A Method for Linearization of Optically Insulated Voltage Transducers

In the perspective of a capillary power system monitoring, measurement transducers must have larger and larger bandwidth and accuracy, due to proliferation on power grids of new power quality phenomena. Various types of voltage transducers, based on different operation principles, have been realized; in particular, those based on voltage dividers and optical insulation with digital communication seem to offer suitable features for an accurate disturbance monitoring. Anyway, very often they present high cost, too, and so this strongly limit their diffusion. Optical insulation with analog communication could offer all the desired features: nevertheless it is obtained through non-linear devices. So, in this paper a low cost method for linearization of voltage transducers for power systems, based on an optical insulation with analog communication, is presented. The described method is used to implement a prototype of a voltage transducer, whose design, simulation and realization are presented. Experimental characterization has shown that, despite the low cost, the transducer has very good performance, in terms of accuracy, bandwidth and linearity. Key-Words: transducers, voltage measurement, power system measurement, power quality, frequency response, linearization.