WO2023152715A1 - Energy measurement apparatus and methods for processing power factor, transmitted, received, dissipated, reserved, residual and reactive ac power - Google Patents
Energy measurement apparatus and methods for processing power factor, transmitted, received, dissipated, reserved, residual and reactive ac power Download PDFInfo
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- WO2023152715A1 WO2023152715A1 PCT/IB2023/051277 IB2023051277W WO2023152715A1 WO 2023152715 A1 WO2023152715 A1 WO 2023152715A1 IB 2023051277 W IB2023051277 W IB 2023051277W WO 2023152715 A1 WO2023152715 A1 WO 2023152715A1
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- power
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- calculating
- instantaneous
- power factor
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R21/00—Arrangements for measuring electric power or power factor
- G01R21/006—Measuring power factor
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R21/00—Arrangements for measuring electric power or power factor
- G01R21/001—Measuring real or reactive component; Measuring apparent energy
Definitions
- the present invention relates to measurement of a.c. power components and power factor measurements under all conditions of a.c. power load including harmonic distortion in a circuit.
- the circuit is coupled to an a.c. power source generating a.c. current and a.c. voltage.
- the invention is useful for application in power billing industry to determine more accurate prices, measurements and to aid in effective design of electrical systems such as insulation of conductors.
- Power factor helps in measuring the amount of apparent power required in order to maintain a similar value of current as if there were no reactive loads.
- Nonlinear loads include: fluorescent and arc-discharge lighting; adjustable- speed motor drives; computers and computerized controls; and heating elements and temperature-controlled furnaces.
- Nonlinear loads rather than using AC electric power directly, often convert AC power into direct current before it is used to accomplish their functions.
- a common element in nonlinear loads is some kind of rectifier to accomplish this AC to DC conversion. Some elements such as rectifiers do not draw sinusoidal currents.
- electrical meter of Nikola Tesla of patent USS 14974 of 1894 discloses a meter that utilizes predictive effect of gas particles on conductors.
- Patent US 12197238 of 2011 discloses harmonic decomposition through P'ourier series.
- the patent US14471107 discloses a meter consisting of a processor that computes values in the frequency domain.
- Patent. US5072187 of 1991 discloses apparatus for accurately determining the total harmonic distortion and the power factor attributable only to a non-linear load circuit coupled to an a.c, power source when a.c. current input to the non-linear load circuit is substantially in phase with the a.c. voltage provided across the load circuit by the a.c. power source.
- Patent CA2062914 of 1991 discloses a process that avoids computation of power law functions.
- Patent US20 180331551 of 2018 discloses a meter that produces a hybrid mix of alternating-current and direct-current power.
- PF power factor
- a.c. power is mainly treated as a two-component entity in literature. Some researchers have proposed that a.c. power is equivalent to a beer in a glass, where the active power is the liquid and the frothy foam being the apparent power. We show in the present invention that this analogy is an incomplete depiction of cyclic power flow. The analogy is true in the first cycle when the inductive load is turned on, but changes as soon as the inductor has magnetized. True analogy shows that two layers of residue should exist at the bottom of the glass as well as the top part.
- the components are shown in FIG. 1. These components of a.c. power can be used to effectively provide billing formula.
- the difficulty is in the fact that in conventional absorption coefficient of transmission lines, the absorbed power is treated as the difference between the input supply and the reflected energy.
- the absorption coefficient p A is given as, where E i refers to incident energy, E r refers to reflected energy and E t is the transmitted energy.
- a principle of energy gradient analysis for AC power flow is used to derive the power components of the present invention.
- the present art of the invention introduces the amount dissipated, reserved at input, reserved at load, amount received at load, residual power stored at load and the total amount transmitted and phasor reactive power, redefine absorption coefficient and devise a less complex algorithm to estimate phasor values of a.c. power.
- the absorption coefficient is the difference between power received at load and reserved amount.
- the key aspect of the present invention is the discovery that equal amount of the reflected power is returned back to the source and to the load in a cyclic manner and it is half the constant amount that is residual amount at the load. So the absorption coefficient in a.c. power network is substantially different from that of a transmission line.
- the coefficient p AI of the present invention is expressed as,
- the true components of power are necessary in providing occupancy rates of the a.c. power channel and that is important in determining the pricing for power bills and for designing adequate insulation.
