Transformer bushing monitoring system and method

Abstract

The invention provides a transformer bushing monitoring system and method, and the method comprises the steps: enabling a partial discharge signal filtering unit to be disposed on a connection line between a bushing sensor and a transformer bushing in the anti-interference process of a partial discharge signal, and carrying out the limiting of a frequency band of a signal collected by the bushing sensor, and filtering out the partial discharge signal of an overhead line; collecting an external grounding signal and a bushing partial discharge channel signal, comparing the external grounding signal with the bushing partial discharge channel signal, and filtering the same type of data; the monitoring main body compares the received grounding signal with the partial discharge signal and eliminates an interference signal in the partial discharge signal; and meanwhile, phase information is obtained based on the voltage tap signal, and an interference signal in the partial discharge signal is further eliminated according to the phase information.

Description

Technical Field

[0001] The present application belongs to the technical field of transformer monitoring, and in particular, to a transformer bushing monitoring system and method. Background Art

[0002] The current monitoring method for bushing partial discharge mainly adopts the high-frequency current method. The main monitoring frequency band of this method is 1MHz-30MHz. When applied to bushing monitoring, since the bushing is generally connected to the overhead line, there is a great problem of external partial discharge interference when performing partial discharge monitoring in a wide frequency band, which affects the actual monitoring of partial discharge inside the bushing and greatly affects the accuracy.

[0003] The existing transformer bushing partial discharge monitoring method uses a wide-band sensor, which is not conducive to on-site monitoring and cannot completely eliminate external discharge, affecting the monitoring and determination of partial discharge inside the bushing. In addition, the current bushing dielectric loss monitoring projection method usually takes the power supply voltage or one-phase PT voltage as a reference signal. If the voltage is unstable or has other problems, the test data will be inaccurate, affecting the determination of the results. Summary of the invention

[0004] In view of this, the main purpose of the present application is to provide a transformer bushing monitoring system and method.

[0005] As one aspect of the present application, the technical solution adopted in the present application is as follows: a transformer bushing monitoring system, comprising at least a bushing partial discharge monitoring device, wherein the bushing partial discharge monitoring device comprises a monitoring body, and a bushing sensor, a voltage tap acquisition unit and a current mutual inductance unit respectively connected to the monitoring body;

[0006] The bushing sensor is connected to the transformer bushing and is used to collect partial discharge signals of the transformer bushing;

[0007] A partial discharge signal filtering unit is provided on the connection line between the bushing sensor and the transformer bushing, which is used to limit the frequency band of the signal collected by the bushing sensor and filter out the partial discharge signal of the overhead line;

[0008] The voltage tap acquisition unit is used to acquire the voltage tap signal of the transformer bushing;

[0009] The current mutual inductance unit is connected to the transformer and grounded, and is used to obtain a grounding signal;

[0010] The monitoring subject eliminates interference signals in the partial discharge signal by comparing the received grounding signal with the partial discharge signal; and simultaneously obtains phase information based on the voltage tap signal, and further eliminates interference signals in the partial discharge signal according to the phase information.

[0011] As one aspect of the present application, further, the partial discharge signal filtering unit includes an inductor unit and a bandpass filtering circuit connected to the inductor;

[0012] The inductance unit is mounted on the transformer bushing sensor;

[0013] The bandpass filter circuit is connected to the bushing sensor, and is used to limit the frequency band of the input partial discharge signal within a set range, thereby filtering out the overhead line partial discharge signal and obtaining an effective bushing partial discharge signal.

[0014] As one aspect of the present application, further, the bandpass filter circuit is arranged in parallel with the inductance unit, and the bandpass filter circuit includes at least two LC parallel circuits arranged in parallel; a second capacitor and a fourth capacitor connected in series are arranged on the connecting line of the two LC parallel circuits; and a resistor is arranged on the connecting line between the LC parallel circuit and the inductance unit.

[0015] As one aspect of the present application, further, the voltage tap acquisition unit includes a transformer bushing capacitor core lead-out terminal, and the lead-out terminal is equipped with a voltage divider unit for dividing the output voltage of the transformer bushing tap to obtain a voltage tap signal.

[0016] As an aspect of the present application, further, the phase distribution of the voltage tap signal is consistent with the phase distribution of the partial discharge signal.

