125VDC Substation Battery Simulator

[thermionic1]

I'm looking for either a ready made device or something simple for one of our test racks and a few other applications. The primary use would be powering logic (opto isolated) inputs on protection relays, PLC's and similar. Most of our SEL devices have a universal power supply input, so I'll use AC for the larger loads. We have the SEL power supply unit, however this gets used in the field often and my intention is to keep something permanent with the test rack. The SEL has 2 125 VDC outputs, but they are not very well regulated. I can find all kinds of 48V / 24V supplies, just can't seem to find a reasonably priced 125V unit. I'm thinking 2A max, or less would be fine.

I put together a small unit using a boost converter, which is OK for now, but was wondering if there is something better out there with built in protection, etc.

 

[JG2828]

I have also looked for them in the past. Have never really found anything. I usually end up using a Sorensen 150vdc adjustable power supply. Something like this

https://store.programmablepower.com/collections/dc-power-supplies/products/xg-1500w-series-dc-supply

 

[thermionic1]

I found a $50 solution on Ebay. An Electrophoresis Power Supply is used in medical work. Used units are quite inexpensive. My unit goes up to 300W / 2kV.

I found the trick is hanging a 1 Mohm resistor in parallel with the output, else the unit won't start up.

I'll continue to power the various relays (SEL with universal AC/DC) with line voltage. This supply is for wetting logic inputs.