CN114487915B - Method and system for detecting damper of capacitive voltage transformer - Google Patents
Method and system for detecting damper of capacitive voltage transformer Download PDFInfo
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- CN114487915B CN114487915B CN202210401262.3A CN202210401262A CN114487915B CN 114487915 B CN114487915 B CN 114487915B CN 202210401262 A CN202210401262 A CN 202210401262A CN 114487915 B CN114487915 B CN 114487915B
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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
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/52—Testing for short-circuits, leakage current or ground faults
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
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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
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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
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/54—Testing for continuity
Abstract
The invention relates to the technical field of power equipment fault testing, and discloses a method and a system for detecting a damper of a capacitor voltage transformer. The method comprises the steps of inputting power frequency voltages with different voltage values under different frequencies into a damper to be tested of the capacitor voltage transformer, measuring damping current of each detection point to obtain volt-ampere characteristic curves under different frequencies, extracting a damping current measurement value of a preset fault point from the volt-ampere characteristic curves, and comparing the damping current measurement value with a reference current threshold value of a corresponding fault type, so that fault judgment of the damper to be tested is realized; and when the damper to be tested has no fault, judging whether the damper to be tested belongs to a fast saturation type damper or not, if not, calculating impedance phase difference among different frequencies according to the volt-ampere characteristic curve, and judging whether the type of the damper to be tested is a resistance type damper or a resonance type damper according to the impedance phase difference. The invention realizes the automatic and accurate analysis of the faults and types of the damper and can quickly judge the performance of the damper.
Description
Technical Field
The invention relates to the technical field of power equipment fault testing, in particular to a method and a system for detecting a damper of a capacitive voltage transformer.
Background
The capacitive voltage transformer is widely used for monitoring the voltage of a line or a bus between transformer substations at present. In order to avoid the resonance of the capacitor voltage transformer and protect the capacitor voltage transformer from being damaged when the power grid is in a bad state, a damper is arranged on the residual winding on the secondary side of the electromagnetic unit of the capacitor voltage transformer. Common dampers include resistive dampers, resonant dampers, and fast-saturating dampers.
In the prior art, a single power frequency voltage is applied to a damper through a frequency conversion device, the current of the damper at the moment is measured, and the measurement result is analyzed and compared with factory data, so that the aim of detecting whether the damper has a fault is fulfilled. The detection mode cannot realize accurate judgment of the type of the damper, so that the performance of the damper cannot be judged quickly.
Disclosure of Invention
The invention provides a method and a system for detecting a damper of a capacitor voltage transformer, which solve the technical problem that the existing damper detection method cannot accurately judge the type of the damper so as not to quickly judge the performance of the damper.
The invention provides a capacitor voltage transformer damper detection method in a first aspect, which comprises the following steps:
according to a preset frequency detection range and a preset voltage detection range, inputting power frequency voltages with different voltage values under different frequencies to a damper to be detected of the capacitor voltage transformer, determining detection points, measuring damping current of each detection point, and drawing volt-ampere characteristic curves under different frequencies according to obtained damping current measurement results;
extracting a damping current measurement value of a preset fault point from the volt-ampere characteristic curve, comparing the extracted damping current measurement value with a reference current threshold value of a corresponding fault type, and judging the fault of the damper to be tested according to a comparison result;
if the damper to be tested has no fault, judging whether the damper to be tested belongs to a fast saturation type damper or not according to the volt-ampere characteristic curve;
if the damper does not belong to the fast saturation type damper, calculating impedance phase difference among different frequencies according to the volt-ampere characteristic curve, and judging whether the type of the damper to be tested is a resistance type damper or a resonance type damper according to the impedance phase difference.
According to a mode that can be realized by the first aspect of the present invention, the frequency detection range is 30 to 70Hz, the voltage detection range is 0 to 200V, and the inputting of the power frequency voltages with different voltage values at different frequencies to the damper to be measured of the capacitive voltage transformer includes:
dividing the frequency detection range into a plurality of frequency intervals according to preset frequency intervals, and taking the end point of each frequency interval as a detection frequency;
and under each detection frequency, inputting power frequency voltages with different voltage values to the damper to be detected according to the sequence from 0 to 200V until the damping current is greater than 3A.
According to a manner that can be realized by the first aspect of the present invention, the preset frequency interval is 5 Hz, the dividing the frequency detection range into a plurality of frequency intervals according to the preset frequency interval, and taking an end point of each frequency interval as a detection frequency includes:
30Hz, 35 Hz, 40 Hz, 45 Hz, 50Hz, 55 Hz, 60 Hz, 65 Hz and 70Hz were used as the detection frequencies.
