WO2022106910A1 - Appareils et procédés de traitement de puissance et de facteur de puissance (pf) réel dans des réseaux ca - Google Patents

Appareils et procédés de traitement de puissance et de facteur de puissance (pf) réel dans des réseaux ca Download PDF

Info

Publication number
WO2022106910A1
WO2022106910A1 PCT/IB2021/055349 IB2021055349W WO2022106910A1 WO 2022106910 A1 WO2022106910 A1 WO 2022106910A1 IB 2021055349 W IB2021055349 W IB 2021055349W WO 2022106910 A1 WO2022106910 A1 WO 2022106910A1
Authority
WO
WIPO (PCT)
Prior art keywords
power
phase shift
correlative
reactive
total
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/IB2021/055349
Other languages
English (en)
Inventor
Peter AKUON
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of WO2022106910A1 publication Critical patent/WO2022106910A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R21/00—Arrangements for measuring electric power or power factor
    • G01R21/133—Arrangements for measuring electric power or power factor by using digital technique
    • G01R21/1331—Measuring real or reactive component, measuring apparent energy
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R25/00—Arrangements for measuring phase angle between a voltage and a current or between voltages or currents

Definitions

  • the present disclosure relates generally to systems, processes and applications for determining total electrical power conveyed by power signals, especially alternating current (AC) waveforms. It is useful in power quality and energy analysis through power factor analysis, insulation, calibration and instrumentation management and correlative signal modulation in telecommunications.
  • AC alternating current
  • the invention discloses methods, processes and apparatuses for determining the output power through an energy meter that produces the total power required by an electrical power network.
  • An AC electrical power network consists of voltage and current that flow with sinusoidal amplitude values.
  • the network contains a source generator, wiring, resistive load components and reactive load components.
  • When the current and voltage waveforms are injected into a power network with resistive loads only, then there is no phase shift between them, since the impedance in homogeneous.
  • inductive loads are switched on, they start by lowering the average active power significantly as they store energy in their magnetic fields.
  • the ratio of active power to total power is termed as power factor (PF).
  • the PF corresponds to the value of the reactance in the network.
  • capacitors are used as reactors to reduce inductive reactance in order to ensure that maximum power is delivered to the resistive loads.
  • power delivered to the resistive load reduces and the power factor is also said to have reduced.
  • power quality is lowered.
  • a poor PF means that heat could damage insulation parts of power equipment, reduction in useful power and an increase in conductor sizes since more current is required to reach the loads in the network.
  • Power factor correction is performed by adding capacitive reactance to cancel the inductive reactance, and thus improve power factor.
  • it is expensive to install the capacitive reactors in the whole network.
  • power distributors end up in requesting for more reactive power from power producers to provide the sufficient pressure required in order to support the full resistive load [1], [2], [3], [4],
  • the total power is estimated through energy meters and the active resistive load is deducted appropriately.
  • the method of the prior art overestimates the average active power.
  • the principle applied to derive the active power in the prior art assumes that the impedance between the resistive loads and inductive loads is homogeneous. This way, the average power is computed from algebraically additive power expression instead of a phasor sum.
  • a measurement technique for the total amount of instantaneous power injected in an alternating current (AC) power system is presented. It is shown that the power network consisting of reactances and resistances will have covariance elements of voltage and current.
  • a demodulator is used to reduce correlated current and voltage waveforms into singular waveforms and the amount of power is accurately estimated from an analysis of 3- dimensional (3D) complex sinusoids.
  • the proposed technique will find use in smart power meters to determine accurate amount of power generation needed, amount of power stored, and amount of power consumed, power system quality and billing rates for different classes of loads.
  • the present disclosure will also find applications in signal analysis, measurements, asset management and insulation systems.
  • Power Factor stored correlative power, correlative variance factor, correlative power factor, Reactive power, Real power, Apparent power, Singular value decomposition (SVD), eigenvalues, demodulation, elliptical flow components and complex sinusoids.
  • the total power is estimated as the power that flows in the network without considering correlation ellipses of real and reactive components due to interactive impedance between resistances and reactances.
  • the average active power value in the prior art is not resolved in the direction of the load. Therefore, the true average power delivered to consumers in the network is not accurately derived in the prior art.
  • Two principles may be used in power networks to determine active power.
  • the total current injected into the network is held constant and used to derive the average active power, whereas quadrature reactive and resistive powers are left to vary through a phase shift angle.
  • the power flow has a circular signature, which means both active and reactive power are independent and maximum correlative reactive power will be stored.
  • the power signature will be elliptical as will be described later on.
  • Instantaneous power can be computed to derive more realistic values of apparent power.
  • the instantaneous values of the product of the voltage waveform and the current waveform have been used to compute power, but underlying theoretical approaches are required to obtain true results.
  • the voltage waveform was modified in [1],[2] to conform to Plancherel’s relation, but the Schwarz inequality was rendered a constant equality.
  • the results in [1] show that the power factor is limited to a maximum of even in a purely resistive power network and this is effectively similar to the conventional scheme since apparent power in [1],[2] is given as
  • the results in [1],[2] were obtained by considering only the voltage signal as a complex sinusoid, while the current signal is treated as a real function.
