Zero sequence voltage injection method for DC cluster voltage equalization in cascaded H-bridge D-STATCOM

In a power system, the requirement of reactive power make burden on the transmission line or a distribution line. Especially, an unbalanced linear load can make the point of common coupling voltage (PCC) unbalanced however for an unbalanced non-linear load it may distort the PCC voltage. Cascaded H-bridge D-STATCOM, which works as a shunt compensator will be used to solve this problem. This process commences the deviations in the cluster voltage. The main reason for deviations is uneven power delivered by phase legs. Here, compensator power under the balanced source voltage and unbalanced load are found analytically. Further, an analytical method to estimate zero sequence voltage (Vo) i.e magnitude and angle of the to be injected are investigated. The inculcated (Vo) assist the cluster voltage to follow the reference voltage. Moreover, the estimated (Vo) implemented in control strategy of D?STATCOM. This work is verified by modeling the system in MATLAB/SIMULINK.