Building industrial equipment that is installed outside. These systems are modular in nature and can be or will be moved from one location to another.
General set up is a central power entry module, that then feeds one to six sub systems. Power for each subsystem is plugged in via a suitable cord and weather tight connector.
Total system power is between 10 and 50 KVA at 3 phase 240 depending on system configuration.

Bonding will probably be separate suitably sized conductor(s) tying all of the structures together.

My question is: What would be a suitable method of testing the bonding to verify everything has a nice low impedance path back to the PE terminal?

I believe I need approximately 200 A AC or DC for 1 minute to perform this verification test.

My thoughts are a constant current power supply like a stick arc welder or perhaps a 1 KW 12/24 buck/boost transformer and a large variac.

Larry,

One test may be done using an array of Fixed Resistance Heater Elements connected to the far end of each Circuit, then measure the Voltage at each end to determine the Voltage Loss.
Apply the Volt Drop (E-loss) against the drawn Amperes (I) to achieve the Conductor Impedance (Z).

--Scott (EE)