  • the results for total power in [1] imply that no correlation was considered.
  • the solution to the problem is to insert a demodulator to shift the frequency back to its original position and the waveforms appear with their singular frequency components. This decomposition is consistent with SVD for principal components.
  • the results obtained from the demodulator show that the total power in the network can be implemented through a summer circuit in the energy meter that adds two power factor components and multiplies RMS values of current, I m peak and RMS value of the voltage peak, V m .
  • the power factor angle is computed from the phase shift between current and voltage waveforms.
  • the demodulator gives a total power output factor as the sum of the cosine of the PF angle and the sine of the PF angle. It means that additional generator supply must incorporate the extra power due to correlation.
  • the total power factor is given as the ratio of cos ( ⁇ ) to the sum cos ( ⁇ ) + sin ( ⁇ ).
  • correlative power factor which is useful in measuring power of AC signals in a laboratory set-up, without shifting the waveform and integrating over a period.
  • the correlative power factor is given as where .
  • the measured signal power is given as the product of the square of the correlative power factor and the peak-to-peak amplitude of the effective power signal waveform.
  • phase shift angle When a current and voltage values in a network are calibrated using input power, an alternative way of measuring the phase shift angle is provided by comparing the received power to the correlative reactive power to compute the angle.
  • the process for computing total power in AC systems is applicable in single-phase and multiple-phase power systems.
  • an energy meter is proposed that is able to measure the total energy and total instantaneous power delivered by an AC power network of the homogeneous equation.
  • the energy meter consists of a demodulator and algebraic adder circuit devices.
  • the energy meter consists of a demodulator and an algebraic adder processes.
  • the energy meter is configured to measure total power in an AC power network.
  • the energy meter is configured to measure phase shift angle between current and voltage waveforms.
  • a meter is configured to measure correlative reactive power, P s .
  • a process is provided for experimentally measuring total power, P t .
  • a process is provided for experimentally measuring reactive power, Q.
  • a process is provided for computing correlative variance for instantaneous power.
  • a process for computing phase shift angle by comparing correlative reactive power equation and the received effective total instantaneous power.
  • the energy meter is configured to measure total power factor as a ratio of cosine of the phase shift angle and the sum of the cosine and sine of the phase shift angle between current and voltage waveforms.
  • true power factor is derived based on varying quadrature currents, while keeping quadrature resistive and inductive power equal in an inhomogeneous impedance network.
  • a process is provided for implementing correlative modulation by mapping bits on different phase shift angles to convey information to a receiver, which then detects the phase shift angle in order to decode the transmitted bits.
  • the applications can be any of energy services in the power industry or signal processing in telecommunication or computer systems.
  • FIG. 1 shows a block diagram illustrating a 3-dimensional AC power flow
  • FIG. 2 shows a block diagram illustrating apparatus for the total power energy meter system
  • FIG. 3 shows circuit transforms for AC power source
  • FIG. 4 is an illustration of the results obtained from the total energy meter
  • FIG. 5 is an illustration of comparison of power factor values with the present invention
  • FIG. 6 is an illustration of comparison of total power value of the present invention and that of the prior art
  • FIG. 7 is an illustration of decorrelated AC power signal waveforms
  • FIG. 8 illustrates graphical method for estimating AC signal power
  • FIG. 9 illustrates different methods for estimating AC power
  • FIG. 10 illustrates bit error rates against signal-to-noise ratio for correlative modulation
  • FIG. 11 illustrates a power triangle for decorrelated power system
  • FIG. 12 illustrates correlation effects on shift angle between power and voltage or current waveforms.
  • FIG. 13 illustrates variation of adjusted phase shift.
  • I R where V, is the effective voltage supplied to R from storage.
  • a complex sinusoid is considered to describe the power flow in the AC network, where The flow can be represented as an elliptical motion in the 3D diagram of FIG. 1. Since the quadrature and in-phase components of the complex sinusoids are symmetrical, we use the projection of the components on x-, y- and z-axis as shown and then apply simple sinusoids in the analysis.
  • V X , V R is the voltage across the inductor and resistor, respectively.
  • the power across the resistor which is the active load can be written directly from a resolved voltage value (which takes care of changes in both voltage and current), i.e.
  • the average active power then becomes,
  • the result in (4) consists of two waveforms and a constant power, namely a constant term proportional to the phase angle, ⁇ , a second term of P and the third term of Q. which depict correlated components of power. It shows that part of average power P is transferred to reactive component, Q as additional stored power.
  • the correlated form of the waveforms is analogous to signals present at the output of a modulator.
  • the modulator is characterized by a mixed signal output.
  • an adjustment factor of is needed to adjust the power factor so as to incorporate the effects of correlation, where the stored power acts as a source of to the load.
  • PF cos ( ⁇ ), where, ⁇ denotes the observed angle by which the current and voltage leads or lags each other in their phases.
  • the RHS of (11) is equivalent to the product of individual square of RMS values. From the SVD approach used in this disclosure, from (8), the RMS value of the voltage may be written as while that of the current is given as As a result, the Schwarz inequality equivalent to one in (11) is given as,
  • FIG. 2 is an illustration of the apparatus for the total energy meter.
  • the supply power from the generator is passed through a bus (1) into an AC power network (2).
  • a connector (3) is used to connect an energy meter (4).
  • the meter consists of a power factor demodulator (5), and an algebraic adder (8).
  • Device (5) computes the phase shift angle between current and voltage.
