CN111458616A - Device and method for improving signal-to-noise ratio of common-mode interference suppression partial discharge - Google Patents
Device and method for improving signal-to-noise ratio of common-mode interference suppression partial discharge Download PDFInfo
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- CN111458616A CN111458616A CN202010412241.2A CN202010412241A CN111458616A CN 111458616 A CN111458616 A CN 111458616A CN 202010412241 A CN202010412241 A CN 202010412241A CN 111458616 A CN111458616 A CN 111458616A
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- 230000006698 induction Effects 0.000 claims abstract description 14
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- 238000009413 insulation Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
- G01R31/14—Circuits therefor, e.g. for generating test voltages, sensing circuits
Abstract
The application discloses a device and a method for improving the signal-to-noise ratio of common-mode interference rejection partial discharge, wherein the device comprises the following steps: the voltage source is respectively connected with the variable capacitor and the to-be-tested object; the other end of the variable capacitor is connected with the first wire, and the other end of the first wire is grounded; the other end of the to-be-tested sample is connected with a second wire, and the other end of the second wire is grounded; the first wire and the second wire are parallel and are in induction connection with the Rogowski coil, so that currents generated by partial discharge signals in the common mode interference suppression partial discharge signal-to-noise ratio improving device are in the same direction in the first wire and the second wire. The Rogowski coil is in induction connection with the parallel conducting wire in the circuit, so that partial discharge signals in the external environment are offset in the Rogowski coil.
Description
Technical Field
The application relates to the technical field of signal denoising, in particular to a device and a method for improving a common-mode interference suppression partial discharge signal-to-noise ratio.
Background
In order to check the insulation characteristics of equipment such as line insulators, cables, sleeves, capacitors and the like, a partial discharge test needs to be carried out, and a pulse current method is adopted to carry out a partial discharge test on a large-capacity test article at present. This method cannot eliminate the effect of common mode interference. The common mode interference means that the interference voltage has the same amplitude on the signal line and the return line thereof (generally called signal ground), wherein the voltage takes any one object (earth, metal chassis, reference ground plate, etc.) nearby as a reference potential, and the interference current loop flows in a loop formed by the wire and the reference object.
Disclosure of Invention
The embodiment of the application provides a device and a method for improving the signal-to-noise ratio of common-mode interference suppression partial discharge, so that external interference signals are suppressed, and useful signals are amplified.
In view of the above, a first aspect of the present application provides a device for improving a common mode interference rejection partial discharge signal-to-noise ratio, where the device includes:
the voltage source is respectively connected with the variable capacitor and the to-be-tested object;
the other end of the variable capacitor is connected with a first wire, and the other end of the first wire is grounded;
the other end of the to-be-tested sample is connected with a second wire, and the other end of the second wire is grounded;
the first lead and the second lead are parallel and are in induction connection with the Rogowski coil, so that currents generated by partial discharge signals in the common mode interference suppression partial discharge signal-to-noise ratio improving device are in the same direction in the first lead and the second lead.
Optionally, the voltage source is a constant dc voltage.
Optionally, the size of the capacitor can be adjusted by the variable capacitor, and the adjustment range of the variable capacitor includes the capacitance value of the to-be-tested sample.
A second aspect of the present application provides a method for improving a common-mode interference rejection partial discharge signal-to-noise ratio, where the method includes:
measuring the capacitance value of a to-be-tested sample, and adjusting the capacitance value of the variable capacitor to be consistent with the capacitance value of the to-be-tested sample;
if the partial discharge signal comes from the external environment, currents generated by the partial discharge signal on the first lead and the second lead are equal in magnitude and opposite in direction, induced voltages generated by the currents passing through the Rogowski coil are equal in magnitude and opposite in direction, and therefore the actual voltage is equivalent to zero;
if the partial discharge signal comes from the to-be-tested object, the currents generated by the local electricity-proof signal on the first lead and the second lead are equal in magnitude and same in direction, and the induced voltages generated by the currents passing through the Rogowski coil are equal in magnitude and same in direction, namely the actual voltage is equivalent to twice the induced voltage.
