COMBINER BOX OF A DC PART OF A PV PLANT AND A DC PART COMPRISING THE COMBINER BOX

摘要

A box (SCB1) for combining n strings or m arrays of a DC part of a PV plant comprises a plurality of n DC inputs (21, 22, 23, 24) for electrical connection to the n strings or to a plurality of m DC inputs for electrical connection to the m arrays, at least n or m DC direction sensors for detecting the direction of direct currents (IS1, IS2, IS4, IR) conducted in the n or m DC inputs (21, …, 24) and a combiner control unit (SCCU). The DC direction sensors communicate their output signals to the combiner control unit. The combiner control unit communicates a first tripping signal to first switching units associated to the DC direction sensors for opening n-1 or m-1 of the n or m pairs of first switching units in order to interrupt the direct currents (IS1, IS2, IS4) between each of n-1 or m-1 DC inputs (21, 22, 24) and the two busbars when in a remaining one (23) of the DC inputs the direct current changes from a forward (IS3) to a first reverse current (IR). This allows a fast localization and removal of a faulty string or array without any remarkable interruption of the PV plant and with small-sized switching units, typically with hybrid breakers. Thus the PV plant is distinguished by a high yield rate and a high reliability and can be installed and operated in a cost-efficient manner. Furthermore for reason of the small-sized switching units the combiner box can be realized as rail arrangement with a plurality of box-shaped modules which are attached to the rail arrangement.