CN117110815A - Partial discharge detection system, method, equipment and medium for power equipment - Google Patents
Partial discharge detection system, method, equipment and medium for power equipment Download PDFInfo
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Abstract
The application discloses a system, a method, equipment and a medium for detecting partial discharge of power equipment, and relates to the technical field of power equipment detection. The pulse current detection method and the ultrahigh frequency detection method are integrated by adopting an electric detection method, the high frequency pulse current and the ultrahigh frequency electromagnetic wave signals generated by partial discharge are respectively received by the partial discharge pulse current detection device and the ultrahigh frequency sensor device, the partial discharge capacity is detected by the signal processing module based on the pulse current corresponding to the ultrahigh frequency electromagnetic wave signals, then fault position location is carried out by the partial discharge positioning module based on the partial discharge capacity and the ultrahigh frequency electromagnetic waves, and target partial discharge data corresponding to the power equipment is generated. The ultrahigh frequency detection method and the pulse current method can be combined to determine the discharge capacity and accurately position the fault occurrence position of the equipment.
Description
Technical Field
The application relates to the technical field of power equipment detection, in particular to a power equipment partial discharge detection system, a method, equipment and a medium.
Background
Whether the power equipment can safely and reliably operate in the power system determines the stable operation of the power system. When the insulation defect occurs in the operation process of the power equipment, partial discharge can occur first, the long-term partial discharge can expand the insulation defect range, and the insulation breakdown of the power equipment can be caused when the insulation defect is serious, so that the potential safety hazard is great. Therefore, research on the local discharge detection technology of the electrified equipment is necessary to be carried out, equipment health degree identification and judgment are carried out under the uninterrupted power supply state, the working efficiency of equipment pre-test and production operation and maintenance is improved, and the operation safety and the power supply reliability of the equipment and the power grid are further improved.
At present, an ultra-high frequency detection method and an ultrasonic detection method are commonly used for detecting partial discharge of power equipment. Although both the ultra-high frequency detection method and the ultrasonic detection method can perform the charged detection, the ultrasonic detection method has low accuracy, and the ultra-high frequency detection method cannot accurately measure the discharge amount. Therefore, the existing partial discharge detection method has low detection precision and can not accurately position the fault occurrence position of the equipment.
Disclosure of Invention
The application provides a system, a method, equipment and a medium for detecting partial discharge of power equipment, which solve the technical problems that the existing method for detecting partial discharge is low in detection precision and cannot accurately locate the fault occurrence position of the equipment.
The application provides a partial discharge detection system of power equipment, which comprises: the device comprises a partial discharge pulse current detection device, an ultrahigh frequency sensor device, a signal processing module and a partial discharge positioning module;
the partial discharge pulse current detection device is used for acquiring high-frequency pulse current of the power equipment, carrying out signal identification by adopting the high-frequency pulse current and generating initial partial discharge data;
the ultrahigh frequency sensor device is used for detecting ultrahigh frequency electromagnetic wave signals according to the initial partial discharge data and generating a plurality of ultrahigh frequency electromagnetic wave signals;
the signal processing module is used for performing signal conversion on the ultrahigh frequency electromagnetic wave signal to generate intermediate partial discharge data;
the partial discharge positioning module is used for performing positioning calculation by adopting the ultrahigh frequency electromagnetic wave signals and updating the intermediate partial discharge data to generate target partial discharge data corresponding to the power equipment.
Optionally, the partial discharge pulse current detection device performs the steps of:
acquiring high-frequency pulse current of the power equipment;
converting the high-frequency pulse current into a corresponding voltage signal to generate an initial voltage signal;
amplifying and filtering the initial voltage signal to generate a target voltage signal;
carrying out digital processing on the target voltage signal through a digital signal processor, extracting spectrum characteristics, and generating spectrum characteristics corresponding to the high-frequency pulse current;
and when the frequency spectrum characteristic is larger than a preset frequency spectrum threshold value, generating initial partial discharge data corresponding to the power equipment.
