China
Africa
Explore chapters and articles related to this topic
Review of Control Topologies for Shunt Active Filters
Published in L. Ashok Kumar, S. Albert Alexander, Computational Paradigm Techniques for Enhancing Electric Power Quality, 2018
L. Ashok Kumar, S. Albert Alexander
Figure 5.4a shows a zigzag transformer connected in parallel to the load for filtering the zero-sequence components of the load. The zigzag transformer consists of three single-phase transformers with turn ratio 1:1. It acts as an open circuit for positive sequence and negative sequence component of load currents and the current flowing through the zigzag transformer is only the zero-sequence components. The phasor diagram of the transformer shows that the resultants voltages are 120° phase shifted. The zero-sequence component of load currents can be locally circulated using a star/delta transformer as shown in Figure 5.4c. The secondary delta-connected winding provides a path for the zero-sequence currents and hence the supply neutral current is reduced to zero. The relative value of a series inductance (Zsn) with transformer impedance plays a significant role in the effectiveness of the neutral current compensation. Therefore, the transformers must be installed near the load or it is required to connect a high value of series inductance. In this paper, some new transformer configurations are proposed for the neutral current compensation in a three-phase four-wire distribution system. The Scott-transformer and T-connected transformer are used in the power system for different applications. The proposed configuration of T-connected transformer for neutral current compensation is shown in Figure 5.4b and in this two single-phase transformers are used for neutral current compensation. These single-phase transformers are connected in T-configuration and it shows that the resultant voltages are 120° phase shifted. The transformer is simple and the windings are suitably designed for MMF balance. A Scott-transformer for neutral current compensation with fourth-wire topology in Figure 5.7 (e and f) and as compared to earlier T-connected transformer, the required numbers of windings is reduced. A star–hexagon transformer is reported along with VSCs as SHAF, which also helps in neutral current compensation as shown in Figure 5.4d. A star–polygon transformer is reported for some other application, but it is proposed for neutral current compensation. Similarly, a zigzag transformer is analyzed in detail for zero-sequence harmonic compensation in the literature.
DSTATCOM using model predictive control associated with LMS control
Published in International Journal of Electronics, 2023
Sabha Raj Arya, Rakesh Maurya, Jayadeep Srikakolapu
In this work, a 3P4W (3 Phase 4 Wire)-equipped DSTATCOM has been controlled using WZAVSSLMS and FCS MPC. DSTATCOM’s reference currents are produced through an extraction facilitated by WZAVSSLMS. Switching selection using FCSMPC approach with WASPAS method includes second-order Lagrenge’s extrapolation. Switching selection using FCSMPC methodology is utilised proper when it comes to power quality concerns, such as enhancing grid current THD and reducing grid reactive power owing to a non-linear load load’s burden on the grid. Using weighting factors, two constraints are applied in the cost function to decrease the error of stationary reference frame compensator currents. Next one is reduction of switching frequency. For the purpose of neutral current compensation at the point of common coupling, a delta-zigzag transformer is utilised. WZAVSSLMS is described in detail, along with its operational concept. When using MATLAB Simulink, both LMS and FCSMPC techniques are evaluated. The resulting findings are then confirmed empirically in a laboratory setting.