According to an implementable manner of the first aspect of the present invention, the determining a detection point includes:
under each detection frequency, when the damping current is not more than 0.5A, taking power frequency voltage at intervals of 5V as a detection point; when the damping current is larger than 0.5A, taking power frequency voltage at intervals of 2V as a detection point; when the damping current exceeds 1A, the power frequency voltage at intervals of 1V is used as a detection point until the damping current is greater than 3A.
According to one possible implementation of the first aspect of the invention, the preset fault point comprises
And
comparing the extracted damping current measurement value with a reference current threshold value corresponding to the fault type, and performing fault judgment on the damper to be tested according to the comparison result, wherein the fault judgment comprises the following steps:
if it is
When the power frequency voltage under the frequency is 5V, the corresponding damping current measured value is larger than 3A, and the damper to be tested is judged to be in short circuit fault;
if not more than 3A, judging
And if so, judging that the damper to be tested has an open-circuit fault.
According to a manner that can be realized in the first aspect of the present invention, the determining whether the damper to be tested belongs to a fast saturation type damper according to the volt-ampere characteristic curve includes:
according to the volt-ampere characteristic curve, determining the power frequency voltage when the damping current measurement value is 1A under the frequency of 30Hz, and setting the power frequency voltage as
The nonlinear coefficient at this time is calculated as follows:
in the formula (I), the compound is shown in the specification,
the non-linear coefficients are represented by,
，
，
the damping current is a damping current measured value corresponding to the power frequency voltage of 5V under the frequency of 30 Hz;
and if the obtained nonlinear coefficient is more than 2, judging that the damper to be tested belongs to a fast saturation type damper, otherwise, judging that the damper to be tested does not belong to the fast saturation type damper.
According to one implementable aspect of the first aspect of the invention, the method further comprises:
when the obtained nonlinear coefficient is more than 2, judging whether the corresponding damping current measured value is more than 1A when the rated voltage is 1.2 times under the 50Hz frequency; if so, judging that the damper to be tested belongs to a qualified speed saturation type damper, otherwise, judging that the damper to be tested belongs to an unqualified speed saturation type damper.
According to a manner that can be realized in the first aspect of the present invention, the determining whether the type of the damper to be tested is a resistance type damper or a resonance type damper according to the impedance phase difference includes:
if the maximum value of the impedance phase difference exceeds 20%, judging that the type of the damper to be tested is a resonance type damper; otherwise, judging that the type of the damper to be tested is a resistance type damper.
According to an enabling aspect of the first aspect of the invention, the method further comprises:
when the maximum value of the impedance phase difference exceeds 20%, judging whether the impedance under the 50Hz frequency is the maximum impedance in the impedances under all the frequencies; and if not, comparing the impedance under each frequency, if the corresponding impedance is larger when the frequency is higher, judging that the inductance of the damper to be tested is in a disconnection state, otherwise, judging that the capacitance of the damper to be tested is in a disconnection state.
A second aspect of the present invention provides a capacitive voltage transformer damper detection system, including:
the variable frequency power supply is connected with a damper to be tested of the capacitor voltage transformer;
the controller is connected with the variable frequency power supply and is used for controlling the variable frequency power supply to input power frequency voltages with different voltage values under different frequencies to a damper to be tested of the capacitor voltage transformer according to a preset frequency detection range and a preset voltage detection range;
the measuring device is used for determining the detection points, measuring the damping current of each detection point and drawing volt-ampere characteristic curves under different frequencies according to the obtained damping current measurement result;
the detection device is connected with the measurement device and used for extracting a damping current measurement value of a preset fault point from the volt-ampere characteristic curve, comparing the extracted damping current measurement value with a reference current threshold value corresponding to a fault type and judging the fault of the damper to be measured according to a comparison result; if the damper to be detected has no fault, the detection device is further used for judging whether the damper to be detected belongs to a fast saturation type damper or not according to the volt-ampere characteristic curve; if the damper does not belong to the fast saturation type damper, calculating impedance phase difference among different frequencies according to the volt-ampere characteristic curve, and judging whether the type of the damper to be tested is a resistance type damper or a resonance type damper according to the impedance phase difference.
According to an implementation manner of the second aspect of the present invention, the frequency detection range is 30-70Hz, the voltage detection range is 0-200V, and the controller is specifically configured to:
dividing the frequency detection range into a plurality of frequency intervals according to preset frequency intervals, and taking the end point of each frequency interval as a detection frequency;
and under each detection frequency, controlling the variable frequency power supply to input power frequency voltages with different voltage values to the damper to be detected according to the sequence from 0 to 200V until the damping current is greater than 3A.
