Besides its main application, each turns ratio tester from this TRT advanced series also measures transformer excitation current and phase shift. Furthermore, all models perform automatic vector group detection and magnetic balance on three-phase transformers and three-phase autotransformers. They have a built-in true three-phase power source. For that reason, they can test transformers with special configurations, such as phase-shifting, rectifier, arc-furnace, traction transformers, etc.
The instruments can output test voltages from 1 V AC to 430 V AC, depending on the model. With the highest test voltage 430 V AC, TRT400 provides the most accurate turns ratio testing of power transformers used in power generation and transmission. With the low test voltage of 1 V AC, it enables turns ratio verification of current transformers. Other two models, TRT250 and TRT100, can output up to 250 V and 170 V respectively.
All models have a large 7” graphical touch screen display. Besides making the interface much more user-friendly compared to older turns ratio testers, it also brings certain options that were previously available only with DV-Win software. The most important are test templates and automatic test mode. Users can simply create test templates, store them in the instrument’s memory, and load when in the field with just a few clicks.
This turns ratio test set, as well as all other DV Power turns ratio testers, has a built-in tap changer control unit. It enables remote control of on-load tap changer (OLTC) directly from the instrument. In order to make the most out of this feature, the instrument can be programmed to do everything automatically – running turns ratio tests, changing OLTC tap positions, and saving results. This option, especially in combination with test templates, significantly facilitates and shortens the turns ratio testing time. Automatic test mode minimizes human errors, which makes the measurement more reliable.