[0017] As an aspect of the present application, further, the monitoring system also includes a casing dielectric loss monitoring unit;

[0018] The bushing dielectric loss monitoring unit comprises a processor, and a bushing current monitoring unit, a bushing voltage monitoring unit and a temperature monitoring unit respectively connected to the processor;

[0019] The bushing current monitoring unit is used for collecting current data at the bushing;

[0020] The bushing voltage monitoring unit is used for collecting voltage data at the bushing;

[0021] The temperature monitoring unit is used to collect the ambient temperature of the casing;

[0022] The processor receives the current data collected by the bushing current monitoring unit, the voltage data collected by the bushing voltage monitoring unit, and the ambient temperature data of the bushing monitored by the temperature monitoring unit, and determines the bushing dielectric loss according to the received data.

[0023] As another aspect of the present application, the technical solution adopted in the present application is as follows: a transformer bushing monitoring method, the method comprising at least the following steps:

[0024] Collect partial discharge signals of transformer bushings, voltage tap signals and transformer grounding signals;

[0025] Before collecting the partial discharge signal, filtering the collected signal to filter out the overhead line partial discharge signal;

[0026] Comparing the partial discharge signal with the ground signal, and eliminating interference signals in the partial discharge signal;

[0027] Corresponding phase information is acquired based on the voltage tap signal, and interference signals in the partial discharge signal are further eliminated based on the phase information to obtain the bushing partial discharge monitoring result.

[0028] As another aspect of the present application, further, the filtering processing method is: before collecting the partial discharge signal, an induced electromotive force is formed by inductance at the collection end to form an initial signal, and the initial signal is filtered through a bandpass filter, so that the signal to be collected is configured within a frequency band with a center frequency of 5MHz and a bandwidth of 2Mhz, so as to eliminate the partial discharge signal of the overhead line

[0029] As another aspect of the present application, further, comparing the partial discharge signal with the ground signal to remove the interference signal in the partial discharge signal includes the following steps:

[0030] The bushing sensor collects the partial discharge signal of the transformer bushing, and the current mutual inductance unit obtains the grounding signal. Both the partial discharge signal and the grounding signal contain the spectrum data of the pulse signal, the amplitude comparison data of the pulse signal, and the period distribution data of the pulse signal.

[0031] The spectrum data of the two signals are compared, and the data with the same spectrum distribution are eliminated through a bandpass filter; according to the transmission attenuation characteristics of the pulse signal, the spectrum of the grounding signal is analyzed, and the data with the same spectrum distribution of the partial discharge signal is eliminated through a bandpass filter;

[0032] The same category of signals of periodic distribution data in the two signals are phase-windowed, and the signals at fixed phase positions are filtered out by a bandpass filter.

[0033] As another aspect of the present application, further, corresponding phase information is obtained based on the voltage tap signal, and interference signals in the partial discharge signal are further eliminated based on the phase information, including: dividing the output voltage of the transformer bushing tap by a voltage divider unit to obtain a voltage tap signal; the voltage division requirement is: the voltage of the voltage tap signal is adapted to the phase voltage on the high-voltage side of the transformer, so that the phase distribution of the voltage tap signal is consistent with the phase distribution of the partial discharge signal, comparing the spectrum data of the two signals, and eliminating the data with consistent spectrum distribution through a bandpass filter;

[0034] Preferably, the method further comprises monitoring the dielectric loss of the casing, including:

[0035] The bushing current monitoring unit collects current data at the bushing;

[0036] The bushing voltage monitoring unit collects voltage data at the bushing;

[0037] The temperature monitoring unit collects the ambient temperature of the casing;

[0038] The processor receives the current data collected by the bushing current monitoring unit, the voltage data collected by the bushing voltage monitoring unit, and the ambient temperature data of the bushing monitored by the temperature monitoring unit; the processor calculates by a formula, and the calculation formula is:

[0039] V(t)=Vm*e iωt ;

[0040] Where: Vm is the peak voltage; ω is the angular frequency; e is a natural constant; i is an imaginary number; t is time;

[0041] The voltage, current and power factor are calculated to obtain the angular relationship between the phase voltages. The bushing dielectric loss is monitored based on the relationship between the phase dielectric loss and the angular deviation.

