I'm not sure the EGC from the ground mount array needs to run with the conductors all the way to the inverter & MSP [2017 NEC 690.43(C)], over 200 ft away, since they are grounded to the ground mount GE system [2017 NEC 690.43(A)]. If there were no GE system at the array there would be an obvious need. But I've always designed in an EGC with the PV output circuit in the conduit - doesn't seem right to have none in there. It's an ungrounded / transformerless inverter, PVC conduit.
The problem is that the electrode-to-Earth contact resistance likely will be too high, for it to be an effective ground fault current path. Everything on the customer's side of the service disconnect, needs to have an EGC ran with every circuit, whether it is a wire or a metal conduit. The purpose of the EGC, is to bond every electrically inactive piece of metal (structures, equipment housings, wiring methods, etc) together, and provide a return current path back to the source. If there is no EGC, there will be no fault current path with enough conductance capable of completing the circuit.
It is a common misconception that "we want current to return to ground" when there is a fault. The truth is, it needs to return to the source. The Earth is a good conductor due to a lot of parallel paths, but it doesn't come with good terminations. The grounding electrode's purpose is to establish that the absolute voltage (i.e. electric potential) of the groundING and groundED conductors, are at the same absolute voltage as the surrounding Earth.
