CN115542018A - On-line monitoring method and device for dielectric loss and capacitance of high-voltage bushing - Google Patents
On-line monitoring method and device for dielectric loss and capacitance of high-voltage bushing Download PDFInfo
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- CN115542018A CN115542018A CN202211226823.7A CN202211226823A CN115542018A CN 115542018 A CN115542018 A CN 115542018A CN 202211226823 A CN202211226823 A CN 202211226823A CN 115542018 A CN115542018 A CN 115542018A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
- G01R27/26—Measuring inductance or capacitance; Measuring quality factor, e.g. by using the resonance method; Measuring loss factor; Measuring dielectric constants ; Measuring impedance or related variables
- G01R27/2688—Measuring quality factor or dielectric loss, e.g. loss angle, or power factor
- G01R27/2694—Measuring dielectric loss, e.g. loss angle, loss factor or power factor
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K13/00—Thermometers specially adapted for specific purposes
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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
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
- G01R27/26—Measuring inductance or capacitance; Measuring quality factor, e.g. by using the resonance method; Measuring loss factor; Measuring dielectric constants ; Measuring impedance or related variables
- G01R27/2605—Measuring capacitance
Abstract
The invention discloses a method and a device for monitoring dielectric loss and capacitance of a high-voltage bushing on line, wherein the high-voltage bushing is positioned on a transformer, a leakage current sensor is arranged on the inner wall of a tap screen of the high-voltage bushing, the leakage current sensor collects leakage current when the high-voltage bushing operates, and the leakage current sequentially passes through a current processing component and a microprocessor; the voltage transformer measures the operating voltage of the high-voltage bushing, and the operating voltage sequentially passes through the voltage processing assembly and the microprocessor; the microprocessor converts the operating voltage and the leakage current into the sum of fundamental wave component and each subharmonic component, and transmits the sum to the industrial computer to calculate the dielectric loss value and the capacitance; the temperature measuring sensor measures the operating temperature of the high-voltage sleeve and transmits the operating temperature to the industrial personal computer; the industrial personal computer obtains and displays the converted dielectric loss value according to the dielectric loss value and the operating temperature; the industrial personal computer is provided with a threshold value, and when the dielectric loss value of the capacitance or the converted dielectric loss value exceeds the threshold value, the industrial personal computer sends out an alarm signal.
Description
Technical Field
The invention relates to the technical field of power equipment measurement, in particular to a method and a device for monitoring dielectric loss and capacitance of a high-voltage bushing on line.
Background
The equipment such as transformer, current transformer often use oiled paper insulation or adhesive tape insulation high-voltage bushing, and dielectric loss value and electric capacity are the key parameter of representation high-voltage bushing insulating state, through to the dielectric loss value of high-voltage bushing and the measurement of electric capacity, can find the insulating problem that high-voltage bushing probably exists.
The traditional method for measuring the dielectric loss value and the capacitance of the high-voltage bushing adopts a power failure measurement mode, the change of the dielectric loss value and the capacitance of the high-voltage bushing cannot be found in real time and in time by the measuring method, the dielectric loss value and the capacitance of the high-voltage bushing are monitored in real time by an online monitoring device, the early-stage defects and faults of the high-voltage bushing can be identified and judged, and the development of the defects and the generation of the faults are avoided.
At present, a direct measurement method is commonly used for a high-voltage bushing dielectric loss value and capacitance online monitoring device, and the problems of difficult micro signal extraction and low measurement accuracy exist in a complex electromagnetic environment of a transformer substation. On the other hand, the traditional online monitoring device for the dielectric loss value of the high-voltage bushing does not consider the influence of the measured temperature, does not perform uniform conversion of the temperature, and has the problem that the measured result is inaccurate because the measured result has no temperature basis.
Disclosure of Invention
The invention aims to solve the technical problems that when a traditional online monitoring device measures the dielectric loss value of a high-voltage bushing, the influence of measured temperature on the dielectric loss value is not considered, and uniform conversion of the temperature is not carried out, so that the measurement result is inaccurate, and aims to provide the online monitoring method and the online monitoring device for the dielectric loss and the capacitance of the high-voltage bushing, so as to solve the problem that the measurement result of the dielectric loss value and the capacitance of the high-voltage bushing in a transformer substation is inaccurate.