According to an implementable manner of the second aspect of the present invention, the preset frequency interval is 5 Hz, and the dividing the frequency detection range into a plurality of frequency intervals according to the preset frequency interval with an end point of each frequency interval as a detection frequency includes:
30Hz, 35 Hz, 40 Hz, 45 Hz, 50Hz, 55 Hz, 60 Hz, 65 Hz and 70Hz were used as the detection frequencies.
According to an implementable aspect of the second aspect of the invention, the measuring device is specifically configured to:
under each detection frequency, when the damping current is not more than 0.5A, taking power frequency voltage at intervals of 5V as a detection point; when the damping current is larger than 0.5A, taking power frequency voltage at intervals of 2V as a detection point; when the damping current exceeds 1A, the power frequency voltage at intervals of 1V is used as a detection point until the damping current is larger than 3A.
According to an enabling mode of the second aspect of the present invention, the preset failure point includes
And
the detection device is specifically configured to:
if it is
When the power frequency voltage under the frequency is 5V, the corresponding damping current measured value is larger than 3A, and the damper to be tested is judged to be in short circuit fault;
if not more than 3A, judging
And if so, judging that the damper to be tested has an open-circuit fault.
According to an implementation manner of the second aspect of the present invention, when the detecting device determines whether the damper to be tested belongs to a fast saturation type damper according to the volt-ampere characteristic curve, the detecting device is specifically configured to:
according to the volt-ampere characteristic curve, determining the power frequency voltage when the damping current measurement value is 1A under the frequency of 30Hz, and setting the power frequency voltage as
The nonlinear coefficient at this time is calculated as follows:
in the formula (I), the compound is shown in the specification,
the non-linear coefficients are represented by,
，
，
the damping current is a damping current measured value corresponding to the power frequency voltage of 5V under the frequency of 30 Hz;
and if the obtained nonlinear coefficient is more than 2, judging that the damper to be tested belongs to a fast saturation type damper, otherwise, judging that the damper to be tested does not belong to the fast saturation type damper.
According to an implementable manner of the second aspect of the invention, the detection means is further configured to:
when the obtained nonlinear coefficient is more than 2, judging whether the corresponding damping current measured value is more than 1A when the rated voltage is 1.2 times under the 50Hz frequency; if so, judging that the damper to be tested belongs to a qualified speed saturation type damper, otherwise, judging that the damper to be tested belongs to an unqualified speed saturation type damper.
According to an implementable manner of the second aspect of the present invention, when the detection device determines, according to the impedance phase difference, whether the type of the damper to be tested is a resistance-type damper or a resonance-type damper, the detection device is specifically configured to:
if the maximum value of the impedance phase difference exceeds 20%, judging that the type of the damper to be tested is a resonance type damper; otherwise, judging the type of the damper to be tested to be a resistance type damper.
According to an implementable manner of the second aspect of the invention, the detection means is further configured to:
when the maximum value of the impedance phase difference exceeds 20%, judging whether the impedance under the 50Hz frequency is the maximum impedance in the impedances under all the frequencies; if not, comparing the impedance under each frequency, if the corresponding impedance is larger when the frequency is higher, judging that the inductance of the damper to be tested is in a disconnection state, otherwise, judging that the capacitance of the damper to be tested is in a disconnection state.
According to the technical scheme, the invention has the following advantages:
according to the invention, power frequency voltages with different voltage values under different frequencies are input into a damper to be tested of a capacitor voltage transformer according to a preset frequency detection range and a preset voltage detection range, the damping current of each detection point is measured, volt-ampere characteristic curves under different frequencies are drawn according to the obtained damping current measurement result, the damping current measurement value of a preset fault point is extracted from the volt-ampere characteristic curves to be compared with a reference current threshold value corresponding to a fault type, and the damper to be tested is subjected to fault judgment according to the comparison result; when the damper to be tested has no fault, further judging whether the damper to be tested belongs to a fast saturation type damper or not, if not, calculating impedance difference among different frequencies according to a volt-ampere characteristic curve, and judging whether the type of the damper to be tested is a resistance type damper or a resonance type damper according to the impedance difference; the invention detects the damper to be detected based on the volt-ampere characteristic curves under different frequencies, realizes the automatic and accurate analysis of the fault and the type of the damper, and can quickly judge the performance of the damper.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without inventive exercise.
