CN208334478U - A kind of current signal Acquisition Circuit of capacitive apparatus - Google Patents
A kind of current signal Acquisition Circuit of capacitive apparatus Download PDFInfo
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- CN208334478U CN208334478U CN201821096437.XU CN201821096437U CN208334478U CN 208334478 U CN208334478 U CN 208334478U CN 201821096437 U CN201821096437 U CN 201821096437U CN 208334478 U CN208334478 U CN 208334478U
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Abstract
The utility model discloses a kind of current signal Acquisition Circuits of capacitive apparatus, and the end shield current terminal of capacitive apparatus is arranged in；Including the first inductance, the second inductance, first capacitor, sampling resistor, the input terminal of current signal Acquisition Circuit is electrically connected with the end shield current terminal of capacitive apparatus；Input terminal of the one end of first inductance as current signal Acquisition Circuit, the other end of the first inductance are electrically connected with one end of the second inductance；The other end of second inductance is electrically connected with one end of sampling resistor；One end of first inductance is electrically connected with one end of first capacitor；The other end of first capacitor is electrically connected with the other end of sampling resistor；The other end of first capacitor is grounded.The utility model ensure that by the way that the electric current of revealing of end shield current terminal is converted to sampled voltage on sampling resistor and reveal the precise measurement of circuit to milliampere grade, while being also equipped with the effect of anti-open circuit duplicate protection and the measurement function of Partial discharge signal.
Description
Technical field
The utility model relates to Electric Power Equipment Insulation performance evaluation fields, more particularly, to a kind of capacitive apparatus
Current signal Acquisition Circuit.
Background technique
Capacitive apparatus generallys use the insulation system that capacitance plate presses mode, for this structure, dielectric loss
Tg δ and capacitance parameter more can delicately find the insulation defect of capacitive apparatus, and existing preventive trial is also upper
Two parameters are stated as main measurement object.The above-mentioned two parameter of real-time monitoring in the operational process of equipment, not only can be timely
It was found that the insulation defect of running equipment, also can reach the purpose for extending and even substituting conventional preventive trial.On-line monitoring (electrification
Test) principle be illustrated in fig. 2 shown below, by measure end shield current and potential transformer PT secondary voltage signal, it can be obtained
Dielectric loss and capacitance parameter.
Realize the on-line monitoring of capacitance type equipment dielectric loss parameter, most critical technology is how accurately to obtain and seek
The phase difference of two fundamental frequency current signals." the zero passage being built upon used by early stage on the basis of analog signal processing
Compare " technology, the time difference of two signals is obtained by counter type, is then converted into phase difference further according to the signal period,
This method is higher to the stability requirement of hardware circuit, and the drift of circuit itself, the influence of harmonic wave interference are difficult to overcome
Problem.
If can the end shield current terminal to capacitive apparatus be monitored the insulation that can also analyze capacitive apparatus
Whether performance is good.The above method not will cause the end shield current terminal of current transformer access capacitive apparatus, when test
End shield and ground disconnect, and bottom shielding of bushing just will not be made to generate high pressure in this way, and safety is fine.But because by end shield current terminal
Revealing electric current is milliampere grade, and the electromagnetic field generated is very small.If using current transformer, even if in view of selection perm closes
Gold simultaneously uses negative-feedback technology, and precision is also relatively difficult to guarantee.
Utility model content
The utility model overcomes existing defect, provides a kind of current signal acquisition electricity of new capacitive apparatus
Road.The utility model ensure that by the way that the electric current of revealing of end shield current terminal is converted to sampled voltage on sampling resistor to milli
Pacify the measurement for revealing circuit of grade.
In order to solve the above technical problems, the technical solution of the utility model is as follows:
A kind of current signal Acquisition Circuit of capacitive apparatus, is arranged in the end shield current terminal of capacitive apparatus；Packet
Include the first inductance, the second inductance, first capacitor, sampling resistor, wherein
The input terminal of the current signal Acquisition Circuit is electrically connected with the end shield current terminal of capacitive apparatus；
Input terminal of the one end of first inductance as current signal Acquisition Circuit, the other end of the first inductance and
One end of two inductance is electrically connected；
The other end of second inductance is electrically connected with one end of sampling resistor；
Described one end of the first inductance is electrically connected with one end of first capacitor；
The other end of the first capacitor is electrically connected with the other end of sampling resistor；
The other end of the first capacitor is grounded.