Optionally, if the partial discharge signal is from an external environment, currents generated by the partial discharge signal on the first wire and the second wire are equal in magnitude and opposite in direction, induced voltages generated by the currents through the rogowski coil are equal in magnitude and opposite in direction, that is, the actual voltage equivalence is zero, specifically:
if the partial discharge signal comes from the external environment, the current generated in the variable capacitor and the to-be-tested sample is i1、i2，i1、-i1＝i2The current is respectively induced by the Rogowski coil to obtain an induced voltage U1And U2：
U1＝Li1
U2＝Li2
Where L represents the inductance, the actual voltage U is equivalent to:
U＝U1+U2＝L(i1+i2)＝0。
optionally, if the partial discharge signal is from the test article to be tested, the currents generated by the local electricity-proof signal on the first wire and the second wire are equal in magnitude and same in direction, and the induced voltages generated by the currents passing through the rogowski coil are equal in magnitude and same in direction, that is, the actual voltage equivalence is two times of the induced voltages:
if the partial discharge signal comes from the to-be-tested sample, the current generated in the variable capacitor and the to-be-tested sample is i1、i2，i1＝i2The current is respectively induced by the Rogowski coil to obtain an induced voltage U1And U2：
U1＝Li1
U2＝Li2
The actual voltage U is equivalent to:
U＝U1+U2＝L(i1+i2)＝2Li1＝2Li2。
according to the technical scheme, the method has the following advantages:
the application provides a device and a method for improving the common-mode interference rejection partial discharge signal-to-noise ratio, wherein the device comprises: the voltage source is respectively connected with the variable capacitor and the to-be-tested object; the other end of the variable capacitor is connected with the first wire, and the other end of the first wire is grounded; the other end of the to-be-tested sample is connected with a second wire, and the other end of the second wire is grounded; the first wire and the second wire are parallel and are in induction connection with the Rogowski coil, so that currents generated by partial discharge signals in the common mode interference suppression partial discharge signal-to-noise ratio improving device are in the same direction in the first wire and the second wire.
This application is connected through setting up the parallel wire induction in rogowski coil and the circuit for partial discharge signal in the external environment is offset in the rogowski coil, and simultaneously, when the current that the inside examination article and the variable capacitance that await measuring of device produced when the rogowski coil, the induced voltage of production can superpose, makes useful signal amplified.
Drawings
Fig. 1 is a circuit diagram of an embodiment of a device for improving a signal-to-noise ratio in a common mode interference rejection partial discharge according to the present application.
Detailed Description
This application is connected through setting up the parallel wire induction in rogowski coil and the circuit for partial discharge signal in the external environment is offset in the rogowski coil, and simultaneously, when the current that the inside examination article and the variable capacitance that await measuring of device produced when the rogowski coil, the induced voltage of production can superpose, makes useful signal amplified.
In order to make the technical solutions of the present application better understood, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
Referring to fig. 1, fig. 1 is a circuit diagram of an embodiment of a common mode interference rejection partial discharge signal-to-noise ratio improving apparatus according to the present invention, as shown in fig. 1, where fig. 1 includes:
the voltage source is respectively connected with the variable capacitor and the to-be-tested object; the other end of the variable capacitor is connected with the first wire, and the other end of the first wire is grounded; the other end of the to-be-tested sample is connected with a second wire, and the other end of the second wire is grounded; the first wire and the second wire are parallel and are in induction connection with the Rogowski coil, so that currents generated by partial discharge signals in the common mode interference suppression partial discharge signal-to-noise ratio improving device are in the same direction in the first wire and the second wire.
It should be noted that, a voltage source in the common mode interference rejection partial discharge signal-to-noise ratio increasing apparatus provides a current in the same direction for the apparatus. The variable capacitor is connected with the voltage source and the to-be-tested object in sequence, the other end of the to-be-tested object is connected with the second wire, and the other end of the second wire is grounded; the first conducting wire and the second conducting wire are parallel and are connected with the Rogowski coil in an induction mode. The method comprises the steps of measuring the capacitance value of a to-be-tested sample, adjusting the capacitance value of a variable capacitor to be consistent with the capacitance value of the to-be-tested sample, and switching on a voltage source, wherein the to-be-tested sample can be equivalent to a capacitor, when the to-be-tested sample needs to be tested, the capacitance value of the to-be-tested sample can be measured firstly, after the capacitance value of the to-be-tested sample is obtained, corresponding induced currents are generated in the to-be-tested sample and the variable capacitor, the currents are grounded through a first lead and a second lead respectively, the currents of the first lead and the second lead in a Rogowski coil are the same in the same direction. At this time, the useful signal generated by the test article is amplified.
