Study On Electronic Voltage Transformer Based On Capacitive Voltage Dividing

Voltage transducer are the basic measurement instruments for energy measurement and relay protection in the electric power system. With the increasing demand for digitization and automation in the electric power system control and protection etc. , conventional PT and CVT transducers could not satisfy the requirement of the modern power system any more. However, because of technical problem, the optical voltage transducers are still unreliable. At present, people began to show more interests on electronic voltage transducers, which are based on electronics, micro-computer and fiber communication techniques, because of their good stabilization, reliability and well-performed sensor technology.According to analysis and comparison for different sensor technology, the dry type capacitor divider is choosed as voltage sensor, whose temperature will be tested by temperature sensors. The voltage and temperature information is transferred by optic fiber and processed mainly in control room. This paper introduces the design details about data acquisition system and the idea and design about merging unit. With studying on the temperature characteristic about the capacitor divider, the paper discusses temperature test and compensation about EVT.To qualify for the insulating property, accuracy and stability of the EVT, series of tests were done in the laboratory and Wuhan Institute of High Voltage. According to IEC 60044-7 and GB 1207-1997, and main parameter of the EVT, this paper represents the execution of the tests and analyses the test result.Finally, this paper introduce EMC measures about the whole EVT system.