Merenje komponenti električne snage po standardu IEEE 1459-2010

Merenje u nesinusoidalnim uslovima je u centru istraživanja i mnogo se napora ulaže da se pojam reaktivne snage star više od sedamdeset godina definiše na nov način. Postoji niz pristupa rešavanju problema definisanja snaga i/ili pokušaja koncipiranja merne instrumentacije za merenje snaga u sistemima naizmenične struje pod nesinusoidalnim uslovima. Jedini standard koji se odnosi na specifične zahteve za tačnost i odgovarajuće uslove testiranja u prisustvu harmonijskih izobličenja je IEEE Std. 1459-2010, koji ne daje definiciju reaktivne snage u nesinusoidalnim uslovima. Koncept ovog IEEE standarda je baziran na raz-dvajanju snage na fundamentalni i nefundamentalni deo. U literaturi su prisutne različite tehnike za imple-mentaciju standarda IEEE Std. 1459-2010. Ovaj standard je implementiran pomoću dva osnovna prilaza: (1) dvostepeni algoritam sa estimacijom harmonijskih spektara naponskog i strujnog signala u prvom koraku i računanjem nepoznatih komponenti snage u drugom koraku i (2) filterska implementacija kombinovana sa Clarke-Park transformacijom u slučaju trofaznog sistema. U radu je prikazana nova metoda za merenje električnih veličina definisanih standardom IEEE 1459-2010 koristeći drugi pristup. Ključni elementi su adaptivni pojasni i niskopropusni FIR filteri koji izdvajaju fundamentalnu i jednosmernu komponentu. U radu su korišćene tehnike oversemplinga i decimacionih filtera, čime se izbegavaju problemi vezani za osetljivost na zaokruživanje koeficijenata FIR kaskadnih filtera velikog reda, smanjuje obim numeričkih računanja i povećava tačnost merenja. Estimacija simetričnih komponenti vrši se pomoću matrice adaptivnih faznih korektora. U cilju procene performansi algoritma izvršene su računarske simulacije i dati njihovi rezultati.In this paper, the design and implementation of a novel recursive method for the power measurement ac-cording to the IEEE Standard 1459-2010 have been described. The most important parts are adaptive band and low-pass FIR filters that extract fundamental and dc components, respectively. In addition, by using oversampling techniques and decimation filters, coefficient sensitivity problems of the large-order FIR comb cascade structure are overridden and the parameter estimation accuracy is improved. The symmetrical components are estimated through a transformation matrix of adaptive phase shifters. The effectiveness of the proposed techniques is demonstrated by simulation results

Impact of Dimming LED Street Luminaires on Power Quality

More and more street lighting deployments use LED technology as a light source. Unfortunately, the new technology also brings some challenges with it that remain unnoticed until installed at scale. This article presents issues related to capacitive reactive power consumed by LED luminaires. The problem is even more profound if the luminaire is dimmed, because it consumes capacitive reactive power, which is very undesirable in the power system. Countermeasures in terms of reactive power compensation for a luminaire working with variable power and their effects are also presented. The article also contains the results of the harmonic analysis of the LED luminaires current for full power and dimmed operation

Impact of Dimming LED Street Luminaires on Power Quality

More and more street lighting deployments use LED technology as a light source. Unfortunately, the new technology also brings some challenges with it that remain unnoticed until installed at scale. This article presents issues related to capacitive reactive power consumed by LED luminaires. The problem is even more profound if the luminaire is dimmed, because it consumes capacitive reactive power, which is very undesirable in the power system. Countermeasures in terms of reactive power compensation for a luminaire working with variable power and their effects are also presented. The article also contains the results of the harmonic analysis of the LED luminaires current for full power and dimmed operation

Relevance of Harmonic Active Power Terms for Energy Consumption in Some Railway Systems

Active power is not carried solely by the fundamental component (either dc or ac) especially for highly distorted systems, as electrified railways. The paper proposes two indexes and a preliminary assessment of the relevance of harmonic active power terms. Results are shown for three major railway systems architectures (3 kV dc, 2x25 kV 50 Hz and 15 kV 16.7 Hz) using experimental pantograph voltage and current. Harmonic power terms are relevant for the estimate of energy consumption especially for ac systems rather than dc, with some significant situations especially for 16.7 Hz systems

Analysis of the Real Energy Consumption of Energy Saving Lamps

[Abstract] Light emitting diode (LED) and compact fluorescent light (CFL) lamps are widely used because they are associated with low energy consumption and a reduced environmental impact. In the present paper, a study of the real consumption of these devices has been carried out. To do this, the active, reactive, distortion and apparent power and electrical efficiency for various lamps have been measured and calculated. The distortions produced in the network provoke the consumed energy to be in the order of 50–75% higher than that which appears in the commercial characteristics. This situation means that for its operation, it is necessary to generate and distribute an amount of energy much higher than that which is declared as the consumption of these lamps, and so far, this amount of energy is neither quantified nor invoiced. Additionally, groups of lamps have also been studied to check whether, when working together on the same network, there is a compensation phenomenon that reduces the negative effects of individual lamps. We have found that this compensation effect does not occur for the type of devices evaluated

A review of electrical metering accuracy standards in the context of dynamic power quality conditions of the grid

