Weird Data from SMA Inverter

sun_day

Hey all,

Recently I found out that my PV plant had been having weird data in the specific yield graph. The PV plant is using SMA STP20000TLEE-10, 3 pieces of them, in bluetooth mode connected to a SMA Sunny WebBox. In Sunny Portal, sometime one of the inverter will plunge to negative value for specific yield for 15mins before going up again to normal. The frequency of this happening is perhaps like once per week and it can happen anytime.

Does anyone with SMA inverter encountered this type of issue? I am worry that there is some problem with the inverter or PV system as a whole.

Thanks.