Implementation of Adaptive Filter in
Distribution Static Compensator
ABSTRACT:
This paper presents an implementation of an adaptive filter in a
three-phase distribution static compensator (DSTATCOM) used for compensation of
linear/nonlinear loads in a three-phase distorted voltage ac mains. The
proposed filter, which is based on adaptive synchronous extraction, is used for
extraction of fundamental active- and reactive-power components of load
currents in estimating the reference supply currents. This control algorithm is
implemented on a developed DSTATCOM for reactive-power compensation, harmonics
elimination, load balancing, and voltage regulation under linear and nonlinear
loads. The performance of DSTATCOM is observed satisfactory under unbalanced
time-varying loads.
KEYWORDS
1. Adaptive filter
(AF)
2. distribution static
compensator (DSTATCOM)
3. harmonics
4. load balancing
5. sinusoidal tracking algorithm
6. voltage-source converter (VSC)
SOFTWARE: MATLAB/SIMULINK
BLOCK DIAGRAM:
Fig.1. Schematic of three-leg DSTATCOM.
EXPECTED SIMULATION RESULTS:
(a)
(b)
Fig. 2. (a), (b), and (c) Various
intermediate signals of the control algorithm at load injection. (a) Ch. 1 and
2: 200 V/div; Ch. 3 and 4: 20 A/div; Time axis: 50 ms/div. (b) Ch. 1, 2, 3, and
4: 20 A/div; Time axis: 20 ms/div. (c) Ch. 1, 2,3, and 4: 20 A/div; Time axis:
20 ms/div.
Fig. 4. Steady-state performance of DSTATCOM
at nonlinear loads in PFC mode. (a) vab, isa. (b) vbc,
isb. (c) vca, isc. (d) Harmonic spectrum of isa.
(e) vab, iLa. (f) Harmonic spectrum of iLa.
Fig. 5. Dynamic performance of DSTATCOM at
unbalanced linear loads. (a) vab, isa, isb, isc.
(b) vab, iLa, iLb, iLc. (c) vdc,
isa, iCa, iLa.
Fig. 6. Dynamic performance of DSTATCOM at
unbalanced nonlinear loads. (a) vab, isa, isb,
isc. (b) vab, iLa, iLb, iLc.
(c) vdc, isa, iCa, iLa
.
Fig. 7. Steady-state performance of DSTATCOM
at linear lagging PF load in ZVR mode. (a) Ps. (b) PL.
(c) Pc. (d) vab, isa. (e) vbc, isb.
(f) vca, isc.
Fig. 8. Steady-state performance of DSTATCOM
at nonlinear load in ZVR mode. (a) vab, isa. (b) vbc,
isb. (c) vca, isc. (d) Harmonic spectrum of isa.
(e) Harmonic spectrum of iLa. (f) iCa. (g) Ps.
(h) PL.
Fig. 9. Variation of Vt, isa,
and iLa with vdc under unbalanced linear loads.
CONCLUSION:
A DSTATCOM has been implemented for a
three-phase distribution system. An AF has been used for control of DSTATCOM.
This AF has been found simple and easy to implement, and its performance has
been observed satisfactory with nonsinusoidal and distorted voltages of ac
mains under load variation. The performance of DSTATCOM with its AF has been
demonstrated for harmonics elimination, reactivepower compensation, and load
balancing with self-supporting dc link in PFC and ZVR modes. The dc-link
voltage of the DSTATCOM has been also regulated to a desired value under
time-varying load conditions.
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