[0042] Compared with the prior art, the present application has the following beneficial effects: in the anti-interference process of the partial discharge signal, the partial discharge signal filtering unit is arranged on the connecting line between the bushing sensor and the transformer bushing, so as to limit the frequency band of the signal collected by the bushing sensor and filter out the partial discharge signal of the overhead line; the external grounding signal and the bushing partial discharge channel signal are collected, and the external grounding signal is compared with the bushing partial discharge channel signal to filter out the data of the same category; the monitoring subject eliminates the interference signal in the partial discharge signal by comparing the received grounding signal with the partial discharge signal; and at the same time, the phase information is obtained based on the voltage tap signal, and the interference signal in the partial discharge signal is further eliminated according to the phase information. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The following drawings are only used to illustrate and explain the present application, and are not used to limit the scope of the present application, wherein:

[0044] Figure 1 This is the schematic diagram of phase A for comprehensive casing monitoring in this application;

[0045] Figure 2 It is the process of removing the casing partial discharge signal in this application;

[0046] Figure 3 Partial discharge anti-interference circuit diagram of the sensor unit for this application;

[0047] Figure 4 This is the connection diagram of the dielectric loss hardware system in this application. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solution, design method and advantages of this application more clear, the following is a further detailed description of this application through specific embodiments in conjunction with the accompanying drawings. It should be understood that the specific embodiments described here are only used to explain this application and are not used to limit this application.

[0049] Reference Figure 1-Figure 3 , the present application provides a transformer bushing monitoring system, comprising at least a bushing partial discharge monitoring device, the bushing partial discharge monitoring device comprising a monitoring body, and a bushing sensor, a voltage tap acquisition unit and a current mutual induction unit respectively connected to the monitoring body;

[0050] The bushing sensor is connected to the transformer bushing and is used to collect partial discharge signals of the transformer bushing;

[0051] A partial discharge signal filtering unit is provided on the connection line between the bushing sensor and the transformer bushing, which is used to limit the frequency band of the signal collected by the bushing sensor and filter out the partial discharge signal of the overhead line;

[0052] The voltage tap acquisition unit is used to acquire the voltage tap signal of the transformer bushing;

[0053] The current mutual inductance unit is connected to the transformer and grounded, and is used to obtain a grounding signal;

[0054] The monitoring subject eliminates interference signals in the partial discharge signal by comparing the received grounding signal with the partial discharge signal; and simultaneously obtains phase information based on the voltage tap signal, and further eliminates interference signals in the partial discharge signal according to the phase information.

[0055] Figure 1Among them, 1 is the bushing voltage tap terminal; 2 is the current transformer terminal; 3 is the partial discharge channel; 4 is the anti-interference channel. The model of the bushing partial discharge monitoring device is BYPD-6000, the filtering unit is Butterworth filter, and the bushing sensor model is BY-CT-100.

[0056] In the above, reference Figure 1-Figure 3 As shown, the partial discharge signal filtering unit includes an inductor unit and a bandpass filtering circuit connected to the inductor;

[0057] The inductance unit is mounted on the transformer bushing sensor;

[0058] The bandpass filter circuit is connected to the bushing sensor, and is used to limit the frequency band of the input partial discharge signal within a set range, thereby filtering out the overhead line partial discharge signal and obtaining an effective bushing partial discharge signal.

[0059] In the above, reference Figure 1-Figure 3 As shown, the bandpass filter circuit is arranged in parallel with the inductance unit, and the bandpass filter circuit includes at least two LC parallel circuits arranged in parallel, and a second capacitor and a fourth capacitor connected in series are arranged on the connecting line of the two LC parallel circuits; a resistor is arranged on the connecting line between the LC parallel circuit and the inductance unit.

[0060] Among them, the second inductor L2 is connected in parallel with the first capacitor C1; the third inductor L3 is connected in parallel with the third capacitor C3; the inductor unit is connected in parallel with the second inductor L2, and a resistor R1 is provided on the connection line between the first inductor L1 and the second inductor L2; the two ends of the first capacitor C1 are connected to the two ends of the third inductor L3; the fourth inductor L4 is connected in series with the second capacitor C2, the output end of the second capacitor C2 is connected to the output end of the first capacitor C1, and the output end of the fourth inductor L4 is connected to the input end of the third inductor L3. .

[0061] In the above steps, the specific process is as follows: first, the high-frequency CT channel and the casing partial discharge monitoring channel simultaneously collect signals, and the collection time is not less than 1s. The data of the two monitoring partial discharge monitoring channels contain the spectrum data, amplitude comparison data, and period distribution data of the pulse signal, wherein each period is 20ms for data storage; the spectrum data is compared, and the data with consistent spectrum distribution is eliminated, and this process is achieved by setting a digital filter; the amplitude comparison is mainly based on the transmission attenuation characteristics of the signal, and the large pulse signal of the high-frequency CT is subjected to spectrum analysis, and then the filter setting conditions are provided for the casing partial discharge acquisition channel; when comparing the period distribution data, the same category of signals are phase windowed, and the signals at fixed phase positions are filtered out, and secondary anti-interference is performed through three-part data analysis.

