EP0203947A1 - A static, electric apparatus for measuring power and energy drawn from a power supply network - Google Patents
A static, electric apparatus for measuring power and energy drawn from a power supply networkInfo
- Publication number
- EP0203947A1 EP0203947A1 EP19850905786 EP85905786A EP0203947A1 EP 0203947 A1 EP0203947 A1 EP 0203947A1 EP 19850905786 EP19850905786 EP 19850905786 EP 85905786 A EP85905786 A EP 85905786A EP 0203947 A1 EP0203947 A1 EP 0203947A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- voltage
- frequency
- power
- pulses
- basis
- 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.)
- Withdrawn
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R21/00—Arrangements for measuring electric power or power factor
-
- 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
Definitions
- the invention concerns an apparatus of the type defined in the introductory portion of claim 1.
- the GB Patent Application 2 061 641 discloses such an appa ⁇ ratus which serves to determine the peak power of each of the phases in a three-phase network and to switch in and out the consumers on each of the phases so that a predeter ⁇ mined maximum load per phase is not exeeded.
- the GB Patent Application 2 046 925 discloses a metering system which serves as an additional unit for a conven ⁇ tional Ferrari meter, and this unit enables registration of the consumption according to three orMmore different tariffs so that different billing rates can be applied for different times of consumption.
- the object of the invention is to provide an apparatus of the present type which ensures correct metering of the actual consumption, even if periodic loads are switched in on the individual phases, and which is convenient in the sense that, in contrast to the conventional Ferrari meter, it requires no regular and thorough service and maintenance, no repair or replacement of worn components and no adjustment.
- the detecting frequency is in ⁇ dependent of the network frequency, and that the detection order of the phases is randomized, whereby these features prevent synchorization of a load, e.g. a heating element, with the meter to avoid registration of the actual con- sumption.
- the apparatus may be designed for self-calibration, as stated in claim 2.
- An expedient embodiment of the self-calibration means is sta- ted in claim 3.
- a power supply network is represented by three phase conductors R, S and T and a neutral conductor N.
- a signal conditioning circuit 10, 11 and 12 is inserted in each phase conductor, and each of these circuits more ⁇ over connects with the neutral conductor and senses the phase voltage through ohmic voltage dividers and the phase currents through measuring transformers and converts these quantities to voltage signals having an acceptable level for the subsequent circuits.
- the signals thus conditioned are fed in pairs to a multiplexer 13 which transfers the signals per phase with time delay with respect to each other to a multiplier 14. This multiplier produces the pro ⁇ duct of current and voltage for each phase.
- pro ⁇ ducts are fed to an RMS converter which is contained in the multiplier 14 and applies a voltage whose size is an expression of the instantaneous power in the phase concerned.
- This voltage is fed to a voltage/frequency converter 15, called V/F converter in the following, whose output signal is a pulse train having a frequency which is pro ⁇ portional to the voltage signal applied to the input.
- the pulse train is fed as an input signal to a microprocessor 16, in which the number of pulses per second from the V/F converter is counted. This count is an expression of the instantaneous power.
- the microprocessor 16 multiplies the power expression with a time factor, and the result of this multiplication is an expression of the consumed amount of energy.
- the micro ⁇ processor 16 also controls the signal transfer from the signal conditioning circuits 10, 11 and 12 to the multi ⁇ plexer 13 through an address bus 17. This transfer takes place sequentially in an arbitrarily varying order and with a frequency which is independent of the network frequency. This makes it impossible for a consumer to avoid registra- tion of the consumption by synchronized switching in of the load to the network with the metering system.
- the sequential signal transfer causes registration of the power consumption on all three phases.
- the total consump ⁇ tion of energy is calculated as the sum of the consumption of the individual phases.
- a random access store 18 which is so de ⁇ signed as to maintain the stored data even in case of failure in its supply voltage.
- the stored consumption of energy can be read by actuation of a switch 19, which causes a pulse to be fed to the microprocessor 16, which is caused by the pulse to transfer the energy consumption stored in the store to a read-out unit 20, which corre- sponds to the counter in a conventional electricity meter.
