SMA SSM16-11 - Manual (Page 15)

SMA Solar Technology AG 3 Product Description
Installation Guide SSM16-24-IA-IEN105120 15
With the Sunny Central inverters in the CP and the HE-20 series, you can set the parameters on the
PC via the WebBox interface and read the mean values and the messages.
With the parameterization, the Sunny String-Monitor can determine the total malfunction of a string
within a polling interval. Slightly elevated string currents are reliably detected in several polling
intervals and distinguished from typical current fluctuations of the PV array.
The following describes:
• The circumstances under which the string current is monitored
• The intervals at which data is transmitted
• Which parameters are important for the sensitivity with which the string current is monitored.
Requirements for Activating the String Current Monitoring
☐ The DC power of the PV array exceeds 5% of the nominal AC power of the Sunny Central.
P
DC
> 0.05 * P
AC nom
☐ The string current mean value of the individual groups is equal or greater than 0.5 A.
I
M String
≥ 0.5 A
Error Sum
The error sum is a measure of the sensitivity of the string current monitoring. It can be parameterized
via the tripping time and tolerance, and is described by the following formula:
The individual error sums of the measuring channels are reset at 00:00 o'clock.
Value Designation
P
DC
PV array power
P
AC nom
Sunny Central nominal AC power
Value Designation
I
M String
Mean value of string-current from each group