Numerous changes in electrical grid schemes, like the inclusion of renewable energy, the rise of non-linear loads and the emergence of electric vehicle charging, increases variable power quality conditions of the grid. In this dynamic scenario where energy could flow in both directions and the waveforms could be highly distorted, accuracy becomes a crucial factor for the correct measurement of electrical energy and power values. Errors in the assessment of these values have significant ramifications for revenue, billing and/or control. This non-ideal power quality scenario produces an error in electricity meters, that is not yet well known since there is no standardised procedure to calibrate meters under typical or emerging distorted waveform conditions. Current standards relevant for revenue energy meters like EN 50470-3:2006 allows measurements error up to ±2.5% while local regulations could be even more permissive. In order to establish an electricity fair trade market and meet expectations from consumers and utilities, electricity meters should arguably comply with higher accuracy standards. In this paper, the pertinence and possible impact of including tests under distorted waveform conditions, as well as new accuracy requirements on standards applicable to electricity meters for billing purposes will be discussed

An Improved Walsh Function Algorithm for Use in Sinusoidal and Nonsinusoidal Power Components Measurement

This paper presents an improved Walsh function IWF algorithms as an alternative approach for active and reactive powers measurement in linear and nonlinear, balanced and unbalanced sinusoidal three-phase load system. It takes advantage of Walsh function unified approach, simple algorithm and its intrinsic high level of accuracy as a result of coefficient characteristics and energy behaviour representation. The developed algorithm was modeled on the Matlab Simulink software; different types of load, linear and nonlinear, were also modeled based on practical voltage and current waveforms and tested with the proposed improved Walsh algorithms. The IEEE standard 1459-2000 which is based on fast Fourier transform FFT approach was used as benchmark for the linear load system. The data obtained from laboratory experiment to determine power components in harmonic load systems using Fluke 435 power quality analyzer PQA which complies with IEC/EN61010-1-2001 standard was modeled and used to validate the improved algorithm for nonlinear load measurement. The results showed that the algorithm has the potential to effectively measure three-phase power components under different load conditions

Working active power, reflected active power, and detrimental active power in the power system

Study of decomposition of the active power into components with deeper economical meanings, namely working active power, reflected active power, and detrimental active power is the subject of the thesis. The decomposition of active power will be based on the Current’s Physical Component (CPC) Theory. Working active power is equivalent to useful power that is the rate of energy used to do work, such as mechanical power. Reflected active power is the rate of energy transfer that the load sends back to the supply which dissipates off the supply resistance. This reflected active power is not taken into account on traditional power meters and the utility is not compensated for the power sent to the load to generate the reflected active power. Detrimental active power is the power that the supply sends to the load that is not considered useful power. The traditional power meter takes into account detrimental active power and the customer is paying for power that does not convert to useful work and potentially harming equipment. Working active power shows that the standard definition for active power does not fully take into account all economical responsibilities. With active power decomposed into economical components, the economic responsibilities can be accounted to the correct party

Harmonic assessment based adjusted current total harmonic distortion

Power systems suffer from harmonic distortion and extra ohmic losses associated with them. Moreover, all harmonic frequencies are mostly assumed to have the same effect on the system losses. However, the frequency-dependency of the resistances should be taken into account, so that the apparent power and the power factor have to considerably reflect power losses under nonsinusoidal conditions. In this paper, the difference between unweighted and weighted non-sinusoidal losses, is addressed. A new harmonic-adjusted total harmonic distortion definition is proposed for both voltage and current. Besides, a new formula that relates the proposed harmonic-adjusted total harmonic distortion and a generalised harmonic derating factor definition of the frequency dependent losses of the power transmission and distribution equipment, is derived. An optimal C-type passive filter design for harmonic mitigation and power factor correction based on the minimisation of the proposed harmonic-adjusted total harmonic distortion for a balanced nonsinusoidal system is introduced. A comparative study of the proposed filter design based on the new harmonic-adjusted definition, and a conventional filter design based on standard total harmonic distortion definition, is presented

Measurement of Working, Reflected, and Detrimental Active Power in a Three Phase System

Study of the decomposition of the active power into composite components with respects to power industry economics namely, working active power, reflected active power, and detrimental active power. The working active energy is considered the permanent flow of useful energy to the load that results in deliberate heat, lighting, or torque on the motor shaft. The reflected active energy is the extra component of active energy originating from the load and dissipates on the supply impedance that does not contribute to useful energy. Lastly, detrimental active energy is the flow of harmonic energy from the supply to the load due to supply asymmetry and distortion that does not contribute to useful energy to the load. Traditional revenue meters measure active energy as a whole. This means that the reflected active energy component does not get billed to the customer even though the utility must provide energy for the reflected active power and ultimately, not being compensated for energy delivered. Detrimental active energy gets charged by the traditional revenue meter yet does not contribute to useful energy. Instead this detrimental active energy is converted to useless energy, namely heat in an induction motor\u27s windings yet the customer still pays for the useless energy harming his own equipment. As one can see, active power in the sense of economics is not a simple quantity as originally thought. With the introduction of a new working active power concept, energy accounts can be fairer to both the customer and utility. Using revenue meters based on working active power concept can pinpoint economic responsibilities of the customer and utility and accurately compensated