The function can be enabled and disabled with the Operation setting. The corresponding parameter values are "On" and "Off".
The operation of ARCSARC can be described by using a module diagram. All the modules in the diagram are explained in the next sections.
Level detector 1
The measured phase currents are compared phasewise to the set Phase start value. If the measured value exceeds the set Phase start value, the level detector reports the exceeding of the value to the operation mode selector.
Level detector 2
The measured residual currents are compared to the set Ground start value. If the measured value exceeds the set Ground start value, the level detector reports the exceeding of the value to the Operation mode selector.
ARC light detection
ARC detection information is received directly as LOC_FLT_ARC input. The detected ARC fault is directly signalled to the Operation mode selector and Fixed delay 2 modules. There are ARC_DETECTED FSTADAGGIO module outputs from the relay hardware in the protection relay. Each output is connected to a ARCSARC function.
| ARC input | ARC protection function |
|---|---|
| 1/ARC | ARCSARC1 |
| 2/ARC | ARCSARC2 |
| 3/ARC | ARCSARC3 |
Operation mode selector
Depending on the Operation mode setting, Operation mode selector makes sure that all required criteria are fulfilled for a reliable decision of an arc fault situation. The operation is based on both current and light information in “Light+current” mode, on light information only in “Light only” mode or on remotely controlled information in “BI controlled” mode. When the "BI controlled" mode is in use and the OPR_MODE input is activated, the operation of the function is based on light information only. When the OPR_MODE input is deactivated, the operation of the function is based on both light and current information. When the required criteria are met, Fixed delay 1 timer is activated.
Fixed delay 1
Once this timer is activated, the OPERATE signal output is activated immediately. The output is kept active for minimum 25 ms or as long as the input is activated. The BLOCK signal can be used to block the OPERATE signal.
Fixed delay 2
Once this timer is activated, the ARC_FLT_DET output is activated immediately. The output is kept active for minimum 25 ms or as long as the input is activated. The BLOCK signal can be used to block the ARC light signal output ARC_FLT_DET.