Monitor PV String Currents Without an Additional Power Supply

Phoenix Contact is now offering its Solarcheck monitoring system – a reliable tool for monitoring string currents in large-scale photovoltaic installations. The system can be easily integrated into existing network structures. Faults and performance-related issues are quickly identified, and specific countermeasures can be immediately initiated. This enhances system availability and increases the revenue generated by the PV system.

The monitoring system comprises a measurement module and a communication module. The measurement module is simultaneously supplied via the two-core communication cable. This means that no additional power supply is required in the device terminal box and keeps wiring simple. The compact measurement module is only 22.5 mm wide and determines the key parameters of up to eight PV strings, which it then transfers to the communication module. This can be simply integrated into existing networks as a Modbus-RTU node. When fully set up, a communication module collects the values from up to eight measurement modules and transfers them to a central process control system.

The current is measured using Hall sensors. When being installed, the cables are routed through openings in the housing without having to interrupt them. This means that no additional contact points are created, which would otherwise generate transition resistances and represent a potential fault source. Also, for each measurement module a DC voltage of up to 1200 V is captured in isolated systems. This provides an overview of the performance and productivity of the system. In addition, a digital input enables remote signalling contacts to be monitored – such as those from surge voltage protection devices.