Comparison of Models of Single-Phase Diode Bridge Rectifiers for Their Use in Harmonic Studies with Many Devices

Harmonic modeling of low-voltage networks with many devices requires simple but accurate models. This paper investigates the advantages and drawbacks of such models to predict the current harmonics created by single-phase full-bridge rectifiers. An overview is given of the methods, limiting the focus to harmonic analysis. The error of each method, compared to an accurate numerical simulation model, is quantified in frequency and time domain considering realistic input scenarios, including background voltage distortion and different system impedances. The results of the comparison are used to discuss the applicability of the models depending on the harmonic studies scale and the required level of detail. It is concluded that all models have their applicability, but also limitations. From the simplest and fastest model, which does not require a numerical solution, to the more accurate one that allows discontinuous conduction mode to be included, the trade-off involves accuracy and computational complexity.

Control Strategy of 1 kV Hybrid Active Power Filter for Mining Applications

The paper presents a shunt hybrid active power filter for 1 kV mining applications in configuration with a single-tuned passive filter. The focus is on the method of controlling the filter, with particular emphasis on the influence of network voltage distortion and time delays in control on the effectiveness of harmonic reduction, which is one of the most important aspect of power quality. The low-power loss configuration of a hybrid filter with SiC transistors is shown, as well as the control algorithm which limits the influence of voltage distortion. Theoretical considerations are verified by results obtained from simulations and tests of the hybrid active power filter prototype.

Harmonic Mitigation Using Passive Harmonic Filters: Case Study in a Steel Mill Power System

In this study, we mitigated the harmonic voltage in a power system that contained the roughing mill (RM) and finishing mill (FM) motor drives. AC/DC converter type RM drive is a non-linear, large-capacity varying load that adversely affects power quality, e.g., a flicker, voltage distortion, etc. The voltage drop can be compensated within a certain limit by using the proper capacity of a power capacitor bank. In addition, the voltage distortion can be controlled as per the guidelines of IEEE Std. 519 using the passive harmonic filter corresponding to the characteristic harmonics of the motor drive load. The passive harmonic filter can provide an economical solution by mitigating the harmonic distortion with a proper reactive power supply. However, at the planning level, attention should be paid to avoid system overvoltage that is caused by the leading power under light load conditions and also the problem of parallel resonance between the harmonic filter and the step-down transformer. In addition, when designing the filter reactor, the K-factor and peak voltage must be considered; the filter capacitor also requires a dielectric material that considers the harmonic peak voltage. The purpose of this study was to acquire a better understanding of the filter applications as well as verify the field measurement, analysis, and design of harmonic filters together with its performance.

IDENTIFICATION AND EVALUATION OF HARMONIC VOLTAGE SOURCES IN POWER SUPPLY SYSTEMS

Non-sinusoidal voltage in power supply systems leads to economic losses that need to be distributed and compensated. This problem is solved on the basis of the problem of identification and evaluation of the influence of voltage distortion sources. To date, existing methods for identifying and assessing the impact of harmonic voltage sources have significant limitations of practical implementation. This is due to their basic mathematical model and local approach to measuring the parameters of the network. In the given research the new mathematical model of identification and an estimation of harmonic voltage sources that is focused on the distributed measuring system is presented. The criterion for identifying harmonic voltage sources is the distorting nodal current. To adequately determine it, it is necessary not only to measure the parameters of the network mode in the base nodes by the currents of the higher harmonic components, but also to control the structure and parameters of the replacement circuit of the entire power supply system. To achieve this goal, it is proposed to use a distributed measuring system, which is based on vector measurement systems and control systems. The estimation of the influence of harmonic voltage sources is directly proportional to the distorting nodal current, where the coefficient of proportionality is either mutual or intrinsic resistance of power supply systems, that connects the location of the distortion source and the place for which its influence is estimated. In order to control the influence of measurement errors and determine the parameters of circuits for replacing elements of the power supply system, the method and algorithm for identifying and assessing the impact of harmonic voltage sources should be developed based on the principle of excluding one of the voltage distortion sources.

Impact of the hybrid reactive power compensator on the power grid used a fuzzy PI regulator

The work presented in this article is a contribution to the problem of controlling reactive powers and voltages in an electrical network. Among these control tools, the static reactive power compensator (SVC) was chosen because of its simplicity of control. SVC is one of the Alternative Flexible Current Transmission Systems (FACTS) devices which help to solve the problems encountered in the operation of electrical networks, either on the distribution side or on the transport side. To increase its compensation efficiency in the face of harmonic currents which cause voltage distortion, we have introduced a three-phase harmonic filter. This new hybrid SVC is used to control the reactive power, the voltage and in addition to reduce the voltage distortion and the correction of the power factor in the electrical energy transport network. In order to improve its efficiency, two voltage regulation systems have been chosen in the control system for this compensator, the fuzzy PI regulator and the PIP regulator.

Analisis Kualitas Daya Listrik Pada Penggunaan Modul Surya Sederhana Untuk Pompa Air Rumah Tangga

The use of solar modules to meet the needs of everyday life is something interesting to use. Harmonics is a phenomenon of power quality deviation that can distort voltage and current waveforms. In this experiment, a simple inverter with 1000 W capability will be used, then will be loaded with water pumps and other household appliances. The method used is to measure the power factor and harmonics generated by using a measuring device. In this process needs to be assessed and will be seen using the ability of the inverter and the quality of the electric power generated in this solar power generation system. Based on the results of measurements and calculations on a water pump with a power of 680 W and 1 incandescent lamp with a power of 60 Watts, the value of the power factor generated is 0.95 while the total harmonic voltage distortion (THDv) value is when the water pump load is THDv 1.9 % and at THDv incandescent lamps 1.6%.