Fig. 1 is a flowchart of a method for detecting a damper of a capacitor voltage transformer according to an alternative embodiment of the present invention;
fig. 2 is a schematic diagram illustrating a principle of detecting a fault and a type of a damper based on a method for detecting a damper of a capacitor voltage transformer according to an alternative embodiment of the present invention;
fig. 3 is a schematic structural connection diagram of a capacitor voltage transformer damper detection system according to an alternative embodiment of the present invention.
Reference numerals:
1-a variable frequency power supply; 2-a controller; 3-a measuring device; 4-detection means.
Detailed Description
The embodiment of the invention provides a method and a system for detecting a damper of a capacitive voltage transformer, which are used for solving the technical problem that the existing damper detection method cannot accurately judge the type of the damper, so that the performance of the damper cannot be quickly judged.
In order to make the objects, features and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the embodiments described below are only a part of the embodiments of the present invention, 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 invention.
The invention provides a detection method for a damper of a capacitor voltage transformer.
Referring to fig. 1, fig. 1 shows a flowchart of a method for detecting a damper of a capacitive voltage transformer according to an embodiment of the present invention.
The embodiment of the invention provides a method for detecting a damper of a capacitor voltage transformer, which comprises the following steps:
step S1, according to a preset frequency detection range and a preset voltage detection range, inputting power frequency voltages with different voltage values under different frequencies to a damper to be detected of the capacitance voltage transformer, determining detection points, measuring damping current of each detection point, and drawing volt-ampere characteristic curves under different frequencies according to obtained damping current measurement results.
In an implementation manner, the frequency detection range is 30 to 70Hz, the voltage detection range is 0 to 200V, and the inputting of the power frequency voltages with different voltage values at different frequencies to the damper to be tested of the capacitive voltage transformer includes:
dividing the frequency detection range into a plurality of frequency intervals according to preset frequency intervals, and taking the end point of each frequency interval as a detection frequency;
and under each detection frequency, inputting power frequency voltages with different voltage values to the damper to be detected according to the sequence from 0 to 200V until the damping current is greater than 3A.
When power frequency voltages with different voltage values are input to the damper to be tested according to the sequence from 0 to 200V, the voltage can be directly increased from 0 to 5V, and then the voltage is gradually increased, when the measured damping current is larger than 3A, namely the damper is in a protection state, the voltage is stopped, and the volt-ampere characteristics of the damper under other frequencies are continuously detected.
The specific value of the preset frequency interval can be set according to actual conditions. In order to ensure the detection performance of the damper of the capacitor voltage transformer, the preset frequency interval should not be greater than 10 Hz.
As a specific embodiment, the preset frequency interval is 5 Hz, and the set detection frequencies are 30Hz, 35 Hz, 40 Hz, 45 Hz, 50Hz, 55 Hz, 60 Hz, 65 Hz and 70 Hz.
As another specific embodiment, the preset frequency interval is 10Hz, and the set detection frequencies are 30Hz, 40 Hz, 50Hz, 60 Hz and 70 Hz.
In one implementation, the determining a detection point includes:
under each detection frequency, when the damping current is not more than 0.5A, taking power frequency voltage at intervals of 5V as a detection point; when the damping current is larger than 0.5A, taking power frequency voltage at intervals of 2V as a detection point; when the damping current exceeds 1A, the power frequency voltage at intervals of 1V is used as a detection point until the damping current is larger than 3A.
For example, when the measurement is performed at a detection frequency of 30Hz, the following steps are specifically performed:
the power frequency voltage at intervals of 5V is taken as a detection point, namely the damping currents with the power frequency voltages of 5V, 10V, 15V and the like are sequentially measured until the damping currents exceed 0.5A;
if the measured damping current exceeds 0.5A when the power frequency voltage is 35V, taking the power frequency voltage at intervals of 2V as a detection point, namely measuring the damping currents with the power frequency voltages of 37V, 39V, 41V and the like in sequence until the damping current exceeds 1A;
if the damping current measured when the power frequency voltage is 50V exceeds 1A, the power frequency voltage at intervals of 1V is taken as a detection point, namely the damping currents with the power frequency voltages of 51V, 52V, 53V and the like are measured in sequence until the damping current exceeds 3A, the detection is stopped, and other frequencies are detected, so that the detection of all volt-ampere characteristics is completed.
According to the embodiment of the invention, the detection efficiency of the method can be improved on the premise of ensuring the detection precision by setting the detection points.
And step S2, extracting a damping current measurement value of a preset fault point from the volt-ampere characteristic curve, comparing the extracted damping current measurement value with a reference current threshold value corresponding to a fault type, and performing fault judgment on the damper to be tested according to a comparison result.
