Design and modelling of DSTATCOM Using Various Hybrid ANN Control Algorithms

Abstract

Significant research works have been directed on control of reactive power, harmonics, load compensation & low power factor in the distribution system which is due to several causes like switching of the capacitors, loads, starting of large motor along with the proliferation of power electronic equipment, nonlinear loads in residential, commercial & industrial application. Such type of issue leads to the failure of sensitive equipment’s used for controlling & protecting of the plant, which further causes lower efficiency and power factor and increases the risk of electromagnetic interference with the neighbouring communication lines so the cost of the overall system increases.

In order to overcome the various difficulties encountered in power system, such as harmonic current, unbalanced source current, reactive power burden etc. Besides the costs, the solution effectiveness of each alternative needs to be quantified in terms of the performance improvement that can be achieved. Development of compensator to enhance power quality has been an area of active interest for the past few decades. Passive compensators like shunt reactors and capacitors are uncontrolled devices and incapable of continuous variation in parameters. The emergence of custom power devices has led to development of new and fast compensators. The custom power devices include compensators like Distribution Static Compensator (DSTATCOM), Dynamic Voltage Restorer (DVR), Unified Power Quality Conditioner (UPQC), Interline Power quality Conditioner (IPQC), Battery Energy Storage System (BESS), and many more such controllers. So placement of custom power devices may prove to be an effective remedy for solving such type of power quality problems.

This present research work proposes several ANN controlled icosϕ for a three phase two level distribution static compensator (DSTATCOM) to perform the functions such as harmonic mitigation, power factor correction under reactive loads, which further reduces the DC link voltage across the self-supported capacitor of voltage source converter (VSC). The fundamental weighted values of active and reactive power components of load currents are extracted using the proposed control technique to generate the reference source currents. Further, the reference source currents are used to generate switching pulses for VSC of the DSTATCOM. The effectiveness of this control technique is demonstrated through simulation using MATLAB/SIMULINK and Sim Power System (SPS) tool boxes. The real time implementation of DSTATCOM is also carried out using Real time digital simulator (RTDS). The results demonstrate the robustness of the DSTATCOM with the proposed control algorithm as it is showing outstanding harmonic compensation capabilities under balanced and unbalanced loading conditions and keeping the THD of the source current well below 5%, the limit imposed by IEEE-519 standard.