  • the phase shift angle is then used to compute two values of cosine and sine of angle theta. These values are passed on to the algebraic adder (8) through outputs (6) and (7).
  • the output (9) of the algebraic adder is used to calibrate the total power from the product of the RMS value of voltage amplitude and current amplitude.
  • the meter is configured to show newly defined values for correlative power factor, correlative reactive power and display resultant power waveforms.
  • VALIDATION VIA CIRCUIT TRANSFORMATION Consider a system where a resistive load and a reactive load exist in an electrical network supplied by an alternating current. Based on FIG. 3, the reactive load may be reduced to a voltage source since in the first half of the sinusoid; power is returned to the source and delivered to the reactance in the subsequent duration of the wavelength. Let’s express the current through the resistive load in a network that consists of two voltage sources; in the analysis, we treat each voltage as short circuit, while the other source supplies the network:
  • the stored power supplies the load as well. Therefore, the observed angle 9, consists of current derived from the stored energy. In order to calculate the true average power, the amount of current from storage should be deducted from the average power derived from 9.
  • P T (P + P cos (2 ⁇ t) + Q sin (2 ⁇ t)] (16) where Pj contains the covariance elements of real and reactive power, thus correlated components.
  • Equation (16) implies that P is in the z-direction, while S' is the resultant RMS value of power as shown in FIG. 1.
  • S' P' + jQ' , must be resolved back to the //-component of power, as S' sin (0) .
  • Equation (16) is now written as follows,
  • V and I are two random variables, with mean V ⁇ and I ⁇ , and standard deviation, ⁇ 0 V and ⁇ c I, respectively. Then, [6], [7],
  • a function is derived that relates instantaneous power P and 2P under correlation conditions. The same function is then applied to relate the average active power observed and the true active power dissipated under correlation conditions over all values of ⁇ .
  • genV A Phasor refers to the total amount of generation that will be required to maintain the same voltage in the network when the current increases, which is given as
  • genV A proposedAL refers to the total amount of generation required, as calculated from the algebraic meter, which is given as
  • the amount of power generation required follows the requirements of the resistive load.
  • V/ the reactance drops power equal to (V/)
  • V A ProposedAL refers to the power initially delivered to the network through the proposed energy meter. It varies as an arc over the range of PF angles. The power delivered shows a curve that starts at (VI) but rises to a peak of when reactance, X equals the resistive load, R and falls back to (VI) at maximum reactance when the phase shift is 90°.
  • Resistive Load refers to the variation of the dissipative load as it varies with the phase shift in the network. The maximum load is supported when the phase shift between current and voltage waveforms is zero.
  • Reactive Load refers to the variation of the reactive load as it varies with the phase shift in the network. The maximum reactance occurs when the phase shift between current and voltage waveforms is 90°. Extra demand (watts) refers to variation of the resistive load required to be supported when there is reactance in the network. It is determined as,
  • FIG. 5 shows comparisons for the proposed algebraic PF and that proposed by Ghassemi [1] and the one used in the present industry, ConvPF, which always overestimates PF. It is observed that Ghassemi model has a maximum PF value of ⁇ 0.7071, even when the network is purely resistive. However, the proposed algebraic PF one has a maximum of unity at 0 0 of PF angle and a minimum of zero. In addition, there exists a point of inflexion that potrays the behaviour of PF when there is a change in a more resistive network into a more inductive network. It is noted that both the balanced power principle and balanced current principles lead to the same amount of PF as depicted in FIG. 5.
  • Table 1 compares the results of the new generation requirement to reduce the power factor to zero in the network using the conventional phasor method and the proposed algebraic adder method.
  • the table shows that the phasor method, which is the industrial standard underestimates the total power required, when the power factor is high, while it overshoots the requirement when the power factor is low.
  • the underestimation leads to delivery of low quality electrical power at lower prices to consumers with inductive loads. Normally, operation at very low PF is avoided through the implementation of reactors that increase the PF by reducing the total reactance in the network.
  • FIG. 6 illustrates how the total power in the electrical power network is influenced by the power factor angle, ⁇ . As the reactance increases, ⁇ increases and the total power is given by the sum of the three components of power,
  • the correlative distance detector for the phase shift angle is set as follows,
  • the graphical process is estimated using FIG. 8 as follows:
  • results from analytical expressions confirm that the experimental results are correct and give the exact estimation of power when the most accurate statistical error elimination is selected. These results are shown in FIG. 9.
  • the scalar variance estimation is the most accurate process for the experimental measurements, followed by the scalar difference process even for the analytical estimation.
  • the total power processed from the correlative variance show very close match to the decorrelated value of total instantaneous power i.e
  • the present disclosure further presents a method of signal processing, where different phase shift angles are used as sources of information bits.
  • This kind of modulation scheme is referred to as correlative phase modulation or power factor modulation, where a sets of PFs are used as sources of information.
  • a preferable detector is used at the receiver to detect the information conveyed by the received signal. Signals can be images or current or voltage waveforms.
  • bit 0 is decoded if 2
  • bit 1 is decoded if 2
  • VALIDATION FROM PRINCIPLE OF CONSTANT POWER AND VARYING QUADRATURE CURRENTS The second principle of constant quadrature power is now used to confirm the results obtained through the adjusted power coefficients of the first principle.
  • a network of parallel reactance and resistance is considered, where the total current, I is split into the current, IR through the resistive load and the current I ⁇ through the reactance as follows,
  • V R V X

