Arc Faults: Detection and Protection of a Dangerous Phenomenon
The effect of arc faults in electrical applications was once an under estimated problem. Due to serious incidents over the past few decades, we now know how disastrous they can be for photovoltaic applications, electric vehicles, aeroplanes and data centres.
Fire hazards caused by arc faults can have catastrophic effects including: a risk of injury to operators or passengers, costly damages to equipment and potential downtime or service interruptions.
Applications with a high risk of arc fault:
- Aeroplanes (AC on-board electrical systems)
- Photovoltaic systems
- Electric vehicles (hybrid and electric cars)
- Data centres and office units using DC voltage
Technical reasons for arc faults:
Hazardous arcs can occur anywhere in a system due to defective cable connections or insulations. The following reasons are frequently found in photovoltaic systems:
- Defective modules (ie. damage by extreme weather conditions like hail)
- Use of cheap imitations of connectors
- Damaged cables caused by ageing or an animal bite
Fire prevention with new technology, e.g. in photovoltaic applications:
E-T-A’s arc fault detection modules can detect dangerous arcs in circuits on the DC-side of a PV system.
Coupled-in current signals are filtered and analysed with a filter and a pattern recognition algorithm that was developed by E-T-A. The algorithm is applied on a signal processor and analyses the current signals of specific arc characteristics. The algorithm reliably distinguishes between dangerous arc faults, operational effects of inverter operation (e.g. start-up and switching processes, MPP tracking), and harmless interferences (e.g. electromagnetic radiation).