Reactive power compensator
- Renton, WA
- Woodinville, WA
- Kirkland, WA
- Everett, WA
- Seattle, WA
A system and method for determining and providing reactive power compensation for an inductive load. A reactive power compensator (50,50') monitors the voltage and current flowing through each of three distribution lines (52a, 52b, 52c), which are supplying three-phase power to one or more inductive loads. Using signals indicative of the current on each of these lines when the voltage waveform on the line crosses zero, the reactive power compensator determines a reactive power compensator capacitance that must be connected to the lines to maintain a desired VAR level, power factor, or line voltage. Alternatively, an operator can manually select a specific capacitance for connection to each line, or the capacitance can be selected based on a time schedule. The reactive power compensator produces control signals, which are coupled through optical fibers (102/106) to a switch driver (110, 110') to select specific compensation capacitors (112) for connections to each line. The switch driver develops triggering signals that are supplied to a plurality of series-connected solid state switches (350), which control charge current in one direction in respect to ground for each compensation capacitor. During each cycle, current flows from ground to charge the capacitors as the voltage on the line begins to go negative from its positive peak value. The triggering signals are applied to gate the solid state switches into a conducting state when the potential on the lines and on the capacitors reaches a negative peak value, thereby minimizing both the potential difference and across the charge current through the switches when they begin to conduct. Any harmonic distortion on the potential and current carried by the lines is filtered out from the current and potential signals used by the reactive power compensator so that it does not affect the determination of the required reactive compensation.
- Research Organization:
- Univ. of Washington, Seattle, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AI79-87BP65584
- Assignee:
- Board of Regents of University of Washington (Seattle, WA)
- Patent Number(s):
- US 5134356
- Application Number:
- 07/665,774
- OSTI ID:
- 868411
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
power
compensator
method
determining
providing
compensation
inductive
load
50
monitors
voltage
current
flowing
distribution
lines
52a
52b
52c
supplying
three-phase
loads
signals
indicative
waveform
line
crosses
zero
determines
capacitance
connected
maintain
desired
var
level
factor
alternatively
operator
manually
select
specific
connection
selected
based
time
schedule
produces
control
coupled
optical
fibers
102
106
switch
driver
110
capacitors
112
connections
develops
triggering
supplied
plurality
series-connected
solid
switches
350
charge
direction
respect
ground
capacitor
cycle
flows
begins
negative
positive
peak
value
applied
gate
conducting
potential
reaches
minimizing
difference
begin
conduct
harmonic
distortion
carried
filtered
affect
determination
required
voltage waveform
signals indicative
power compensator
line voltage
inductive load
potential difference
reactive power
control signal
optical fibers
optical fiber
current flow
control signals
current flowing
current flows
peak value
selected based
negative peak
distribution lines
connected solid
crosses zero
charge current
power factor
selected base
inductive loads
phase power
power compensation
distribution line
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