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The fast detection of magnitude, frequency, and phase angle of the fundamental-frequency component is very useful in many three-phase power system applications. Most techniques to accomplish this task are based on different versions of three-phase phase-locked loop (PLL) schemes. Some variables of three-phase systems may experience phase angle jumps after some disturbances. In this paper, a method for the fast detection of phase angle jump occurrence, estimation of the phase angle jump, and its use for improving the performance of the generalized delayed signal cancelation (GDSC) PLL is proposed. The proposed method is based on the detailed evaluation of the GDSC filter transient behavior after a phase jump. Results considering typical three-phase grid disturbances are used to evaluate the proposed scheme, in comparison with other usual PLL techniques. The use of the proposed phase jump angle estimator allowed a reduction in the GDSC-PLL convergence time of about 50%. [ABSTRACT FROM AUTHOR]

Integration of distributed generation (DG) such as photovoltaics (PV) represents a challenge for the traditional operation of distribution power systems. As the installed power of DGs grows, grid codes are being modified to involve DGs in the provision of ancillary services. This includes the ability to ride-through large disturbances. In this paper, the behavior of a single-stage PV system under unbalanced voltage conditions is studied, and a fault ride-through control scheme is proposed which is able to support the grid through the injection of reactive power. Furthermore, adjustable power quality is enabled as a tradeoff between power ripple and current harmonics. The control scheme makes use of a current controller based on the space vector Fourier transform concept. No rotational transformation is required, and zero steady-state error is ensured when tracking distorted current references. The controller was tested in detailed PSCAD/EMTDC computer simulations, and implemented in a real grid-connected PV system to demonstrate its performance under unbalanced voltage conditions. [ABSTRACT FROM PUBLISHER]

This paper shows a scheme for improving the detection performance of the fundamental-frequency positive-sequence (FFPS) space vector through the generalized delayed signal cancellation phase-locked loop (GDSC-PLL). We implemented a variable-structure scheme in order to reduce the convergence time by changing the traditional datapath whenever even harmonics are not present in the input signal. If this condition is not true, the performances of the variable-structure GDSC-PLL and the traditional GDSC-PLL for detecting the FFPS space vector will be similar. Therefore, the variable-structure GDSC-PLL does not require a previous knowledge about the harmonic components of the three-phase signal. Furthermore, we improved the frequency-adaptive scheme. The performances of the original and proposed schemes were compared through transient test cases based on IEC 61000 and typical electrical events. The new approach led to a reduction of up to 62% in the convergence time. [ABSTRACT FROM PUBLISHER]

In this paper, two methods for determining the fundamental frequency and harmonic positive- and negative-sequence components of three-phase signals are investigated. Many aspects of the space-vector discrete Fourier transform and generalized delayed signal cancellation (GDSC) such as response time for different possible implementations, frequency adaptation schemes, stability of recursive implementation, and rounding error effects are discussed. A new design procedure for GDSC transformations is presented. New indices for characterizing three-phase unbalanced and distorted signals are proposed. Simulations and experiments are included in order to verify the performances and illustrate the theoretical conclusions. [ABSTRACT FROM PUBLISHER]