José María Maza Ortega

Reference current computation methods for active power filters: accuracy assessment in the frequency domain

This paper focuses on the steady-state response of existing methods for computing the reference current of active power filters. For each class of methods, the main source of discrepancy between the load harmonic current and the computed reference current is identified and the frequency spectrum of the resulting error is analytically determined. Although this topic has been partially addressed in previous publications, the proposed frequency-domain approach provides valuable qualitative information about how the errors are produced and distributed, which is masked when the analysis is carried out in the time domain. First, the frequency-domain formulation is separately presented for each method. Then, a comparison of the resulting errors is performed on a case study. Finally, some experimental results are given to validate the proposed frequency-domain analysis.

A State estimation approach to harmonic polluting load characterization in distribution systems

This paper develops a weighted least-squares methodology for the estimation of relevant parameters characterizing harmonic polluting industrial loads through a set of measurements acquired at the point of common coupling. The proposed method is capable of obtaining an accurate load model in the absence of detailed information about its internal structure and composition.

Power factor correction and harmonic mitigation in industry

Power factor correction in industrial facilities has become a problem nowadays because of the widespread use of power electronic equipment. Frequently, single tuned filters must replace capacitors used to increase the power factor in order to avoid resonances. This paper presents an analytical technique used to improve power factor and reduce harmonics. An orthogonal decomposition of currents in three-phase system is applied in order to compute the optimum power factor compensator for each individual problem.

Load following control issues in the Spanish power system

Load following is carried out in a centralized way in the current Spanish power system, with several AGC modules of the main generation companies responding to the requirements of a master regulator. This service is provided under competition as an ancillary service, including a dedicated daily market. This paper shows that the current structure of the Spanish AGC system can be potentially improved from the load following performance point of view by using new algorithms of load following control. Load following control is proposed to reduce frequency deviations during normal system operation, using, at the same time, the lowest amount of regulation energy as possible, and, consequently, enhancing system reliability and economy.

Reactive power compensation strategies for wind generation in distribution systems: a power quality approach

This paper studies the impact on the voltage profile of wind energy based generators connected to distribution power systems. Voltage fluctuations arise in distribution levels including noncontrollable primary energy sources because of their corresponding active power injection variations. A number of reactive power strategies have been analysed and compared focusing on the voltage fluctuation minimisation. A distribution network with real wind generation data has been used as a benchmark system to establish the results. Finally, once the reactive power profile is deduced using one of the proposed strategies, a Static Var Compensator is designed in order to show the viability of the adopted reactive power compensation scheme.

Reference current errors of instantaneous pq-based methods for active filters

The reference current errors of instantaneous pq-based methods for active filters are analyzed in this paper. First, the error function in steady-state conditions is derived and a numerical harmonic analysis is performed. A theoretical harmonic analysis is developed to carry out the underlying reasons that causes the error harmonics due to the singularity of the harmonic spectrum. Finally, some examples of application are reported.