Welsh Water do this a lot on their Works & Pumping Stations. They have Stage/Stagger start regimens in place to limit the Transient Inrush currents (some sites have several pretty meaty motors)Had a very exciting and interesting visit on Monday. Still amazes me what is hiding in industrial estates up and down the country
Some quick maths and a look at what we needed and a solution was formed, 3 stages of centrifugal compressors, pumps and fans all vfd controlled will allow us to keep the startup current well within limits and on another, bigger, project we are looking at cascading multiple heat pumps but all running as one unit, so we can do much more than a lead/lag setup