Photonic Voltage Transducer with Lightning Impulse Protection for Distributed Monitoring of MV Networks

The design, construction and characterization of a photonic voltage transducer with a lightning impulse protection for distributed measurements on medium voltage (MV) networks (11 kV) was presented in this paper. The sensor prototype, comprising a combination of a piezoelectric transducer and a fibre Bragg grating (FBG) as a core optical sensing element, and a dedicated lightning protection device comprising a set of reactive components, was evaluated through laboratory testing and its performance was assessed based on the accuracy requirements specified by the relevant industry standards. It was demonstrated that the sensor has the potential to meet the accuracy requirements for the 3P protection and 0.2 metering classes specified by the IEC 60044-7. The device successfully underwent lightning impulse withstand tests, satisfying the safety requirements applicable to 11 kV networks as specified by the standard. The usage of an FBG as a photonic sensing component enables the multiplexing of multiple such sensors to provide the distributed measurement of voltage along a power network.

Optical Voltage Transducer for Embedded Medium Voltage Equipment: Design and Parameters Optimization

An Optical Voltage Sensor prototype has been developed suitable for operating as embedded sensor in capacitive dividers for monitoring Medium Voltage in distribution networks. It is based on a retracing scheme, which consists of Lithium Tantalate crystals used as voltage transducers, and on telecom standard single mode fibre components. In this work a optimization of the optical layout via a numerical and an experimental investigation is reported for guaranteeing the OVS sensor survival under fast over-voltages. Tests carried out under different configurations of the electric circuit did not evidenced critical electric field gradients within the transduction path which could damage or deteriorate over time the performance of the OVS sensor.