Implement an efficient multi-loop control scheme using rapid estimating filters to compensate for a variety of voltage drops

Abstract

In this paper, we have discussed a new control design for dynamic voltage recovery (DVR) to obtain a fast response and efficient compensation ability of voltage drop. In this design, the amplitude and phase angle of injected voltage for each phase is controlled separately. Then, phasor parameters of load and supply voltage measured by least square error (LES) filter are estimated in a short time (5 ms). These filters reduce the effect of noise, harmonics, and disorders on estimated parameters. The considered control system does not need a phase-locked loop (PLL), since the angle of measured signals is estimated by LES filters. Besides, separately controlling injected voltage for each phase, help DVR to adjust negative and zero sequence components, as well as positive sequence component. Results of simulation studies in the software environment of PSCAD/EMTDC show that considered control design, first compensate voltage drop for symmetric or unsymmetric errors in a very short time interval without phase jump. Second, perform compensation desirably under conditions of linear and nonlinear load.