The invention is realized by the following technical scheme:
the method for monitoring dielectric loss and capacitance of the high-voltage bushing on line comprises the following steps:
s1: the inner wall of the end screen of the high-voltage bushing is provided with a leakage current sensor which collects leakage current when the high-voltage bushing operates;
s2: the leakage current sequentially passes through the current processing assembly and the microprocessor;
s3: the voltage transformer measures the operating voltage of the high-voltage bushing;
s4: the operating voltage sequentially passes through the voltage processing assembly and the microprocessor;
s5: the microprocessor converts the operating voltage into the sum of the fundamental component and each subharmonic component of the voltage signal, converts the leakage current into the sum of the fundamental component and each subharmonic component of the current signal and transmits the sum to the industrial personal computer;
s6: the industrial personal computer calculates dielectric loss value and electric capacity according to the sum of the fundamental component and each subharmonic component of leakage current and operating voltage;
s7: the temperature measuring sensor measures the operating temperature of the high-voltage sleeve and transmits the operating temperature to the industrial personal computer;
s8: the industrial personal computer obtains a converted dielectric loss value according to the dielectric loss value and the operating temperature;
s9: the industrial personal computer is provided with a threshold value, and when the capacitance or the dielectric loss value after conversion exceeds the threshold value, the industrial personal computer sends out an alarm signal.
In the scheme, the high-voltage bushing is positioned on a transformer or a current transformer and other devices, a leakage current sensor is arranged on the inner wall of a tap screen of the high-voltage bushing, and the leakage current sensor acquires leakage current when the high-voltage bushing operates; the leakage current sensor is connected with a current processing assembly, the current processing assembly is used for preprocessing a current signal, the current processing assembly is connected with a microprocessor, and the microprocessor converts the leakage current into a sum of a fundamental component and each subharmonic component and transmits the sum to the industrial personal computer; the voltage transformer measures the operating voltage of the high-voltage bushing, the voltage transformer is connected with the voltage processing assembly, the voltage processing assembly is used for preprocessing a voltage signal, the voltage processing assembly is connected with the microprocessor, and the microprocessor converts the operating voltage of the high-voltage bushing into a sum of a fundamental component and each subharmonic component and transmits the sum to the industrial personal computer; the industrial personal computer calculates the dielectric loss value and the capacitance of the high-voltage bushing according to the sum of the fundamental component and each harmonic component of the leakage current and the operating voltage; the temperature measuring sensor measures the operating temperature of the high-voltage bushing and transmits the operating temperature to the industrial personal computer, the temperature measuring sensor is utilized, the influence of the measured temperature is fully considered, the unified conversion of the temperature is carried out, the industrial personal computer obtains the converted dielectric loss value according to the dielectric loss value and the operating temperature, the calculated dielectric loss value is stored and displayed by the industrial personal computer, and the problem that when the traditional online monitoring device measures the dielectric loss value of the high-voltage bushing, the influence of the measured temperature on the dielectric loss value is not considered, the unified conversion of the temperature is not carried out, and the measuring result is inaccurate is solved.
The industrial personal computer is preset with a threshold value, compares the threshold value with the capacitance and the dielectric loss value after being reduced, and sends out an alarm signal when the capacitance or the dielectric loss value after being reduced exceeds the threshold value.
In some practical solutions, the step S2 includes:
a1: the leakage current sensor is connected with a current processing assembly, and the current processing assembly sequentially performs current amplification processing, filtering processing, square wave shaping processing and analog-to-digital conversion processing on the leakage current;
a2: the current processing assembly is connected with the microprocessor, and transmits the processed leakage current to the microprocessor.
In this embodiment, the current amplification process is used to protect a circuit; the filtering processing and the square wave shaping processing are used for filtering clutter; the analog-to-digital conversion process is used to convert the analog current signal into a digital signal.
