I have the problem described below and think that fitting an isolating transformer might solve it. If, you agree we want to know prices of equipment
We have a problem at a remote site in Africa where we are running a couple of prime power generator sets (FG Wilson 220/380, 50 Hz (1500 rpm) 450 kVA (409 kVA prime power) single set operation, no synchronization, controlled by a transfer switch. The alternator is connected star, and earth neutral TNS connection is provided inside the unit. The system is running during normal operation at between 40 and 50% of the prime power rating, which should not present us with problems, ambient temperatures remaining constant at around 30 – 32 degrees Celsius. We are at sea level. The connected load is around 65% inductive, comprising reefers, chiller/freezer units –the remaining 35% is made up of general single phase small power and lighting for offices and accommodation. The phases are balanced to within around 5%.
Our problem is that we also supply power to our landlord, who has a construction yard. He uses a lot of heavy duty three phase equipment such as pressing machines and industrial wood saws. There is obviously a fluctuating load on his site, something between 40 and 45 kVA.
When this equipment is being used on the site, the inrush current is causing voltage dips, predominantly on L3, which drops top around 160 volts. We have all gthe usual symptoms – lights flicker and compressors are in constant need of repair. Due to complicated inter-company politics, it is not possible to implement the obvious solution of supplying the landlord’s installation from a separate generator.
I was thinking that an isolating transformer might be a solution – but I am in need of further technical advice.