Output value modification
TMU 210 BOARDS
6. CONTROL SEQUENCES
6.1 Description
A Control Sequence is a basic built-in function on a module (switch, relay, and function). It receives control order, sending back acknowledgement. After checks, control sequence sends control (protocol or DO), and check correct execution with feed back from protocol or from DI.
6.1.1 General
The C264 allows the following functions:
• Control of switching devices (circuit breaker, switch, …)
• Control of transformers
• Control of secondary devices
• Locking of switching devices
• Control of IEDs
• Control of automatisms These types of controls are allowed:
• Select control request
• Execute control request
• Unselect control request
• Cancel control request
Upon reception of one of these requests, the computer behaviour is different according to:
• The configuration of the device control,
• The type of the device,
• The computer operating mode.
6.1.1.1 Device control configuration
By configuration, at SCE level, a control may be executed in one of the following modes:
• “Direct Execute” mode: usually for ancillary devices a control may be performed directly without the selection phase.
• “Select Before Operate once” mode” (SBO once): usually for circuits breakers and disconnectors. The device must be selected before allowing the execution. In that event the device is managed in two phases: selection and execution. Device unselection is done automatically by the computer.
• “Select Before Operate many” (SBO many): usually for transformers. The device must be selected before execute one or more controls before reaching the expected position (low/raise). In that event the device is managed in three phases: selection, execution and unselection. The execution phase is repeated for every new control. To end the controls sequence, the initiator of the request must send an “unselection”
request.
By configuration, each DPC order (close order or open order) and each SPC can activate simultaneously two DO contacts.
6.1.1.2 Types of devices
Every control sequence may be different according to the type of the device to control. The complexity of the control sequence may be more or less important depending on the device:
• Synchronised or not synchronised circuit breakers, disconnectors and earthing switches: They are managed in “Direct execute” mode or “SBO once” mode with optional hardware selection of the device in SBO mode.
• Transformers: They are managed in the three modes: “Direct Execute”, “SBO once” and “SBO many” mode with optional hardware selection of the device in SBO mode.
• Ancillary devices: they are usually managed in “Direct Execute” mode but can be managed also in “SBO once” mode.
• System Controls: System outputs are used to activate or inactivate automatic functions on the computer: for example, Auto-recloser ON/OFF; change operating modes; and so on.
• Controls via Setpoints: are managed in “Direct Execute” mode and in “SBO once”
mode.
6.1.2 Control sequence phase management
According to the configuration of the device control, a control sequence is performed in one, two, or three phases. Each phase of a control sequence (selection, execution and unselection) may have a normal or abnormal termination and positive or negative acknowledgement is sent to the IEC-61850 clients subscribed during the configuration process.
• One phase – “Direct Execute” mode:
Execution phase: If the execution phase ends normally the computer generates a positive acknowledgement and the control sequence ends. In event of abnormal termination, the control sequence is aborted and the computer generates a negative acknowledgement. The hardware selection of the device in “Direct Execute” mode is not allowed.
• Two phases – “SBO once” mode:
Selection phase: In the selection phase for a normal termination the computer generates a positive acknowledgement and proceeds to the next phase of the sequence (execution phase).
Execution phase: If the execution phase ends normally the computer generates a positive acknowledgement and the control sequence ends. In event of abnormal termination, the control sequence is aborted and the computer generates a negative acknowledgement.
• Three phases – “SBO many” mode:
Selection phase: In the selection phase for a normal termination the computer generates a positive acknowledgement and proceeds to the next phase of the sequence (execution phase)
Execution phase: If the execution phase ends normally the computer generates a positive acknowledgement and waits a new execution request. In event of abnormal termination, the control sequence is aborted and the computer generates a negative acknowledgement.
Unselection phase: The computer proceeds to the deselection of the device and ends control sequence sending positive acknowledgement. In event of fail deselecting the device the computer sends a negative acknowledgement.
The following figures show the three control modes of the computer:
C0314ENa
Select Before Operate mode many with device selection
Selection checksExecution checks Selection checksHardware selectionHardware DeselectionExecution checks
Execution checks
Execution via I/O boards or or or or
Execution via IED Execution via I/O boards Execution via IED Execution via I/O boards Execution via IEDSystem controls Select Before Operate mode
Direct execute mode execution phase execution phaseselection phase execution phaseselection phase
FIGURE 35: CONTROL MODES OF THE COMPUTER (1)
C0315ENa
(1) An execution phase with two execution requests is given as an example, it may have more or less
or or
Select Before Operate mode many Select Before Operate mode many with hardware device
Execution via I/O boards Execution via IED Execution via I/O boards
Device unselect Device unselect
Execution via IED
Execution checks Device Selection checks Execution checks execution phase (1)selection phase selection phase
or or
Execution via I/O boards Execution via IED Execution via I/O boards Execution via IED
Execution checks Execution checks execution phase (1)
unselection phase unselection phase
Hardware DeselectionHardware SelectionSelection checks
FIGURE 36: CONTROL MODES OF THE COMPUTER (2)
6.1.3 Direct Execute mode
In this mode a control of device is directly executed without need to be previously selected.
