CN205594091U - Error measurement device for current transformer - Google Patents
Error measurement device for current transformer Download PDFInfo
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- CN205594091U CN205594091U CN201620233464.1U CN201620233464U CN205594091U CN 205594091 U CN205594091 U CN 205594091U CN 201620233464 U CN201620233464 U CN 201620233464U CN 205594091 U CN205594091 U CN 205594091U
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Abstract
The utility model provides an error measurement device for current transformer, including power supply generator (1), reference standard (2) and error tester (3), power supply generator (1) produces heavy current alternating current -direct current composite signal or halfsinusoid signal to apply the signal that produces for being surveyed current transformer (4) and reference standard (2) respectively, reference standard (2) can be with being surveyed accurate undercurrent or the little voltage signal of converting to of AC and DC composition in the heavy current signal, and undercurrent or little voltage signal input to error tester (3) as reference signal, measuring result is carried out obtaining after synchronous sampling, conversion and the calculation to the reference signal of reference standard (2) output and the measured signal of being surveyed current transformer (4) output in error tester (3).
Description
Technical field
This utility model relates to electrical measurement field, particularly relates to a kind of current transformer error measurement apparatus.
Background technology
Current transformer is power generation and electric energy metrical, the key equipment of protection.In power production process,
The links such as generating, power transformation use substantial amounts of current transformer to carry out measurement and the safety guarantor of high-voltage great-current electric energy
Protect.If primary current exists DC component in electrical network, the iron core of the current transformer in electric power meter will be by
Magnetization, magnetizing current is the biggest, and remanent magnetism is the biggest.In the case of not demagnetizing, remanent magnetism can be always maintained at filling next time
Magnetic process.The impact of current transformer error can be reflected on magnetizing current magnetization curve by remanent magnetism.Right
In standard stalloy and iron-nickel alloy sample, weak remanent magnetism makes transformer error change to positive direction mostly, strong remanent magnetism
Transformer error is necessarily made to change to negative direction.
Due to following reason make electrical network produce DC component: the earth magnetism electric current that (1) solar windstorm causes.Earth's magnetic field
Change will Evoked ptential gradient at the earth's surface, the area that ground conductivity is less, low frequency and when continuing a section
Between electric field action when the power transformer of transmission system neutral ground, the electric potential gradient on earth's surface will its around
Group induction frequency is the geomagnetic induction current (GIC) of 0.0001Hz～0.01Hz, and the AC system ratio of 50Hz,
The direct current of approximation can be regarded as.(2) direct current during direct current transportation one pole ground return circuit runs the ground produced.China is
Put into operation a plurality of 500kV, 800kV HVDC transmission line.In the single-stage ground return circuit method of operation or double
Under pole off-center operation mode, as the fortune that electric current is DC transmission system of the earth circulation in direct current transportation loop
Row electric current, can produce surface potential around current conversion station, make periphery neutral grounded transformer exist in certain area
Neutral point produces DC component.(3) DC component that asymmetric load produces.AC network exists voltage electricity
The load of flow relation curve asymmetric.As phased AC load, phase controlled rectifier, unicast commutator, circuit change
DC component all can be produced to inverter.Additionally, controlling asymmetric DC transmission system and some frequency conversion
In device system, Transformer Winding all contains DC component.
General by mutual-inductor tester measurement current transform er error.General mutual-inductor tester uses differential flat
Weighing apparatus comparison principle, the advantage of this tester is that accuracy is high, and its resolving power, up to 1 × 10-8, can be used for school
Testing 0.0001 grade and following transformer, weak point is that this tester needs to regulate manually, zero-detection
Balance difficulties, uses inconvenience.Another kind of conventional mutual-inductor tester uses microcomputer technology and non-equilibrium differential former
Reason, measures transformer secondary circuit and the differential wave of standard mutual inductor secondary circuit and standard mutual inductor secondary returning
Road working signal, and the error of transformer is calculated according to error defined formula.Although the work efficiency of the latter relatively passes
System electrician's formula tester increases, but circuit is complicated, debugging difficulty big, measures standard when differential wave is less
Exactness and stability are the best, poor repeatability, and are normally only applicable to check the transformer of less than 0.01 grade.
