See Also
There are several places in Simulator where functionality is available to close breakers in order to energize a particular device or devices. This functionality is generally available when breakers, or other branch devices that are allowed to be automatically switched, are defined in the case. For some functionality, the Integrated Topology Processing add-on is required in addition to having breakers defined.
This overview is intended to provide information on which branch device types can be automatically switched, how breakers are selected, and the tools in Simulator that make use of close with breakers functionality. Additional information about how this functionality might work differently with specific tools will be described with those particular topics.
Branch Device Types that will Automatically Operate
The Branch Device Type field for a branch must be set to one of the following options in order for a branch to be considered a device that can automatically operate when using close breaker functionality:
- Breaker
- Load Break Disconnect
- Disconnect
- Fuse
- Ground Disconnect
Not all of the types listed above can be used for automatic switching with all tools that allow this. The different tools will indicate which types are allowed. For brevity, the term breaker will be used throughout this discussion to indicate branch devices that can be automatically switched.
Added in version 20
For a branch to be considered for automatic switching it must also have its Allow Open or Close Breakers field set to YES. This field can be changed by the user, and there are several options that will update this field based on the present case. For more information on how this field can be updated by Simulator, see the Update Allow Open or Close Breakers topic. When Allow Open or Close Breakers = NO and a branch is closed, it will be traversed when looking for breakers to close regardless of its Branch Device Type. Normally, in the search process if a branch is a Branch Device Type that is being included in the search, the search will terminate on a path that contains a closed branch.
Algorithm Description for Close Breakers
The following descriptions apply when using automated methods for closing breakers to energize a device. The method for identifying open breakers that might energize a particular device is the same whether using the automated methods to actually close breakers or a method with user input. Methods that allow user input will not actually close breakers until the user determines which breakers to actually close.
Single Terminal Devices
This includes buses, generators, loads, and switched shunts.
In order for a device to be considered de-energized, its terminal bus must be disconnected. If a device is already energized, no determination of breakers is made.
To determine if the device can be energized, the algorithm starts at the terminal bus of the device and traverses closed ac branches (non breakers). Closed breakers will not be traversed. If an open breaker is encountered, it is added to a list of potentially valid breakers. The traversal down a particular connection path terminates when a breaker is found or an open branch of any type is found. The algorithm completes when all paths have been explored.
Some functions require that no additional devices other than the one being checked can be energized by closing the selected breakers. If this check is in place when looking for breakers and it is determined that other devices will be energized, the algorithm is aborted and no breakers are found that can energize the selected device.
An additional check that is made to determine if a device can be energized is based on the normal status of a breaker. If more than one open breaker is found in the search for the open breakers, only those breakers that are normally closed will be considered valid. If only a single open breaker is found, normally open or closed breakers will be considered valid.
Once the final list of valid breakers is known, a final check is made to determine if closing these breakers will actually energize the device. If so, and the function calls for actually closing the breakers, the breakers will be closed.
If breakers are actually closed, the status of the device will also be set to closed if it is presently open. It is anticipated that the close breakers to energize functionality will be used with full-topology models in which the status of the device will always be closed and that breakers will be used to determine the actual energized status of the device, however, there is no strict requirement for this. In order to make sure that the device is actually energized, the status of the device might need to be set as well.
Multi-Terminal Devices
This includes branches (ac lines and transformers) and dc lines.
To find breakers that can be closed to energize a transmission branch, both terminal buses of the branch are examined. Breakers are found for each terminal bus separately by assuming that the branch itself is open and cannot be traversed. The breakers are then determined for each bus by using the same method described above for single terminal devices, i.e. the algorithm starts at a terminal bus and traverses closed ac branches (non breakers). A list of open breakers is built as each open breaker is encountered. The traversal down a particular connection path terminates when a breaker or an open branch of any type is found. The algorithm completes when all paths have been explored.
Because transmission branches are often closed to energize other devices, no restriction is placed on energizing other devices when looking for breakers to energize a branch; the algorithm does not abort when other devices are encountered that will also be energized by closing breakers to energize the branch.
Each set of breakers for the two terminals of the branch are checked separately for the condition based on the normal status of the breaker. If more than one open breaker is found in the set of open breakers, only those breakers that are normally closed will be considered valid. If only a single open breakers is found, normally open or closed breakers will be considered valid.
Once the final list of valid breakers is determined for each terminal bus, no additional check is made to determine if closing these breakers will actually energize the device. If the function calls for actually closing the breakers, all valid breakers will be closed. This is done because closing branches is often done to energize other devices and because closing the breakers that will energize one terminal bus might be needed to energize the other terminal bus.
If breakers are actually closed, the status of the branch will be set to closed if it is presently open.
Added in version 20, build on Oct. 17, 2017
If a branch or dc line is only open at one end, breakers will be identified to completely close the device. To determine if the device is not completely closed, the condition Derived Status <> Closed is used. Information on how Derived Status is determined is found here.
Aggregations
This includes interfaces, injection groups, or groups of objects of the same type selected via filtering.