Usually concerns ancillary devices managed via I/O boards (SPC, DPC, and Setpoints) or via IED.
The ”Direct Execute” sequence ends normally after reception of the expected position information of the device or correct value (if setpoint control). Abnormally if the received position or value is unexpected, or not received in the predefined delay by configuration.
Note that a “cancel” request in ”Direct Execute” mode has no guarantee to be performed before the execution of the request. An “unselect” request has no meaning in ”Direct Execute” mode.
C0316ENa
execution already in progress ? Direct execution request
Execution OK
yes no
device direct execute no
All checks OK execution in progress
no yes
End CO in progress End CO in progress
End of sequence start of sequence
send negative acknowledge
send positive acknowledge
Perform execution Perform execution
checks
FIGURE 37: EXECUTION PHASE FOR DIRECT EXECUTE MODE
6.1.4 SBO once mode
6.1.4.1 Selection phase in “SBO once” mode
During the selection phase initialised by a selection request of the control, the computer performs selection checks in order to verify if the device is selectable or not.
If no fail occurs during these checks, the device is selected and positive acknowledgement is sent. Otherwise the selection request is refused and a negative acknowledgement is sent giving fails cause. If the selection of the device is accepted, the computer starts a delay and waits for:
• An execution request: open/close, low/raise
• A cancel of the selection request.
At the end of this delay if the execution or the cancel request is not sent, the device is automatically unselected and a negative acknowledgement is sent. The selection delay is defined during the configuration step.
Note that only one selection is allowed at a time for a device. When a device is already selected any other selection is not taken into account (none acknowledgement is sent) whichever of the initiator.
The diagram that follows shows the selection phase of a device configured in SBO once mode.
C0317ENa Device selectable ?
Selection request
yes no
All checks OK Device Already selected
Selection Time-out launching
Unselected device
Perform Selection checks
send positive acknowledge
send negative acknowledge
Time-out
Deselect hardware selection Device
Cancel request
Execution request Wait new request
or time-out
Execution phase Device selection
Device selection OK no
no
Set “device selected”
Set “device unselected”
FIGURE 38: SELECTION PHASE IN SBO ONCE MODE
6.1.4.2 Execution phase in “SBO once” mode
The execution phase can start only after reception of an execution request and if the device has been selected before.
In this phase, the computer performs the execution checks, and if no fail, it proceeds to the execution according to the configuration, via the IO boards or IED communication.
If the execution ends normally, a positive acknowledgement is sent, and the control sequence ends. In event of fail the control sequence is aborted and the computer sends a negative acknowledgement.
During this phase a “cancel” request is not guaranteed except for synchronised circuit breakers devices (refer to specifics treatments for synchronised circuit breakers below).
C0318ENa EXECUTION PHASE IN SBO ONCE MODE
Execution OK
yes no
All checks OK execution in progress
to the device
no
End of sequence Execution request –SBO once device selected
send negative acknowledge
send positive acknowledge Perform execution
Perform execution checks
Reset execution in progress deselect the device Execution in progress yes
send negative acknowledge
Operator Cancel request
FIGURE 39: EXECUTION PHASE ON SBO ONCE MODE
6.1.5 SBO many mode
This mode allows you to perform one or more control executions after the selection phase. It is usually used for the tap positioning process in where many controls are sent before reaching the desired position.
6.1.5.1 Selection phase in SBO many mode
The selection phase is identical to the “SBO once” mode selection phase.
6.1.5.2 Execution phase in SBO many mode
The difference with the SBO once mode is that after having performed an “execution request”, the computer stays in execution phase waiting a new execution order or an
“unselect” request. The execution phase ends only after an “unselect” request or “cancel”
request by the initiator.
Upon reception of an “unselect” request the computer ends the execution phase and goes to the selection phase.
C0319ENa Device selected
Execution Phase SBO many
Execution OK
yes no
no
All checks OK execution in progress
to the device
no
End of sequence
Execution phase- device SBO many selectd
send negative acknowledge
send positive acknowledge
Perform execution Perform execution
checks
Reset execution in progress
Execution in progress yes
send negative acknowledge
Execution request Unselect request
Wait request
Deselect the device
Unselection phase
cancel request
FIGURE 40: EXECUTION PHASE IN SBO MANY MODE