**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**

- Adaptive filter (AF)
- distribution static compensator (DSTATCOM)
- harmonics
- load balancing
- sinusoidal tracking algorithm
- voltage-source converter (VSC)

**SOFTWARE:** MATLAB/SIMULINK

** ****BLOCK DIAGRAM:**

Fig.1. Schematic of three-leg DSTATCOM.

**EXPECTED SIMULATION RESULTS:**

(a)

(b)

(c)

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. 3. Steady-state performance of DSTATCOM at linear lagging PF load in PFC mode. (a) P_{s}. (b) P_{L}. (c) P_{c}. (d) v_{ab}, i_{sa}. (e) v_{bc}, i_{sb}. (f) v_{ca}, i_{sc}.

Fig. 4. Steady-state performance of DSTATCOM at nonlinear loads in PFC mode. (a) v_{ab}, i_{sa}. (b) v_{bc}, i_{sb}. (c) v_{ca}, i_{sc}. (d) Harmonic spectrum of i_{sa}. (e) v_{ab}, i_{La}. (f) Harmonic spectrum of i_{La}.

Fig. 5. Dynamic performance of DSTATCOM at unbalanced linear loads. (a) v_{ab}, i_{sa}, i_{sb}, i_{sc}. (b) v_{ab}, i_{La}, i_{Lb}, i_{Lc}. (c) v_{dc}, i_{sa}, i_{Ca}, i_{La}.

Fig. 6. Dynamic performance of DSTATCOM at unbalanced nonlinear loads. (a) v_{ab}, i_{sa}, i_{sb}, i_{sc}. (b) v_{ab}, i_{La}, i_{Lb}, i_{Lc}. (c) v_{dc}, i_{sa}, i_{Ca}, i_{La}

Fig. 7. Steady-state performance of DSTATCOM at linear lagging PF load in ZVR mode. (a) P_{s}. (b) P_{L}. (c) P_{c.} (d) v_{ab}, i_{sa}. (e) v_{bc}, i_{sb}. (f) v_{ca}, i_{sc}.

Fig. 8. Steady-state performance of DSTATCOM at nonlinear load in ZVR mode. (a) v_{ab}, i_{sa}. (b) v_{bc}, i_{sb}. (c) v_{ca}, i_{sc}. (d) Harmonic spectrum of i_{sa}. (e) Harmonic spectrum of i_{La}. (f) i_{Ca}. (g) P_{s}. (h) P_{L}.

Fig. 9. Variation of V_{t}, i_{sa}, and i_{La} with v_{dc} 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.

** ****REFERENCES:**

** **[1] E. F. Fuchs and M. A. S. Mausoum, Power Quality in Power Systems and Electrical Machines. London, U.K.: Elsevier, 2008.

[2] H. Akagi, E. H. Watanabe, and M. Aredes, Instantaneous Power Theory and Applications to Power Conditioning. Hoboken, NJ, USA: Wiley, 2007.

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[4] J. Jacobs, D. Detjen, C. U. Karipidis, and R. W. De Doncker, “Rapid prototyping tools for power electronic systems: Demonstration with shunt active power filters,” IEEE Trans. Power Electron., vol. 19, no. 2, pp. 500– 507, Mar. 2004.

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