When dealing with groups of objects, two methods of determining which breakers to close can be used. The first method assumes that all devices are handled separately and only breakers identified for each device will be examined when determining if a device can be energized by closing breakers. The second method assumes that breakers that are identified for one device might be needed to energize another device. When this method is used, breakers are identified for individual objects first, and then all breakers that have been identified for all devices are assumed to be available to energize any individual device. When identifying which breakers can be closed, the two methods described above for Single Terminal and Multi-Terminal Devices will be used.
Automated methods will generally assume the second method where all breakers can be used to energize individual devices. The CloseWithBreakers script command will allow user input on how to handle the breakers.
Close Normally Closed Disconnects Added in version 20
Some tools allow normally closed disconnects that are currently open to be closed during the process of identifying breakers. The tools that allow this will have an option for using this feature. Disconnects are considered to be only branches where Branch Device Type is Disconnect.
When using this option, if an open but normally closed disconnect is found in the process of searching for breakers, that disconnect will be included in the devices that will close to energize a device, and that disconnect will also be traversed in the search for additional breakers to close. The search on a path will terminate when an open breaker is found. This breaker will also be closed. Additionally, any disconnects that are in series with identified breakers will be closed if they are normally open. This will allow any disconnects that are found beyond the breakers to close to also be closed.
The normal status of a branch is determined by the Normal Status field.
Breakers in Series with Shunt Devices (Switched Shunts, Generators, and Loads) Added in version 20
When attempting to energize any device except for a switched shunt during the process of searching for breakers and disconnects to close, any breaker or disconnect that is strictly in series with only switched shunts and disconnects will be excluded from the switching devices that can close. This check effectively looks for switched shunts that are connected radially by a breaker or disconnect. This will prevent switched shunt breakers from operating inappropriately when closing a line that has a tap point with switched shunts.
Modified in version 20, build on May 18, 2018
In addition to switched shunts, generators and loads are included in the series check for breakers and disconnects when identifying which switching devices can close. If a particular switched shunt, generator, or load should be connected, only that particular device will be connected if other radially connected shunt devices are found.
Tools that Use Close Breakers Functionality
Close Breakers to Energize Switched Shunts
Generator Economic Merit Order Dispatch (Used with PV and ATC tools)
Local menu option for display objects and case information displays
Several objects (buses, branches, dc lines, generators, loads, and switched shunts) have a special local menu option, Close Breakers to Energize, that allows them to be closed using breakers. This option is present on both the local menu for display objects and the local menu of case information displays for the specified types. This option does not require having the Integrated Topology Processing add-on to work.
There are three sub-options available:
Only Breakers
Only Branch Device Type of Breaker will be included as valid switching devices.
Breakers and Load Break Disconnects
Only Branch Device Types of Breaker and Load Break Disconnect will be included as valid switching devices.
With Options
A dialog will open that allows for user input on the Branch Device Types that are included for valid switching devices. There is also an option Close Normally Closed Disconnects. If this option is selected, Disconnects will be included in the search algorithm as described in the Close Normally Closed Disconnects section above.
When using this option, a dialog will open that allows the user to determine which breakers should be closed instead of just closing the breakers automatically. The dialog that is presented will show the list of breakers that have been identified using the methods described above.
If attempting to energize a single terminal device, a single list of breakers, Breakers for Terminal Bus, will be displayed. If attempting to energize a multiple terminal device, two lists of breakers, will be displayed. One will show the list of breakers identified to energize the from terminal bus, Breakers for From Terminal Bus, and the other will show the list of breakers identified to energize the to terminal bus, Breakers for To Terminal Bus.
Regardless of how many lists of breakers are shown, they will be listed with a set of common fields:
From Number, From Name_Nominal kV, To Number, To Name_Nominal kV, Circuit
These are the key field identifiers for the breaker.
Energized Bus Number
At most one terminal bus of a selected breaker can be energized. This field indicates which, if any, of the buses is energized. This field is used to help determine which combination of breakers will actually energize the device.
Normal Status
This indicates the normal status of a breaker. Options are Closed or Open.
Close?
Set this to YES for this breaker to be closed when clicking the Close Breakers button. When the dialog is first opened, this field is set according to how automatic methods would choose which breakers are valid for closing based on the conditions described above in the How Breakers are Selected section.
There are some additional options on the dialog that provide information about the device to be energized:
Device
This identifies the device that is to be energized by closing breakers.
Device Status
This provides the status of the device prior to trying to energize the device. If the status is Open, the status will be set to Closed when the Close Breakers button is clicked.
Check if Can Be Energized
Clicking this button will run a check on the combination of breakers that have been selected for closing to determine if the device will actually be energized by closing them. The check is done without actually closing any breakers or changing the status of the device.
Use the following options to actually close breakers or just close the dialog:
Close Breakers
Click this button to close the breakers that have the Close? field set to YES and then close the dialog. If the status is Open, the status will be set to Closed.
Cancel
Click this button to close the dialog without changing the status of any breakers.
CloseWithBreakers script command
Scheduled Actions