Measurement Of Power Factor Research Articles

An electrical comparative study of two atmospheric pressure dielectric barrier discharge reactors

The experimental work reported here is devoted to the electrical study of two atmospheric pressure dielectric barrier discharge (DBD) reactors operating at high gas flow, conceived for surface treatment applications in spatial afterglow conditions. Both reactors are of coaxial geometry with the dielectric covering the active electrode, and are driven by a power generator delivering quasi-sinusoidal voltage waveforms in the 100–160 kHz range. The influence of the gas flow value and of the input power on the electrical operation of these systems is investigated. The comparative study performed here, by means of electrical measurements, reveals the influence of parameters such as geometrical dimensions and dielectric material used on the operation of the DBD. Power factor measurements are used to quantify the reactors' electrical performance. Optical diagnostics and kinetic modelling reveal a high chemical activity of the systems appropriate for the treatment of surfaces at atmospheric pressure.

Transient analysis on current sensor of resin molded type for measurement of power factor in power distribution system

AbstractThe authors have proposed the resin molded type of voltage–current sensor for the real‐time observation of the power factor. The sensor has been designed and implemented based on the FEM; however, the current waveform and practical power distribution system includes harmonic components due to the inverter‐fed power apparatuses in households and factories. Therefore, it is necessary to apply not the conventional jω method but the finite‐difference approximation to the time derivative term in a transient electromagnetic field analysis using FEM. In the paper, the authors will show the result of electromagnetic field analysis of the sensor adopting the finite‐difference approximation. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 157(1): 1–9, 2006; Published online in Wiley InterScience (http://www.interscience.wiley.com). DOI 10.1002/eej.20294

Analysis of Some Measurement Issues in Bushing Power Factor Tests in the Field

The power factor measurement is widely used in the evaluation of bushing insulation conditions in the field. Some measurement issues occur in the field tests which give abnormal readings of bushing C/sub 1/ and/or C/sub 2/ power factors. This paper provides an engineering analysis of the possible measurement issues in the bushing field tests such as testing a bushing on a transformer or in its shipping crate, or a bushing with wet/contaminated voltage/test tap or wet/dirty porcelain surface.

The Development of a Digital Sampling System for Low Power Factor Measurements of High-Voltage Capacitive/Inductive Reactors

A digital sampling system for high-accuracy low power factor measurements of high-voltage capacitive/inductive reactors is described in this paper. The system measures these reactors with respect to a known reference providing reactance ratio and phase difference. It is suitable for automation and offers a number of advantages with respect to current-comparator-based bridges: faster operation, since no balancing is required, and operation in the presence of noise, harmonics, and power-line voltage and frequency fluctuations. Yet it retains high accuracy with an estimated relative uncertainty of less than 40/spl middot/10/sup -6/ in magnitude and 40 /spl mu/rad in phase under real high-voltage or high-current conditions.

Power factor definition in single phase system with arbitrary waveform according to similarity

A new definition of power factor, which is suitable for an arbitrary waveform of voltage and current in a single‐phase system, is presented according to similarity between voltage and current waveforms. The similarity is described in infinite dimensions real vector space, and the power factor is defined as the multiplication of rootmean‐ square (RMS) value factor λ RMS and phase factor λϕ. The new definition is compatible with IEEE Trial‐Use Standard 1459–2000, and can be a useful reference for power factor measurement, power factor correction and power compensation.

A reactive power control relay design with a new approach

In this study, the design and implementation of a mixed-signal microcontroller based reactive power control relay that is superior to existing reactive power control relays is presented. This device measures the fundamental reactive power of the system and determines the switching pattern of the capacitor banks which brings the measured fundamental reactive power to the desired value. During measurement, it yields minimal computational load for the fundamental reactive power measurement by employing the Goertzel algorithm instead of the fast Fourier transform (FFT). Consequently, measurement accuracy can be increased without increasing the time required for the FFT-based power measurement by a running average using the last five measured values of the fundamental reactive power. Possible mechanical and electrical failures in capacitor banks are detected by using a simple feedback loop and the user is warned. It has all the other classical features such as P, Q, I, V, and power factor measurement, harmonic analysis, and failure warning signals that a relay should possess.

Basics of power factor measurements on high voltage stator bars and stator windings

This article is a tutorial on power factor (PF) measurements on high voltage stator bars and coils and describes the basic theory associated with this important test method. In addition, the most commonly used measuring techniques and typical equipment setup used to make PF measurements are described. The coil manufacturing industry has a lot of experience performing this test and had a major part in updating the current standard. Although measured values are a function of the coil insulation system, some typical trends in measured values are described.

