What kind of testing equipment is used for UPS (>15 kVA)?
I think you need to leave the testing of systems with rated powers of 15kVA and 30kVA to certified professionals. Even if you could get your hand on equipment to test a UPS with mentioned power, it would be extremely expensive !

Power Analyzers and Spectrum Analyzers are not meant to test UPSes. They are intended for analyzing equipment that generates less than 1000x the power you are looking at !

So: contact the professionals who will install this equipment for you !