Existing mutual-inductor tester is only calibrated under 50/60Hz and is traced to the source, and is limited by its components and parts and operation principle limits,
All can not work under conditions of harmonic wave or DC component are higher, it is impossible to for measurement current transform er by direct current and
Error characteristics during harmonic effects, it is therefore desirable to a kind of novel measurement apparatus and measuring method are provided.
Utility model content
For the deficiencies in the prior art, the utility model proposes a kind of current transformer error measurement apparatus, application
Data acquisition technology and the secondary singal of the direct measurement current transform er of Digital Signal Processing, calculate it effective
Value error, fundamental voltage amplitude error, fundamental phase error, as evaluating current transformer harmonic wave and anti-DC performance
Appreciation gist.
A kind of current transformer error measurement apparatus, including power source generator (1), reference standard (2) and
Error testing instrument (3)；Described power source generator (1) respectively with reference standard (2) and tested transformer (4)
Connecting, described error testing instrument (3) is connected with reference standard (2), and is provided with and tested transformer (4)
The connection end connected, described reference standard (2) is provided with the connection end being connected with tested transformer (4), institute
State measurement apparatus and use alternating current-direct current composite signal or half-sinusoid signal both of which.
When described device uses alternating current-direct current composite signal pattern, described power source generator (1) includes alternating current
Source (5) and DC current source (6), described ac current source (5) includes pressure regulator and current lifting device, described liter
One end of stream device is connected with electric capacity C, and the other end of electric capacity C is connected with inductance L, the other end of inductance L and direct current
One end of current source (6) connects, the other end of described current lifting device and the other end of described DC current source (6)
Connect.
When described device uses half-sinusoid signal mode, described power source generator (1) includes ac current source
(5) and commutation diode, described ac current source (5) includes pressure regulator and current lifting device, described current lifting device
One end is connected with resistance R, the other end of resistance R respectively with anode and the moon of the second diode of the first diode
Pole connects, the other end of described current lifting device and resistance RBOne end connect, described resistance RBThe other end and
Two diode anodes connect.
Described reference standard (2) uses the accurate AC/DC universal measurement such as diverter, Zero flux sensor to set
Standby, its direct current, the amplitude error of exchange are less than 0.05%, and industrial frequency AC phase error is less than 2 points.
Described error testing instrument (3) includes sampling resistor, double channel data acquisition card and data processing module.
Described sampling resistor rated current is 1A or 5A, and error is less than 0.01%, and current signal is converted into voltage
Signal.
The resolution of described double channel data acquisition card is not less than 24bit, carries out reference signal and measured signal same
Step sampling.
With immediate prior art ratio, the technical scheme that this utility model provides has following excellent effect
(1) DC content in the biggest current loop both can arbitrarily regulate, and can produce again alternation,
Multiple different on-the-spot operating condition can be simulated；
(2) mark using the diverter or Zero flux sensor that can measure alternating current and direct current signal simultaneously as reference
Quasi-device, can accurately monitor the size of DC content in primary current, improves the concordance of result of the test；
(3) error testing instrument uses digitized direct measuring, and overcoming tradition tester can not be at harmonic wave
With work under the influence of direct current, need the shortcoming that standard is identical with tested mutual inductor ratio, and can be according to need
Testing other parameter in addition to virtual value, amplitude, phase place, its higher automaticity improves simultaneously
Measure efficiency.
Accompanying drawing explanation
Fig. 1 is this utility model a kind of current transformer direct current and the structured flowchart of harmonic effects measurement apparatus；
Fig. 2 is schematic diagram during power source generator generation alternating current-direct current composite signal in this utility model；
Fig. 3 is schematic diagram during power source generator generation half-sinusoid signal in this utility model.
Detailed description of the invention
Below in conjunction with the accompanying drawings and detailed description of the invention, this utility model is described in further detail.