In one implementation, as shown in FIG. 2, the preset failure point comprises
And
comparing the extracted damping current measurement value with a reference current threshold value corresponding to the fault type, and performing fault judgment on the damper to be tested according to the comparison result, wherein the fault judgment comprises the following steps:
if it is
When the power frequency voltage under the frequency is 5V, the corresponding damping current measured value is larger than 3A, and the damper to be tested is judged to be in short circuit fault;
if not more than 3A, judging
And if so, judging that the damper to be tested has an open-circuit fault.
In the embodiment of the invention, the mode of judging the fault of the damper to be tested is simple and effective, and is easy to implement.
And step S3, if the damper to be tested has no fault, judging whether the damper to be tested belongs to a fast saturation type damper or not according to the volt-ampere characteristic curve.
In an implementation manner, when whether the damper to be measured belongs to a fast saturation type damper is judged according to the volt-ampere characteristic curve, the measurement can be performed by using a nonlinear coefficient.
Specifically, the power frequency voltage when the measured value of the damping current is 1A at the frequency of 30Hz can be determined according to the volt-ampere characteristic curve, and is set as
The nonlinear coefficient at this time is calculated according to the following equation:
in the formula (I), the compound is shown in the specification,
the non-linear coefficients are represented by,
，
，
the measured value of the damping current is corresponding to the working frequency voltage of 5V under the frequency of 30 Hz.
As shown in fig. 2, if the obtained nonlinear coefficient is greater than 2, it is determined that the damper to be measured belongs to a fast saturation type damper, otherwise, it is determined that the damper to be measured does not belong to the fast saturation type damper.
Further, when the obtained nonlinear coefficient is greater than 2, judging whether a damping current measured value corresponding to 1.2 times of rated voltage under 50Hz frequency is greater than 1A; if so, judging that the damper to be tested belongs to a qualified speed saturation type damper, otherwise, judging that the damper to be tested belongs to an unqualified speed saturation type damper.
Wherein the rated voltage is the rated voltage of the damper.
And the voltage value of the inflection point under 30Hz can be adopted to judge whether the damper is abnormal. At 30Hz, the current rises rapidly after the inflection point. According to the embodiment of the invention, the nonlinear coefficient is used as the measurement parameter for judging the type of the rapid saturation damper, and the specific calculation mode of the nonlinear coefficient is set, so that the automatic detection of the type of the rapid saturation damper is realized. And whether the corresponding damping current measured value is greater than 1A when the 1.2 times rated voltage is obtained under the 50Hz frequency is judged, so that the qualified state of the damper to be tested is judged.
And step S4, if the damper does not belong to the fast saturation type damper, calculating impedance phase difference among different frequencies according to the volt-ampere characteristic curve, and judging whether the type of the damper to be tested is a resistance type damper or a resonance type damper according to the impedance phase difference.
In an implementation manner, as shown in fig. 2, the determining, according to the impedance phase difference, whether the type of the damper to be tested is a resistance type damper or a resonance type damper includes:
if the maximum value of the impedance phase difference exceeds 20%, judging that the type of the damper to be tested is a resonance type damper; otherwise, judging the type of the damper to be tested to be a resistance type damper.
If the type of the damper to be tested is judged to be a resistance type damper, the resistance value of the damper to be tested can be further calculated according to the volt-ampere characteristic curve.
Further, when the maximum value of the impedance phase difference exceeds 20%, judging whether the impedance at the frequency of 50Hz is the maximum impedance in the impedances at all the frequencies; and if not, comparing the impedance under each frequency, if the corresponding impedance is larger when the frequency is higher, judging that the inductance of the damper to be tested is in a disconnection state, otherwise, judging that the capacitance of the damper to be tested is in a disconnection state.
According to the embodiment of the invention, according to the characteristics of the resistance type damper and the resonance type damper, the impedance phase difference between different frequencies is selected as the measurement parameter for type judgment, and the judgment is carried out based on the measurement parameter, so that the automatic detection of whether the type of the damper to be detected is the resistance type damper or the resonance type damper is realized, and the detection process is simple and convenient. Furthermore, the change rule of the impedance under different frequencies is compared to judge whether the inductor is in a disconnection state or the capacitor is in a disconnection state, so that the performance of the damper is further detected effectively.
The invention also provides a detection system for the damper of the capacitor voltage transformer. The detection system can be used for realizing the detection method of the capacitive voltage transformer damper in any embodiment.
