Background technology
Three-phase three-wire electric energy meter (claiming again the two element electric energy meter) needs calculate active power and reactive power, and its integration is realized active energy metering and reactive energy measurement.
The correct wiring schematic diagram of three-phase three-wire electric energy meter (hereinafter to be referred as electric energy meter) as shown in Figure 1.TV1, TV2 are the primary side voltage transformer (VT), the former edge joint of TV1
Secondary connects
The former edge joint of TV2
Secondary connects
TA1, TA2 are the primary side current mutual inductor, and former limit is by the A phase current
With the B phase current
Secondary is by the A phase current
With the B phase current
Be input to electric energy computation chip after surveying voltage and surveying electric current process voltage and current mutual inductor, complete the calculating of active power and reactive power, and its integration is obtained active energy and reactive energy.
Wherein, total active power of recording of phase three-wire three ammeter is as shown in formula (1-1):
Total reactive power that the phase three-wire three ammeter records is as shown in formula (1-2):
Under the correct mode of connection, between line voltage/line current between and have a relatively-stationary phase relation and amplitude relation between voltage and current.If there is false wiring, can cause so the relative angle of voltage and current to rotate, amplitude changes, and supposes line voltage
And I
aAngle with
And I
cRelative angle rotated respectively
With
Total active power of recording of phase three-wire three ammeter will change so, as shown in formula (1-3).
Total reactive power also can change, as shown in formula (1-4):
As formula (1-3) with (1-4), due to the variation of three-phase three-line voltage and electric current relative angle, total active power that electric energy meter records and total reactive power have produced error.Wherein,
λ
1, λ
2For causing the current amplitude variation factor by reasons such as A/C channel errors wiring, equal to change current amplitude ratio under the amplitude of after-current and correct wiring.
This shows, the correct wiring of electric energy meter is the most important condition that guarantees the correct metering of electric energy meter, because the error of electric energy meter is generally very little, but false wiring is but often very large to the error that electric energy metrical brings.Owing to often easily making a mistake in the installation wiring process of electric energy meter, three-phase electric energy meter particularly, false wiring of a great variety.
For fear of three-phase three-wire electric energy meter false wiring problem, traditional method need to be passed through following steps:
The first step: by the survey instrument of specialty, personnel measure electric energy meter at the scene by grid company, obtain vector plot;
Second step: the vector plot that obtains according to the scene judges whether to exist false wiring;
The 3rd step: the user is had a power failure, at the scene false wiring is corrected or changed electric energy meter;
The 4th step: the electric quantity loss that metering causes to mistake compensates or recovery.
Apparent with the shortcoming that upper type exists: find that false wiring relies on in-site measurement, the efficient that wastes time and energy is extremely low; The accuracy of measuring easily causes mistake to survey due to site environment/survey instrument etc.; Can cause user's interruption maintenance; Because the electric weight miscount is easy to cause legal dispute.
Therefore, how to guarantee the accurate wiring of three-phase three-wire electric energy meter, with can the accurate-metering electric energy, become one of technical barrier that current urgent need solves.
Summary of the invention
The present invention proposes a kind of device and correlation method of correcting metering of three-phase three-wire false wiring, automatically completes more orthofunction of false wiring detection, measuring error by the electric energy computation chip of three-phase three-wire electric energy meter inside.
The present invention adopts following technical scheme to realize: a kind of method of correcting metering of three-phase three-wire false wiring, and it comprises step: the voltage of input and input current are carried out active-power P ' (m) and reactive power Q ' (m) measure; Measure angle and amplitude according to voltage and the input current of input, the polar plot that forms according to angle and amplitude judges whether to exist false wiring, if there is false wiring, active power and reactive power is corrected; Complete electric energy metrical, the output Electric energy measurement.
Wherein, described step to active-power P ' (m) correct comprises: will be according to input voltage
And input current
Multiplying each other to process obtains the first active-power P ' 1 (m) and correction coefficient Coff_A phase multiplication, operation result and Coff_BQ ' 1 (m) is carried out additive operation, the first active-power P 1 (m) that obtains correcting; With input voltage
And input current
Multiply each other the second active-power P of process obtaining ' 2 (m) with carry out the phase multiplication with correction coefficient Coff_C, operation result and Coff_DQ ' 2 (m) are carried out additive operation, the second active-power P 2 (m) that obtains correcting; The first active-power P 1 (m) of correcting and the second active-power P 2 (m) of correcting are carried out the active-power P (m) that additive operation obtains correcting.
Wherein, described step to reactive power Q ' (m) correct comprises: with input voltage
And input current
The first reactive power Q that obtains through multiplying each other after 90 ° of phase shifts processing ' 1 (m) carries out the phase multiplication with correction coefficient Coff_A, and operation result is deducted Coff_BP ' 1 (m), obtains the first reactive power Q 1 (m) of correcting; With input voltage
And input current
The second reactive power Q that obtains as multiplying each other after 90 ° of processing of phase shift ' 2 (m) carry out the phase multiplication with correction coefficient Coff_C, and operation result is deducted Coff_DP ' 2 (m), obtain the second reactive power Q 2 (m) of correcting; The first reactive power Q 1 (m) of correcting and the second reactive power Q 2 (m) of correcting are carried out additive operation, obtain at last the reactive power Q (m) of correcting.
