Download Sparq_Reactive Power Control

Active and Reactive Power Control
Praveen Jain
19 September 2014
Reactive power
Definition and Static Compensation


Voltage and current are not in-phase  Reactive Power  for the same voltage
and current amplitude (constant Apparent Power), less active (real) power is
allowed to be transferred.
Most of the loads (such as motors) draw current not in phase with the voltage
(large reactive power)  Since reactive power generation does not require any
source of energy, traditionally capacitor banks and recently smart converters
even with no source of energy can produce the required reactive power locally
to free up some real power transfer capacity on the transmission and
distribution systems.
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Sparq Confidential
June 2014
New Requirements for
Reactive and Active Power Control
Dynamic Compensations

Dynamic active power compensation
proportional to the frequency
deviation helps the grid frequency
becomes stable because of the way all
the generators are controlled.

It can be shown that negative reactive
power generation can locally cause a
small grid voltage sag.  Dynamic
reactive power compensation
depending on grid voltage deviation
can stabilize the grid voltage.
During the fault new standards
require smart dynamic reactive power
support from the smart inverters to
help the grid voltage stabilize faster.
This is called Fault Ride Through
(FRT).

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Sparq Confidential
July 2014
Instantaneous Power control
(Ultra-fast Reactive power
control)
Instantaneous power reference
New control strucutre
Instantaneous power feedback
No current feedback
New control block diagram which controls the instantaneous power directly
instead of active and reactive power independently.
This improves the dynamic response of the system and improves stability of the system
When there are several microinverters in the grid.
Experimental Results for different active and
reactive power levels: case 1: P= low, Q = low
Steady state condition for early in the
morning or late in the afternoon with no
reactive power
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Case 2: P= low, Q = medium
Steady state condition for early in the morning or late in the afternoon with
100Var reactive power
07/20/2012
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Case 3: P= low, Q = High
Steady state condition for early in
the morning or late in the
afternoon with 300Var reactive
power
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Case 4: P= High, Q = Low
Steady state condition for full
sun and low Reactive power
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Case 5: P= High, Q = High
Steady state condition for full
sun 300Var Reactive power
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Case 6: Ppv= zero, Q= low
Steady state condition for night
operation with 30Var Reactive
power
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Case 7: Ppv= zero, Q= medium
Steady state condition for night
operation with 150Var Reactive
power
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Case 8: Ppv= zero, Q= High
Steady state condition for night
operation with 300Var Reactive
power
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Case 9: Ppv= jump, Q= zero
Transient response for input power jump with no reactive power
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Case 10: Ppv= jump, Q= High
Transient response for input power jump while injecting 200Var reactive
power
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Case 11: Ppv= zero, Q= jump
Transient response for reactive power jump with zero active power
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Case 12: Ppv= High, Q= jump
Transient response for reactive power jump when injecting 100W active
power
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Case 13: Ppv= zero, Q=jump
inductive to capacitive
Qref
jump
Transient response for reactive power jump from inductive to capacitive at
night
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Case 14: Ppv= high, Q=jump
indutive to capacitive
Qref jump
Transient response for reactive power jump from inductive to capacitive
when injecting 100W active power
07/20/2012
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