Optionally, the ultra-high frequency sensor device comprises a reference sensor and a plurality of positioning sensors; the ultra-high frequency sensor device performs the steps of:
when the initial partial discharge data is received, starting the reference sensor and the positioning sensor to acquire ultrahigh frequency electromagnetic wave signals corresponding to the power equipment, and generating a plurality of ultrahigh frequency electromagnetic wave signals;
the ultra-high frequency electromagnetic wave signal includes sensor coordinates and a signal arrival time.
Optionally, the signal processing module comprises a switch unit, a differential amplifying circuit, a digital-to-analog converter and a signal amplifying circuit;
the switch unit is used for controlling the acquisition circuit to transmit voltage data corresponding to the ultrahigh frequency electromagnetic wave signal to the differential amplification circuit;
the differential amplifying circuit is used for inputting the voltage data into an amplifier for gain amplification to generate an amplified signal;
the digital-to-analog converter is used for carrying out digital-to-analog conversion on the amplified signal and carrying out current calculation to generate initial partial discharge current;
and the signal amplifying circuit is used for carrying out fitting calibration on the initial partial discharge current and corresponding data multimeter data to generate intermediate partial discharge data.
Optionally, the switching unit performs the steps of:
the control acquisition circuit applies partial discharge pulse current corresponding to the ultrahigh frequency electromagnetic wave signal to a power resistor to generate voltage drop data;
and transmitting voltage data corresponding to the voltage drop data to the differential amplifying circuit.
Optionally, the digital-to-analog converter performs the steps of:
performing digital-to-analog conversion on the amplified signal to generate an initial digital-to-analog sampling value;
calculating the ratio of the initial digital-analog sampling value to the corresponding gain multiple to generate a target digital-analog sampling value;
and calculating the target digital-analog sampling value and the corresponding power resistor resistance value to generate an initial partial discharge current.
Optionally, the partial discharge positioning module performs the following steps:
substituting the sensor coordinates corresponding to the ultrahigh frequency electromagnetic wave signals into a preset partial discharge distance formula to perform coordinate calculation, and generating partial discharge power coordinates;
the preset partial discharge distance formula is as follows:
wherein r is i Representing the distance between each sensor and the partial discharge source, the coordinates of the partial discharge source are P (x, y, z), and the coordinates of each sensor are S i (x i ,y i ,z i ) The method comprises the steps of carrying out a first treatment on the surface of the v represents the propagation speed of the ultrahigh frequency electromagnetic wave in the current space and medium; t represents the time required for the ultrahigh frequency electromagnetic wave signal released by the partial discharge source to propagate to the reference sensor; t (T) 1i Representing the time difference between the ultra-high frequency electromagnetic wave signal to the reference sensor and the ultra-high frequency electromagnetic wave signal to the positioning sensor;
and updating the intermediate partial discharge data by adopting the partial discharge source coordinates to generate target partial discharge data corresponding to the power equipment.
The application also provides a method for detecting the partial discharge of the power equipment, which is applied to the partial discharge detection system of the power equipment, and the partial discharge detection system of the power equipment comprises the following steps: the device comprises a partial discharge pulse current detection device, an ultrahigh frequency sensor device, a signal processing module and a partial discharge positioning module; the method comprises the following steps:
the high-frequency pulse current of the power equipment is obtained through the partial discharge pulse current detection device, and signal identification is carried out by adopting the high-frequency pulse current, so that initial partial discharge data are generated;
detecting ultrahigh frequency electromagnetic wave signals according to the initial partial discharge data by the ultrahigh frequency sensor device to generate a plurality of ultrahigh frequency electromagnetic wave signals;
the ultrahigh frequency electromagnetic wave signal is subjected to signal conversion through the signal processing module, and intermediate partial discharge data are generated;
and carrying out positioning calculation by adopting the ultrahigh frequency electromagnetic wave signal through the partial discharge positioning module, updating the intermediate partial discharge data, and generating target partial discharge data corresponding to the power equipment.
The application also provides an electronic device comprising a memory and a processor, wherein the memory stores a computer program, and the computer program when executed by the processor causes the processor to execute the steps of implementing the method for detecting partial discharge of any one of the above power devices.
