CN2136476Y - Ac reactive power and electric energy measuring arrangement - Google Patents

Abstract

The utility model belongs to the technical field of electric measurement, in particular to a reactive power and electric energy measuring arrangement, comprising measuring and computing units for electric current, voltage, active power, electric energy, etc. A reactive current meter is not used, and cross-phase connection is also not used, so that measurement errors can be effectively reduced. The arrangement is applicable for measuring reactive power and electric energy under various conditions, and applicable for verifying various reactive power and electric energy meters. The arrangement can simultaneously measure electric current, the active power of voltage, and electric energy by using the same one apparatus. A verifying arrangement can simultaneously verify a current meter, a voltmeter, an active power meter, an electric energy meter and a transmitter. The wiring is the same as the wiring for measuring active power and electric energy. The utility model has convenient use.

Description

AC reactive power and electric energy measuring arrangement

The invention belongs to the Electric Measurement Technology field, relate to a kind of reactive power, device for measurement of electrical energy, particularly a kind of three phase reactive power, device for measurement of electrical energy.

Interchange reactive power, device for measurement of electrical energy are a kind of application electrical measuring devices very widely, correct measurement reactive power, electric energy are significant: because idle component is when increasing, the power factor (COS φ) that is load reduces, the additional electrical energy loss of power transmission line, transformer and generator is increased, obtain same power and must strengthen electric current, perhaps improve the rated voltage of electric equipment, must increase generating set, cause very big waste.

At present, the measurement instrument of measuring reactive power, electric energy generally is divided into sine or non-sinusoidal formula, and the non-sinusoidal formula can be divided into the idle table of phase three-wire three band 60 phase angle differences and the idle table of three-phase and four-line band additional serial coil etc. again.When circuit is asymmetric, all can cause additive error, though the idle table of sinusoid is subjected to that circuit is asymmetric to be influenced lessly, be applicable to unsymmetric circuit, power consumption is big, make complexity causes relevant additive error to increase, so reality is seldom used.Reactive power measurement is except that above-mentioned additive error, also exist frequency error or angle error, because exist inductance or electric capacity in the circuit of reactive power measurement device, and make electric current and voltage on it that a little displacement be arranged, the existence at phasing degree makes power, device for measurement of electrical energy angle error occur.In the power frequency measurement range, the phasing degree is very little, and during meritorious the measurement, the frequency of first-harmonic is near specified work frequency, so angle error is less, and measures when idle, and the frequency of harmonic wave and work frequency differ several times to tens times, so the also corresponding increase of angle error.

In order to address these problems, many researchs and improvement have been carried out both at home and abroad, the idle table produced of Switzerland and Harbin ammeter factory for example, built-in phase shifter and become the idle table of sinusoid can reduce the asymmetric influence of load like this, but the phase place of phase shifter is relevant with frequency, the idle multiple harmonic that contains, the harmonic wave process phase shift that these frequencies are different, complicated variation has taken place in phase place, and can influence accuracy of measurement.

The purpose of this utility model be to provide a kind of and reduce the influence of measuring condition and measuring method, simplify the mode of connection and can improve measuring accuracy exchange reactive power, device for measurement of electrical energy.

Invention is achieved in that interchange reactive power of the present invention, device for measurement of electrical energy mainly comprise: current measuring unit, voltage measurement unit, wattful power messurement unit, active energy measuring unit, computing unit, display unit, record cell and input, output unit etc.

Expression formula according to AC power:

S＝UI＝

（1）

Q＝ $\sqrt{S^2-p^2}=\sqrt{{\left(\mathrm{UI}\right)}^2-p^2}$ ＝UIsinφ （2）

In the formula: Q-reactive power S-applied power U-voltage

The phasing degree of P-active power I-electric current φ-electric current and voltage

By electric current, voltage measurement unit, wattful power messurement unit circuit is measured, and the unit calculates as calculated output in output, demonstration, record cell, demonstration, record reactive power by formula (2); Also can measure circuit, and the unit calculates as calculated output in output, demonstration, record cell, demonstration, record reactive power by formula (2) by wattful power messurement unit, apparent power measurement unit; Perhaps by current measuring unit, voltage measurement unit, power factor or phase measurement unit, the unit calculates output in output in output, demonstration, record cell, demonstration, the record cell, demonstration, record reactive power by formula (2) as calculated.