In some practical solutions, the step S4 includes:
c1: the voltage transformer is connected with a voltage processing assembly, and the voltage processing assembly sequentially performs voltage amplification processing, filtering processing, square wave shaping processing and analog-to-digital conversion processing on the operating voltage;
c2: the voltage processing assembly is connected with the microprocessor and transmits the processed operating voltage to the microprocessor.
In this embodiment, the voltage amplification process is used to protect a circuit; the filtering processing and the square wave shaping processing are used for filtering clutter; the analog-to-digital conversion process is used to convert an analog voltage signal into a digital signal.
In some practical schemes, the step S5 of the method for online monitoring dielectric loss and capacitance of the high voltage bushing includes:
d1: the microprocessor performs discrete Fourier transform on the operating voltage, converts the voltage signal into the sum of fundamental wave component and each subharmonic component, and transmits the sum to the industrial personal computer;
d2: meanwhile, the microprocessor performs discrete Fourier transform on the leakage current, converts a current signal into a sum of a fundamental component and each subharmonic component, and transmits the sum to the industrial personal computer.
In some implementable schemes, the step S1, the step S3 and the step S7 are performed synchronously and in consistent time;
when the leakage current sensor collects the leakage current of the high-voltage bushing, the voltage transformer collects the operating voltage of the high-voltage bushing, and the collection time and the collection frequency of the leakage current sensor and the voltage transformer are consistent;
when the voltage transformer collects the operating voltage of the high-voltage bushing, the temperature measuring sensor collects the operating temperature of the high-voltage bushing, and the collecting time and the collecting frequency of the voltage transformer and the temperature measuring sensor are consistent.
In the scheme, when the leakage current sensor starts to collect leakage current of the high-voltage bushing, the voltage transformer starts to collect the operating voltage of the high-voltage bushing, the temperature measuring sensor starts to collect the operating temperature of the high-voltage bushing, the working time of the leakage current sensor, the working time of the voltage transformer and the working time of the temperature measuring sensor are consistent, signals are synchronously collected, and the working efficiency is improved.
In some practical solutions, the step S9 includes:
the industrial personal computer is provided with an alarm threshold value and is connected with an alarm device, and when the capacitance or the dielectric loss value after conversion exceeds the threshold value, the industrial personal computer controls the alarm device to send out an alarm signal.
In the scheme, the alarm device can be an LED flash lamp connected with an industrial personal computer, or a horn or other alarm devices arranged in an industrial personal computer system.
In some embodiments, the device for on-line monitoring dielectric loss and capacitance of a high voltage bushing comprises:
the leakage current sensor is arranged on the inner wall of the end screen of the high-voltage bushing;
a current processing component connected with the leakage current sensor;
the microprocessor is connected with the current processing assembly;
the voltage transformer is used for measuring the operating voltage of the high-voltage bushing;
the voltage processing assembly is used for connecting the voltage transformer with the microprocessor;
the temperature sensor is used for measuring the operating temperature of the high-voltage bushing;
the industrial computer, above-mentioned industrial computer is connected with microprocessor and temperature sensor respectively, and above-mentioned industrial computer is provided with the threshold value, and above-mentioned industrial computer is used for calculating high-voltage bushing's electric capacity and dielectric loss value according to the data of microprocessor and temperature sensor transmission, and above-mentioned electric capacity and dielectric loss value exceed the threshold value, and above-mentioned industrial computer sends alarm signal.
In the scheme, the leakage current sensor measures a leakage current signal of the high-voltage bushing and transmits the leakage current signal to the current processing assembly, the current processing assembly preprocesses the leakage current signal and transmits the leakage current signal to the microprocessor, the microprocessor performs discrete Fourier transform on the leakage current, converts the current signal into the sum of a fundamental component and each subharmonic component and transmits the sum to the industrial personal computer;
the voltage transformer measures the operating voltage of the high-voltage bushing and transmits the operating voltage to the voltage processing assembly, the voltage processing assembly preprocesses an operating voltage signal and transmits the operating voltage signal to the microprocessor, and the microprocessor performs discrete Fourier transform on the operating voltage, converts the voltage signal into the sum of fundamental wave components and each subharmonic component and transmits the sum to the industrial personal computer;
the temperature measuring sensor measures the operating temperature of the high-voltage sleeve and transmits the operating temperature to the industrial personal computer, the industrial personal computer calculates the dielectric loss value and the capacitance according to the sum of the fundamental component and each subharmonic component of the leakage current and the operating voltage, and calculates the dielectric loss value after conversion according to the operating temperature;
the industrial personal computer is provided with a threshold value, and when the capacitance or the dielectric loss value after conversion exceeds the threshold value, the industrial personal computer sends out an alarm signal.