The present application also provides a computer-readable storage medium having stored thereon a computer program which, when executed, implements a method of partial discharge detection of an electrical device as described in any one of the above.
From the above technical scheme, the application has the following advantages:
the application combines the pulse current detection method and the ultrahigh frequency detection method into a whole by adopting an electric detection method, respectively receives high-frequency pulse current and ultrahigh frequency electromagnetic wave signals generated by partial discharge by a partial discharge pulse current detection device and an ultrahigh frequency sensor device, firstly detects the partial discharge capacity by a signal processing module based on the pulse current corresponding to the ultrahigh frequency electromagnetic wave signals, and then performs fault position positioning by a partial discharge positioning module based on the partial discharge capacity and the ultrahigh frequency electromagnetic waves to generate target partial discharge data corresponding to the power equipment. The method solves the technical problems that the existing partial discharge detection method has low detection precision and can not accurately position the fault occurrence position of equipment. The ultrahigh frequency detection method and the pulse current method can be combined to determine the discharge capacity and accurately position the fault occurrence position of the equipment. When equipment faults are determined, namely target partial discharge data are generated, the measuring result of the sensor data is abnormal, and an alarm can be sent out through an upper computer to remind professionals of maintenance as soon as possible and provide specific information of the fault occurrence position.
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In order to more clearly illustrate the embodiments of the application or the technical solutions of the prior art, the drawings which are used in the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the description below are only some embodiments of the application, and that other drawings can be obtained from these drawings without inventive faculty for a person skilled in the art.
Fig. 1 is a block diagram of a partial discharge detection system of an electrical device according to a first embodiment of the present application;
fig. 2 is a diagram of an on-line detection structure corresponding to a partial discharge pulse current detection device according to a first embodiment of the present application;
FIG. 3 is a schematic diagram of an online detection system of an ultrahigh frequency sensor device according to a first embodiment of the present application;
fig. 4 is a circuit diagram of a differential amplifying circuit according to a first embodiment of the present application;
fig. 5 is a flowchart of a main procedure for collecting partial discharge signals of a partial discharge detection system of a power device according to a second embodiment of the present application;
fig. 6 is a flowchart illustrating steps of a method for detecting partial discharge of an electrical device according to a third embodiment of the present application.
Detailed Description
The embodiment of the application provides a system, a method, equipment and a medium for detecting partial discharge of power equipment, which are used for solving the technical problems that the existing partial discharge detection method is low in detection precision and cannot accurately locate the fault occurrence position of the equipment.
In order to make the objects, features and advantages of the present application more comprehensible, the technical solutions in the embodiments of the present application are described in detail below with reference to the accompanying drawings, and it is apparent that the embodiments described below are only some embodiments of the present application, but not all embodiments of the present application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
Example 1
Referring to fig. 1, fig. 1 is a block diagram illustrating a partial discharge detection system of an electrical device according to an embodiment of the application.
The application provides a partial discharge detection system for power equipment, which comprises a partial discharge pulse current detection device, an ultrahigh frequency sensor device, a signal processing module and a partial discharge positioning module.
The partial discharge pulse current detection device is used for acquiring high-frequency pulse current of the power equipment, and adopting the high-frequency pulse current to perform signal identification to generate initial partial discharge data.
The ultra-high frequency sensor device is used for detecting the ultra-high frequency electromagnetic wave signals according to the initial partial discharge data and generating a plurality of ultra-high frequency electromagnetic wave signals.
And the signal processing module is used for carrying out signal conversion on the ultrahigh frequency electromagnetic wave signal to generate intermediate partial discharge data.
And the partial discharge positioning module is used for performing positioning calculation by adopting the ultrahigh frequency electromagnetic wave signals and updating the intermediate partial discharge data to generate target partial discharge data corresponding to the power equipment.