Thermoelectric power factor measurements in GeSe single crystals grown using different transporting agents

Thermoelectric power factor measurements in GeSe single crystals grown using different transporting agents

Locked-rotor and acceleration testing of large induction machines-methods, problems, and interpretation of the results

The measurement of locked-rotor current, torque, and power factor has been a standard test for induction machines for many years. Measurement of torque has evolved from using a brake, a dynamometer, a torque arm, and scale, through strain gauges and load cells to acceleration tests. The test must be of short duration to prevent damage to the machine and large machines present problems because of facility limitations in either kilovoltampere or torque measurement. A single test at reduced voltage when prorated to operating voltage by the square of the ratio of rated voltage to test voltage neglects the impact of saturation and results in significantly lower values of predicted torque and current. This paper discusses several methods for performing the locked-rotor and the speed-torque tests on large machines. It also discusses some of the problems associated with the test methods and shows how the tests can be performed and the results evaluated to account for saturation effects. Finally, the paper shows how to extract some machine circuit parameters from the test data.

A new circuit for measuring power factor in nonsinusoidal load current

This letter presents a new method for measuring the power factor in nonsinusoidal load current. The proposed method is based on the technique of sampling and holding the amplitude of the real part of the load current. Because no Fourier or fast Fourier transform calculation is used, this method can be implemented by a simple electronic circuit.

三相配電系における力率測定用静電誘導円筒型電圧検出センサの数値電界解析

三相配電系における力率測定用静電誘導円筒型電圧検出センサの数値電界解析

95/03680 Power factor measurement and correction techniques

95/03680 Power factor measurement and correction techniques

Power factor measurement and correction techniques

The prevailing method of power factor measurement is debatable. Certain methods are suggested in this paper with hints to improve power factor measurement and correction.

Fast-response power factor detector

In this paper, a new power factor measurement method is proposed. The proposed method is implemented by an analog electronic circuit. Its response time is less than a half-cycle. The test results show that it can measure the power factor of the measured load quickly and accurately, and its response time is superior to the conventional power factor measurement methods.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

配電系力率測定用電圧検出センサの実用化に関する研究

配電系力率測定用電圧検出センサの実用化に関する研究

A fast method for determining electrical and mechanical qualities of induction motors using a PC-aided detector

A unique computer-aided detector is presented that determines the mechanical and electrical qualities of single-phase and three-phase induction motors. Measurements of voltage, current, power factor, active power, and reactive power as well as evaluations of centrifugal switch and airgap eccentricity, i.e., misalignment between rotor and stator, of induction motors can be rapidly conducted, and test results are available on the screen within a few seconds. The feasibility and usefulness of this detector are impressively demonstrated through application examples. >

A microprocessor-based adaptive power factor corrector for nonlinear loads

A microprocessor-based adaptive power factor corrector for poor power factor (linear or nonlinear) loads is introduced. The system power factor is measured by the microprocessor and compared with a predetermined reference value. Accordingly, the microprocessor adjusts the power factor to get the predetermined value. This is achieved by controlling the firing angle of a thyristorized static VAR (volt-ampere reactive) compensator through microcomputer software. The system power factor is measured by the microprocessor at every supply cycle, and the above sequence is repeated. The proposed scheme achieves both accurate measurement and adjustment of the system power factor.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Phase shift and power factor measurement for a wide frequency range using ROM

Abstract This paper introduces the theory and implementation of a new technique for the measurement of phase shift and power factor for a wide frequency range. Hardware realization is implemented using a read only memory (ROM) as a lookup table. Measurement is made with a resolution of one degree. The circuit is applicable for phase shift angles between 0 and 180 degree. Accuracy of less than ±1 degree has been achieved.

Microprocessor-Based PHESS Meter

The present investigation introduces engineers and technologists to a new microprocessor-based on-line performance recorder called the ``PHESS Meter'' for measurement and display of power factor, horse power, percentage efficiency, slip, and speed of a slip ring induction motor. The instrument continuously displays each set of data for a desirable time in a specific order and provides the under-voltage alarm sound and the overload protection disconnecting the system from the supply.

A frequency invariant phase-difference and power-factor meter

Abstract A technique baaed on zero cross-over time is developed for the measurement of phase difference and power-factor in an AC system, A complete solid-state circuit, with inherent lead-lag indication, is proposed. The circuit is immune to variations in the frequency as well as the magnitude of the input signal. A digital display is also possible by an appropriate analogue-to-digital conversion