Arrangement comprising a measuring device (30, 31, 32) which is suitable for measuring an output signal (I1', I2', I3', U1', U2', U3'), delivered by a measuring unit (20, 21, 22, 20U, 21U, 22U), that describes an operating variable of a technical installation and for producing a measured value (Im1, Im2, Im3, φim1, φim2, φim3, Um1, Um2, Um3, φum1, φum2, φum3), - wherein the arrangement forms a protection or measuring device for connection to an analogue measuring unit (20, 21, 22, 20U, 21U, 22U) of a high-voltage, medium-voltage or low-voltage system or at least also includes such a protection or measuring device, - wherein the arrangement comprises a correction unit (40, 41, 42) which is configured to correct the measured value produced by the measuring device (30, 31, 32) in accordance with a correction instruction associated with each individual measuring unit and to produce a corrected measured value (Ik1, Ik2, Ik3, φik1, φik2, φik3, Uk1, Uk2, Uk3, φuk1, φuk2, φuk3), wherein the corrected measured value describes an electrical state of the high-voltage, medium-voltage or low-voltage system, - wherein the correction instruction specific to the measuring units depends on the measured value produced by the measuring device (30, 31, 32), - and wherein the correction instruction specific to the measuring units has been determined on the basis of an error curve or a family of error curves, measured for the measuring unit (20, 21, 22, 20U, 21U, 22U), that quantifies an error produced by the measuring unit (20, 21, 22, 20U, 21U, 22U) in the output signal (I1', I2', I3', U1', U2', U3') according to operating variables, and - correction of the measured value produced by the measuring device (30, 31, 32) by means of the correction instruction compensates for or at least reduces the error produced by the measuring unit (20, 21, 22, 20U, 21U, 22U), characterized in that - the correction instruction contains a function or family of functions that is inverse or complementary with respect to the measured error curve or family of error curves, or said correction function is formed by such an inverse or complementary function or family of functions, the correction instruction also depending on the level of another operating variable of the technical installation. - wherein the arrangement forms a protection or measuring device for connection to an analogue measuring unit (20, 21, 22, 20U, 21U, 22U) of a high-voltage, medium-voltage or low-voltage system or at least also includes such a protection or measuring device, - wherein the arrangement comprises a correction unit (40, 41, 42) which is configured to correct the measured value produced by the measuring device (30, 31, 32) in accordance with a correction instruction associated with each individual measuring unit and to produce a corrected measured value (Ik1, Ik2, Ik3, φik1, φik2, φik3, Uk1, Uk2, Uk3, φuk1, φuk2, φuk3), wherein the corrected measured value describes an electrical state of the high-voltage, medium-voltage or low-voltage system, - wherein the correction instruction specific to the measuring units depends on the measured value produced by the measuring device (30, 31, 32), - and wherein the correction instruction specific to the measuring units has been determined on the basis of an error curve or a family of error curves, measured for the measuring unit (20, 21, 22, 20U, 21U, 22U), that quantifies an error produced by the measuring unit (20, 21, 22, 20U, 21U, 22U) in the output signal (I1', I2', I3', U1', U2', U3') according to operating variables, and - correction of the measured value produced by the measuring device (30, 31, 32) by means of the correction instruction compensates for or at least reduces the error produced by the measuring unit (20, 21, 22, 20U, 21U, 22U), characterized in that - the correction instruction contains a function or family of functions that is inverse or complementary with respect to the measured error curve or family of error curves, or said correction function is formed by such an inverse or complementary function or family of functions, the correction instruction also depending on the level of another operating variable of the technical installation.