Certification of photovoltaic inverters: the initial step toward PV system certification

There is no complete photovoltaic product (component or system) certification program in effect today in the United States. Photovoltaic (PV) modules and inverters are listed for safety (using standards UL1703 and UL1741, respectively), and certification for environmental qualification of PV modules is conducted. However these do not provide critical performance information such as PV module energy rating, inverter performance characteristics, or system performance. Domestic and international standards organizations have begun waiting requirements for photovoltaic system certification that are aimed primarily at small stand-alone applications. The module and balance-of-system industries often provide inconsistent or insufficient specifications and data to designers and customers to allow adequate comparison or a true prediction of performance for installed systems. This paper describes an industry consensus process to establish necessary testing protocols for certification of inverters.