Measure reactive energy, can measure power by the method for above-mentioned measurement power, the standard time-frequency in elapsed time measurement unit or the computing unit multiply by power the time or it is carried out integration again, can measure reactive energy.

According to the interchange reactive power that the present invention makes, device for measurement of electrical energy has following advantage:

1,, be that the present invention measures reactive power, electric energy according to the idle definition of extending fully, so does not have method error by derivations of extending of active power and applied power because reactive power, electric energy do not have independent accurate definition.

2, stride the method measurement reactive power that is connected because the present invention can not use, can effectively reduce because the asymmetric caused error of circuit.

3, because the present invention does not use reactive power, electric energy meter is measured reactive power, electric energy, can reduce angle error.

4, the phase shifter that does not need reactive power, electric energy meter inside, need be when calibrating reactive power, electric energy meter yet, the phase phasic difference is 90 ° between tested table and the standard scale, can reduce the error that angular frequency causes, therefore, can reduce degree of distortion to influence of measurement error.

5, owing to do not set up reactive power, electric energy benchmark as yet with China in the world, so standard reactive power, electric energy meter can't directly carry out transmission of quantity value, standard used in the present invention, reometer, voltage table, power meter, power factor, phase meter active electric energy meter, standard chronometer all have corresponding national benchmark and each grade standard, can realize transmission of quantity value very easily.

6, the present invention has wide range of applications, and both can be used for the measurement of reactive power in the various alternating circuits or electric energy, can be used for exchanging reactive power or electric energy meter again, the calibrating of transmitter or other measuring units.Also can be used for the calibrating of the measurement of electric current, voltage, phase place, power factor and active power and meritorious, power ammeter, electric energy meter calibrating apparatus simultaneously.

7, the present invention's wiring of wiring during with calibrating active power, electric energy meter of examining and determine reactive power, electric energy meter is identical, the wiring of AC electrical energy meter calibration is simplified, and can be utilized the existing apparatus transformation.As long as use method of the present invention, can obtain same effect.

Accompanying drawing is an electrical principle synoptic diagram of the present invention.

Describe the working condition of the concrete device that proposes according to the present invention in detail below in conjunction with accompanying drawing.

