The success of PV power plants is strongly depending on the quality of their project and realization. Precise analyses of the technical characteristics, of the performance behaviors and of the correct application of national regulations are, then, crucial for evaluating the quality of a PV power plant. Often, the methods to make these analyses are not covered by suitable international standards and then the plant quality is not subject of certification. As consequence, PV operators are currently adopting procedures which are based on their best practices and/or on contractual agreements, which are not widely recognized. This work presents the experience gained by RSE during acceptance tests of PV plants according to the procedures of the Italian regulations and is focused on the measurement and calculation methods described in the normative document “Guide CEI 82-25”, issued by the Standardization Italian Electro-technical Committee and on RSE experience in performing tests on large Italian PV plants. The results could be useful both for PV operators and for PV international community, supplying a contribution to the development of standards and certification procedures.