In some embodiments, the device for on-line monitoring dielectric loss and capacitance of a high voltage bushing comprises:
a current amplifier for protecting a circuit, the current amplifier being connected to the leakage current sensor;
the filter is used for filtering clutter and is connected with the current amplifier;
the square wave shaping circuit is connected with the filter;
the analog-to-digital converter is electrically connected with the square wave shaping circuit and is used for converting the current signal into a digital signal; the analog-to-digital converter is connected with an industrial personal computer.
In some embodiments, the voltage processing assembly comprises:
the voltage amplifier is used for protecting a circuit and is connected with the voltage transformer;
the filter is used for filtering clutter and is connected with the voltage transformer;
the square wave shaping circuit is connected with the filter;
the analog-to-digital converter is electrically connected with the square wave shaping circuit and is used for converting the voltage signal into a digital signal; the analog-to-digital converter is connected with an industrial personal computer.
In some implementable schemes, the on-line monitoring device for dielectric loss and capacitance of the high-voltage bushing further comprises an alarm device, the alarm device is connected with an industrial personal computer, and the industrial personal computer is used for controlling the alarm device to send out an alarm signal when the capacitance or the dielectric loss value exceeds a threshold value.
In the scheme, a threshold value is preset in the industrial personal computer, the current standard dielectric loss value and capacitance of the high-voltage bushing are called in real time after the industrial personal computer is networked, and the threshold value is adjusted in real time according to the standard dielectric loss value and capacitance; and the industrial personal computer compares the threshold value with the capacitance and the dielectric loss value after the dielectric loss is reduced, and sends out an alarm signal when the capacitance or the dielectric loss value after the dielectric loss value is reduced exceeds the threshold value.
Compared with the prior art, the invention has the following advantages and beneficial effects:
the inner wall of the end screen of the high-voltage bushing is provided with a leakage current sensor which collects leakage current when the high-voltage bushing operates; the leakage current sensor is connected with a current processing assembly, the current processing assembly is used for preprocessing a current signal to enable the capacitance and dielectric loss value of the high-voltage bushing to be measured more accurately, the current processing assembly is connected with a microprocessor, and the microprocessor converts the leakage current into the sum of a fundamental component and each subharmonic component and transmits the sum to an industrial personal computer; the voltage transformer measures the operating voltage of the high-voltage bushing, the voltage transformer is connected with the voltage processing assembly, the voltage processing assembly is used for preprocessing a voltage signal to enable the capacitance and dielectric loss value of the high-voltage bushing to be measured more accurately, the voltage processing assembly is connected with the microprocessor, and the microprocessor converts the operating voltage of the high-voltage bushing into the sum of fundamental wave components and each subharmonic component and transmits the sum to the industrial personal computer; the industrial personal computer calculates dielectric loss value and electric capacity of the high-voltage bushing according to the sum of the leakage current and the fundamental component and each subharmonic component of the operating voltage; the temperature measuring sensor measures the operating temperature of the high-voltage bushing and transmits the operating temperature to the industrial personal computer, the temperature measuring sensor is utilized, the influence of the measured temperature is fully considered, the unified conversion of the temperature is carried out, the industrial personal computer obtains a converted dielectric loss value according to the dielectric loss value and the operating temperature, the industrial personal computer stores and displays the calculated dielectric loss value, and the capacitance and the dielectric loss value of the high-voltage bushing are indirectly measured through the unified conversion of the temperature, so that the capacitance and the dielectric loss value of the high-voltage bushing are accurately monitored.
