Active and Reactive Power Control Praveen Jain 19 September 2014

Reactive power June 2014 Sparq Confidential2  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. Definition and Static Compensation

New Requirements for Reactive and Active Power Control July 2014Sparq Confidential3  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). Dynamic Compensations

Instantaneous Power control (Ultra-fast Reactive power control) 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. Instantaneous power feedback No current feedback Instantaneous power reference New control strucutre

5SPARQ CONFIDENTIAL 07/20/2012 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

6SPARQ CONFIDENTIAL 07/20/2012 Case 2: P= low, Q = medium Steady state condition for early in the morning or late in the afternoon with 100Var reactive power

7SPARQ CONFIDENTIAL 07/20/2012 Case 3: P= low, Q = High Steady state condition for early in the morning or late in the afternoon with 300Var reactive power

8SPARQ CONFIDENTIAL 07/20/2012 Case 4: P= High, Q = Low Steady state condition for full sun and low Reactive power

9SPARQ CONFIDENTIAL 07/20/2012 Case 5: P= High, Q = High Steady state condition for full sun 300Var Reactive power

10SPARQ CONFIDENTIAL 07/20/2012 Case 6: Ppv= zero, Q= low Steady state condition for night operation with 30Var Reactive power

11SPARQ CONFIDENTIAL 07/20/2012 Case 7: Ppv= zero, Q= medium Steady state condition for night operation with 150Var Reactive power

12SPARQ CONFIDENTIAL 07/20/2012 Case 8: Ppv= zero, Q= High Steady state condition for night operation with 300Var Reactive power

13SPARQ CONFIDENTIAL 07/20/2012 Case 9: Ppv= jump, Q= zero Transient response for input power jump with no reactive power

14SPARQ CONFIDENTIAL 07/20/2012 Case 10: Ppv= jump, Q= High Transient response for input power jump while injecting 200Var reactive power

15SPARQ CONFIDENTIAL 07/20/2012 Case 11: Ppv= zero, Q= jump Transient response for reactive power jump with zero active power

16SPARQ CONFIDENTIAL 07/20/2012 Case 12: Ppv= High, Q= jump Transient response for reactive power jump when injecting 100W active power

17SPARQ CONFIDENTIAL 07/20/2012 Case 13: Ppv= zero, Q=jump inductive to capacitive Transient response for reactive power jump from inductive to capacitive at night Qref jump

18SPARQ CONFIDENTIAL 07/20/2012 Case 14: Ppv= high, Q=jump indutive to capacitive Transient response for reactive power jump from inductive to capacitive when injecting 100W active power Qref jump