[0062] In the above, reference Figure 1-Figure 3 As shown, the voltage tap acquisition unit includes a transformer bushing capacitor core lead-out terminal, and the lead-out terminal is equipped with a voltage divider unit for dividing the output voltage of the transformer bushing tap to obtain a voltage tap signal; the phase distribution of the voltage tap signal is consistent with the phase distribution of the partial discharge signal.

[0063] As an implementation method of this application, refer to Figure 4 As shown, the monitoring system further includes a casing dielectric loss monitoring unit;

[0064] The bushing dielectric loss monitoring unit comprises a processor, and a bushing current monitoring unit, a bushing voltage monitoring unit and a temperature monitoring unit respectively connected to the processor;

[0065] The bushing current monitoring unit is used for collecting current data at the bushing;

[0066] The bushing voltage monitoring unit is used for collecting voltage data at the bushing;

[0067] The temperature monitoring unit is used to collect the ambient temperature of the casing;

[0068] The processor receives the current data collected by the bushing current monitoring unit, the voltage data collected by the bushing voltage monitoring unit, and the ambient temperature data of the bushing monitored by the temperature monitoring unit.

[0069] In the above, corresponding phase information is obtained based on the voltage tap signal, and interference signals in the partial discharge signal are further eliminated based on the phase information, including: dividing the output voltage of the transformer bushing tap by a voltage divider unit, and filtering out interference signals through a phase deviation relationship.

[0070] In the above steps, the system directly extracts phase information through the voltage tap. The voltage tap is a terminal directly led out through the capacitor core. The output voltage is generally designed to be around 115V. The voltage is divided to 3V through capacitor voltage division, which is convenient for the acquisition board to directly collect. The bushing partial discharge mainly comes from the effect of voltage. Therefore, the divided 3V voltage is consistent with the high voltage phase, and the phase of the partial discharge is consistent with the 3V voltage division phase. The zero deviation phase can be obtained through traditional monitoring methods; the phase accuracy can be compared with the external partial discharge spectrum and the bushing spectrum with the spectrum information, that is, the interference signal is filtered out through the phase deviation relationship. According to the bushing partial discharge phase distribution, it is consistent with the 3V voltage phase, which generally occurs near the voltage rise peak. For signals of other phases, they can be filtered out according to this relationship to prevent false alarms.

[0071] The method further includes monitoring the dielectric loss of the casing, including:

[0072] The bushing current monitoring unit collects current data at the bushing;

[0073] The bushing voltage monitoring unit collects voltage data at the bushing;

[0074] The temperature monitoring unit collects the ambient temperature of the casing;

[0075] The processor receives the current data collected by the bushing current monitoring unit, the voltage data collected by the bushing voltage monitoring unit, and the ambient temperature data of the bushing monitored by the temperature monitoring unit; the processor calculates by a formula, and the calculation formula is:

[0076] V(t)=Vm*e iωt ;

[0077] Where: Vm is the peak voltage; ω is the angular frequency; e is a natural constant; i is an imaginary number; t is time;

[0078] The voltage, current and power factor are calculated to obtain the angular relationship between the phase voltages. The bushing dielectric loss is monitored based on the relationship between the phase dielectric loss and the angular deviation.

[0079] In the above, the monitoring signal of the first channel includes the A phase current and the A phase voltage, the monitoring signal of the second channel includes the B phase current and the B phase voltage, and the monitoring signal of the third channel includes the C phase current and the C phase voltage. Each channel is connected to an electric energy metering chip, the model of which is HLW8112. At the same time, a temperature sensor is connected to the heel of the MCU chip, and the model of the temperature sensor is 18B20.

[0080] In the above, the current and voltage data are collected through the HLW8112 chip. After the collection is completed, the data is calculated and measured through the MCU chip. The ambient temperature is measured during the data collection process to achieve temperature supplementary calibration. After the MCU chip processes the data of the three channels, the information is exchanged with the server through the communication module MAX485, and the server performs data analysis and display.