The industrial personal computer compares the threshold value with the capacitance and the dielectric loss value after the dielectric loss is reduced, and when the capacitance or the dielectric loss value after the dielectric loss is reduced exceeds the threshold value, the industrial personal computer sends out an alarm signal to realize the purpose of early warning by monitoring the capacitance and the dielectric loss value of the high-voltage bushing in real time.
Drawings
In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the drawings that are required in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and that those skilled in the art may also derive other related drawings based on these drawings without inventive effort. In the drawings:
fig. 1 is a flowchart of an on-line monitoring method for dielectric loss and capacitance of a high-voltage bushing according to embodiment 1;
fig. 2 is a system configuration diagram of an on-line monitoring device for dielectric loss and capacitance of a high-voltage bushing provided in embodiment 1;
fig. 3 is a block diagram of measurement circuitry providing voltage and current processor components for example 1.
Reference numbers and corresponding part names in the figures:
the device comprises a leakage current sensor, a current processing component 2, a microprocessor 3, a voltage transformer 4, a voltage processing component 5, an industrial personal computer 6, a temperature measuring sensor 7 and an alarm device 8.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples and accompanying drawings, and the exemplary embodiments and descriptions thereof are only used for explaining the present invention and are not meant to limit the present invention.
Example 1
As shown in fig. 1 to fig. 3, embodiment 1 provides an online monitoring method for dielectric loss and capacitance of a high voltage bushing, and the online monitoring method for dielectric loss and capacitance of a high voltage bushing, where the method includes:
s1: the inner wall of the end screen of the high-voltage bushing is provided with a leakage current sensor 1, and the leakage current sensor 1 collects leakage current when the high-voltage bushing operates;
s2: the leakage current passes through the current processing assembly 2 and the microprocessor 3 in sequence;
s3: the voltage transformer 4 measures the operating voltage of the high-voltage bushing;
s4: the operating voltage passes through the voltage processing component 5 and the microprocessor 3 in sequence;
s5: the microprocessor 3 converts the operating voltage into the sum of the fundamental component and each harmonic component of the voltage signal, converts the leakage current into the sum of the fundamental component and each harmonic component of the current signal and transmits the sum to the industrial personal computer 6;
s6: the industrial personal computer 6 calculates dielectric loss value and electric capacity according to the sum of the leakage current and the fundamental component and each subharmonic component of the operating voltage;
s7: the temperature sensor 7 measures the operating temperature of the high-voltage bushing and transmits the operating temperature to the industrial personal computer 6;
s8: the industrial personal computer 6 obtains a converted dielectric loss value according to the dielectric loss value and the operating temperature;
s9: the industrial personal computer 6 is provided with a threshold value, and when the capacitance or the dielectric loss value after conversion exceeds the threshold value, the industrial personal computer 6 sends out an alarm signal.
In a specific embodiment, the high-voltage bushing is located on a transformer or a current transformer, a leakage current sensor 1 is arranged on the inner wall of a high-voltage bushing end screen, the leakage current sensor 1 collects leakage current generated when the high-voltage bushing operates, the leakage current sensor 1 is connected with a current processing assembly 2, and the current processing assembly 2 is used for preprocessing a current signal and comprises current amplification protection, filtering, square wave shaping and analog-to-digital conversion; the current processing assembly 2 is connected with the microprocessor 3, the microprocessor 3 performs discrete Fourier transform on leakage current, converts a current signal into a sum of a fundamental component and each subharmonic component, and transmits the sum to the industrial personal computer 6;
leakage current as measured by the leakage current sensor 1:
in the formula I 0 Is the direct current component of the current; i is km Is the amplitude of each harmonic of the current; beta is a k For each harmonic phase angle of the current (k =1,2, …, ∞);
the transformer substation is connected with the high-voltage bushing, the transformer substation is used for providing required operating voltage for the high-voltage bushing, the voltage transformer 4 measures the operating voltage of the high-voltage bushing through the transformer substation, the voltage transformer 4 is connected with the voltage processing assembly 5, the voltage processing assembly 5 is used for preprocessing voltage signals and comprises current amplification protection, filtering, square wave shaping and analog-to-digital conversion, the voltage processing assembly 5 is connected with the microprocessor 3, the microprocessor 3 performs discrete Fourier transform on the operating voltage of the high-voltage bushing, the voltage signals are converted into fundamental wave components and the sum of each subharmonic component and transmitted to the industrial personal computer 6;
