Event number 4001
Event number 4001 indicates that the STP has detected a reverse current of more than 2 A on one of the string inputs. If this detected reverse current constitutes a danger for the other strings, e.g., because four strings feed in the reverse current through one string, the excess current detection is triggered, the Sunny Tripower beeps and the affected input (A or B) is short circuited for safety reasons. Thanks to the input’s short circuit, the STP protects the PV modules from possible dangerously high reverse currents and creates a safe state to prevent further string defects.
The cause of the reverse currents measured by the Sunny Tripower can be module defects, connection errors, reverse polarity of individual strings, or a malfunction of the STP’s measured value recording function. In exceptional circumstances, this error message may be triggered by soiling or shading of the modules (e.g. by leaves or snow).
Corrective measures for system operators:
• DANGER! Do not, under any circumstances, disconnect the Electronic Solar Switch (ESS handle) or the DC connector during daylight.
• If the ESS handle is not connected during daylight but the DC connector is, connect the ESS handle.
• If possible without danger: Check whether the modules are soiled or shaded
• Contact an installer or an SMA solar power professional. The subsequent steps require the specialist knowledge of an electrically qualified person or installer.
Corrective measures for installers:
DANGER! The tasks described below may only be performed by electrically qualified persons:
• Check whether the modules are soiled or shaded
• Disconnect Sunny Tripower (see installation or service manual)
DANGER! If the STP beeps and the display shows an error message that prohibits disconnecting the ESS, wait until dark. The ESS can only be disconnected once it is dark.
• Measure the open-circuit voltages of all strings when the irradiation is sufficient.
• During connection, connect the asymmetrical string to input B or remedy the reverse polarity if necessary and/or replace faulty modules.
• Measure the short-circuit currents of all strings. A suitable measuring device and a suitable device for safe disconnection and short-circuiting of the strings is required for this.
• Compare the measurement data with the information on the module data sheet and the design of the PV system (taking the irradiation values / weather into consideration)
If the message keeps on appearing, even though the PV system has been checked as described, the subsequent steps must be clarified with SMA Service.
In this case, please contact SMA Service with the following information:
• Device type and serial number of the inverter
• Are there further error messages?
• How long has the error been present for now? Did it occur during the (new) installation?
• Measured DC voltages of all strings
• If present, measure the short-circuit currents of all strings.
• Type and number of connected PV modules Example for STP15000TL-10:
Input A: 3 strings each with 16 Heckert Solar NeMo 60P250 modules; Input B: 1 string with 13 Heckert Solar NeMo 60P250 modules
All work on the inverter and the cabling of the PV array must be carried out by an electrically qualified person. SMA accepts no liability for the information and solutions given in the Online Service Center. Additional information can be found in our Online Service Center’s terms and conditions of use.