Fig. 1 is the wiring diagram of the single-phase reactive power of calibrating, electric energy meter.I is a current return among the figure, and U is a voltage circuit, and the phase place between current return and the voltage circuit can be aligned.Solid line is represented alternating circuit, and dotted line is represented signal, data, address, instruction, communication transmission circuit, can use wireless transmission, also can use wire transmission, wiredly can use transmission line, connecting line, printed panel or in electron device inside.CT is a standard current transformer, and PT is a standard potential transformer.What draw among the figure is through electric current, voltage transformer (VT) access type, when the range of standard meter is enough, also can insert without mutual inductor, or only inserts through current transformer or voltage transformer (VT).Var is tested reactive power or electric energy meter, reactive power or electric energy transmitter or reactive power, electric energy measurement unit be called for short tested table can be induction type also can be electronic type.W is active power meter or electric energy meter, active power or electric energy transmitter, active power, electric energy measurement unit or power factor meter (measuring unit) phase meter (phase measurement unit) are called for short standard scale, it can be induction type, it also can be electronic type, analog multiplier can be used, also digital multiplier can be used; Can use electrodynamic type power, electric energy standard, thermoelectric (al) type power, electric energy standard, current comparator formula power, electric energy standard, sampling processing active power, electric energy standard, Hall transform power, electric energy standard etc.Can be power, electric energy measurement unit, also can be power factor or phase measurement unit.A is reometer, current transducer or electrical measurement unit, is called for short reometer, can use the A/D conversion, and I/f conversion or the conversion of other effective values are as also available transporting discharging type digital instruments such as thermoelectricity conversion, electrodynamic type, electrostatic comparator, multipliers.V is voltage table, voltage transmitter or voltage measurement unit, is called for short voltage table, can use A/D conversion, V/f conversion or the conversion of other effective values, and as thermoelectricity conversion, electrodynamic type, electrostatic comparator, multiplier etc. also can use the transporting discharging type digital instrument.Calculation processing unit is a single-chip microcomputer, single card microcomputer, microcomputer or computer network (abbreviation calculation processing unit), bear the collection of data, storage, calculate, the function of transmission and measuring system management, with electric current, voltage, power, electric energy, time, power factor, the amount of phase place etc., after formula (2) calculating, value is sent into demonstration note degree unit, show that note degree unit is a digital indicator, conformable display or mechanical type electricity meter counter, machine-electric formula electricity meter counter, display or electricity meter counter can be one or more, can show power and electric energy, can in a plurality of displays, show respectively, also can in a display, order show, electricity meter counter mainly adds up electric energy, a plurality of electricity meter counters can tire out the note electric energy of different periods, if show electric energy, should be able to keep certain hour in accordance with regulations for electric power meter with display.Calculation processing unit also can be sent into the print record unit to data, and the print record unit is register or other pen recorder of printer, tape or disk, data can be printed as certificate, record, form, conformity certification, notics of charge etc. in accordance with regulations.A/D, D/A converting unit are one or more A/D, D/A converter; can be with various simulating signals; as to measure electric current, voltage, power, electric energy and other information translation be digital quantity; also digital quantity can be converted to analog quantity; as 0-10mA, 4-20mA, 0-5V etc., for telemetering device, inspection device; protective device, telltale, automatic power factor compensator use.Input, output unit are interface or other data transmission links of parallel or serial, can form network with measuring system.Mutual Data transmission and information.It is a table that each measuring unit can be produced, calculation processing unit, show note degree unit, print record unit, D/A, D/A converting unit, all or part of unit in the input-output unit can use single-chip microcomputer, single card microcomputer or a computing machine, can form measurement mechanism by multifunctional meter and computing machine.Also can form a measurement mechanism with various unit, can only use a part of unit simultaneously, such as electric current, voltage, power measurement unit etc., data are given the data of the dispatching center of electrical network by output interface through COMPUTER CALCULATION and demonstration, record reactive power and electric energy.Also can have in the reactive power device for measurement of electrical energy in some part is not included in, for example on one section bus a plurality of electric power meters be arranged, as long as there is a voltage measurement unit just passable, the value of voltage is sent into each device through IO interface.

So far, by the agency of a kind of AC power, device for measurement of electrical energy, it has satisfied the requirement that reduces the measurement device error, the instrument that relates in the invention, transmitter, measuring unit, mutual inductor, calculation processing unit, demonstration note degree unit, print record unit, A/D, D/A converting unit, input, output unit etc. but are that those skilled in the art are known, short of from category of the present invention and spirit, can make various variations and replacement, only lift a few example explanation embodiment of the present invention.

Fig. 2 is the wiring diagram of calibrating three-phase and four-line reactive power, electric energy meter, and Var1 is the mutually tested table of A among the figure, and Var2 is the mutually tested table of B, and Var3 is the mutually tested table of C, and they can be three tables, also can be three-phase and four-line tables; Both can be used for examining and determine the idle table of sinusoid, also can be used to examine and determine the idle table of non-sinusoidal, as the reactive energy-meter of three-phase and four-line band additional serial coil, the three-phase and four-line reactive energy-meter that internal phase angle is 60 ° etc., mode of connection is different a bit when just examining and determine, and has not just drawn one by one here.A1 is an A phase current table, and A2 is a B phase current table, and A3 is a B phase voltage table, V1 is an A phase voltage table, and V2 is a B phase voltage table, and V3 is a C phase voltage table, W1 is an A phase standard scale, W2 is a B phase standard scale, and W3 is a C phase standard scale, can be three single standard scales, it also can be a three-phase standard scale, CT, PT, calculation processing unit, demonstration note degree unit, A/D, D/A converting unit etc. are the same with last figure, have not just repeated here, and the content the same with last figure just no longer repeats to descend to the mortal world.