operating voltage as measured by the voltage transformer 4:
in the formula of U 0 Is the direct current component of the voltage; u shape km Is the amplitude of each harmonic of the voltage; alpha (alpha) ("alpha") k For each harmonic phase angle of voltage (k =1,2, …, ∞);
the industrial personal computer 6 calculates and obtains the dielectric loss value and the capacitance of the high-voltage bushing according to the sum of the fundamental component and each harmonic component of the leakage current and the operating voltage, and displays the dielectric loss value and the capacitance;
according to
Wherein alpha is 1 、β 1 The fundamental wave phase angles of the operating voltage and the leakage current are respectively. Since the current flowing through the high-voltage bushing leads the voltage by 90 °, the dielectric loss value of the high-voltage bushing is:
and calculating to obtain: tan δ = tan [ arctan (C) 1 /C 0 )-arctan(D 1 /D 0 )]；
Capacitor with a capacitor element
(where ω =2 π f, f is 50 Hz);
the temperature sensor 7 is preferably a passive temperature sensor, the operating temperature of the high-voltage bushing is obtained and is transmitted to the industrial personal computer 6, and the measuring time of the temperature sensor 7 is consistent with the measuring time of the leakage current and the measuring time of the operating voltage;
the industrial personal computer 6 obtains the dielectric loss value of the high-voltage bushing at a certain temperature through conversion, and simultaneously displays the measured temperature and the converted bushing dielectric loss value on the system, such as converting the dielectric loss value of the high-voltage bushing at 20 ℃;
the conversion formula of the dielectric loss value is
Wherein, tan delta 1 、tanδ 2 Respectively at a temperature t 1 、t 2 Dielectric loss value of time;
the industrial personal computer 6 is preset with a threshold value, the current standard dielectric loss value and capacitance of the high-voltage bushing are called in real time after the industrial personal computer 6 is networked, and the threshold value is adjusted in real time according to the standard dielectric loss value and capacitance; the industrial personal computer 6 compares the threshold value with the capacitance and the dielectric loss value after the dielectric loss is reduced, and when the capacitance or the dielectric loss value after the dielectric loss is reduced exceeds the threshold value, the industrial personal computer 6 sends out an alarm signal.
Preferably, the difference between the capacitance after the high-voltage bushing works and the initial capacitance is not more than +/-5% according to the setting reference of the threshold value; the loss factor tan delta of the dielectric loss value meets the following requirements:
| U m (KV) | 126/72.5 | 252/363 | ≥550 |
| tanδ | ≤0.01 | ≤0.08 | ≤0.007 |
on-line monitoring device that high-tension bushing is situated between and is decreased and electric capacity includes:
the leakage current sensor 1, the above-mentioned leakage current sensor 1 is set up in the end screen inboard wall of the high-tension bushing;
a current processing module 2, the current processing module 2 being connected to the leakage current sensor 1;
a microprocessor 3, wherein the microprocessor 3 is connected with the current processing component 2;
the voltage transformer 4, the above-mentioned voltage transformer 4 is used for measuring the operating voltage of the high-tension bushing;
a voltage processing component 5, wherein the voltage transformer 4 is connected with the microprocessor 3 through the voltage processing component 5;
the temperature sensor 7, the above-mentioned temperature sensor 7 is used for measuring the operating temperature of the high-tension bushing;
In a specific embodiment, the leakage current sensor 1 measures a leakage current signal of the high-voltage bushing and transmits the leakage current signal to the current processing component 2, the current processing component 2 preprocesses the leakage current signal and transmits the leakage current signal to the microprocessor 3, the microprocessor 3 is an online monitoring terminal, the microprocessor 3 performs discrete fourier transform on the leakage current, converts the current signal into a sum of a fundamental component and each subharmonic component, and transmits the sum to the industrial personal computer 6;
the voltage transformer 4 measures the operating voltage of the high-voltage bushing and transmits the operating voltage to the voltage processing component 5, the voltage processing component 5 preprocesses an operating voltage signal and transmits the operating voltage signal to the microprocessor 3, the microprocessor 3 performs discrete Fourier transform on the operating voltage, converts the voltage signal into the sum of fundamental wave components and each subharmonic component and transmits the sum to the industrial personal computer 6;
the temperature measuring sensor 7 measures the operating temperature of the high-voltage bushing and transmits the operating temperature to the industrial personal computer 6, the industrial personal computer 6 calculates dielectric loss values and electric capacity according to the sum of fundamental wave components and each subharmonic component of leakage current and operating voltage, and calculates the converted dielectric loss values according to the operating temperature;
the industrial personal computer 6 is provided with a threshold value, and when the capacitance or the dielectric loss value after conversion exceeds the threshold value, the industrial personal computer 6 sends out an alarm signal.
