Zbigniew Hanzelka

Comparative tests of flickermeters

It can be shown that different digital flickermeters implementations that meet the performance tests defined in IEC 61000-4-15 can still disagree significantly in some actual measurements. This paper is intended to apply a set of tests proposed by UIE/CIGRE WG 2 to ensure that implementation is correct and different meters will agree with all types of actual measurements. The main objectives are: (i) test how well flickermeters comply with IEC standards, (ii) provide a reproducible method of testing so that tests can be repeated at another time with any flickermeter designed to IEC 61000-4-15, (iii) prepare test data and test programs for distribution to potential flickermeter manufacturers, (iv) gain knowledge about additional functionality or limitations provided by the tested flickermeters. The tests have been performed using five instruments.

Power system harmonic estimation using neural networks

The increasing application of power electronic facilities in the industrial environment has led to serious concerns about source line pollution and the resulting impacts on system equipment and power distribution systems. Consequently, active power filters (APFs) have been used as an effective way to compensate harmonic components in nonlinear loads. Obviously, fast and precise harmonic detection is one of the key factors to design APFs. Various digital signal analysis techniques are being used for the measurement and estimation of power system harmonics. Presently, neural network has received special attention from the researchers because of its simplicity, learning and generalization ability. This paper presents a neural network-based algorithm that can identify both in magnitude and phase of harmonics. Experimental results have testified its performance with a variety of generated harmonies and interharmonics. Comparison with the conventional DFT method is also presented to demonstrate its very fast response and high accuracy.

The influence of a phase change in the measured voltage on flickermeter response

The influence of a phase change in the measured voltage on a flickermeter response is discussed. The paper shows that the instant of occurrence of a phase change can influence the flickermeter response if the disturbance occurs just before the termination of the ten-minute Pst evaluation interval.

Application of neural networks to voltage fluctuations measurement-a proposal for a new flickermeter

This paper discusses the standard IEC 61000-4-15 flickermeter design and the principle of measuring voltage fluctuations based on human eye-brain perception. The conception of a neural network performs the measuring part of a flicker meter. The flicker is developed with Matlab environment to set input and output signals, which is taken as the training set for the neural network. The simulation results are obtained from the estimation of the input signal envelope employed to the processes of training the neural network.

International white book on the grid integration of static converters

Grid inverters are the key elements to massively integrate distributed renewable energy resources (DER) into electricity grids. This paper deals with the future requirements for static converters to support the operation of the power systems considering in particular ancillary services, disturbed network conditions, and control and communication requirements.

Negative-sequence active power stream as an index of unbalance source

This paper discuses the properties of negative-sequence active power stream relative to the point of measurement in the unbalanced three-phase electric circuit. Analysis of the negative-sequence active power stream for the typical circuit asymmetry cases is carried out. It was shown that the stream direction can be used as an unbalance source index.

Application of neural networks to voltage fluctuations measurement — neural networks flickermeter

It can be shown, that many flickermeters do not yield credible output readings although the manufacturers declare their compliance with the requirements of standard IEC 61000-4-15. Modifications or revisions to the standard and increasing the number of requirements, what is currently taking place, seem to be interim actions, whose results are dubious. On the other hand, it should be acknowledged that since over ten years the standardization of voltage fluctuations is based on the UIE flickermeter. The authorspsila idea is to treat a flickermeter - from its analogue input to the output of block 4 - as a black box, filled in by a designer accordingly to its decision, while maintaining the IN/OUT characteristics in conformity with those of the flickermeter regarded as a standard one.

Voltage-current and harmonic characteristic analysis of different FC-TCR based SVC

Static VAr Compensator (SVC) is one of the most popular modern power system elements to stabilize voltage as well as to compensate reactive power demand. There are varieties of such circuit which deal with different technical arrangement, reactive power compensation technique, contribution to power system stability and individual features as well. In this paper simulation and experimental results of different types of SVC, more specifically Fixed Capacitor-Thyristor controlled reactor (FC-TCR), are presented. The experiments are carried out to verify the simulation result of two different configuration of FC-TCR. Finally, a comprehensive analysis on current-voltage characteristics and harmonic characteristics are reported in this paper.

Bank Harmonic Filters Operation in Power Supply System – Cases Studies

DC drives can be a significant plant load in many industries. They are commonly used in the oil, chemical, metal and mining industries. These drives are still the most common large power type of motor speed control for applications requiring very fine control over wide speed ranges with high torques. Power factor correction is particularly important for this drives because of relatively poor power factor, especially when the motor is at reduced speeds. Additional trans‐ former capacity is required to handle the poor power factor conditions and more utilities are charging a power factor penalty that can significantly impact the total bill for the facility. The DC drives also generate significant harmonic currents. The harmonics make power factor cor‐ rection more complicated. Power factor correction capacitors can cause resonant conditions which magnify the harmonic currents and cause excessive distortion levels. For the same rea‐ sons arc furnaces are very difficult loads for a supplier and for the customer they are very diffi‐ cult objects of reactive power compensation and harmonics filtering.

Capacitor bank impact on harmonic filters operation in power supply system

Power factor correction of the facilities requires a design that is able to compensate for reactive power demand as well as for harmonic currents injected by the equipment into power supply system. In the circumstances many of industrial supply systems consist of a combination of tuned filters and a capacitor bank. Investigation of interaction between capacitor banks and harmonic filters within an industrial power supply system is carried out.