In the embodiment of the application, the pulse current detection method and the ultrahigh frequency detection method are combined into a whole by adopting an electric detection method, the high frequency pulse current and the ultrahigh frequency electromagnetic wave signals generated by partial discharge are respectively received by the partial discharge pulse current detection device and the ultrahigh frequency sensor device, the partial discharge capacity is detected by the signal processing module based on the pulse current corresponding to the ultrahigh frequency electromagnetic wave signals, and then fault position positioning is performed by the partial discharge positioning module based on the partial discharge capacity and the ultrahigh frequency electromagnetic waves, so that target partial discharge data corresponding to the power equipment is generated. The method solves the technical problems that the existing partial discharge detection method has low detection precision and can not accurately position the fault occurrence position of equipment. The ultrahigh frequency detection method and the pulse current method can be combined to determine the discharge capacity and accurately position the fault occurrence position of the equipment. When equipment faults are determined, namely target partial discharge data are generated, the measuring result of the sensor data is abnormal, and an alarm can be sent out through an upper computer to remind professionals of maintenance as soon as possible and provide specific information of the fault occurrence position.
Further, the partial discharge pulse current detection device performs the steps of:
and acquiring high-frequency pulse current of the power equipment, converting the high-frequency pulse current into a corresponding voltage signal, and generating an initial voltage signal. Amplifying and filtering the initial voltage signal to generate a target voltage signal. And carrying out digital processing on the target voltage signal through a digital signal processor, extracting spectral features, and generating spectral features corresponding to the high-frequency pulse current. And when the frequency spectrum characteristic is larger than a preset frequency spectrum threshold value, generating initial partial discharge data corresponding to the power equipment.
In the embodiment of the application, as shown in a device diagram of the on-line detection of the partial discharge pulse current detection device shown in fig. 2, HV is a high-voltage terminal of a bushing connection power grid, C1 is a bushing main insulation capacitor, and C2 is a voltage tap, so that the normal operation of a transformer bushing is ensured. The voltage tap provides conditions for direct coupling of the discharge pulse current signal and the sleeve capacitance ground current. The intelligent terminal HV and the sleeve C2 form a coupling unit in a capacitive mode, impedance pre-matching of transformer partial discharge monitoring is achieved, an output signal is a weak signal, and personal injury is avoided. C2 does not bear insulating effect in the system, and the voltage tap should be reliably grounded when not in use in the operation process, even if the voltage tap is open-circuited, the transformer bushing still has a fixed grounding point, and serious accidents caused by poor grounding can not occur. The normal operation of the power system is ensured.
When partial discharge occurs in the transformer, a high-frequency pulse current is generated. By detecting the characteristics of amplitude, frequency and the like of the pulse currents through the partial discharge pulse current detection device, whether the partial discharge phenomenon exists in the equipment can be judged. The current signal is converted into a voltage signal by a sensor, and an initial voltage signal is generated. And amplified by an amplifier. Then, the signal is subjected to processing such as high-frequency noise removal by a filter, and a target voltage signal is generated. Then, the target voltage signal can be digitally processed by a digital signal processor to extract its spectral features. And finally, judging whether the frequency spectrum characteristic is larger than a preset frequency spectrum threshold value, if so, indicating that the equipment has partial discharge, and generating initial partial discharge data corresponding to the power equipment. If not, the equipment is normally operated, and the partial discharge pulse current detection device is continuously used for detecting the equipment.
Further, the ultra-high frequency sensor device includes a reference sensor and a plurality of positioning sensors; the ultra-high frequency sensor device performs the steps of:
when the initial partial discharge data is received, the reference sensor and the positioning sensor are started to collect ultrahigh frequency electromagnetic wave signals corresponding to the power equipment, and a plurality of ultrahigh frequency electromagnetic wave signals are generated. The ultra-high frequency electromagnetic wave signal includes sensor coordinates and signal arrival time.
In the embodiment of the present application, as shown in fig. 3, the uhf sensor device includes a reference sensor and a plurality of positioning sensors, the reference sensor is a standard signal with a known distance, and the signal detected by the positioning sensor is determined based on the reference signal. The transformer main wiring sleeve, the transformer grounding sleeve and the intelligent terminal can carry out filtering sampling on data acquired by the intelligent terminal, carry out data collection on the data after filtering processing and the ultrahigh frequency electromagnetic wave signals acquired by the sensor, and transmit the data to the industrial control terminal for data processing analysis. When partial discharge occurs in the equipment, electromagnetic waves generated by the partial discharge signals can propagate to the periphery in space in the form of spherical waves, and finally are received by UHF sensors at different positions through different propagation paths.
