Power Electronics Freesun String Supervisor FSITG0012AI, Getting Started Manual

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FREESUN SERIES
– String Supervisor
POWER ELECTRONICS
8
SAFETY INSTRUCTIONS
CAUTION
SPECIAL HAZARDS OF PHOTOVOLTAIC SYSTEMS
Photovoltaic systems have special characteristics that can represent special hazards:

An active power source is connected. This means that, regardless to the operating mode of the
inverter, there may be voltage present, either from the photovoltaic generator and/or the
FREESUN. This is especially important to consider when disconnecting particular parts of the
system (the String Supervisor must be connected to the DC input in the inverter).

Very high DC voltages are present (no zero-crossing) which, in case of a fault or inappropriate
use of fuses or plugs, may lead to arcing.

The short-circuit current of the photovoltaic generator is only slightly higher than the maximum
operating current and is also dependent on the level of a solar irradiation.

A highly branched generator array may be difficult to disconnect if a fault develops (e. g. short
circuit). We recommend the extra use of external DC circuit breakers for disconnecting the
inverter and/or the DC main cables / String supervisors (DC circuit breakers are built-in). One
circuit breaker should be allocated to each input, and these should be located near to de
FREESUN as described in the standard VDE0100 part 7-712 and the VDI 6012 regulations.

The inverter contains capacitors on the AC and DC sides. The discharge time of the capacitors is
longer than 10 minutes. For this reason, it is required to wait longer than this time before making
any operation or maintenance actions related to the connection between the String Supervisor
and the inverter.