Operating photovoltaic systems safely with high availability

Using a fuse on grounded solar arrays for ground-fault protection can create the "blind spot" issue - a ground fault on the already grounded conductor of a PV array may not drive sufficient current to trip the fuse. Additional faults can go undetected and may cause unexpected behavior, leading to a high risk of fire.

Bender's ground-fault relays detect low-level AC and DC ground faults on grounded arrays by using a differential measurement method, mitigating the blind spot issue. Advanced technology alerts technicians to conditions that may lead to damage to equipment or fire.

In small photovoltaic systems, protection of the house residents and possible operators (fire department, chimney sweep) is very important. The inverters are mostly factory-equipped with the appropriate safety equipment. They are only safe enough if they can also detect symmetric faults caused by moisture and dirt. At the point of transfer between the internal network and the general power grid, the voltage and frequency must be checked at a predefined range.

Before internal generation systems (photovoltaics, water power, CHP, biogas, etc.) can feed electrical energy into the public grid, an automatic switching point must be installed between the generation system and the low voltage network. This checks whether the frequency and voltage fed in are within the specified range. The three-phase voltage monitoring relay is used to pre-configure numerous standard specifications at the touch of a button.