- the analog components incorporated in the measuring loop i.e. the multiplexer 13, the multiplier 14 with its RMS converter and the V/F converter 15 are subject to ageing and temperature drift, since electricity meters are often placed in surroundings in which temperature and air humi ⁇ dity vary greatly. Accordingly, it is important to take measures to prevent these phenomena from affecting the metering accuracy.
- a reference vol ⁇ tage source 21 is provided, said source being based on a semiconductor reference diode having a very low temperature drift and very great long-term stability.
- the apparatus is self-calibrated by means of this voltage reference upon start of the apparatus and then at intervals of e.g. 30 minutes.
- the microprocessor applies a control signal to the multiplexer 13, said signal causing all inputs to the multiplexer to be disconnected, and then the signal from the V/F converter 15 is measured.
- This sig ⁇ nal is then an expression of the zeropointerror of the system.
- the microprocessor now applies a new control signal to the multiplexer, said signal causing the reference vol ⁇ tage source to be connected to the multiplexer, and the signal from the V/F converter is measured again.
- a reference power incor- porated in the store at the manufacture of the meter it is now possible to calculate the number of pulses from the V/F converter which correspond to e.g. 0.1 kilowatt hour, and this value is stored in the store IB.
- This calibration procedure which relies on the accuracy of the reference voltage and the knowledge of the corre ⁇ sponding reference power, serves to currently and automati ⁇ cally recalibrate/adjust the electricity meter, so that ageing and temperature drift have no influence of the long- term accuracy of the metering system.
Abstract
Un compteur d'électricité statique comprend pour chaque phase un circuit de conditionnement de signaux (10, 11 et 12) qui détecte la tension et le courant transmet des impulsions de tension représentant ces quantités à un multiplexeur (13), d'où celles-ci sont transférées en série à travers un multiplicateur (14) jusqu'à un convertisseur de tension/fréquence (15) dont le signal de sortie est une série d'impulsions dont la fréquence est une expression de la consommation de puissance sur la phase détectée à n'importe quel moment. Cette série d'impulsions est transmise à un microprocesseur (16) qui compte les impulsions et calcule la consommation d'énergie sur la base d'un facteur temps incorporé et transfère le résultat du calcul à une mémoire à accés sélectif (18). Le microprocesseur commande également le transfert de signaux du multiplexeur, de sorte que la détection des phases se fait dans un ordre qui varie de façon arbitraire et à une fréquence indépendante de la fréquence du réseau. Cela empêche le consommateur d'éviter l'enregistrement de la consommation en connectant synchroniquement la charge au réseau avec le système de mesure. Afin d'éviter des mesures inexactes dues au vieillissement ou à la dérive thermique du composant du compteur d'électricité, le compteur se calibre/ajuste automatiquement sur la base d'une source précise de tension de référence ayant une stabilité à long terme et une dérive thermique très basse.A static electricity meter comprises for each phase a signal conditioning circuit (10, 11 and 12) which detects the voltage and the current transmits voltage pulses representing these quantities to a multiplexer (13), from where these ci are transferred in series through a multiplier (14) to a voltage / frequency converter (15) whose output signal is a series of pulses whose frequency is an expression of the power consumption on the detected phase at any moment. This series of pulses is transmitted to a microprocessor (16) which counts the pulses and calculates the energy consumption on the basis of an incorporated time factor and transfers the result of the calculation to a memory with selective access (18). The microprocessor also controls the transfer of signals from the multiplexer, so that the phases are detected in an order which varies arbitrarily and at a frequency independent of the frequency of the network. This prevents the consumer from avoiding recording the consumption by synchronously connecting the load to the network with the measurement system. In order to avoid inaccurate measurements due to aging or thermal drift of the component of the electricity meter, the meter automatically calibrates / adjusts on the basis of a precise source of reference voltage with long-term stability and very low thermal drift.
