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Report
A Grid Compatible Methodology for Reactive Power
Compensation in Renewable Based Distribution System
Tareq Aziz, U. P. Mhaskar, Tapan K. Saha, N. Mithulananthan
School of Information Technology and Electrical Engineering, The University of Queensland, Australia
Grid Requirements
Motivations
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Results (Continued)
Voltage recovery requirement : Time Domain simulation
Reactive Power Generation Capability
High penetration of small Distributed Generation
(DG) units
Grid standard
Power-factor control mode
Slow post-fault voltage recovery
Sensitivity index dV/dIR based methodology is
proposed to ensure faster recovery
Voltage at Bus 6 with DG2
Steady State Voltage, Continuous Operation range
 DG bus voltage should remain within the range of ±10% of nominal voltage.
Interconnection System Response to Abnormal Voltage
Voltage Range (p.u.)
V < 0.5
0.5 ≤ V < 0.88
1.1 < V < 1.2
V ≥ 1.2
Clearing time (sec)
0.16
2.00
1.00
0.16
Test Systems
16 Bus Commercial Feeder
Proposed Methodology
Voltage at Bus 3 with DG1
 IEEE Std 1547-2003 does not allow DG units to actively regulate voltage at PCC.
Voltage recovery time for 16 Bus System
43 Bus Industrial Feeder
DG node
Without Capacitors
With Capacitors
3 (DG1)
6 (DG2)
N/A
N/A
1.15 Sec
1.59 Sec
Voltage at Bus 4 with DG1
With STATCOM at
bus 3
1.26 Sec
1.97 Sec
With STATCOM at
bus 7
0.26 Sec
1.26 Sec
Voltage at Bus 50 with DG2
Take DG integrated Distribution System
Optimal Capacitor Placement to minimize grid loss with load variation
Time domain simulation
Dynamic Voltage
restoring compatibility to
meet grid requirement
New Index
Yes
Complete
Simulation Tool used : DigSILENT PowerFactory Release 14.0
No
Calculate dV/dIR and its direction for
optimal capacitor nodes
Replace capacitor with STATCOM on the
bus with most negative dV/dIR
Time domain simulation
Dynamic Voltage
restoring compatibility to
meet grid requirement
Yes
Complete
Voltage recovery time for 43 Bus System
Index dV/dIR
Check
next
location
for
STATCOM
No
Results
V
Per unit
change in
node voltage
(V) with
reactive
current (IR)
injection/
absorption
XT
V0
VSC
VDC
Without Capacitors
With Capacitors
4 (DG1)
50 (DG2)
3.12 Sec
0.71 Sec
2.35 Sec
0.54 Sec
With STATCOM at
bus 21
2.49 Sec
0.42 Sec
With STATCOM at
bus 39
1.61 Sec
0.37 Sec
Conclusions
Steady State requirement: Optimal Capacitor
Solution for 16 Bus System
Optimal Node
Capacitor Size
(MVAr)
Sensitivity index dV/dIR
(Vp.u/Ip.u.)
7
3
1.8×2
1.2
-0.1428 (Inductive)
0.11 (Capacitive)
IR
DG node
Steady State requirement: Optimal Capacitor
Solution for 43 Bus System
Optimal Node
Capacitor Size
(MVAr)
Sensitivity index dV/dIR
(Vp.u/Ip.u.)
39
21
1.1
0.6
-0.25 (Inductive)
0.33 (Capacitive)
School of Information Technology and Electrical Engineering, The University of Queensland
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A step by step method has been proposed for static and
dynamic reactive power planning of DG integrated
distribution system.
Proposed index-based approach ensures fast voltage
recovery and hence improves uptime of DG units.
Minimizes number of expensive STATCOM in a system
with multiple DG units.

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