[0081] As another aspect of this application, reference Figure 1-Figure 3 As shown, a transformer bushing monitoring method comprises at least the following steps:

[0082] Collect partial discharge signals of transformer bushings, voltage tap signals and transformer grounding signals;

[0083] Before collecting the partial discharge signal, filtering the collected signal to filter out the overhead line partial discharge signal;

[0084] Comparing the partial discharge signal with the ground signal, and eliminating interference signals in the partial discharge signal;

[0085] Corresponding phase information is acquired based on the voltage tap signal, and interference signals in the partial discharge signal are further eliminated based on the phase information to obtain the bushing partial discharge monitoring result.

[0086] In the above, the filtering processing method is: before collecting the partial discharge signal, an induced electromotive force is formed by inductance at the collection end to form an initial signal, and the initial signal is filtered through a bandpass filter, so that the signal to be collected is configured within a frequency band with a center frequency of 5MHz and a bandwidth of 2Mhz, so as to eliminate the partial discharge signal of the overhead line;

[0087] Comparing the partial discharge signal with the ground signal to remove interference signals from the partial discharge signal comprises the following steps:

[0088] The bushing sensor collects the partial discharge signal of the transformer bushing, and the current mutual inductance unit obtains the grounding signal. Both the partial discharge signal and the grounding signal contain the spectrum data of the pulse signal, the amplitude comparison data of the pulse signal, and the period distribution data of the pulse signal.

[0089] The spectrum data of the two signals are compared, and the data with the same spectrum distribution are eliminated through a bandpass filter; according to the transmission attenuation characteristics of the pulse signal, the spectrum of the grounding signal is analyzed, and the data with the same spectrum distribution of the partial discharge signal is eliminated through a bandpass filter;

[0090] The same category of signals of periodic distribution data in the two signals are phase-windowed, and the signals at fixed phase positions are filtered out by a bandpass filter.

[0091] In the above, in the anti-interference process of the partial discharge signal, the filter unit is set at the front end of the sensor unit to eliminate the partial discharge signal of the overhead line, so as to realize the first-level anti-interference of the partial discharge signal; the external grounding signal and the bushing partial discharge channel signal are collected, and the external grounding signal is compared with the bushing partial discharge channel signal to filter out the data of the same category, so as to realize the second-level anti-interference of the partial discharge signal; the phase information extraction unit is used to extract the phase information at the bushing, and realize the third-level anti-interference of the partial discharge signal through the phase deviation, and eliminate the interference of the external partial discharge through the external grounding partial discharge monitoring method, so as to realize the monitoring of the partial discharge inside the bushing.

[0092] The embodiments of the present application have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. Transformer bushing monitoring system, characterized in that: At least comprises a bushing partial discharge monitoring device, the bushing partial discharge monitoring device comprises a monitoring body, and a bushing sensor, a voltage tap acquisition unit and a current mutual inductance unit respectively connected to the monitoring body; The bushing sensor is connected to the transformer bushing and is used to collect partial discharge signals of the transformer bushing; A partial discharge signal filtering unit is provided on the connection line between the bushing sensor and the transformer bushing, which is used to limit the frequency band of the signal collected by the bushing sensor and filter out the partial discharge signal of the overhead line; The voltage tap acquisition unit is used to acquire the voltage tap signal of the transformer bushing; The current mutual inductance unit is connected to the transformer and grounded, and is used to obtain a grounding signal; The monitoring subject eliminates interference signals in the partial discharge signal by comparing the received grounding signal with the partial discharge signal; and simultaneously obtains phase information based on the voltage tap signal, and further eliminates interference signals in the partial discharge signal according to the phase information.

2. The transformer bushing partial discharge system according to claim 1, characterized in that: The partial discharge signal filtering unit comprises an inductor unit and a bandpass filtering circuit connected to the inductor; The inductance unit is mounted on the transformer bushing sensor; The bandpass filter circuit is connected to the bushing sensor, and is used to limit the frequency band of the input partial discharge signal within a set range, thereby filtering out the overhead line partial discharge signal and obtaining an effective bushing partial discharge signal.

3. The transformer bushing partial discharge system according to claim 2, characterized in that: The bandpass filter circuit is arranged in parallel with the inductor unit, and the bandpass filter circuit includes at least two LC parallel circuits arranged in parallel; a second capacitor and a fourth capacitor connected in series are arranged on the connecting line of the two LC parallel circuits; a resistor is arranged on the connecting line between the LC parallel circuit and the inductor unit.