The method and the system for monitoring the dielectric loss and the capacitance of the high-voltage bushing on line comprehensively improve the accuracy of the online monitoring and measuring of the insulation state of the bushing under the complex operating condition, and improve the accuracy and the stability of the dielectric loss measuring by one order of magnitude compared with the existing standard, as shown in the following table:
the above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only illustrative of the present invention and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (10)
1. The method for monitoring dielectric loss and capacitance of the high-voltage bushing on line is characterized by comprising the following steps:
s1: the inner wall of the end screen of the high-voltage bushing is provided with a leakage current sensor (1), and the leakage current sensor (1) collects leakage current generated when the high-voltage bushing operates;
s2: the leakage current passes through the current processing assembly (2) and the microprocessor (3) in sequence;
s3: the voltage transformer (4) measures the operating voltage of the high-voltage bushing;
s4: the operating voltage sequentially passes through the voltage processing assembly (5) and the microprocessor (3);
s5: the microprocessor (3) converts the operating voltage into the sum of the fundamental component and each subharmonic component of the voltage signal, converts the leakage current into the sum of the fundamental component and each subharmonic component of the current signal and transmits the sum to the industrial personal computer (6);
s6: the industrial personal computer (6) calculates the dielectric loss value and the capacitance according to the leakage current, the fundamental component of the operating voltage and the sum of the harmonic components;
s7: the temperature measuring sensor (7) measures the operating temperature of the high-voltage bushing and transmits the operating temperature to the industrial personal computer (6);
s8: the industrial personal computer (6) obtains a converted dielectric loss value according to the dielectric loss value and the operating temperature;
s9: the industrial personal computer (6) is provided with a threshold value, and when the dielectric loss value after capacitance or conversion exceeds the threshold value, the industrial personal computer (6) sends out an alarm signal.
2. The method according to claim 1, wherein the step S2 comprises:
a1: the leakage current sensor (1) is connected with the current processing component (2), and the current processing component (2) sequentially performs current amplification processing, filtering processing, square wave shaping processing and analog-to-digital conversion processing on leakage current;
a2: the current processing assembly (2) is connected with the microprocessor (3), and the processed leakage current is transmitted to the microprocessor (3) by the current processing assembly (2).
3. The method according to claim 2, wherein the step S4 comprises:
c1: the voltage transformer (4) is connected with a voltage processing component (5), and the voltage processing component (5) sequentially performs voltage amplification processing, filtering processing, square wave shaping processing and analog-to-digital conversion processing on the operating voltage;
c2: the voltage processing assembly (5) is connected with the microprocessor (3), and the voltage processing assembly (5) transmits the processed operating voltage to the microprocessor (3).
4. The on-line monitoring method for dielectric loss and capacitance of a high voltage bushing as claimed in claim 3, wherein step S5 comprises:
d1: the microprocessor (3) performs discrete Fourier transform on the operating voltage, converts a voltage signal into a sum of a fundamental component and each subharmonic component, and transmits the sum to the industrial personal computer (6);
d2: meanwhile, the microprocessor (3) carries out discrete Fourier transform on the leakage current, converts a current signal into a sum of a fundamental component and each subharmonic component, and transmits the sum to the industrial personal computer (6).
