Common use of Open Circuit Voltage Test Clause in Contracts

Open Circuit Voltage Test. The open circuit voltage test provides a simple method to determine that a string is properly connected and that all strings are producing the appropriate level of voltage. This test should be done under stable sky conditions. a) Measure string Voc at the combiner box for all strings at the combiner box. b) Measure average module temperature. c) Measure plane of array irradiance. d) Calculate the expected Voc for each measurement using the following formula: Where n is the number of modules in series, Voc, expected is the Expected Open Circuit Voltage, Voc,ref is the open circuit voltage of a single module as specified on the module data sheet, b is the module Voc temperature coefficient measured in [1/°C] as listed on the module data sheet, and Tmeasured is the measured module temperature during the time of Voc measurement. e) Compare the expected Voc to the measured Voc for every string using the following equation (Voc measured – Voc expected) / Voc expected. This value shall be 95% to 105% for the string to pass. If the string does not pass, the string connectivity shall be inspected; all modules in the string shall be inspected for visible damage, and j-box tabs shall be re-soldered as required. Defective modules shall be replaced.