The course of work of the utility model: when normal operation, the fundamental current for revealing electric current of end shield current terminal is power frequency
50Hz can be approximately considered short circuit, and the capacitive reactance of capacitor is very since the reactance of the first inductance and the second inductance at this time is very small
Open circuit can be regarded as greatly.Leakage Current enters ground, on-line monitoring after flowing to sampling resistor by the first inductance and the second inductance at this time
Device can find out the size and phase of Leakage Current by the voltage of measurement sampling resistor two sides.If supervised in operational process
It surveys between device and end shield current terminal and open circuit has occurred, electric current will enter ground by first capacitor, and because of first capacitor and capacitive
The capacitor of power equipment is compared to very big, so the voltage very little that capacitive apparatus is got, thus will not because of open circuit and
End shield is set to generate high voltage, to bring safety problem.In addition, the structure can also take into account partial discharge measurement.When operating normally, because
Very low for work frequency, the voltage of sampling resistor two sides is smaller, and keeps stable.When there is Partial discharge signal to pass through, the office of high frequency
The meeting of putting is similar to short circuit, and two concatenated inductance can regard a voltage as at this time so that the capacitive reactance of first capacitor becomes smaller
Mutual inductor, the voltage of sampling resistor two sides will be proportional to the turn ratio of two inductance coils at this time, acquires by this principle
Voltage value and voltage value when normal operation no matter from waveform, amplitude or frequency it is several in terms of from the point of view of it is all completely different.This
Sample just can easily measure Partial discharge signal.
In a preferred solution, the current signal Acquisition Circuit further includes the second capacitor, second electricity
One end of appearance is electrically connected with one end of the first inductance；The other end of second capacitor is electrically connected with the other end of first capacitor
In a preferred solution, the current signal Acquisition Circuit further includes the first arrester, and described first
One end of arrester is electrically connected with one end of first capacitor；The other end of first arrester and the other end of first capacitor
Electrical connection
In a preferred solution, the current signal Acquisition Circuit further includes the second arrester, and described second
One end of arrester is electrically connected with one end of first capacitor；The other end of second arrester and the other end of first capacitor
Electrical connection.
In this preferred embodiment, due to two arresters of parallel connection, play the role of anti-open circuit duplicate protection.
Compared with prior art, the beneficial effect of technical solutions of the utility model is:
The utility model ensure that by the way that the electric current of revealing of end shield current terminal is converted to sampled voltage on sampling resistor
The precise measurement of circuit is revealed to milliampere grade, while being also equipped with effect and the Partial discharge signal of anti-open circuit duplicate protection
Measure function.
Detailed description of the invention
Fig. 1 is the circuit diagram of embodiment.
Fig. 2 is Electric Power Equipment Insulation performance measurement schematic diagram.
Specific embodiment
The attached figures are only used for illustrative purposes and cannot be understood as limitating the patent；
In order to better illustrate this embodiment, the certain components of attached drawing have omission, zoom in or out, and do not represent actual product
Size；
To those skilled in the art, it is to be understood that certain known features and its explanation, which may be omitted, in attached drawing
's.
The technical solution of the utility model is described further with reference to the accompanying drawings and examples.
As shown in Figure 1, a kind of current signal Acquisition Circuit of capacitive apparatus, including the first inductance, the second inductance,
One capacitor C1, the second capacitor C2, sampling resistor RL, the first arrester M1 and the second arrester M2, wherein
The input terminal of current signal Acquisition Circuit is electrically connected with the end shield current terminal of capacitive apparatus；
Input terminal of the one end of first inductance as current signal Acquisition Circuit, the other end of the first inductance and the second inductance
One end electrical connection；
The other end of second inductance is electrically connected with one end of sampling resistor RL；
One end of first inductance is electrically connected with one end of first capacitor C1；
The other end of first capacitor C1 is electrically connected with the other end of sampling resistor RL；
The other end of first capacitor C1 is grounded；
One end of second capacitor C2 is electrically connected with one end of the first inductance；
The other end of second capacitor C2 is electrically connected with the other end of first capacitor C1；
One end of first arrester M1 is electrically connected with one end of first capacitor C1；
The other end of first arrester M1 is electrically connected with the other end of first capacitor C1.
One end of second arrester M2 is electrically connected with one end of first capacitor C1；
The other end of second arrester M2 is electrically connected with the other end of first capacitor C1.
