A. J. Ustariz-Farfan

Voltage sag segmentation under deformation tensor parameters

This paper introduces a new algorithm of polyphasic segmentation. This new algorithm combines the strength of the concept of voltage signal tensor with the benefits offered by the residual segmentation technique in order to generate a unique pattern of segmentation. This segmentation strategy is validated using a set of synthetic signals with voltage variation in the remnant voltage and the start point of the event. The proposed algorithm is tested using a set of real signals captured by a local network operator.

Hybrid simulation to test control strategies in active power filters using generalized power tensor theory

This paper presents a hybrid simulation to test control strategies in active power filters using the generalized power tensor theory. The tensor theory is based on the dyadic or tensor product between voltage and current vectors. This new definition allows the estimate of reference currents for the control of active power filters “APFs” in multiphase systems. The hybrid simulation consists in a combination of computer simulation and laboratory tests. This approach is a cost effective alternative to physically testing the whole system and allows study the dynamic behaviour of complex engineering systems. Besides, it describes implementing an active power filter (APF) hybrid prototype where the source system and load are implemented as a real-time simulation and the active power filter is implemented in physical hardware. It also confirmed the hybrid simulation results by implementing the simulation in MATLAB-Simulink regarding the same system implemented during the active power filter analysis and design stage.

Analysis of Voltage Sag Severity Case Study in an Industrial Circuit

This paper presents the results of a power quality study carried out in an industrial distribution system. The main objective of this study was to quantify the negative impact caused by voltage sags in industrial processes and its relationship to generated interruptions. A series of measurements of power quality variations were taken at the substation that feeds the circuit and at the point-of-common coupling of each industrial user. The new standard IEEE Std 1564-2014 “Guide for Voltage Sag Indices” was used to determine the indicators to assess the severity of voltage sags and also the calculation method. Sag severity was selected as it allows the calculation of the probability of voltage sags to generate interruptions in industrial processes or electrical equipment. Thus, an analysis of the quality of the supply voltage can be done. Severity was initially calculated at the substation that feeds the industrial circuit and later, at the point-of-common coupling of each user. Subsequently, the relationship between user interruptions and severity values was determined. Finally, recommendations of good engineering practices in industrial processes were done.

Visualizing two- and three-dimensional maps for power quality loss assessment

Constructing maps of loss or deterioration of power quality, due to stationary and non-stationary disturbances, is of great importance for the control, protection and analysis of power systems. Therefore, a technique for two- and three-dimensional maps visualization of the deterioration of power quality in electrical networks based in the power tensor theory is proposed. The objective of the technique is to provide images of the electrical network with easily identifiable characteristics through the construction of graphic schemes (maps) of power quality loss. Finally, the effectiveness of the tool is illustrated via different scenarios which are created using the IEEE 13-bus test feeder as an example.

Segmentation and characterization of voltage sags in the analysis of industrial circuits

Power quality management systems can provide information related with voltage sags as the duration, remnant voltage and affected phases associated with a point of measurement. Given a strong relation of these parameters with severity and energy indexes of voltage sags an improvement of the segmentation and characterization process is needed. For this reason a new method of analysis of voltage sags is presented in this paper. This new method uses a single parameter for the segmentation and classification process which is generated from the tensor concept of voltage signals. This parameter has a constant behavior under ideal conditions and oscillations during the occurrence of voltage sags. The classification process is performed from the maximum and minimum peaks of the parameter under a voltage sag condition. Comparisons between characterization results of the proposed method and a power quality management system in an industrial distribution system are shown. The shortcomings in the characterization that may result from the segmentation stage and its subsequent impact on the calculation of voltage sags indexes on an industrial circuit of the local utility feeder are shown as well.

Validation and reception of electric arc furnace transformers

The electric arc furnace transformer is one of the most important devices in the steelmaking industry. Installing used transformers is very common nowadays taking into account the huge investment that represents the acquisition of a new one. The transformer is subjected to electrical stress, thus it is necessary to assess the wear and tear levels in the reception process before accepting a trade agreement and before setting the device into operation. Analysis parameters are the input variables of a new fuzzy model to calculate the remaining life of the transformer.

Implementation of IEEE Std 1564-2014 for voltage sag severity analysis on a medium voltage substation

Voltage sags can be measured by the probability to generate an interruption of a process or equipment. Such quantification is known as severity. Recently, the new standard IEEE Std 1564-2014 Guide for Voltage Sag Indices determines the indicators for assessing the severity of voltage sags and the method of its calculation as well. In this paper, its implementation is presented for the analysis of the severity index at a substation of the local area network operator. This analysis allows an assessment of the state of the voltage quality at the point of common coupling of a commercial customer. Based on this assessment, the relationship between the severity index in the substation and the point of common coupling is obtained. Finally, considerations about present measurement standards that determine the proper use of such standard practice are presented.

Power quality causes of failures in Colombia's Rural

This paper undertakes the study of failures in energy meters installed in low-voltage power network. The objective is to find a way to reduce the high failure rate that this type of equipment currently presents in the eastern zone of the departmento de Caldas, especially in the areas of greatest keraunic level. The methodology implemented enables root cause analysis, the proposal of remedial actions and the validation of the proposed solutions.

Teoría generalizada de la potencia instantánea aplicada a la compensación de cargas polifásicas

The use of the instantaneous reactive power theory is greater than before due to the increased interest to use active power filters to compensate the non-sinusoidal currents produced by nonlinear loads. However, this theory can only be applied to three-phase systems of three or four conductors. This paper presents a new definition of instantaneous power that can be applied to all multiphase systems. Thus, the concept of tensor product is introduced to define the instantaneous power tensor and also the current decomposition in active and reactive components regardless of the number of phases of the power system. Finally, an exhaustive analysis of practical cases has been carried out at a simulation level which verified the proposed approach.

Modeling of a centralized microgrid protection scheme

This paper presents the simulation and modeling process of an over-current protection scheme with pre-established configurations and centralized control of such configurations. Consequently, it was necessary to classify, characterize and parameterize the different protection schemas proposed in the related literature. In addition, a digital relay protection adaptation and a centralized decision scheme are proposed. Finally, the microgrid model characteristics and its implementation in MATLAB/SIMULINK, with their respective results, are presented.