Wherein, correction coefficient
Correction coefficient
Correction coefficient
Correction coefficient
Voltage during for false wiring
And I
aThe relative correct wiring of angle the time relative rotation angle that occurs,
Voltage during for false wiring
And I
cThe relative correct wiring of angle the time relative rotation angle that occurs, λ
1And λ
2Be respectively the A phase and cause the variation factor of current amplitude with C due to false wiring.
Wherein, described electric energy metrical is that active power and reactive power are carried out respectively integral and calculating, obtains active energy and reactive energy.
The present invention proposes a kind of device of correcting metering of three-phase three-wire false wiring, and it comprises:
The false wiring detection module, for detection of the voltage, angle and the amplitude of electric current of input, the polar plot that forms according to angle and amplitude judges whether to exist false wiring;
The power measurement module is used for calculating active-power P ' (m) and reactive power metering Q ' (m) according to the voltage of input and input current;
Correct module, be used for detecting when making a mistake wiring according to the false wiring detection module, the metering result of power measurement module is corrected processing;
Electric energy metering module is used for obtaining active energy and reactive energy to carrying out integral and calculating through active-power P (m) and the reactive power Q (m) of correcting after processing.
Wherein, described false wiring detection module comprises:
Angle Measurement Module is used for input voltage
And input current
Between angle measure, obtain
Angle each other;
The amplitude measurement module is used for input voltage
And input current
Amplitude measure, obtain
Amplitude;
The false wiring judge module is used for judging whether there is false wiring according to the angle of voltage, electric current and the polar plot of amplitude composition.
Compared with prior art, the present invention has following useful technique effect:
The present invention program completes more orthofunction of false wiring detection, measuring error automatically in computation chip inside.Therefore, adopt the present invention not need in-site measurement, according to the polar plot that electric energy computation chip provides, the discovery false wiring that grid company can be real-time, and dealing with problems at once, time saving and energy saving and efficient is very high.When detecting false wiring, computation chip can be corrected accurately according to the kind of false wiring, guarantees and the equal accurate metering of correct wiring, thereby avoid the maximum error that causes because of false wiring, avoided the legal dispute that causes because of the electric energy metrical mistake.In addition, detecting when having false wiring, do not needing to have a power failure and correct wiring or change electric energy meter, the power measurement that electric energy computation chip can be corrected a mistake automatically.
Embodiment
As shown in Figure 2, in three-phase three-wire electric energy meter (hereinafter to be referred as electric energy meter), electric energy computation chip comprises: the false wiring detection module; The power measurement module; Correct module; Electric energy metering module.The false wiring detection module provides complete voltage, current phasor figure for detection of the voltage, angle and the amplitude of electric current of input, for the detection of false wiring provides foundation; The power measurement module is used for voltage and current according to input and calculates active-power P ' (m) and reactive power Q ' (m); Correct module for the result according to the false wiring detection module, judge whether the metering result of power measurement module is corrected, and how to correct, if there is no false wiring is corrected module and can not corrected active power and reactive power; Electric energy metering module is used for correct active-power P (m) and reactive power Q (m) are carried out integral and calculating, obtains at last active energy and reactive energy.
In conjunction with shown in Figure 3, the false wiring detection module comprises: Angle Measurement Module, amplitude measurement module and false wiring judge module.
Wherein, the false wiring detection module realizes that the step of false wiring detection is as follows:
The first step, Angle Measurement Module is to input voltage
And input current
Between angle measure, obtain
Angle each other.
Second step, the amplitude measurement module is to input voltage
And input current
Amplitude measure, obtain
Amplitude.
In the 3rd step, the false wiring judge module judges whether there is false wiring according to the angle of voltage, electric current and the polar plot of amplitude composition.Because false wiring is of a great variety, this false wiring judge module uses the hardware realization except electric energy computation chip is inner, can also judge voluntarily by choice for use software, then passes to electric energy computation chip with under judged result.
In addition, the power measurement module comprises meritorious power measurement module and reactive power metering module.Wherein, the principle schematic of active power metering module as shown in Figure 4.The step of active power metering is as follows:
The first step, input voltage
And input current
After turning through digital-to-analogue, sampled point is stored in sampled point register 410,412,411 and 413 respectively.
Second step, input voltage
And input current
Sampled point in corresponding sampled
point register 410 and 411 carries out multiplying as 2 inputs of
multiplier 414, output P1 (m).Input voltage in like manner
And input current
Sampled point in corresponding sampled
point register 412 and 413 carries out multiplying as the input of
multiplier 415, output P2 (m).
In the 3rd step, P1 (m) and P2 (m) carry out additive operation as the input of totalizer 416, export at last total active-power P (m).
In addition, the measuring principle schematic diagram of reactive power as shown in Figure 5, the step of reactive power metering is as follows:
The first step, input voltage
And input current
The phase shift of carrying out 90 ° as the input of 90 ° of
wave filters 417 of phase shift is processed, in like manner input voltage
And input current
The phase shift of carrying out 90 ° as the input of 90 ° of
wave filters 421 of phase shift is processed.