Further, the signal processing module comprises a switch unit, a differential amplifying circuit, a digital-to-analog converter and a signal amplifying circuit.
And the switch unit is used for controlling the acquisition circuit to transmit voltage data corresponding to the ultrahigh frequency electromagnetic wave signal to the differential amplification circuit.
And the differential amplifying circuit is used for inputting the voltage data into the amplifier for gain amplification and generating an amplified signal.
And the digital-to-analog converter is used for carrying out digital-to-analog conversion on the amplified signal and carrying out current calculation to generate initial partial discharge current.
And the signal amplifying circuit is used for carrying out fitting calibration on the initial partial discharge current and the corresponding data multimeter data to generate intermediate partial discharge data.
In the embodiment of the application, since the insulating layer of the transformer has high insulating strength, when partial discharge occurs inside the transformer, pulse electromagnetic waves of the order of up to gigahertz are released. Therefore, the pulse signal sensor meeting the specification can be selected, the partial discharge load is captured by detecting the frequency of electromagnetic waves, and the pulse signal is analyzed and processed to obtain the partial discharge condition and energy level of the transformer system, so that the running condition and stability of the power system are better monitored.
The voltage and current circuit is controlled by the switch unit, the analog-digital converter receives the analog-digital signal at the acquisition circuit, converts the analog-digital signal into a digital signal, then sends the conversion result to the control unit of the lower computer, namely the singlechip, and the singlechip transmits the data to the upper computer for display. The specific implementation process is as follows:
the input of external power supply firstly needs to have an acquisition circuit to acquire the electric signal, the acquisition circuit is controlled by a switch unit to acquire the voltage by adopting the principle of resistance voltage division, then a relay is arranged to switch gears in consideration of the size of the electric signal, and two-stage voltage is connected to the acquisition circuit and then is input into an A/D converter in a differential mode. By utilizing ohm law, the principle that current flows through resistors to generate voltage is utilized, two sampling resistors are arranged, a switch selects which resistor to use, the voltage generated at the resistor is subjected to gain through a programmable amplifier INA225, and an amplified signal is generated in a differential input mode, namely through a differential amplifying circuit and is sent into an analog-to-digital converter. The analog signal is converted into a digital signal, and the digital signal is sent to the singlechip for processing.
The lower computer sends the measurement data to the upper computer based on serial communication. In order to improve accuracy of measured data, a universal meter is connected to a power end to be measured, data are read and sent to an upper computer, after the upper computer collects data of the universal meter and a measuring circuit, calibration data are obtained, namely initial partial discharge current and corresponding data of the data universal meter are subjected to fitting calibration through a signal amplifying circuit, middle partial discharge data are generated and sent to a singlechip through serial port communication, finally the singlechip writes the calibration data, namely the middle partial discharge data into a storage chip, and the middle partial discharge data comprise current amounts generated by equipment partial discharge.
Specifically, the signal amplifying circuit is to realize stable output voltage, so that the LT3045 is selected and used as an LDO low dropout linear voltage regulator, when the LT3045 is enabled, the circuit starts to work to output 3V voltage and is very stable at 3V, the requirement of supplying power to the DUT is met, considering that a tested small signal possibly reaches a uA level, different sampling resistor gears are selected for switching, the tested small signal can be more accurate, three relay switches are selected for switching the sampling resistor, the testing is very convenient, and the relays are controlled by the I/O port.
After the sampling resistor is determined, the signal in the acquisition circuit can be started, the voltage difference at two ends of the sampling resistor is connected, the signal is amplified by the AD8421, the amplified voltage value is obtained by the signal through the MCU, and the current value in working is obtained through the conversion of the software code value.