- the billing approach for a.c. power applies both constant rates and variable costs based on the amount of power dissipated and reactive power.
- the rates per kWh are the consumption, fuel energy charge (FEC), forex charge (FERFA) for foreign exchange rate fluctuation adjustment, inflation adjustment (IA), variable cost (WRA), Energy Regulatory Authority levy (e.g. ERA), REP charge, which is a percentage of base rate (e.g. 5%) and value-added tax (VAT) as a percentage of total cost less levies.
- FEC fuel energy charge
- FERFA forex charge
- IA inflation adjustment
- WRA variable cost
- ERA Energy Regulatory Authority levy
- REP charge which is a percentage of base rate (e.g. 5%)
- VAT value-added tax
- An example of cost elements for domestic power use is in Table I with a base rate of 57.629% of total cost.
- the average PF is derived from the average integral of the power waveform, (IPF) and the apparent power is computed from the product of the true root-mean-square (TRMS) values of current and voltage waveforms.
- the integral power factor (IPF) is determined from the following function,
- THD total harmonic distortion
- this technique does provide a harmonic distortion and power factor measurement for non-linear load circuits when the current and voltage waveforms are in phase.
- the total power factor under harmonic distortion is computed as
- the present invention discloses a simple energy meter that is able to measure accurate PF even in cases of harmonic distortion from non-linear loads and under frequency variations.
- the approach used in the present invention is based on the coefficient of the amount of power dissipated and the amount of power reserved at reactive load beyond the residue. This new technical solution is called absorption coefficient PF (APF) or simply as absorption PF.
- APF absorption coefficient PF
- Step 1 culminates into apparent power towards the load.
- Step 2 culminates into active power towards the load.
- the gradient from the load is given by the amount of reactive residual power stored at the load during the initial supply, i.e., .
- the gradient becomes zero, so there will be a permanent residue that is twice the amount that is returned, thus,
- Step 3 culminates into reactive power reserved at the source.
- the PF can be estimated directly from the peak value .
- Step 4 culminates into a fraction of the apparent power towards the load.
- Step 5 the reactive component , will be forwarded to the load in order to balance out the reserved at the source. Step 5 culminates into reactive power reserved the load in addition to the residue .
- Step 6 culminates into a constant active power towards the load.
- the power dissipated is the difference between the total power consumed from source and the power reserved at load, i.e.
- a more realistic form of AC power can be expressed in terms of five (5) concurrent instantaneous components that form the total power in a reactive circuit. In this way, it is easy to experimentally measure the role of each component on the changes that occur on the physical conducting medium. Considering a case where all a.c. power components of the present disclosure are flowing concurrently, then it is clear that the power waveform s m oscillates between a maximum peak S + and minimum peak S-. A value P m is the positive peak, of the power waveform s m , while the residual power stored is the negative peak , of the power waveform.
- the power dissipated be which means that the source will be supplying active power of 2P in order to be able to dissipate an amount of P.
- Reactive power returned to source is given as as an equal amount, is being concurrently supplied into the circuit.
- the first four terms are sinusoidal waveforms while the residual power is a constant quantity and the waveform is conveniently placed on the positive side of the axes so that, in theory, the concurrent power equation can be written as,
- the concurrent power waveform is plotted in FIG. 1 to depict the 5 concurrent instantaneous components of AC power.
- S + be the maximum amplitude of the waveform on the positive side
- S + max(+s m ) be the maximum amplitude of the waveform on the negative side
- the power dissipated is given as (difference between input power and power residue stored at the load),
- the PF technique of the present disclosure is advantageous since it involves a simple task of measurements of the peaks of the power waveform.
- the technique is resilient to current and voltage harmonics since both upper and lower peaks are equally affected by the distortions and are therefore reciprocating after tuning. Furthermore, frequency fluctuations result in reciprocating effects on these peak values, so the present invention leads to a resilient technique against these fluctuations as the load changes in the network.
- the integral tuner of the present invention estimates the integral average and determines its distortion from the real power absorption value i.e. P d , thus the integral tuned power factor is given as,
- the power factor can be tuned to cater for harmonic distortion based on the normalized total power function.
- the tuned power factor is given as, where T ⁇ denotes the 77th root of the normalized total power function and T) > 3.
