Electrical current measurement based on elastic waves propagation through dielectric materials

Abstract

Instrument transformers are key elements within the modern transmission and distribution systems of electrical energy. Conventional inductive transformers for electrical currents measurement in high-voltage grids are expensive devices with a significant risk of explosion. This paper describes a new approach based on the propagation of elastic waves through dielectric media. The measurement system is composed by a current sensor and the associated electronic modules. The current sensor is formed by emitter, transmission structure, and receiver. The magnetostrictive material of the emitter generates elastic (mechanical) waves under the alternate magnetic field induced by the primary current to be measured. Thus the 50 Hz, or 60 Hz, electrical signals are converted into elastic waves that propagate through a dielectric coupling structure until they reach the receiver. In the receiver side the elastic waves are converted back into electrical signals.