shunts are excluded here)
- Whether or not a device is Online has no impact on the Derived Status
- For switching devices (Breaker, Load Break Disconnect, Disconnect, Fuse, and Ground Disconnect) Derived Status = Status
The following provides examples of how the Derived Status field is set for various breaker settings:
Derived Online is another field that is available for branches. This combines the Online field and the Derived Status field.
Derived Online is determined by the following:
- Online = NO --> Derived Online = Open
- Else
- Derived Online = Derived Status
When determining if a branch end is CLOSED as part of the Derived Status check, several conditions must be met:
- A closed circuit breaker must be found. A breaker is a branch whose Branch Device Type = Breaker.
- Beyond the closed breaker there must be a device of consequence such as:
- Closed branch (this is any Branch Device Type)
- Generator
- Load
- Switched shunts are not included in this check
- Breakers directly in parallel with a Line, Transformer, or Series Capacitor are excluded
The following are examples of Derived Status = Closed lines:
The following are examples of Derived Status = Open To lines:
