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Pole Pig Simulation Data 1
Hi All, (view with fixed width font)
Here is data from Microsim regarding ballasting & PFC cap:
I checked LTR, RESO, and STR tank cap sizes (10KVA, 14.4kv Pole Pig).
The voltage angle is set to cross zero at 50.000ms. This is the point of
reference used to check the current waveforms zero-crossing. In some
instances, the current leads the voltage, and in others it lags the
voltage. I used ArcCOS (lead-t/lag-t) for degrees.
In the last two weeks, I've looked at a lot of waveforms. My purpose here
is to simply look at ballasting and PFC relationships, not actual values.
There is a lot more information with regards to voltage and current due to
waveform phase relationships and where the break is within the waveforms.
But for this, I just wanted to look at the line voltage and current.
Terry, I read your other post and I agree fully. Keeping it simple is
difficult with this particular testing (that's actually what I'm trying to
do here). The data is interesting and there are relationships here that
appear to follow theory.
I first ran a test of each cap size using no ballast or PFC in the circuit.
I won't go into current readings, I just wanted to look at the phase prior
to the remaining test. PFC values and ballast values are the same for LTR,
STR, and RESO. I'm not looking for the PFC to use, but simply relationships.
LTR - 250nF (larger than resonant)
W/no pfc/ballast: R = 0.1 ohms, V-t =50.000ms, I-t=52.572ms, 18.00 degrees
Ballast PFC V-time I-time Angle
(mH) (uF) (ms) (ms) (degrees)
------- ---- ------ ------ -----
5 0 50.000 52.854 18.91 << angle increases w/L >>
10 0 50.000 53.047 19.51 ** current lagging in all
15 0 50.000 53.186 19.93 ** needing PFC
20 0 50.000 53.291 20.24
30 0 50.000 53.435 20.66
50 0 50.000 53.592 21.10
5 370 50.000 48.950 11.76 << w/PFC, angle decreases w/L >>
10 370 50.000 51.255 12.71 ** needs more PFC
15 370 50.000 49.104 10.86 ** notice anomoly's with
lead or lag
20 370 50.000 51.195 12.40 I tracked this: Due to
poor waveform,
30 370 50.000 49.472 8.33
50 370 50.000 49.279 9.74
15 200 50.000 52.031 16.06 - current lagging
15 300 50.000 52.059 16.17 - current lagging
15 400 50.000 49.964 2.17 <<< Only slight phase shift
15 500 50.000 48.044 16.08 - current leading
15 600 50.000 47.851 16.86 - current leading
-----------------------------------------------
RESO - 128nF (resonant)
W/no pfc/ballast: R = 0.1 ohms, V-t=50.000ms, I-t=50.883ms, 10.69 degrees
Ballast PFC V-time I-time Angle
(mH) (uF) (ms) (ms) (degrees)
------- ---- ------ ------ -----
5 0 50.000 51.439 13.58 << again, w/L, angle increases >>
10 0 50.000 51.871 15.44 ** current lagging in all
15 0 50.000 52.194 16.67
20 0 50.000 52.436 17.53
30 0 50.000 52.769 18.64
50 0 50.000 53.136 19.78
5 370 50.000 49.726 6.00 << Too much PFC? going up.
10 370 50.000 50.574 8.64 ** current lagging here and on
15 370 50.000 50.141 4.30
20 370 50.000 50.995 11.34
30 370 50.000 51.650 14.52
50 370 50.000 51.607 14.34
15 200 50.000 51.254 12.70 < current lagging
15 300 50.000 51.001 11.37 < current lagging
15 400 50.000 50.316 6.42 <<< Small phase angle
15 500 50.000 50.458 7.73 < current leading
15 600 50.000 49.149 10.59 < current leading
-------------------------------------------------
STR (smaller than resonant) - 64nF
W/no pfc/ballast: R = 0.1 ohms, V-t=50.000ms, I-t=49.158ms, 10.53 degrees
Ballast PFC V-time I-time Angle
(mH) (uF) (ms) (ms) (degrees)
------ ----- ------ ------ -------
5 0 50.000 49.515 7.99 << w/L, angle increases
10 0 50.000 49.871 4.12 < leading
15 0 50.000 50.219 5.35 < lagging
20 0 50.000 50.555 8.50 < lagging
30 0 50.000 51.163 12.24 < lagging
50 0 50.000 52.024 16.03 < lagging
5 370 50.000 49.295 9.63 < leading
10 370 50.000 49.969 2.02 << slightly leading
15 370 50.000 50.573 8.63 < lagging
20 370 50.000 51.130 12.07 < lagging
30 370 50.000 52.177 16.61 < lagging
50 370 50.000 53.549 20.98 < lagging
15 200 50.000 50.280 6.05 << PFC is not helping?
15 300 50.000 50.419 7.39 ** lagging in all
15 400 50.000 50.616 8.95 ** I have had strange problems
w/STR's
15 500 50.000 50.736 9.77
15 600 50.000 50.634 9.08 **I will run these again
(blunder?)
In STR above, the ballast of 10mH with a PFC cap of 370uF looks good, but
in reality, the amount of current may be too much (it's close). STR wave
forms can get really messy, especially with a PFC added. In everything else
I've looked at, using a PFC in an STR set up has identified some problem
(typically - cap voltages become dangerous to the cap if the cap is too
small and the xfmr current is to high).
LTR's and RESO cap sizes appear to favor PFC use without problems as long
as the PFC value is correct. If the PFC is too small, waveforms get ugly.
Bart