An AC power amplifier for testing instrument transformer test equipment
Enrico Mohns, S. Fricke, F. Pauling · 2016
This paper describes the design and setup of analogue power amplifiers for generating calibration signals for test equipment for instrument transformers. Two amplifiers have been set up for a rating of 600 VA and 70 VA, respectively. The 600 VA version is used for testing standard burdens, while the other one is used as a source for a calibrator for testing test sets for conventional and non-conventional current or voltage transformers. The amplifiers offer the possibility to switch between a voltage mode and a current mode. The bandwidth of the amplifiers covers the range from 16.7 Hz to at least 3 kHz. Different ranges between 80 V to 280 V in the voltage mode, and 2 A to 10 A in the current mode are realized with a transformer-coupled output stage. The gain accuracy is in the order of 1 %, while the stability is better than 0.01 %. The smaller amplifier will be used to set up future measurement systems in the EMRP project "Non-conventional voltage and current sensors for future power grids".