Referring to fig. 3, fig. 3 is a schematic structural connection diagram of a detection system for a damper of a capacitive voltage transformer according to an embodiment of the present invention.
The embodiment of the invention provides a capacitor voltage transformer damper detection system, which comprises:
the variable frequency power supply 1 is connected with a damper to be tested of the capacitor voltage transformer;
the controller 2 is connected with the variable frequency power supply 1 and is used for controlling the variable frequency power supply 1 to input power frequency voltages with different voltage values at different frequencies to a damper to be tested of the capacitance voltage transformer according to a preset frequency detection range and a preset voltage detection range;
the measuring device 3 is used for determining the detection points, measuring the damping current of each detection point and drawing volt-ampere characteristic curves under different frequencies according to the obtained damping current measurement result;
the detection device 4 is connected with the measurement device 3 and is used for extracting a damping current measurement value of a preset fault point from the volt-ampere characteristic curve, comparing the extracted damping current measurement value with a reference current threshold value corresponding to a fault type, and performing fault judgment on the damper to be detected according to a comparison result; if the damper to be detected has no fault, the detection device 4 is further configured to determine whether the damper to be detected belongs to a fast saturation type damper according to the volt-ampere characteristic curve; if the damper does not belong to the fast saturation type damper, calculating impedance phase difference among different frequencies according to the volt-ampere characteristic curve, and judging whether the type of the damper to be tested is a resistance type damper or a resonance type damper according to the impedance phase difference.
Wherein corresponding software may be provided to implement the functionality of the detection apparatus, which software may be provided in a computer device, such as a tablet computer, as the detection apparatus.
In an implementation manner, the frequency detection range is 30 to 70Hz, the voltage detection range is 0 to 200V, and the controller 2 is specifically configured to:
dividing the frequency detection range into a plurality of frequency intervals according to preset frequency intervals, and taking the end point of each frequency interval as a detection frequency;
and under each detection frequency, controlling the variable frequency power supply 1 to input power frequency voltages with different voltage values to the damper to be detected according to the sequence from 0 to 200V until the damping current is greater than 3A.
In one implementation manner, the preset frequency interval is 5 Hz, the dividing the frequency detection range into a plurality of frequency intervals according to the preset frequency interval, and taking an end point of each frequency interval as a detection frequency includes:
30Hz, 35 Hz, 40 Hz, 45 Hz, 50Hz, 55 Hz, 60 Hz, 65 Hz and 70Hz were used as the detection frequencies.
In an implementable manner, the measuring device 3 is specifically configured to:
under each detection frequency, when the damping current is not more than 0.5A, taking power frequency voltage at intervals of 5V as a detection point; when the damping current is larger than 0.5A, taking power frequency voltage at intervals of 2V as a detection point; when the damping current exceeds 1A, the power frequency voltage at intervals of 1V is used as a detection point until the damping current is larger than 3A.
In one implementation, the preset fault point includes
And
the detection device 4 is specifically configured to:
if it is
When the power frequency voltage under the frequency is 5V, the corresponding damping current measured value is larger than 3A, and the damper to be tested is judged to be in short circuit fault;
if not more than 3A, judging
And judging whether the damping current measured value corresponding to the power frequency voltage of 200V is less than 0.5A or not under the frequency, and if so, judging that the damper to be tested has an open-circuit fault.
In an implementation manner, when the detecting device 4 determines whether the damper to be measured belongs to a fast saturation type damper according to the volt-ampere characteristic curve, the detecting device is specifically configured to:
according to the volt-ampere characteristic curve, determining the power frequency voltage when the damping current measurement value is 1A under the frequency of 30Hz, and setting the power frequency voltage as
The nonlinear coefficient at this time is calculated as follows:
in the formula (I), the compound is shown in the specification,
which is a representation of the non-linear coefficients,
，
，
the damping current is a damping current measured value corresponding to the power frequency voltage of 5V under the frequency of 30 Hz;
and if the obtained nonlinear coefficient is more than 2, judging that the damper to be tested belongs to a fast saturation type damper, otherwise, judging that the damper to be tested does not belong to the fast saturation type damper.
In an implementation manner, the detection device 4 is further configured to:
when the obtained nonlinear coefficient is larger than 2, judging whether a damping current measured value corresponding to 1.2 times of rated voltage under 50Hz frequency is larger than 1A; if so, judging that the damper to be tested belongs to a qualified speed saturation type damper, otherwise, judging that the damper to be tested belongs to an unqualified speed saturation type damper.