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Emergency Protection Circuit Devices (AREA)

Abstract

Sont divulgués des appareils et des procédés de traitement de quantité totale d'énergie injectée dans des réseaux électriques à courant alternatif (CA), la quantité totale d'énergie étant constituée à la fois d'une puissance stockée, réactive, corrélative et consommée. Est divulgué un compteur d'énergie précis qui calcule un facteur de puissance réel en tant que rapport de cosinus d'angle de déphasage à la somme à la fois de cosinus et de sinus de l'angle de déphasage entre des formes d'onde de courant et de tension et un facteur de puissance corrélative. Le réglage de puissance total est une somme algébrique de puissance réelle et de puissance réactive. Les applications de la divulgation concernent l'industrie de l'énergie électrique pour la détermination d'une quantité précise de génération d'énergie nécessaire, d'une quantité de puissance stockée, d'une quantité de puissance consommée, d'une qualité de système électrique et de taux de facturation et de charge. La divulgation s'applique en outre à la modulation corrélative de signal dans les télécommunications, la gestion d'actifs et l'étalonnage et l'isolation d'équipements.
PCT/IB2021/055349 2020-11-17 2021-06-17 Appareils et procédés de traitement de puissance et de facteur de puissance (pf) réel dans des réseaux ca Ceased WO2022106910A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
KEP202003745 2020-11-17
KEKE/P/2020/003745 2020-11-17

Publications (1)

Publication Number Publication Date
WO2022106910A1 true WO2022106910A1 (fr) 2022-05-27

Family

ID=81709880

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IB2021/055349 Ceased WO2022106910A1 (fr) 2020-11-17 2021-06-17 Appareils et procédés de traitement de puissance et de facteur de puissance (pf) réel dans des réseaux ca

Country Status (1)

Country Link
WO (1) WO2022106910A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115146744A (zh) * 2022-09-01 2022-10-04 安徽南瑞中天电力电子有限公司 一种融合时间特征的电能表负荷实时辨识方法、识别系统
CN117890849A (zh) * 2023-12-06 2024-04-16 国网江西省电力有限公司供电服务管理中心 一种电能表计量补偿方法、装置、存储介质以及电子设备