The present embodiment course of work:
When normal operation, the fundamental current for revealing electric current of end shield current terminal is power frequency 50Hz, due to the first inductance at this time
It is very small with the reactance of the second inductance, it can be approximately considered short circuit, and the capacitive reactance of first capacitor C1 and the second capacitor C2 are very big
Open circuit can be regarded as.Leakage Current enters ground, on-line monitoring after flowing to sampling resistor RL by the first inductance and the second inductance at this time
Device can find out the size and phase of Leakage Current by the voltage of the measurement two sides sampling resistor RL.If in operational process
Having occurred open circuit between monitoring device and end shield current terminal, electric current will enter ground by first capacitor C1 and the second capacitor C2, and because
It is very big compared with the capacitor of capacitive apparatus for first capacitor C1 and the second capacitor C2, so what capacitive apparatus was got
Voltage very little will not thus make end shield generate high voltage, to bring safety problem because of open circuit.First arrester M1 and
The parallel connection of second arrester M2 plays the role of anti-open circuit duplicate protection.In addition, the structure can also take into account partial discharge measurement.When
When normal operation, because work frequency is very low, the voltage of the two sides sampling resistor RL is smaller, and keeps stable.When there is Partial discharge signal
When passing through, the partial discharge of high frequency can make the first C1 capacitor and the capacitive reactance of the second capacitor C2 become smaller, and be similar to short circuit, and two at this time
Concatenated inductance can regard a voltage transformer as, and the voltage of sampling resistor two sides is by the circle with two inductance coils at this time
Number is than proportional, and no matter voltage value when the voltage value and normal operation that acquire by this principle is from waveform, amplitude or frequently
It is all completely different from the point of view of the several aspects of rate.Partial discharge signal just can be easily measured in this way.
The same or similar label correspond to the same or similar components；
The terms describing the positional relationship in the drawings are only for illustration, should not be understood as the limitation to this patent；
Obviously, the above embodiments of the present invention is merely examples for clearly illustrating the present invention, and
It is not limitations of the embodiments of the present invention.For those of ordinary skill in the art, in above description
On the basis of can also make other variations or changes in different ways.There is no need and unable to give all embodiments
Exhaustion.Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention etc., should be included in
Within the protection scope of the utility model claims.
Claims (4)
1. the end shield current terminal of capacitive apparatus is arranged in a kind of current signal Acquisition Circuit of capacitive apparatus；It is special
Sign is, including the first inductance, the second inductance, first capacitor, sampling resistor, wherein
The input terminal of the current signal Acquisition Circuit is electrically connected with the end shield current terminal of capacitive apparatus；
Input terminal of the one end of first inductance as current signal Acquisition Circuit, the other end of the first inductance and the second electricity
One end of sense is electrically connected；
The other end of second inductance is electrically connected with one end of sampling resistor；
Described one end of the first inductance is electrically connected with one end of first capacitor；
The other end of the first capacitor is electrically connected with the other end of sampling resistor；
The other end of the first capacitor is grounded.
2. current signal Acquisition Circuit according to claim 1, which is characterized in that the current signal Acquisition Circuit is also
Including the second capacitor, one end of second capacitor is electrically connected with one end of the first inductance；Second capacitor it is another
End is electrically connected with the other end of first capacitor.
3. current signal Acquisition Circuit according to claim 1 or 2, which is characterized in that the current signal acquires electricity
Road further includes the first arrester, and described one end of the first arrester is electrically connected with one end of first capacitor；Described first is kept away
The other end of thunder device is electrically connected with the other end of first capacitor.
4. current signal Acquisition Circuit according to claim 3, which is characterized in that the current signal Acquisition Circuit is also
Including the second arrester, described one end of the second arrester is electrically connected with one end of first capacitor；Second arrester
The other end be electrically connected with the other end of first capacitor.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201821096437.XU CN208334478U (en) | 2018-07-11 | 2018-07-11 | A kind of current signal Acquisition Circuit of capacitive apparatus |
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| CN201821096437.XU CN208334478U (en) | 2018-07-11 | 2018-07-11 | A kind of current signal Acquisition Circuit of capacitive apparatus |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112540337A (en) * | 2020-12-30 | 2021-03-23 | 广东电网有限责任公司电力科学研究院 | Transformer substation outgoing line capacitive voltage transformer monitoring method, device and equipment |
-
2018
- 2018-07-11 CN CN201821096437.XU patent/CN208334478U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112540337A (en) * | 2020-12-30 | 2021-03-23 | 广东电网有限责任公司电力科学研究院 | Transformer substation outgoing line capacitive voltage transformer monitoring method, device and equipment |
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