In an implementation manner, when the detecting device 4 determines, according to the impedance phase difference, whether the type of the damper to be measured is a resistance type damper or a resonance type damper, the detecting device is specifically configured to:
if the maximum value of the impedance phase difference exceeds 20%, judging that the type of the damper to be tested is a resonance type damper; otherwise, judging the type of the damper to be tested to be a resistance type damper.
In an implementation manner, the detection device 4 is further configured to:
when the maximum value of the impedance phase difference exceeds 20%, judging whether the impedance under the 50Hz frequency is the maximum impedance in the impedances under all the frequencies; and if not, comparing the impedance under each frequency, if the corresponding impedance is larger when the frequency is higher, judging that the inductance of the damper to be tested is in a disconnection state, otherwise, judging that the capacitance of the damper to be tested is in a disconnection state.
According to the embodiment of the invention, the damper to be detected is detected based on the volt-ampere characteristic curves under different frequencies, so that the faults and types of the damper can be automatically and accurately analyzed, and the performance of the damper can be rapidly judged.
It can be clearly understood by those skilled in the art that, for convenience and simplicity of description, the specific working processes of the system and the system components described above may refer to the corresponding processes in the foregoing method embodiments, and the specific beneficial effects of the system and the system components described above may refer to the corresponding beneficial effects in the foregoing method embodiments, which are not described herein again.
In the several embodiments provided in the present application, it should be understood that the disclosed system and method may be implemented in other ways. For example, the above-described system embodiments are merely illustrative, and for example, the division of system components into only one logical functional division may be implemented in practice in another way, e.g., multiple system components may be combined or integrated into another system, or some features may be omitted, or not implemented. In addition, the shown or discussed coupling or direct coupling or communication connection between each other may be an indirect coupling or communication connection through some interfaces, devices or modules.
In various embodiments of the present invention, the functions of the detection apparatus may be implemented in one processing module or a plurality of processing modules. The modules can be realized in a hardware mode, and can also be realized in a software functional module mode.
The modules, if implemented in the form of software functional modules and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
The above-mentioned embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will 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 of the embodiments of the present invention.
Claims (10)
1. A detection method for a damper of a capacitive voltage transformer is characterized by comprising the following steps:
according to a preset frequency detection range and a preset voltage detection range, inputting power frequency voltages with different voltage values under different frequencies to a damper to be detected of the capacitor voltage transformer, determining detection points, measuring damping current of each detection point, and drawing volt-ampere characteristic curves under different frequencies according to obtained damping current measurement results;
extracting a damping current measurement value of a preset fault point from the volt-ampere characteristic curve, comparing the extracted damping current measurement value with a reference current threshold value of a corresponding fault type, and judging the fault of the damper to be tested according to a comparison result;
if the damper to be tested has no fault, judging whether the damper to be tested belongs to a fast saturation type damper or not according to the volt-ampere characteristic curve;
if the damper does not belong to the fast saturation type damper, calculating impedance phase difference among different frequencies according to the volt-ampere characteristic curve, and judging whether the type of the damper to be tested is a resistance type damper or a resonance type damper according to the impedance phase difference.
2. The detection method for the damper of the capacitor voltage transformer according to claim 1, wherein the frequency detection range is 30-70Hz, the voltage detection range is 0-200V, and the step of inputting the power frequency voltages with different voltage values at different frequencies to the damper to be detected of the capacitor voltage transformer comprises the steps of:
dividing the frequency detection range into a plurality of frequency intervals according to preset frequency intervals, and taking the end point of each frequency interval as a detection frequency;
and under each detection frequency, inputting power frequency voltages with different voltage values to the damper to be detected according to the sequence from 0 to 200V until the damping current is greater than 3A.
3. The detection method for the damper of the capacitor voltage transformer according to claim 2, wherein the preset frequency interval is 5 Hz, the frequency detection range is divided into a plurality of frequency intervals according to the preset frequency interval, and the end point of each frequency interval is used as the detection frequency, and the method comprises the following steps:
30Hz, 35 Hz, 40 Hz, 45 Hz, 50Hz, 55 Hz, 60 Hz, 65 Hz and 70Hz were used as the detection frequencies.
4. The capacitive voltage transformer damper detection method of claim 2, wherein the determining a detection point comprises:
under each detection frequency, when the damping current is not more than 0.5A, taking power frequency voltage at intervals of 5V as a detection point; when the damping current is larger than 0.5A, taking power frequency voltage at intervals of 2V as a detection point; when the damping current exceeds 1A, the power frequency voltage at intervals of 1V is used as a detection point until the damping current is larger than 3A.
