storage system in plants must be able to absorb reactive power in an automatic and autonomous (local control logic) according to a characteristic curve of the power factor vs. active power = f (P).for integrated storage systems, the test must be performed with the photovoltaic array which supplies power to obtain, together with the maximum storage power, the nominal power of the inverter.The test aims to verify that the inverter follows the procedures for automatic delivery of the reactive power according to the characteristic curve standard cos φ = f (P) defined in annex E.2, (curve of type a).The test has the purpose to verify that the storage system, through its own converter, follow the automatic deliver mode of reactive power according to the standard characteristic curve cos φ = f (P) shown in E.2, according to the method a):The standard curve shown in Figure 7Bbis is uniquely defined by the linear interpolation of the three characteristic points: