Elecgene
The TRT-20 TTR tester is designed to test all power, instrument (CTs and PTs), and distribution transformers without the need of traditional high voltage excitation. The electrical integrity tester is also an innovative product with compact size, more portable and easy to carry. With three phase output voltage, testing is up to five times faster than previous phase-by-phase switching single instruments, easier to test phase shift measurement, vector recognition, winding balance.
https://www.elecgenetest.com/products/trt-20-3-phase-ttr-tester/