When a partial discharge signal is generated in an external environment and acts on the common-mode interference suppression partial discharge signal-to-noise ratio improving device, corresponding induced currents are generated in a to-be-tested object and the variable capacitor, the currents are grounded through the first lead and the second lead respectively, the currents of the first lead and the second lead in the Rogowski coil are the same in magnitude and opposite in direction, induced voltages with the same magnitude and opposite in positive and negative are obtained by induction in the Rogowski coil respectively, and the generation of the partial discharge signal from the external environment in the circuit is suppressed.
As shown in FIG. 1, HV is a voltage source, C, used in the device for improving the signal-to-noise ratio of the common mode interference rejection partial discharge1Is a variable capacitance, C2The other end of the variable capacitor is connected with a first lead, the other end of the to-be-tested object is connected with a second lead, the first lead and the second lead are arranged in an inverse parallel mode, and the first lead and the second lead are connected with the Rogowski coil in an induction mode.
When the test is needed, the capacitance value of the to-be-tested sample can be measured firstly, after the capacitance value of the to-be-tested sample is obtained, the capacitance value of the variable capacitor is adjusted to be consistent with the capacitance value of the to-be-tested sample, the voltage source is connected, and at the moment, the current generated by the variable capacitor and the to-be-tested sample is i1、i2，i1＝i2The current is respectively induced by the Rogowski coil to obtain an induced voltage U1And U2：
U1＝Li1
U2＝Li2
The actual voltage U is equivalent to:
U＝U1+U2＝L(i1+i2)＝2LI。
when a partial discharge signal is generated in an external environment and acts on the common-mode interference suppression partial discharge signal-to-noise ratio improving device, corresponding induction currents are generated in the to-be-tested object and the variable capacitor, the currents are grounded through the first conducting wire and the second conducting wire respectively, and at the moment, corresponding induction currents i are generated in the to-be-tested object and the variable capacitor1、i2，-i1＝i2The current is respectively induced by the Rogowski coil to obtain an induced voltage U1And U2：
U1＝Li1
U2＝Li2
Where L represents the inductance, the actual voltage U is equivalent to:
U＝U1+U2＝L(i1+i2)＝0。
in a specific embodiment, the voltage source is a constant dc voltage.
In a specific embodiment, the variable capacitor can adjust the size of the capacitor, and the adjustment range of the variable capacitor includes the capacitance value of the sample to be tested.
The application further provides an embodiment of a method for improving the signal-to-noise ratio of the common-mode interference rejection partial discharge, which specifically includes:
and measuring the capacitance value of the to-be-tested sample, and adjusting the capacitance value of the variable capacitor to be consistent with the capacitance value of the to-be-tested sample.
If the partial discharge signal comes from the external environment, the currents generated by the partial discharge signal on the first wire and the second wire are equal in magnitude and opposite in direction, the induced voltages generated by the currents passing through the rogowski coil are equal in magnitude and opposite in direction, and the actual voltage is equivalent to zero.
It should be noted that, if the partial discharge signal comes from the test object, the current generated in the variable capacitor and the test object is i1、i2，i1＝i2The current is respectively induced by the Rogowski coil to obtain an induced voltage U1And U2：
U1＝Li1
U2＝Li2
The actual voltage U is equivalent to:
U＝U1+U2＝L(i1+i2)＝2Li1＝2Li2。
if the partial discharge signal comes from the to-be-tested object, the currents generated by the partial electricity-proof signal on the first lead and the second lead are equal in magnitude and same in direction, and the induced voltages generated by the currents passing through the Rogowski coil are equal in magnitude and same in direction, namely the actual voltage is equivalent to twice the induced voltage.
It should be noted that, if the partial discharge signal is from the external environment, the current generated in the variable capacitor and the sample to be tested is i1、i2，i1、-i1＝i2The current is respectively induced by the Rogowski coil to obtain an induced voltage U1And U2：
U1＝Li1
U2＝Li2
Where L represents the inductance, the actual voltage U is equivalent to:
U＝U1+U2＝L(i1+i2)＝0。
this application is connected through setting up the parallel wire induction in rogowski coil and the circuit for partial discharge signal in the external environment is offset in the rogowski coil, and simultaneously, when the current that the inside examination article and the variable capacitance that await measuring of device produced when the rogowski coil, the induced voltage of production can superpose, makes useful signal amplified.
