Inputs

Arc flash protection can either be embedded in an electrical protection relay (PowerLogic P5 30 series or P3 Advanced) or provided as an autonomous system when required (PowerLogic A125 / Arc V121).

NOTE: Embedded arc flash detection and protection capabilities are available in the PowerLogic P3 Advanced and P5 30 series. The PowerLogic P3 Standard and P5 20 series can also provide the arc flash protection capabilities when accompanied by standalone detection devices such as the PowerLogic A125 and Arc V121. The distinction between the embedded and standalone arc flash capabilities will be made throughout this application.

In all cases, the following data is required:

Arc Flash Detection Device

Light detection

To detect an arc flash, light sensors are installed in the critical areas of the switchboards. Arc VA1DA (or VA1EH) sensors offer a wide area arc flash detection with a typical detection time <1 ms.


Arc VA1DA

These sensors can be connected to different arc flash protection devices like PowerLogic P5 30 series, P3 Advanced, PowerLogic A125, or Arc V121.


PowerLogic P5 30 series	PowerLogic P3 Advanced	PowerLogic P5 20 series	PowerLogic P3 Standard


PowerLogic A125	Arc V121

Current detection (optional)

In switchboards that could be exposed to unintentional light, the occurrence of an arc flash must be confirmed with the simultaneous detection of inrush current.

Protection relays PowerLogic P5 30 series or P3 Advanced directly acquire these measurements through their standard current transformers.
PowerLogic A125 requires an additional module (Arc VAM4C) with dedicated current transformers to detect high current values.
Arc V121 cannot interface with a current metering system, it must only be used in switchboards that are not exposed to unintentional light sources.

Arc
VAM4C

Circuit Breakers

When an arc flash is detected, the main supply of the affected area must be disconnected to stop the effects of the arc. Due to high currents resulting from an arc flash, only a circuit breaker can perform this operation. For root cause analysis, circuit breakers must thus be monitored to get a comprehensive view of the arc flash event.

Status information

The arc flash protection system (embedded in protection relay or autonomous) must be able to control the circuit breaker. The following status information is monitored:

Position (open, closed, racked-in, racked-out, etc.)
Trip status, protection status
Operating mode (local/remote when applicable)

Physical measurements

As the arc flash will generate high currents, the overcurrent protection of a protection relay is mandatory in parallel with the arc flash protection system. Therefore the circuit breaker must measure current values.

In addition, protection relays or trip units (PowerLogic P5/P3, MicroLogic X trip unit of MasterPacT MTZ with WFC Digital Module) will be able to capture current waveforms that can be leveraged to analyze the arc flash occurrence.

NOTE: In case the circuit breakers installed in the switchboard cannot communicate, the above information can be provided by a power meter equipped with digital inputs for status information and current measurements for waveform captures (PowerLogic ION9000, PM8000).


PowerLogic P5 30 series	PowerLogic P3 Advanced	PowerLogic P5 20 series	PowerLogic P3 Standard


MasterPacT MTZ	PowerLogic ION9000	PowerLogic PM8000

Uninterruptible Power Supply (UPS)

Arc flash incidents can happen during the initial power up of the switchboards or during power restoration after maintenance activities.

To help ensure proper protection at switchboard power-up, the auxiliaries of all products involved in arc flash protection should be powered before the switchboard. To achieve this, auxiliaries should be powered from an external source through UPS, such as Galaxy VX/VL/VM/VS.

Therefore, it is recommended to monitor the status of any UPS used for that purpose throughout the electrical distribution network.

Galaxy
VX/VL/VM/VS