A voltage-to-voltage transducer for distorted signals in high-voltage systems

Measuring voltages in HV electric power systems requires scaling the signal amplitude to the levels suitable for the input section of the employed instruments and, for safety reason, insulating the measuring instrument from the system. Both these operations are usually performed by capacitive voltage transformers, but such systems do not assure high measurement accuracy when the signals are distorted. A new approach for the implementation of a measurement system for HV electric power systems is presented. The power supply of the HV station of the measurement system, together with the required galvanic isolation, is obtained by means of a suitable energy transfer from the LV to the HV station. This energy transfer system is based on the conversion of the optical power generated by a laser source into the electrical power needed for the measurement circuit. The structure of the insulated transducer is then based on a capacitive divider and two electrically-isolate signal conditioning stations. The proposed solution allowed for designing a Voltage-to-Voltage transducer for high-voltage, in-field applications. The results of the preliminary experimental work on a laboratory prototype demonstrate, for the first time, the feasibility of such electrically-isolated laser-supplied systems.