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106610450A (zh) * 2015-10-23 2017-05-03 上海贝岭股份有限公司 一种单相电能计量芯片
US20180198512A1 (en) * 2015-06-29 2018-07-12 University Of Kwazulu-Natal A receive decorrelator for a wireless communications system
CN110879311A (zh) * 2019-12-02 2020-03-13 北京四方继保自动化股份有限公司 一种计算电网功率的方法
US10750587B2 (en) * 2017-01-15 2020-08-18 Ecosense Lighting Inc. Lighting systems, and systems for determining periodic values of a phase angle of a waveform power input
US20200293627A1 (en) * 2019-03-13 2020-09-17 General Electric Company Method and apparatus for composite load calibration for a power system

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20180198512A1 (en) * 2015-06-29 2018-07-12 University Of Kwazulu-Natal A receive decorrelator for a wireless communications system
CN106610450A (zh) * 2015-10-23 2017-05-03 上海贝岭股份有限公司 一种单相电能计量芯片
US10750587B2 (en) * 2017-01-15 2020-08-18 Ecosense Lighting Inc. Lighting systems, and systems for determining periodic values of a phase angle of a waveform power input
US20200293627A1 (en) * 2019-03-13 2020-09-17 General Electric Company Method and apparatus for composite load calibration for a power system
CN110879311A (zh) * 2019-12-02 2020-03-13 北京四方继保自动化股份有限公司 一种计算电网功率的方法

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
MALENGRET MICHEL; GAUNT C. TREVOR: "Active Currents, Power Factor, and Apparent Power for Practical Power Delivery Systems", IEEE ACCESS, IEEE, USA, vol. 8, 20 July 2020 (2020-07-20), USA , pages 133095 - 133113, XP011801249, DOI: 10.1109/ACCESS.2020.3010638 *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115146744A (zh) * 2022-09-01 2022-10-04 安徽南瑞中天电力电子有限公司 一种融合时间特征的电能表负荷实时辨识方法、识别系统
CN115146744B (zh) * 2022-09-01 2022-12-06 安徽南瑞中天电力电子有限公司 一种融合时间特征的电能表负荷实时辨识方法、识别系统
CN117890849A (zh) * 2023-12-06 2024-04-16 国网江西省电力有限公司供电服务管理中心 一种电能表计量补偿方法、装置、存储介质以及电子设备

Similar Documents

Publication Publication Date Title
EP3084913B1 (fr) Procédés et systèmes d'injection ou d'extraction de puissance dans un réseau électrique
WO2022106910A1 (fr) Appareils et procédés de traitement de puissance et de facteur de puissance (pf) réel dans des réseaux ca
CN109030941A (zh) Hanning自乘卷积窗FFT三谱线插值谐波分析方法
CN109870649A (zh) 一种交流充电桩检定装置的校准系统及方法
KR100537018B1 (ko) 전력계에서 주파수 보상에 대한 시스템 및 방법
Pfajfar et al. Influence of instrument transformers on harmonic distortion assessment
dos Santos et al. Assignment of harmonic voltage contributions using the harmonic current injection method
Han et al. A new assessment for the total harmonic contributions at the point of common coupling
Ikram et al. Advanced real and reactive power measurement using analog multiplier and phase-controlled switching technique
Gopalapillai et al. Quantification of harmonic pollution using non-fundamental apparent power
Skamyin Method for determining the harmonic contribution of consumer installations based on the application of passive filters
Akuon Power Delivered in AC Networks as an Algebraic Sum, P+ Q not Phasor Sum, P+ jQ when power is expressed as V m I m sin (ωt) sin (ωt− θ)
Srinivasan Errors in digital measurement of voltage, active and reactive powers and an on-line correction for frequency drift
Adebayo et al. Online thévenin equivalent impedance measuring system
HANZELKA Single-point methods for location of electromagnetic disturbances in power system
Hanzelka et al. Single-point methods for location of distortion, unbalance, voltage fluctuation and dips sources in a power system
Zajkowski et al. Description of a three-phase, four-wire system with a nonlinear receiver and an asymmetric voltage source using CPC power theory
Solé-Lloveras et al. Distance conversion factors for in situ h-field emissions tests
Yang et al. Analysis of factors influencing electric energy measurement in power systems
CN121347883B (zh) 基于智能融合终端提高电路精度的方法及系统
JPH04217821A (ja) 電力系統の無効電力運転基準値演算方式
Malengret et al. Accurate Metering of Apparent Power Based on General Power Theory
WO2020198041A1 (fr) Validation d'une mesure d'énergie d'une composante fondamentale uniquement
Veeramuthu et al. Phasor measuring unit calibration considering topology expansion of electric power utilities
CA3133636C (fr) Validation d'une mesure d'energie d'une composante fondamentale uniquement

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 21894113

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 21894113

Country of ref document: EP

Kind code of ref document: A1