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DK5494/84 | 1984-11-20 | ||
DK549484A DK152458C (en) | 1984-11-20 | 1984-11-20 | STATIC ELECTRIC ELECTRIC MEASUREMENT FOR POWER AND ENERGY MEASURED FROM A POWER SUPPLY NETWORK |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0203947A1 true EP0203947A1 (en) | 1986-12-10 |
Family
ID=8142915
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19850905786 Withdrawn EP0203947A1 (en) | 1984-11-20 | 1985-11-19 | A static, electric apparatus for measuring power and energy drawn from a power supply network |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP0203947A1 (en) |
JP (1) | JPS62501445A (en) |
AU (1) | AU5092885A (en) |
DK (1) | DK152458C (en) |
FI (1) | FI862941A0 (en) |
WO (1) | WO1986003301A1 (en) |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0465476A4 (en) * | 1989-04-04 | 1992-07-08 | Alcatel Australia Limited | A sampling circuit |
EP0866976B1 (en) * | 1995-12-05 | 2001-03-21 | Siemens Aktiengesellschaft | Electronic measurement device |
ES2132019B1 (en) * | 1997-03-17 | 2000-03-01 | Univ Sevilla | STATIC ELECTRIC ENERGY METER BASED ON RANDOM SIGNAL PROCESSING. |
CN100348984C (en) * | 2006-01-24 | 2007-11-14 | 北京万工科技有限公司 | Electric energy metrical pulse generation method for ammeter |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4077061A (en) * | 1977-03-25 | 1978-02-28 | Westinghouse Electric Corporation | Digital processing and calculating AC electric energy metering system |
JPS54137649A (en) * | 1978-04-18 | 1979-10-25 | Tokyo Electric Power Co Inc:The | Digital protective relay device |
GB2040051B (en) * | 1979-01-11 | 1982-12-08 | South Eastern Elec Board | Electroni kolowatthour meter |
SU845109A1 (en) * | 1979-07-06 | 1981-07-07 | Львовский Ордена Ленина Политехническийинститут Им. Ленинского Комсомола | Active power-to-pulse quantity converter |
US4360879A (en) * | 1980-08-28 | 1982-11-23 | The Valeron Corporation | Power measuring device |
WO1983003011A1 (en) * | 1982-02-25 | 1983-09-01 | Scientific Columbus Inc | Multi-function electricity metering transducer |
-
1984
- 1984-11-20 DK DK549484A patent/DK152458C/en not_active IP Right Cessation
-
1985
- 1985-11-19 WO PCT/DK1985/000107 patent/WO1986003301A1/en not_active Application Discontinuation
- 1985-11-19 AU AU50928/85A patent/AU5092885A/en not_active Abandoned
- 1985-11-19 EP EP19850905786 patent/EP0203947A1/en not_active Withdrawn
- 1985-11-19 JP JP50519385A patent/JPS62501445A/en active Pending
-
1986
- 1986-07-14 FI FI862941A patent/FI862941A0/en not_active Application Discontinuation
Non-Patent Citations (1)
Title |
---|
See references of WO8603301A1 * |
Also Published As
Publication number | Publication date |
---|---|
DK152458B (en) | 1988-02-29 |
FI862941A (en) | 1986-07-14 |
JPS62501445A (en) | 1987-06-11 |
DK549484A (en) | 1986-05-21 |
FI862941A0 (en) | 1986-07-14 |
WO1986003301A1 (en) | 1986-06-05 |
AU5092885A (en) | 1986-06-18 |
DK549484D0 (en) | 1984-11-20 |
DK152458C (en) | 1988-07-25 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
17P | Request for examination filed |
Effective date: 19860711 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AT BE CH DE FR GB IT LI LU NL SE |
|
17Q | First examination report despatched |
Effective date: 19880718 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
|
18D | Application deemed to be withdrawn |
Effective date: 19880531 |
|
RIN1 | Information on inventor provided before grant (corrected) |
Inventor name: SERUP, KURT Inventor name: LAURITZEN, JORGEN Inventor name: PEDERSEN, FRANK |