| US 7,504,806 B2 | ||
| Apparatus and methods for controlling operation of a single-phase voltage regulator in a three-phase power system | ||
| Casper A. Labuschagne, Pullman, Wash. (US) | ||
| Assigned to Schweitzer Engineering Laboratories, Inc., Pullman, Wash. (US) | ||
| Filed on Mar. 06, 2006, as Appl. No. 11/368,826. | ||
| Claims priority of provisional application 60/728922, filed on Oct. 21, 2005. | ||
| Prior Publication US 2007/0222421 A1, Sep. 27, 2007 | ||
| Int. Cl. G05F 1/14 (2006.01); H01F 29/04 (2006.01) | ||
| U.S. Cl. 323—255 [323/340; 307/50; 700/298] | 63 Claims |
| 1. An apparatus for controlling operation of a voltage regulator via a tap position change, the voltage regulator operatively
coupled to a single-phase of a three-phase power system to regulate a measured voltage of the single-phase to an in-band area
for delivery to a load, the apparatus comprising:
a means for deriving a digitized voltage stream representative of the measured voltage of the single-phase; and
a microcontroller operatively coupled to the means for deriving the digitized voltage stream and configured to enable the
tap position change, the microcontroller having a microprocessor and a memory operatively coupled to the microprocessor, the
microcontroller being programmed to:
start a countdown time period of a first timer upon detecting a first excursion of the measured voltage from the in-band area
to an out-of-band area,
upon detecting a first return of the measured voltage to the in-band area, record a first elapsed time of the first timer,
reset the first timer to the countdown time period, and start a second timer,
upon detecting a second excursion of the measured voltage from the in-band area to the out-of-band area, record a second elapsed
time of the second timer, compare the second elapsed time to a predetermined dip time period,
if the second elapsed time is less than the predetermined dip time period, start an adjusted countdown time period of the
first timer, and
if the second elapsed time is more than the predetermined dip time period, start the countdown time period of the first timer
upon subsequent entry of the measured voltage into the out-of-bound area.
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