5. The method according to claim 1, wherein the steps S1, S3 and S7 are performed synchronously and in time;
when the leakage current sensor (1) collects leakage current of a high-voltage bushing, the voltage transformer (4) collects operating voltage of the high-voltage bushing, and the collection time and frequency of the leakage current sensor (1) and the voltage transformer (4) are consistent;
when the voltage transformer (4) collects the operating voltage of the high-voltage bushing, the temperature measuring sensor (7) collects the operating temperature of the high-voltage bushing, and the collecting time and the collecting frequency of the voltage transformer (4) and the temperature measuring sensor (7) are consistent.
6. The method according to claim 1, wherein the step S9 comprises:
industrial computer (6) are provided with the threshold value, just industrial computer is connected with alarm device (8), and dielectric loss value after electric capacity or the conversion surpasss the threshold value, industrial computer (6) control alarm device (8) send alarm signal.
7. An on-line monitoring device for dielectric loss and capacitance of a high voltage bushing based on the method of any one of claims 1 to 6, comprising:
the leakage current sensor (1), the leakage current sensor (1) is arranged on the inner wall of the high-voltage bushing end screen;
a current handling assembly (2), the current handling assembly (2) being connected to a leakage current sensor (1);
the microprocessor (3), the said microprocessor (3) is connected with current processing assembly (2);
a voltage transformer (4), the voltage transformer (4) being for measuring an operating voltage of a high voltage bushing;
the voltage processing assembly (5), the voltage transformer (4) is connected with the microprocessor (3) through the voltage processing assembly (5);
the temperature sensor (7), the said temperature sensor (7) is used for measuring the operating temperature of the high-tension bushing;
industrial computer (6), industrial computer (6) are connected with microprocessor (3) and temperature sensor (7) respectively, just industrial computer (6) are provided with the threshold value, industrial computer (6) are used for calculating high-voltage bushing's electric capacity and dielectric loss value according to the data of microprocessor (3) and temperature sensor (7) transmission, the electric capacity with dielectric loss value surpass the threshold value, industrial computer (6) send alarm signal.
8. The on-line monitoring device for dielectric losses and capacitances of a high voltage bushing as claimed in claim 7, wherein said current handling assembly (2) comprises:
a current amplifier for protecting the circuit, said current amplifier being connected to the leakage current sensor (1);
the filter is used for filtering clutter and is connected with the current amplifier;
the square wave shaping circuit is connected with the filter;
the analog-to-digital converter is electrically connected with the square wave shaping circuit and is used for converting the current signal into a digital signal; the analog-to-digital converter is connected with an industrial personal computer (6).
9. The on-line monitoring device for dielectric losses and capacitances of a high voltage bushing as claimed in claim 8, wherein said voltage processing assembly (5) comprises:
the voltage amplifier is used for protecting the circuit and is connected with the voltage transformer (4);
the filter is used for filtering clutter and is connected with the voltage transformer (4);
the square wave shaping circuit is connected with the filter;
the analog-to-digital converter is electrically connected with the square wave shaping circuit and is used for converting the voltage signal into a digital signal; the analog-to-digital converter is connected with an industrial personal computer (6).
10. The device for on-line monitoring of dielectric loss and capacitance of a high voltage bushing according to claim 7, further comprising an alarm device (8), wherein the alarm device (8) is connected to the industrial personal computer (6), and the industrial personal computer (6) is configured to control the alarm device (8) to send out an alarm signal when the capacitance or dielectric loss value exceeds a threshold value.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202211226823.7A CN115542018A (en) | 2022-10-09 | 2022-10-09 | On-line monitoring method and device for dielectric loss and capacitance of high-voltage bushing |
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| CN202211226823.7A CN115542018A (en) | 2022-10-09 | 2022-10-09 | On-line monitoring method and device for dielectric loss and capacitance of high-voltage bushing |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116819219A (en) * | 2023-08-31 | 2023-09-29 | 山东思极科技有限公司 | Online monitoring device for service life of capacitor |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116819219A (en) * | 2023-08-31 | 2023-09-29 | 山东思极科技有限公司 | Online monitoring device for service life of capacitor |
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