5. The capacitive voltage transformer damper detection method of claim 1, wherein the pre-set fault point comprises
And
comparing the extracted damping current measurement value with a reference current threshold value corresponding to the fault type, and performing fault judgment on the damper to be tested according to the comparison result, wherein the fault judgment comprises the following steps:
if it is
When the power frequency voltage under the frequency is 5V, the corresponding damping current measured value is larger than 3A, and the damper to be tested is judged to be in short circuit fault;
if not more than 3A, judging
And if so, judging that the damper to be tested has an open-circuit fault.
6. The detection method for the damper of the capacitor voltage transformer according to claim 1, wherein the step of judging whether the damper to be tested belongs to a fast saturation type damper according to the volt-ampere characteristic curve comprises the following steps:
according to the volt-ampere characteristic curve, determining the power frequency voltage when the damping current measurement value is 1A under the frequency of 30Hz, and setting the power frequency voltage as
The nonlinear coefficient at this time is calculated as follows:
in the formula (I), the compound is shown in the specification,
the non-linear coefficients are represented by,
，
，
the damping current is a damping current measured value corresponding to the power frequency voltage of 5V under the frequency of 30 Hz;
and if the obtained nonlinear coefficient is more than 2, judging that the damper to be tested belongs to a fast saturation type damper, otherwise, judging that the damper to be tested does not belong to the fast saturation type damper.
7. The capacitive voltage transformer damper detection method of claim 6, further comprising:
when the obtained nonlinear coefficient is more than 2, judging whether the corresponding damping current measured value is more than 1A when the rated voltage is 1.2 times under the 50Hz frequency; if so, judging that the damper to be tested belongs to a qualified speed saturation type damper, otherwise, judging that the damper to be tested belongs to an unqualified speed saturation type damper.
8. The detection method for the damper of the capacitor voltage transformer according to claim 1, wherein the step of judging whether the type of the damper to be tested is a resistance type damper or a resonance type damper according to the impedance phase difference comprises the following steps:
if the maximum value of the impedance phase difference exceeds 20%, judging that the type of the damper to be tested is a resonance type damper; otherwise, judging the type of the damper to be tested to be a resistance type damper.
9. The capacitive voltage transformer damper detection method of claim 8, further comprising:
when the maximum value of the impedance phase difference exceeds 20%, judging whether the impedance under the 50Hz frequency is the maximum impedance in the impedances under all the frequencies; and if not, comparing the impedance under each frequency, if the corresponding impedance is larger when the frequency is higher, judging that the inductance of the damper to be tested is in a disconnection state, otherwise, judging that the capacitance of the damper to be tested is in a disconnection state.
10. A capacitive voltage transformer damper detection system, comprising:
the variable frequency power supply is connected with a damper to be tested of the capacitor voltage transformer;
the controller is connected with the variable frequency power supply and is used for controlling the variable frequency power supply to input power frequency voltages with different voltage values under different frequencies to a damper to be tested of the capacitance voltage transformer according to a preset frequency detection range and a preset voltage detection range;
the measuring device is used for determining the detection points, measuring the damping current of each detection point and drawing volt-ampere characteristic curves under different frequencies according to the obtained damping current measurement result;
the detection device is connected with the measurement device and used for extracting a damping current measurement value of a preset fault point from the volt-ampere characteristic curve, comparing the extracted damping current measurement value with a reference current threshold value corresponding to a fault type and judging the fault of the damper to be measured according to a comparison result; if the damper to be detected has no fault, the detection device is further used for judging whether the damper to be detected belongs to a fast saturation type damper or not according to the volt-ampere characteristic curve; if the damper does not belong to the fast saturation type damper, calculating impedance phase difference among different frequencies according to the volt-ampere characteristic curve, and judging whether the type of the damper to be tested is a resistance type damper or a resonance type damper according to the impedance phase difference.
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| CN107607787B (en) * | 2017-10-18 | 2023-07-21 | 广东电网有限责任公司佛山供电局 | Loop resistance detection system and method based on supercapacitor group |
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| JP7136727B2 (en) * | 2019-03-14 | 2022-09-13 | 株式会社免制震ディバイス | Malfunction determination device for eddy current dampers |
| CN112731255A (en) * | 2020-12-11 | 2021-04-30 | 云南电网有限责任公司红河供电局 | System and method for detecting damping loop of capacitive voltage transformer |
| CN114089018A (en) * | 2021-11-05 | 2022-02-25 | 国网青海省电力公司检修公司 | Method for testing faults of electromagnetic units of capacitor voltage transformer |
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