4. The transformer bushing partial discharge system according to claim 1, characterized in that: The voltage tap acquisition unit comprises a transformer bushing capacitor core lead-out terminal, and a voltage dividing unit is installed on the lead-out terminal for dividing the output voltage of the transformer bushing tap to obtain a voltage tap signal.

5. The transformer bushing partial discharge system according to claim 1, characterized in that: The phase distribution of the voltage tap signal is consistent with the phase distribution of the partial discharge signal.

6. The transformer bushing partial discharge system according to claim 1, characterized in that: The monitoring system also includes a casing dielectric loss monitoring unit; The bushing dielectric loss monitoring unit comprises a processor, and a bushing current monitoring unit, a bushing voltage monitoring unit and a temperature monitoring unit respectively connected to the processor; The bushing current monitoring unit is used for collecting current data at the bushing; The bushing voltage monitoring unit is used for collecting voltage data at the bushing; The temperature monitoring unit is used to collect the ambient temperature of the casing; The processor receives the current data collected by the bushing current monitoring unit, the voltage data collected by the bushing voltage monitoring unit, and the ambient temperature data of the bushing monitored by the temperature monitoring unit, and determines the bushing dielectric loss according to the received data.

7. A transformer bushing monitoring method, characterized in that: The method comprises at least the following steps: Collect partial discharge signals of transformer bushings, voltage tap signals and transformer grounding signals; Before collecting the partial discharge signal, filtering the collected signal to filter out the overhead line partial discharge signal; Comparing the partial discharge signal with the ground signal, and eliminating interference signals in the partial discharge signal; Corresponding phase information is acquired based on the voltage tap signal, and interference signals in the partial discharge signal are further eliminated based on the phase information to obtain the bushing partial discharge monitoring result.

8. The transformer bushing monitoring method according to claim 7, characterized in that: The filtering processing method is as follows: before collecting the partial discharge signal, an induced electromotive force is formed by inductance at the collection end to form an initial signal, and the initial signal is filtered through a bandpass filter, so that the signal to be collected is configured within a frequency band with a center frequency of 5MHz and a bandwidth of 2Mhz, thereby eliminating the partial discharge signal of the overhead line.

9. The transformer bushing monitoring method according to claim 7, characterized in that: Comparing the partial discharge signal with the ground signal to remove interference signals from the partial discharge signal comprises the following steps: The bushing sensor collects the partial discharge signal of the transformer bushing, and the current mutual inductance unit obtains the grounding signal. Both the partial discharge signal and the grounding signal contain the spectrum data of the pulse signal, the amplitude comparison data of the pulse signal, and the period distribution data of the pulse signal. The spectrum data of the two signals are compared, and the data with the same spectrum distribution are eliminated through a bandpass filter; according to the transmission attenuation characteristics of the pulse signal, the spectrum of the grounding signal is analyzed, and the data with the same spectrum distribution of the partial discharge signal is eliminated through a bandpass filter; The same category of signals of periodic distribution data in the two signals are phase-windowed, and the signals at fixed phase positions are filtered out by a bandpass filter.

10. The transformer bushing monitoring method according to claim 7, characterized in that: Acquiring corresponding phase information based on the voltage tap signal, and further eliminating interference signals in the partial discharge signal based on the phase information, including: dividing the output voltage of the transformer bushing tap by a voltage dividing unit to obtain a voltage tap signal; the voltage division requirement is: the voltage of the voltage tap signal is adapted to the phase voltage on the high-voltage side of the transformer, so that the phase distribution of the voltage tap signal is consistent with the phase distribution of the partial discharge signal, comparing the frequency spectrum data of the two signals, and eliminating the data with consistent frequency spectrum distribution by a bandpass filter; Preferably, the method further comprises monitoring the dielectric loss of the casing, including: The bushing current monitoring unit collects current data at the bushing; The bushing voltage monitoring unit collects voltage data at the bushing; The temperature monitoring unit collects the ambient temperature of the casing; The processor receives the current data collected by the bushing current monitoring unit, the voltage data collected by the bushing voltage monitoring unit, and the ambient temperature data of the bushing monitored by the temperature monitoring unit; the processor calculates by a formula, and the calculation formula is: V(t)=Vm*e ιωτ ; Where: Vm is the peak voltage; ω is the angular frequency; e is a natural constant; i is an imaginary number; t is time; The voltage, current and power factor are calculated to obtain the angular relationship between the phase voltages. The bushing dielectric loss is monitored based on the relationship between the phase dielectric loss and the angular deviation.

Images