As shown in Figure 1, for this utility model a kind of current transformer direct current and the structure of harmonic effects measurement apparatus
Block diagram, is made up of power source generator 1, reference standard 2 and error testing instrument 3, described power source generator 1
Be connected with reference standard 2 and tested transformer 4 respectively, reference standard 2 and tested transformer 4 connect and
It is connected with error testing instrument 3 respectively.
Described power source generator 1 can produce big electric current alternating current-direct current composite signal or half-sinusoid signal, and will produce
Signal be applied to tested current transformer 4 and reference standard 2；
AC and DC composition in tested big current signal can be converted into by described reference standard 2 accurately
Small area analysis or small voltage signal, input to error testing instrument 3 as reference signal；
Reference signal that reference standard 2 is exported by described error testing instrument 3 and tested current transformer 4 output
Measured signal carries out synchronized sampling, is converted into two groups of digital signals, uses Digital Signal Processing to be calculated
Final measurement.
Current transformer direct current as above and even-order harmonic affect measurement apparatus, and described power source generator produces to be handed over
During direct current composite signal, its principle as shown in Figure 2, including an alternating current for the big electric current of output AC
Stream source 5 and a DC current source 6 being used for exporting DC current, formed on branch roads that both connect jointly
Alternating current-direct current composite signal.In fig 2, electric capacity C has stopping direct current and leads to the characteristic of exchange, is possible to prevent up-flow
Device occurs saturated, reduces primary current distortion.The effect of inductance L is the characteristic utilizing inductance to lead to direct current resistance exchange,
Increase the impedance of DC source branch road, thus reach to prevent from burning the purpose of DC source.
Current transformer direct current as above and even-order harmonic affect measurement apparatus, and described power source generator is just producing
During string half-wave voltage signal, its principle as shown in Figure 3, including ac current source 5, diode, resistance etc., is handed over
Stream electric current, after halfwave rectifier, is formed containing only direct current and the half-wave sinusoidal of even-order harmonic.In accompanying drawing 3 two
The model of commutation diode should be identical, and R is steady resistance, and its effect is to reduce commutation diode voltage drop pair
The impact of loop current, RBFor balancing resistance, its resistance is approximately equal to reference standard and once hinders with tested transformer
Anti-sum.
Described reference standard uses the accurate AC/DC universal such as diverter, Zero flux sensor to measure equipment.Quilt
The accuracy surveying current transformer is up to 0.2S level, and the standard of therefore referring to need to meet the amplitude of direct current, exchange
Error is less than 0.05%, the requirement less than 2 points of the industrial frequency AC phase error.By relatively existing current measurement
Principle, possesses AC/DC universal function, and accuracy higher have accurate diverter and Zero flux current sensor
Two kinds.Present case selects FLUKE A40B type precision diverter and LEM ITZ type Zero flux sensor as reference
Standard.The current range of A40B type diverter is from 0.1mA to 100A, and bandwidth is from DC to 100kHz, specified
Output voltage 0.8V, accuracy can reach 0.001 grade.The rated current of ITZ type Zero flux sensor is the highest
Up to 24000A, DC measurement accuracy 2 × 10 6, AC measurment accuracy 0.02%.
Described error testing instrument includes sampling resistor, double channel data acquisition card and data processing module.Present case with
The A40B type diverter of rated current 1A and 5A is as sampling resistor, by tested current transformer with reference to mark
The current signal that accurate (when selecting Zero flux sensor as reference standard) exports is converted into voltage signal.This case
Example is using NI 5922 type digitizer as dual pathways simultaneous data-acquisition, and its resolution is 24bit, sampling speed
Rate 500k/s, can carry out synchronized sampling to reference signal and measured signal.Present case is made with LabView program
For software, it carries out Initialize installation, and the market demand FFT function collected is carried out Fu NI 5922
In leaf transformation, obtain the information such as virtual value, DC content, fundamental voltage amplitude, fundamental phase, pass through comparison reference
Difference between standard channel and tested transformer passage measured value, can try to achieve the virtual value of needs by mistake
The information such as difference, fundamental voltage amplitude error, fundamental phase error.
