Question: BDD testing with Omircon

[Jay27]

I'm having some issues here. It seems like it should be so straight forward. I'm trying to follow the testing instructions per the manual but I'm not having any luck. I can hear the relay buzzing when I apply current but do not get a trip. I am ramping to the pickup value. Anyone have any experience testing this relay? (GE BDD trans. diff w/ harmonic restraint).

Taps are set appropriately, etc. The answer is something stupid and simple!

 

[slavag]

Hi Jay27.
According to your explanation, "problem" is your injection current.
Try change setting of harmonic restraint and not pick-up value of diff current.
Please meas level of harmonics in the injection current with some analaizer.

Good Luck.
Slava

 

[oldfieldguy]

Jay--

Sounds like your test set's output waveform is breaking down as you ramp up the current. I never used and Omicron, but I've run into that issue on other solid-state test sets.

It usually means that at higher current levels, the voltage developed across the relay is higher than the test set is putting out comfortably.

These sets sometimes have problems with electromechanical relays. You might try a test setting with a higher output voltage, paralleling two or three current output channels to reach the desired level of current. Use the current setting with the highest voltage output that will let you get to the desired current levels.

I usually tested BDD's in tap 5/5 for all the tests (pickup, slope, harmonic restraint, instantaneous) and then did a final pickup test in the working taps unless the client required otherwise. With some solid-state test sets, though, the current requirement and the relay impedance required that I performed the instantaneous test in the lowest tap.

old field guy

 

[DTR2011]

Depending on the type of Omicron, there are different hardware configurations, which produce the maximum output voltage. 2x 37.5A is designed for this type of relay. As well, I believe BDD needs DC control voltage applied. Make sure the test set inputs are configured for DC input voltage.