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Hi there,

I am currently working as an engineer in a power systems company who are designing an manufacturing AC and DC UPS systems.

During the testing of our AC UPS systems a major part of the testing is carrying out a battery discharge test. We do this by connecting an AC load bank to the output of the UPS inverter and failing the mains (thus causing the batteries to discharge through the inverter until they reach an end of discharge voltage).

The issue with this is that we are wasting a huge amount of electricity by year as these load banks are effectively wasting electricity by turning the electrical energy into heat and blasting it into the atmosphere.

We would like to look into a way of harnessing this wasted energy by feeding it back onto the mains grid or back into our local factory mains distribution board. This can be easily achieved but the only difficult part is controlling how much of the electricity used in the factory is drawn from the inverter (from the UPS on test) and how much from the grid.

Ideally we could set the load manually on a control unit so that the load from the inverter will not exceed a set value (i.e. 60kW) and then any extra electricity required is drawn from the grid. For example if the total electricity usage in the building is 100kW then the remaining 40kW will be supplied by the grid.

My question is, does anyone know of anyone who manufacturers a system that could do this? I'm thinking a box with two AC inputs (mains from grid and mains from inverter) with 1 output (to distribution board) and a couple of controller which monitor and limit the amount of electricity being drawn from each supply.

Any ideas or suggestions?

Thanks,

Andy.