It can be clearly understood by those skilled in the art that, for convenience and brevity of description, the specific working processes of the apparatus and the method described above may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.
In this application, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps is not necessarily limited to those steps or elements explicitly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
The above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.
Claims (6)
1. A common mode interference suppression partial discharge signal-to-noise ratio improving device is characterized by comprising: the voltage source is respectively connected with the variable capacitor and the to-be-tested object;
the other end of the variable capacitor is connected with a first wire, and the other end of the first wire is grounded;
the other end of the to-be-tested sample is connected with a second wire, and the other end of the second wire is grounded;
the first lead and the second lead are parallel and are in induction connection with the Rogowski coil, so that currents generated by partial discharge signals in the common mode interference suppression partial discharge signal-to-noise ratio improving device are in the same direction in the first lead and the second lead.
2. The device according to claim 1, wherein the voltage source is a constant dc voltage.
3. The apparatus according to claim 1, wherein the variable capacitor is adjustable in capacitance, and an adjustment range of the variable capacitor includes a capacitance value of the test object.
4. A method for improving a common mode interference suppression partial discharge signal-to-noise ratio, applied to the device according to any one of claims 1 to 3, comprising:
measuring the capacitance value of a to-be-tested sample, and adjusting the capacitance value of the variable capacitor to be consistent with the capacitance value of the to-be-tested sample;
if the partial discharge signal comes from the external environment, currents generated by the partial discharge signal on the first lead and the second lead are equal in magnitude and opposite in direction, induced voltages generated by the currents passing through the Rogowski coil are equal in magnitude and opposite in direction, and therefore the actual voltage is equivalent to zero;
if the partial discharge signal comes from the to-be-tested object, the currents generated by the local electricity-proof signal on the first lead and the second lead are equal in magnitude and same in direction, and the induced voltages generated by the currents passing through the Rogowski coil are equal in magnitude and same in direction, namely the actual voltage is equivalent to twice the induced voltage.
5. The method according to claim 4, wherein if the partial discharge signal is from an external environment, currents generated by the partial discharge signal on the first conducting wire and the second conducting wire are equal and opposite in direction, induced voltages generated by currents passing through the rogowski coil are equal and opposite in direction, that is, actual voltages are equivalent to zero specifically:
if the partial discharge signal comes from the external environment, the current generated in the variable capacitor and the to-be-tested sample is i1、i2，i1、-i1＝i2The current is respectively induced by the Rogowski coil to obtain an induced voltage U1And U2：
U1＝Li1
U2＝Li2
Where L represents the inductance, the actual voltage U is equivalent to:
U＝U1+U2＝L(i1+i2)＝0。
6. the method according to claim 4, wherein if the partial discharge signal is from the test object, the local anti-electric signal generates equal currents on the first wire and the second wire in the same direction, and the induced voltages generated by the currents passing through the rogowski coil have equal magnitudes and the same direction, that is, the actual voltage equivalent to twice the induced voltages specifically includes:
if the partial discharge signal comes from the to-be-detectedThe current generated in the variable capacitor and the sample to be tested is i1、i2，i1＝i2The current is respectively induced by the Rogowski coil to obtain an induced voltage U1And U2：
U1＝Li1
U2＝Li2
The actual voltage U is equivalent to:
U＝U1+U2＝L(i1+i2)＝2Li1＝2Li2。
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2020
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Address after: Room 501-503, annex building, Huaye building, No.1-3 Chuimao new street, Xihua Road, Yuexiu District, Guangzhou City, Guangdong Province 510000 Applicant after: China Southern Power Grid Power Technology Co.,Ltd. Address before: Room 501-503, annex building, Huaye building, No.1-3 Chuimao new street, Xihua Road, Yuexiu District, Guangzhou City, Guangdong Province 510000 Applicant before: GUANGDONG DIANKEYUAN ENERGY TECHNOLOGY Co.,Ltd. |
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Application publication date: 20200728 |