Fig. 3 uses two single-phase standard scales or a two element three-phase standard scale for wiring diagram () this programme of calibrating phase three-wire three power, electric energy meter, letter mark two element method, can be used for examining and determine the idle table of sinusoid phase three-wire three, also can examine and determine the three-way reactive energy-meter of non-sinusoidal, as the idle table of phase three-wire three band 60 phase angle differences, the idle table of phase three-wire three of band autotransformer etc., wiring difference when just examining and determine, and device itself does not have difference, so draw no longer one by one, V ₁₂For measuring U _AbThe voltage table of voltage, V ₂₃For measuring U _AbVoltage table, V ₃₁For measuring U _CaVoltage table.

Fig. 4 is the wiring diagram of calibrating phase three-wire three reactive power, electric energy meter, the standard scale that uses among the figure is the three element standard scale, be called for short the three element method, can examine and determine the idle table of various phase three-wire threes, the connection that this figure only draws a kind of table, various idle tables inside connects various bonding lines, is connected on that connection is the same on the calibrating installation, because the back panel wiring of idle table is various, just do not drawn one by one.

Fig. 5 is the wiring of electric power meter in the single-phase circuit.

Fig. 6 is the wiring of electric power meter in the three-phase and four-line circuit.

Fig. 7 is the wiring of electric power meter in the phase three-wire three circuit.

Wiring in the various electric power meters is of a great variety, and the wiring of reactive power of the present invention, device for measurement of electrical energy is with meritorious identical, and the electric power meter of various wiring all can use.

Claims (4)

1, a kind of interchange reactive power, device for measurement of electrical energy are by exchanging active power or electric energy meter, reometer, voltage table, reactive power or electric energy meter, voltage transformer (VT), current transformer, calculation processing unit, demonstration note degree unit, print record unit; A/D, D/A converting unit; Input, output unit are formed, it is characterized in that being useful on the current interface of measuring power network current and the voltage interface of measuring line voltage, reactive volt-ampere meter is connected to respectively on current interface and the voltage interface, reometer is connected on the current interface by current transformer, measure power network current, reometer also with exchange the series connection of active power meter or electric energy meter, and exchange active power meter or electric energy meter also links to each other with voltage transformer (VT), be used to measure power; Voltage table links to each other with voltage transformer (VT), measures line voltage; Formula of Reactive Power is Q= $\sqrt{S^2-p^2}=\sqrt{{\left(\mathrm{UI}\right)}^2-p^2}$ =UIsinφ。

2, device as claimed in claim 1, the interface that it is characterized in that being used on the device measuring power network current and line voltage is single-phase, and the setting of corresponding reactive volt-ampere meter, voltage table, reometer, active power meter, voltage transformer (VT), current transformer also is provided with by single-phase measurement.

3, device as claimed in claim 1, the interface that it is characterized in that being used on the device measuring power network current and line voltage is a phase three-wire three, and the setting of corresponding reactive volt-ampere meter, voltage table, reometer, active power meter, voltage transformer (VT), current transformer also is by the phase three-wire three setting.

4, device as claimed in claim 1, the interface that it is characterized in that being used on the device measuring power network current and line voltage is a three-phase and four-line, and the setting of corresponding voltage table, reometer, active power meter, voltage transformer (VT), current transformer also is by the three-phase and four-line setting.

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