An adjusting and measuring method for a photovoltaic power plant comprising at least one photovoltaic string, each photovoltaic string comprising solar panels connected in series and comprising an inverter suitable for converting a DC voltage generated by said photovoltaic string into an AC voltage, each inverter comprising at least one DC-voltage input, said method comprising the following steps: A. measuring a frequency f of an AC voltage generated by said photovoltaic power plant, computing a frequency variation Δ f of said AC voltage with respect to a predetermined reference frequency f ref such that: Δ f = f - f ref and computing a power variation Δ P to be applied by the photovoltaic power plant from said frequency variation, B. if ΔP = 0, repeating step A, otherwise: selecting a DC-voltage input from the M > 1 DC-voltage inputs, referred to as the i-th input with i an integer ranging from 1 to M, in order to start or resume a measurement of a curve of "current as a function of voltage" of the i-th input, the i-th input having a so-called initial DC voltage V ini, then measuring a power P i generated by the inverter of the i-th input, and creating a measurement point of abscissa x = V ini and of ordinate y = P i / V ini on said curve of "current as a function of voltage", C. if a DC-voltage control range of the i-th input, formed of a so-called maximum DC voltage V max and of a so-called minimum DC voltage V min of the i-th input, is unknown: determining, by applying a voltage or power setpoint to the i-th input depending on said power measurement P i, the maximum voltage V max and the minimum voltage V min of the i-th input, C'.: - applying a voltage V n ( p) to the i-th input, with p an integer comprised between 1 and N > 1 called the measurement point, said voltage V n ( p) being different from the p - 1 voltages V n ( q) for q ranging from 1 to p - 1 and being comprised between the maximum voltage V max and the minimum voltage V min, then - measuring a power P i (p) generated by the inverter of the i-th input and creating a p-th measurement point on said curve of "current as a function of voltage" of abscissa x = V n ( p) and of ordinate y = P i (p)/V n (p), D. computing a so-called residual power variation ΔP' to be applied by said photovoltaic power plant such that ΔP' = Δ P - (P i (p) - P i), E. if Δ P' ≠ 0: cancelling said residual power variation Δ P' by distributing said variation over inputs different from the i-th input, F. repeating steps C' to E a plurality of times, incrementing p between each iteration, so as to create a plurality of different measurement points of said measured curve of "current as a function of voltage". A. measuring a frequency f of an AC voltage generated by said photovoltaic power plant, computing a frequency variation Δ f of said AC voltage with respect to a predetermined reference frequency f ref such that: Δ f = f - f ref and computing a power variation Δ P to be applied by the photovoltaic power plant from said frequency variation, B. if ΔP = 0, repeating step A, otherwise: selecting a DC-voltage input from the M > 1 DC-voltage inputs, referred to as the i-th input with i an integer ranging from 1 to M, in order to start or resume a measurement of a curve of "current as a function of voltage" of the i-th input, the i-th input having a so-called initial DC voltage V ini, then measuring a power P i generated by the inverter of the i-th input, and creating a measurement point of abscissa x = V ini and of ordinate y = P i / V ini on said curve of "current as a function of voltage", C. if a DC-voltage control range of the i-th input, formed of a so-called maximum DC voltage V max and of a so-called minimum DC voltage V min of the i-th input, is unknown: determining, by applying a voltage or power setpoint to the i-th input depending on said power measurement P i, the maximum voltage V max and the minimum voltage V min of the i-th input, C'.: - applying a voltage V n ( p) to the i-th input, with p an integer comprised between 1 and N > 1 called the measurement point, said voltage V n ( p) being different from the p - 1 voltages V n ( q) for q ranging from 1 to p - 1 and being comprised between the maximum voltage V max and the minimum voltage V min, then - measuring a power P i (p) generated by the inverter of the i-th input and creating a p-th measurement point on said curve of "current as a function of voltage" of abscissa x = V n ( p) and of ordinate y = P i (p)/V n (p), - applying a voltage V n ( p) to the i-th input, with p an integer comprised between 1 and N > 1 called the measurement point, said voltage V n ( p) being different from the p - 1 voltages V n ( q) for q ranging from 1 to p - 1 and being comprised between the maximum voltage V max and the minimum voltage V min, then - measuring a power P i (p) generated by the inverter of the i-th input and creating a p-th measurement point on said curve of "current as a function of voltage" of abscissa x = V n ( p) and of ordinate y = P i (p)/V n (p), D. computing a so-called residual power variation ΔP' to be applied by said photovoltaic power plant such that ΔP' = Δ P - (P i (p) - P i), E. if Δ P' ≠ 0: cancelling said residual power variation Δ P' by distributing said variation over inputs different from the i-th input, F. repeating steps C' to E a plurality of times, incrementing p between each iteration, so as to create a plurality of different measurement points of said measured curve of "current as a function of voltage".