In the process, the data acquired by the AD is considered to have certain error, so that a professional instrument can be used for calibration, a 2PIN interface is designed and used for being connected with a DMM digital multimeter, and then the data acquired by the DMM and the data acquired by the AD are fitted to obtain a relatively accurate current value.
As shown in the circuit diagram of the differential amplifying circuit in FIG. 4, the MCU of the main control chip is selected to meet project requirements, so that development cost is reduced, and economic benefit is improved. In the design, fewer IO interfaces are needed, and firstly, the MCU with fewer pins is determined. MCU functions used in the design are USART serial port communication and I2C communication, and communication is carried out with an external analog-to-digital converter ADS1115, a serial port expansion chip CAT9555 and a memory chip AT24C02D through an I2C protocol, so that data receiving and sending are realized, and relevant data results are printed through the USART serial port.
Optionally, the switching unit performs the steps of:
the control acquisition circuit applies partial discharge pulse current corresponding to the ultrahigh frequency electromagnetic wave signal to the power resistor to generate voltage drop data. And transmitting voltage data corresponding to the voltage drop data to the differential amplifying circuit.
In the embodiment of the application, the switch unit mainly generates high and low levels by CAT9555 controlled by STM32, and controls the switch and the gain selection. The CAT9555 chip is compatible with an I2C communication bus, is provided with 16I/O ports, can be connected with a plurality of devices and control the devices, is internally provided with two 8-bit configuration registers, can configure the I/O into an input or output mode, an input register, an output register and a polarity reverser, can read and write the two registers at the same time during I2C communication, and has simple time sequence.
The first-stage control unit STM32 establishes communication with the second-stage control unit CAT9555 through an I2C bus, sends bytes, controls the three-stage control unit relay to perform voltage range selection, and simulates a switch to perform current range selection.
The switch unit controls the acquisition circuit to acquire by using a resistance method, applies a power supply to be detected to the power resistor, causes voltage drop when current flows through the power resistor, and acquires the voltages at two ends of the resistor to the amplifier. After gain amplification by the amplifier, the signal to be tested is output to the positive end of the pin of the analog-to-digital converter and grounded to the negative end of the pin of the converter, so as to form a second path of differential input.
Optionally, the digital-to-analog converter performs the steps of:
and D, performing digital-to-analog conversion on the amplified signal to generate an initial digital-to-analog sampling value. And calculating the ratio of the initial digital-analog sampling value to the corresponding gain multiple to generate a target digital-analog sampling value. And calculating a target digital-analog sampling value and a corresponding power resistor resistance value to generate an initial partial discharge current.
In the embodiment of the application, the sampling value of the digital-to-analog converter is equal to the voltage difference of two pins, the sampling value is divided by the gain multiple to obtain a target digital-to-analog sampling value, and the target digital-to-analog sampling value is divided by the resistance value of the power resistor to obtain the current of the signal to be measured, namely the initial partial discharge current.
Further, the partial discharge positioning module performs the following steps:
substituting the sensor coordinates corresponding to the ultrahigh frequency electromagnetic wave signals into a preset partial discharge distance formula to perform coordinate calculation, and generating partial discharge power coordinates.
The preset partial discharge distance formula is:
wherein r is i Representing the distance between each sensor and the partial discharge source, the coordinates of the partial discharge source are P (x, y, z), and the coordinates of each sensor are S i (x i ,y i ,z i ) The method comprises the steps of carrying out a first treatment on the surface of the v represents the propagation speed of the ultrahigh frequency electromagnetic wave in the current space and medium; t represents the time required for the ultrahigh frequency electromagnetic wave signal released by the partial discharge source to propagate to the reference sensor; t (T) 1i Representing the time difference of the ultra-high frequency electromagnetic wave signal to the reference sensor and to the positioning sensor.
And updating the intermediate partial discharge data by adopting the partial discharge source coordinates to generate target partial discharge data corresponding to the power equipment.
