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Ratio PTs with a 6150?

1. NETA Level III Pro Subscriber
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Ratio PTs with a 6150?

We are doing a large job of nothing but meter and PT checks. 480v board. 480/120 PTs so nothing crazy. Is there a fancy way to run a ratio test in Protection Suite? Or is that just a horrible idea?

2. Originally Posted by bec51392
We are doing a large job of nothing but meter and PT checks. 480v board. 480/120 PTs so nothing crazy. Is there a fancy way to run a ratio test in Protection Suite? Or is that just a horrible idea?
Can't think of a complete test, but you could run a specified voltage on the primary and read the secondary voltage with a multimeter, and calculate a ratio.
So, you could put range your voltage and place 3 phase voltage out (all 3 phases at different voltages) and read the secondary to determine all 3 voltages at the same time, or do each phase individually (much easier).

This is the same thing most TTR perform, as they typically put out 40V and read the return voltage calculating the ratio. If the burden is to high, they will typically drop the voltage to 4V and re-perform the test. Any voltage below 50V is considered de-energized, so I would typically stay below that threshold. Just have to remember your safety protocols and isolate the test sample from the system.
You can develop an easy excel worksheet to assist with quick calculations. So for 40V should output ~10V and 4V should output ~1V.

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I've done it out of the control panel a few times I just didn't know if there was a back handed way to read it back on the inputs. Maybe even get it to do some math.

I think you can set the inputs for voltage feedback but its set thresholds, like 15v or something. I've never tried it. I was thinking I could set it to auto run, record the output voltage when it hit 15 feedback then do the math... but at that point I'm probably not making my life any easier than just using a fluke.

4. Find a way to isolate the primary and test from there, this way you are testing the entire circuit. If the meter reading is correct, the ratio is good.

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