Second step, input voltage
And input current
Voltage and current sample point after processing through 90 ° of phase shifts is stored in sampled
point register 418 and 419; Equally, input voltage
And input current
Be stored in sampled
point register 422 and 423 as the sampled point after 90 ° of processing of phase shift.
In the 3rd step, the voltage and current sample point in sampled point register 418 and 419 carries out multiplying and exports Q1 (m) as the input of multiplier 420.In like manner, the voltage and current sample point in sampled point register 422 and 423 carries out multiplying and exports Q2 (m) as the input of multiplier 424.
In the 4th step, Q1 (m) and Q2 (m) carry out additive operation as the input of totalizer 425, export at last total reactive power Q (m).
When the relative angle of voltage and current rotates and after amplitude changed, the computing formula of its active power was as shown in (1-4).Formula (1-4) is resolved into form as shown in formula (4-1).In like manner the computing formula of reactive power (1-5) can be write as shown in formula (4-2).
As shown in formula (1-1), (1-2), P1 and P2 are (wherein,
) be the active power before the angle rotation, Q1 and Q2 are (wherein,
) be the reactive power before the angle rotation.Suppose,
Can be obtained by formula (4-1), (4-2): P ' 1=λ
1a
1P1-λ
1a
3Q1, P ' 2=λ
2a
2P2-λ
2a
4Q2, Q ' 1=λ
1a
1Q1+ λ
1a
3P1, Q ' 2=λ
2a
2Q2+ λ
2a
4P2.Can obtain P1 thus, P2, Q1, Q2 P ' 1, P ' 2, and Q ' 2, and the relational expression that Q ' 1 forms is as follows.
Active power after can being corrected from above relational expression and the formula of reactive power are as shown in (4-3), (4-4).
If correction coefficient
(4-3), (4-4) can be write as shown in formula (4-5).
Whether as shown in Figure 6, correct module corrects active power and reactive power according to result or the user software Instruction Selection of false wiring detection module.If there is no the situation of false wiring does not just correct the result in the power measurement module.If there is the situation of false wiring, corrects module and just the metering result in the power measurement module is corrected.The correction step of active power is as follows:
The first step, the P ' 1 (m) in the power measurement module and P ' 2 (m) correct computing as the input of correcting module.P ' 1 (m) is input in multiplier 426 and carries out multiplication mutually with correction coefficient Coff_A, and P ' 2 (m) is input in multiplier 428 and carries out multiplication mutually with correction coefficient Coff_C.
Second step is input to the Output rusults of multiplier 426 in totalizer 427 and Coff_BQ ' 1 (m) carries out additive operation, the P1 that obtains correcting (m); Be input to the Output rusults of multiplier 428 in totalizer 429 and Coff_DQ ' 2 (m) carries out additive operation, the P2 that obtains correcting (m).
In the 3rd step, the Output rusults P2 (m) of the Output rusults P1 (m) of totalizer 427 and totalizer 429 is outputed to carry out total active-power P (m) that additive operation obtains correcting in totalizer 430.
Can obtain by formula (4-5) schematic diagram that in this programme, reactive power is corrected, as shown in Figure 7.The correction step of reactive power is as follows:
The first step, the Q ' 1 (m) in the power measurement module and Q ' 2 (m) correct computing as the input of correcting module.Q ' 1 (m) is input in multiplier 431 carries out multiplication mutually with correction coefficient Coff_A, Q ' 2 (m) is input in multiplier 433 carries out multiplication mutually with correction coefficient Coff_C.
Second step passes to the Output rusults of multiplier 431 in subtracter 432 and Coff_BP ' 1 (m) carries out subtraction, the Q1 that obtains correcting (m).Pass to the Output rusults of multiplier 433 in subtracter 434 and Coff_DP ' 2 (m) carries out subtraction, the Q2 that obtains correcting (m).
The 3rd step, the Output rusults Q2 (m) of the Output rusults Q1 (m) of subtracter 432 and subtracter 434 is passed to carry out additive operation in totalizer 435, obtain at last total reactive power Q (m) of correcting.
The course of work of the present invention as shown in Figure 8.Concrete steps are as follows.
Step S1 carries out power measurement to voltage and the input current of inputting.
Step S2, false wiring detects.The false wiring detecting step is measured angle and amplitude according to voltage and the input current of input, and the polar plot that forms according to angle and amplitude judges whether to exist false wiring.
Step S3 judges whether to exist false wiring, and if there is no false wiring just enters step S5 and carries out electric energy metrical.This deterministic process can be completed by electric energy computation chip, also can be completed by electric energy meter software or the long-range master control of grid company.If exist false wiring just to enter step S4.
Step S4 corrects active power and reactive power.
Step S5 completes electric energy metrical, then exports correct Electric energy measurement.
The above is only preferred embodiment of the present invention, not in order to limiting the present invention, all any modifications of doing within the spirit and principles in the present invention, is equal to and replaces and improvement etc., within all should being included in protection scope of the present invention.