In the embodiment of the application, because the partial discharge can generate an electromagnetic disturbance phenomenon, a homogeneous wave equation, namely a darbeol formula, is deduced according to a maxwell equation set by introducing a scalar magnetic potential A and a vector magnetic potential phi:
where μ is the permeability of the medium and ε is the permittivity. The excitation source ρ, the dynamic bit A, the current density δ are illustrated c The relationship between these states illustrates that the vector and the label both propagate in space in the form of fluctuations.
If the position of partial discharge is equivalent to one point, it is assumed that the vector of any point in space is:
a＝(x,y,z,t) (3)
the vector magnetic potential A and the scalar magnetic potential phi are:
as is clear from the above formulas (4) and (5), the partial discharge electromagnetic wave has a relationship between space coordinates and time, and the electromagnetic wave propagates in the direction of r at the velocity v, which is a transverse electromagnetic wave. Thus, when a partial discharge occurs, the electromagnetic wave reaches the sensor after a certain time t, i.e
As shown in FIG. 3, the positioning algorithm of partial discharge signals adopts a signal arrival time difference (time difference of arrival, TDOA) algorithm, S 0 ，S 1 ，S 2 ，S 3 Four sensors, S 0 Is a reference sensor, S 1 ，S 2 ，S 3 To position the sensor, reference the sensor S 0 And establishing a three-dimensional rectangular coordinate system for the origin. Setting the coordinates P (x, y, z) of the partial discharge source, the coordinates of each sensor are S i (x i ,y i ,z i ) R is then i Indicating the distance of each sensor from the local discharge source.
The time of electromagnetic wave to each sensor when partial discharge occurs is t 0 、t 1 、t 2 、t 3 And the time difference between each positioning sensor and the reference sensor can be obtained, so that the coordinates of the partial discharge relative to the reference sensor can be obtained by solving a nonlinear equation set according to the position of each positioning sensor, and the coordinates of the partial discharge source can be obtained. And finally, updating the intermediate partial discharge data by adopting the partial discharge source coordinates to generate target partial discharge data corresponding to the power equipment.
In the embodiment of the application, compared with the existing partial-acoustic-electric combined detection method, the detection method of the technology is simpler and more unified, and is an electric detection method. And the combined detection method of sound and electricity adopts the combination of an ultrasonic method and an ultrahigh frequency method, and adopts the combination of two different types of detection methods, so that the collected data is more complicated to process. The technology adopts a pulse current method to detect faults of the transformer, can quantitatively measure partial discharge, and has the accuracy of pC. Compared with a common pulse current method, the method and an ultrahigh frequency method can be combined to effectively reduce the influence of external electromagnetic interference. In the pulse current detection system, the coupling unit can realize impedance pre-matching of the transformer partial discharge monitoring, and the output signal is a weak signal, so that personal injury is not caused. The transformer bushing has a fixed ground point, and even if the voltage tap is open, serious accidents caused by poor grounding can not occur. The technology has the function of partial discharge positioning on the basis of partial discharge fault detection, compared with the acoustic-electric combination in the positioning method, the ultra-high frequency method has higher sensitivity and reachable precision than the ultrasonic method, the acquired electromagnetic wave signals are used for solving the reachable partial discharge coordinates through the positioning TODA algorithm, and the method is simple. And the signal attenuation of electromagnetic wave and ultrasonic wave is great, and the relative complexity of positioning partial discharge by using double signal time difference processing also brings certain error. Therefore, the partial discharge detection technology is based on the original detection technology, can realize the detection of partial discharge capacity and faults, can determine the partial discharge position, realizes on-line monitoring, has a simpler structure, and has higher detection precision and safety performance.
Example two
Referring to fig. 5, fig. 5 is a flowchart illustrating a main procedure for collecting partial discharge signals of a partial discharge detection system of an electrical device according to a second embodiment of the present application.
