Methods for non-conventional measuring sensor integration in the medium voltage electrical equipment

The present trend in the field of high voltage stations and other medium voltage apparatus is to incorporate in their own construction other specific equipment especially the instrument transformers with non-conventional sensors which reduce drastically the dimensions and weight of the assembly formed in this way, the said assembly having higher reliability coefficients. There is a concordance with the user\´s demands which will be focussed on the manufacturers providing reliability and an automatic program of preventive maintenance (conceived so as the major failures are precluded) more efficient for their products; such a program can be supported only by a coherent information system. In this paper the following types of sensors are considered: current sensors, Rogowski ring-air core and unsaturable magnetic core (LPCT "low power current transformers"); voltage sensors, capacitive divider and resistive divider. In the paper it is presented the method for integrating the sensors directly in the bushings of the medium voltage equipment.