Finally should be noted that: above example is merely to illustrate the technical solution of the utility model rather than to it
The restriction of protection domain, although the application being described in detail with reference to above-described embodiment, art general
Lead to and skilled artisans appreciate that those skilled in the art still can be to the specific embodiment party of application after reading the application
Formula carries out all changes, amendment or equivalent, but these change, revise or equivalent, all in Shen
Within the claims that please await the reply.
Claims (7)
1. a current transformer error measurement apparatus, it is characterised in that: described device includes power source generator
(1), reference standard (2) and error testing instrument (3)；Described power source generator (1) is marked with reference respectively
Quasi-device (2) and tested transformer (4) connect, and described error testing instrument (3) is with reference standard (2) even
Connecing, and be provided with the connection end being connected with tested transformer (4), described reference standard (2) is provided with tested
The connection end that transformer (4) connects, described measurement apparatus uses alternating current-direct current composite signal or half-sinusoid signal
Both of which.
Measurement apparatus the most according to claim 1, it is characterised in that described device uses alternating current-direct current synthesis
During signal mode, described power source generator (1) includes ac current source (5) and DC current source (6), institute
State ac current source (5) and include that pressure regulator and current lifting device, one end of described current lifting device are connected with electric capacity C, institute
The other end stating electric capacity C is connected with inductance L, the other end of described inductance L and one end of DC current source (6)
Connecting, the other end of described current lifting device is connected with the other end of described DC current source (6).
Measurement apparatus the most according to claim 1, it is characterised in that described device uses half-sinusoid letter
During number pattern, described power source generator (1) includes ac current source (5) and commutation diode, described exchange
Current source (5) includes that pressure regulator and current lifting device, one end of described current lifting device are connected with resistance R, described resistance R
The other end be connected with the anode of the first diode and the negative electrode of the second diode respectively, another of described current lifting device
End and resistance RBOne end connect, described resistance RBThe other end and the second diode anode connect.
Measurement apparatus the most according to claim 1, it is characterised in that described reference standard (2) is straight
Stream, the amplitude error of exchange are less than 0.05%, and industrial frequency AC phase error is less than 2 points.
Measurement apparatus the most according to claim 1, it is characterised in that described error testing instrument (3) is wrapped
Include sampling resistor, double channel data acquisition card and data processing module.
Measurement apparatus the most according to claim 5, it is characterised in that described sampling resistor rated current is
1A or 5A, error is less than 0.01%.
Measurement apparatus the most according to claim 5, it is characterised in that described double channel data acquisition card
Resolution is not less than 24bit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620233464.1U CN205594091U (en) | 2016-03-24 | 2016-03-24 | Error measurement device for current transformer |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620233464.1U CN205594091U (en) | 2016-03-24 | 2016-03-24 | Error measurement device for current transformer |
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| Publication Number | Publication Date |
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| CN205594091U true CN205594091U (en) | 2016-09-21 |
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| CN201620233464.1U Active CN205594091U (en) | 2016-03-24 | 2016-03-24 | Error measurement device for current transformer |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105699818A (en) * | 2016-03-24 | 2016-06-22 | 中国电力科学研究院 | Error measurement apparatus and measurement method for current transformer |
| CN106772199A (en) * | 2017-01-05 | 2017-05-31 | 云南电网有限责任公司电力科学研究院 | A kind of DC current transformer frequency response characteristic check system and method |
| CN109342988A (en) * | 2018-12-20 | 2019-02-15 | 广东电网有限责任公司 | A kind of remanence of current transformer influence test method, apparatus and system |
-
2016
- 2016-03-24 CN CN201620233464.1U patent/CN205594091U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105699818A (en) * | 2016-03-24 | 2016-06-22 | 中国电力科学研究院 | Error measurement apparatus and measurement method for current transformer |
| CN106772199A (en) * | 2017-01-05 | 2017-05-31 | 云南电网有限责任公司电力科学研究院 | A kind of DC current transformer frequency response characteristic check system and method |
| CN109342988A (en) * | 2018-12-20 | 2019-02-15 | 广东电网有限责任公司 | A kind of remanence of current transformer influence test method, apparatus and system |
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