- the absorption coefficient can be derived from the concurrent power equation as well from the following set of equations,
- APF absorption coefficient power factor
- APF absorption coefficient power factor
- the invention provides an apparatus for determining absorption coefficient power factor (APF) of a load coupled to an a.c. power source that generates and supplies a.c. current and a.c.
- APF absorption coefficient power factor
- power waveform (s m ) is produced as a product of a.c current and a.c voltage to be used in billing, comprising: first means for measuring the maximum amplitude (S + ) of power waveform; second means for measuring the minimum amplitude (S-) of power waveform; third means coupled to the first means and the second means, for calculating apparent power (5) to the load as a function of both S + and S-; fourth means coupled to the first means, the second means and the third for calculating active power dissipated (P) at the load as a function of S + , S- and 5; fifth means for measuring the instantaneous reactive power (Q I ) component sent to the load; sixth means for measuring the instantaneous residual reactive power component stored at the load; seventh means for measuring the instantaneous exchanged reactive power (QBF) component circulating back and forth between the power source and the load; eighth means coupled to the third means and the fourth means, for calculating the absorption coefficient power factor (APF) of
- the invention also provides a method for determining the absorption coefficient power factor (APF) of a load coupled to an a.c. power source that generates and supplies a.c. current and a.c. voltage to the load, wherein power waveform (s m ) is produced as a product of a.c current and a.c voltage, the method comprising the steps of: measuring the maximum amplitude (S + ) of power waveform; measuring the minimum amplitude (S-) of power waveform; calculating active power dissipated (P) at the load; and operating a computational unit in accordance with a predetermined relationship which takes into account S + , S- and P to determine the absorption coefficient power factor (APF) of the load as a function of S + , S- and P.
- APF absorption coefficient power factor
- PIG. 1 is a waveform diagram for concurrent instantaneous power waveform.
- FIG. 2 is an illustration of a stabilized concurrent instantaneous power flow.
- FIG. 3 is a waveform diagram of the purely sinusoidal voltage, current and power waveforms at the input of the load.
- FIG. 4 is a waveform diagram of the voltage, current and power waveforms at the input of the load with two harmonic components.
- FIG. 5 is a diagram of the variation of instantaneous power components with phase angle.
- FIG. 6 is a diagram of an apparatus for determining absorption coefficient power factor (APF) as constructed in accordance with the present invention.
- APF absorption coefficient power factor
- a method and an apparatus are provided for determining the absorption coefficient power factor (APF) of a load coupled to an a.c. power source that generates and supplies a.c. current and a.c. voltage to the load, wherein power waveform (s m ) is produced as a product of a.c current and a.c voltage to be used in billing.
- APF absorption coefficient power factor
- FIG. 1 is a waveform diagram for concurrent instantaneous power waveform. It illustrates the five components of instantaneous a.c. power that are taken to be concurrently occupying the channel for the power delivery to the load. It is observed that a.c. power delivery consists of a continuous cycle of instantaneous power flow for reactive power towards the load, the active power flowing towards the load as another active power is dissipated, reactive power being returned to source and residual reactive power at the load that maintains the energy gradient to push half of its power back to source. The overall sum of the five components of power results in the peak to peak apparent power in the circuit.
- FIG. 1 depicts the case where the concurrent power flow is plotted where the voltage waveform leads current waveform through 45°.
- FIG. 2 depicts the power flow analysis.
- FIG. 3 is a waveform diagram of purely sinusoidal voltage, current and power waveforms at the input of the load. The concurrent power flow is plotted where the voltage waveform leads current waveform by 20°.
- FIG. 4 is a waveform diagram of the voltage, current and power waveforms at the input of the load with two harmonic components. The concurrent power flow is plotted where the voltage waveform leads current waveform by 30°.
- the power waveform for s m is obtained experimentally as a product of the voltage and current waveforms.
- the concurrent waveform is an analytical form of In order to ascertain the theory of concurrent power, a power factor metric is devised and used to compare the results as obtained from the two scenarios.
- the PF methods in the prior art and the APF are used in the following section to compare measurement results that are obtained from known lagging power angles and results are given in Table II.
- the displacement power factor is determined from the lagging angle between the voltage and current waveform.
- the set up for single- factor harmonics is such that the second harmonic has amplitude which is 2% of the fundamental value for both current and voltage waveforms.
- the absorption technique as disclosed in the present invention, presents a better accuracy compared to the displacement approach of the prior art.
