The document describes a study that designed a self-tuning PI controller for a Static Synchronous Compensator (STATCOM) using a Bats Echolocation Algorithm (BEA). A STATCOM is a Flexible AC Transmission Systems device that helps maintain power system stability. The proposed BEA was used to optimize the PI controller gains to regulate the load bus voltage for a power system configuration that included a STATCOM. Digital simulations showed the self-tuning PI controller using the BEA had a faster dynamic response in maintaining the load bus voltage compared to a fixed gain PI controller, especially for a non-linear load.

1. Design of Self-Tuning PI Controller for
STATCOM using Bats Echolocation
Algorithm
Presented by: Mr.G.Kumaravel
Assistant Professor-EEE
Arunai Engineering College
Tiruvannamalai
Guided by: Dr.C.Kumar,B.E.,M.Sc(Engg).,Ph.D.
Director-Academics
SKP Engineering College
Tiruvannamalai
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2. Abstract
 A Static Synchronous Compensator (STATCOM) is a typical
Flexible AC Transmission (FACTS) device, play a vital role in
stability of a power system under small and large disturbances.
 This paper deals with, Design and Evaluation of a Bats
Echolocation Algorithm (BEA) for self-tuning PI controller of
STATCOM.
 The proposed BEA shows very good performance in non
linear load.
 The effectiveness of the proposed Bats Echolocation
Algorithm is evaluated by computer simulation. Simulations
are carried out using MATLAB/SIMULINK software.
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3. Power System Configuration with STATCOM
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4.  The load impedance is estimated from load voltage and
load current.
 Based on the estimated system load impedance, The
Bats Echolocation algorithm optimize the PI controller
gains.
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5. Principle of STATCOM
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6.  Voltage Source Inverter is the core element of the STATCOM ,
which is in general converts a DC voltage into an AC output
voltage at power frequency, with controllable amplitude and
phase angle.
 This paper proposes a self-tuning PI controller ,to maintain the
magnitude of the bus voltage by controlling the magnitude and
phase shift of the output voltage (Vp) of the VSC.
 Under steady state, there is no real power transfer occurs via
coupling transformer
 If Vs>Vp,the VSC draws reactive power from the AC bus.
Whereas if Vs<Vp , it supplies reactive power to the AC
system
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7. Fixed – Gain PI Controller for STATCOM
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8.  Fixed gain PI controllers are normally used to regulate a load
bus voltage under disturbance conditions
 The d-axis and q-axis current regulators regulate ipd and ipq in
order to get desired ipdref and ipqref by adjusting the epd and epq
values.Inorder to compute the phase angle α as phase angle
difference of Vt and Vs.
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9. Bats Echolocation System
• Bats emits ultrasonic sound of 5 to 20ms duration at a rate of
10Hz, while looking for prey, by measuring the time of flight,
bats estimate their distance from the target.
• When the single pulse repetition rate increases up to
200Hz.bats enter the approach phase to prey.
• By means of this, bats avoid overlapping of pulses which
results in loss of resolution
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10. Bats Echolocation Algorithm
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13. Digital SIMULINK model of system with
STATCOM
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14. Digital SIMULINK model of VSI with self
tuning PI controller using Bats Echolocation
Algorithm.
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15. Digital Simulink model of Non linear load
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16. System parameters
 Source voltage (Erms(p-p)) =25(kV),
 source x/r ratio=7, F=50(Hz),
 Load resistance in the non linear load (Rl) = 3000Ω,
 filter L=0.1(H),C=250μF,
 capacitor value on DC side of VSI=1mF
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17. Stable Regions of Kp and Ki values
KP KI Load
-20 -10 Light Load
-15 -30 15 + j30Ω.
-10 -40
-15 -10 Medium Load
-10 -30 8+ j15Ω.
-5 -55
-10 -10 Heavy Load
-7 -20 3 + j7Ω.
-5 -20

18. Digital Simulation Results
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19. Dynamic response of system for non linear load
with fixed gain PI controller
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20. Dynamic response of system for non linear load
with self tuning PI controller using BEA
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21. Dynamic response of source current for non
linear load
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22. Dynamic response of DC capacitor voltage for
non linear load
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23. Response of q-axis current of STATCOM
controller
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24. Digital Simulation Results
 In fixed gain PI controller, Kp and Ki values are selected as
0.01 and 0.1 respectively for non linear load with 3kΩ.
 The dynamic response of system for non linear load with fixed
gain PI controller shows the stability in load bus voltage is
obtained in 0.017 seconds.
 The dynamic response of system load bus voltage for non
linear load with self tuning PI controller using BEA shows the
stability is obtained within 0.0012 seconds.
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25. Conclusion
 The fast dynamic response obtained in system load bus when
self tuning PI controller using Bats Echolocation algorithm is
used as a STATCOM controller as compared with fixed gain
PI controller.
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26. References
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3. N.G.Hingorani and L.Gyugi, Understanding FACTS. New
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27. 4. T.J.E.Miller, Ed., Reactive Power Control in Electric
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28. 8. Yazdani, A.; Crow, M.L.; Guo, J.; "A comparison of linear
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9. Allen, G. M. (1940), Bats, Harvard University Press.
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