Research On On-line Monitoring For The Primary Converter Of Active Electronic Transformer

With the continuous advancement of smart grid construction,electronic transformers have been widely used for its simple insulation structure,digital output and other outstanding advantages.However the high failure rate is exposed in the electronic transformer,especially in the primary converter.In order to improve the reliability and accuracy of electronic transformers,it is necessary to monitor electronic transformer on line.Based on the running status and the structure of the active electronic transformer,this thesis presents the method of online-fault monitoring and online-error monitoring for the primary converter.By adding a reference signal source of high-stability to the primary converter,the reference signal is measured by the original measurement circuit of the primary converter.The measuring result could be compared with the reference value to judge whether the primary converter is worn or not,so that the fault self-monitoring for the primary converter of active electronic current or voltage transformer can be realized.A high-accuracy standard channel was added to the primary converter,sampling synchronously with the measured channel.Then the ratio error and phase error of the primary converter can be calculated to determine whether the error is over,and realize the error self-monitoring of the active electronic current or voltage transformer.In this thesis,the principle of two methods above was analyzed,appropriate components were selected based on the technical index requirements,and the online monitoring circuit was designed,satisfying the accuracy and power consumption requirements.The software control flow was given based on the hardware circuit,and the performance of the core circuit was tested and analyzed.The experimental results show that the core circuit can meet its technical index requirements.