- the AC power waveform consists of five power elements that are useful in determining billing rates for AC power consumption.
- PIG. 5 is a diagram of the variation of concurrent instantaneous power components with phase angle.
- the concurrent instantaneous power of the present invention is quite useful in prediction of true billing costs based on the electrical activity in the conductor of electricity.
- the present invention classifies power in terms of the forward flow reserve at load, backward flow reserve at source, power received at load, dissipation, phasor reactive and residual power at the load. Furthermore, it is easy to derive the phasor reactive power as a fraction of the instantaneous residual power, rather than the conventional phase-shift operation in estimating the reactive power. This process results in a simple computational operation in the present invention. From FIG.
- FIG. 6 is a diagram of an apparatus for determining absorption coefficient power factor (APF) as constructed in accordance with the present invention. It illustrates the apparatus for the energy meter.
- the energy meter consists of several parts: controller 1, input/ output ports 2, sampler 3, computational unit 4, memory 5 and display unit 6.
- the component 1 is a programmable unit that holds the operating system for the energy meter. It also enables periodic installation of firmware for the hardware drivers of the energy meter.
- the component 1 is responsible for recording input and output information at 2.
- the 3 is enabled by 1 to sense a.c. current and a.c. voltage from 2, which transforms input signal, senses a.c. current and a.c. voltage rectifies power and regulates voltage levels.
- the power regulated by 3 can be optionally used to power the controller 1.
- the component 2 provides a means for connecting a.c. load to the energy meter e.g. load terminal and input power terminal.
- the controller 1 instructs 3 to send the a.c. current and a.c. voltage values to 5.
- 4 consists of a programmable processor that operates through calculations on values stored in 5 according to the instructions programmed into it e.g. the five a.c. power components and cost of billing. The calculations are performed according to the relationships as disclosed in the present invention.
- a communications module is optionally implemented in 1 through 2 to provide remote connectivity for exchanging information contained in 5.
- the output values are displayed onto 6 according to instructions from 1.
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| Application Number | Priority Date | Filing Date | Title |
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| KEKE/P/2022/003993 | 2022-02-14 | ||
| KEP202203993 | 2022-02-14 |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5072187A (en) * | 1990-06-29 | 1991-12-10 | Digital Equipment Corporation | Method and apparatus for determining the total harmonic distortion and power factor of a non-linear load circuit |
| CN101501507A (en) * | 2007-08-24 | 2009-08-05 | 延世大学工业学术合作社 | Apparatus for measuring distortion power quality index and method of operating the apparatus |
| US20110292699A1 (en) * | 2010-05-26 | 2011-12-01 | Texas Instruments Incorporated | Systems and Methods for Distortion Reduction |
| CN106526505A (en) * | 2016-10-14 | 2017-03-22 | 北京东方计量测试研究所 | Method and system for testing non-linear load capacity characteristic of alternating-current voltage-stabilized source |
| CN112886609A (en) * | 2021-01-15 | 2021-06-01 | 北方工业大学 | Alternating current constant power load optimization control model and optimization control method |
| CN113676037A (en) * | 2021-07-15 | 2021-11-19 | 朝阳微电子科技股份有限公司 | Novel passive power factor correction device |
-
2023
- 2023-02-13 WO PCT/IB2023/051277 patent/WO2023152715A1/en not_active Ceased
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5072187A (en) * | 1990-06-29 | 1991-12-10 | Digital Equipment Corporation | Method and apparatus for determining the total harmonic distortion and power factor of a non-linear load circuit |
| CN101501507A (en) * | 2007-08-24 | 2009-08-05 | 延世大学工业学术合作社 | Apparatus for measuring distortion power quality index and method of operating the apparatus |
| US20110292699A1 (en) * | 2010-05-26 | 2011-12-01 | Texas Instruments Incorporated | Systems and Methods for Distortion Reduction |
| CN106526505A (en) * | 2016-10-14 | 2017-03-22 | 北京东方计量测试研究所 | Method and system for testing non-linear load capacity characteristic of alternating-current voltage-stabilized source |
| CN112886609A (en) * | 2021-01-15 | 2021-06-01 | 北方工业大学 | Alternating current constant power load optimization control model and optimization control method |
| CN113676037A (en) * | 2021-07-15 | 2021-11-19 | 朝阳微电子科技股份有限公司 | Novel passive power factor correction device |
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