In the embodiment of the application, the system is initialized, then the pulse current is circularly collected through the partial discharge pulse current detection device, whether the equipment is externally interrupted or not is judged through the pulse current, if not, the circulation waiting step is skipped, and the pulse current of the equipment is continuously collected. If so, judging whether the reference sensor detects the reference signal, and if not, judging whether the reference sensor detects the reference signal again. If yes, data acquisition is carried out through the ultrahigh frequency sensor device. Judging whether the data acquisition is completed or not, judging that the acquisition is completed depending on time, starting an acquisition program, continuing scanning and judging for 30 seconds, and judging that the scanning is completed after 30 seconds. If not, jumping to a data acquisition step, if so, ending data acquisition, and transmitting acquired data to a signal processing module and a partial discharge positioning module for data processing, so as to determine the partial discharge amount and the partial discharge position of the equipment.
Specifically, the design can also comprise the following parts: 220V-12V circuit, programmable signal amplifying circuit, AD analog-to-digital conversion circuit, STM32 microprocessor circuit, W5500 network port communication, etc. Because the integrated circuit is a board used on the handheld partial discharge circuit, the overall block diagram is designed according to the whole machine, and the whole process is that after an operator presses a start test button, signals are connected with a Socket (a carrier for placing a DUT) through an adapter plate, the test is started, and the test result is displayed on a computer. The power supply of the first machine is 220V alternating current, and the power supply of the board card only needs 12V, so that a switching power supply is used for converting 220V voltage into 12V to supply power to the board card, interaction is realized with a computer in an Ethernet mode, the boards are connected in a line-to-line mode, the test can be performed through the operation of an upper computer, a current-voltage conversion part and a high-resolution analog-to-digital conversion circuit can be used for micro-processing, the most widely used STM32 series can be selected, and noise and high power supply rejection ratio are paid attention to the power supply.
Referring to fig. 6, fig. 6 is a flowchart illustrating a method for detecting partial discharge of an electrical device according to a third embodiment of the present application.
The third embodiment of the present application provides a method for detecting partial discharge of electrical equipment, which is applied to the remote security monitoring system of a transformer substation in any one of the above embodiments, where the method for detecting partial discharge of electrical equipment includes: the device comprises a partial discharge pulse current detection device, an ultrahigh frequency sensor device, a signal processing module and a partial discharge positioning module; the method comprises the following steps:
and 601, acquiring high-frequency pulse current of the power equipment through a partial discharge pulse current detection device, and adopting the high-frequency pulse current to perform signal identification to generate initial partial discharge data.
Step 602, ultra-high frequency electromagnetic wave signal detection is performed by the ultra-high frequency sensor device according to the initial partial discharge data, and a plurality of ultra-high frequency electromagnetic wave signals are generated.
And 603, performing signal conversion on the ultrahigh frequency electromagnetic wave signal through a signal processing module to generate intermediate partial discharge data.
And step 604, performing positioning calculation by using an ultrahigh frequency electromagnetic wave signal through a partial discharge positioning module, updating the middle partial discharge data, and generating target partial discharge data corresponding to the power equipment.
In the embodiment of the application, first, a high-frequency pulse current of the power equipment is acquired through a partial discharge pulse current detection device, and signal identification is performed by adopting the high-frequency pulse current, so that initial partial discharge data are generated. Then, the ultra-high frequency electromagnetic wave signals are detected by the ultra-high frequency sensor device based on the initial partial discharge data, and a plurality of ultra-high frequency electromagnetic wave signals are generated. Then, the ultrahigh frequency electromagnetic wave signal is subjected to signal conversion through a signal processing module, and intermediate partial discharge data are generated. And finally, carrying out positioning calculation by adopting an ultrahigh frequency electromagnetic wave signal through a partial discharge positioning module, updating the middle partial discharge data, and generating target partial discharge data corresponding to the power equipment. The pulse current detection method and the ultra-high frequency detection method are combined into a whole, so that the influence of external electromagnetic interference can be effectively reduced, and the sensitivity and the reachable precision are high.
The embodiment of the application also provides electronic equipment, which comprises: a memory and a processor, the memory storing a computer program; the computer program, when executed by a processor, causes the processor to perform the method of partial discharge detection of a power device as in any of the embodiments described above.
The memory may be an electronic memory such as a flash memory, an EEPROM (electrically erasable programmable read only memory), an EPROM, a hard disk, or a ROM. The memory has memory space for program code to perform any of the method steps described above. For example, the memory space for the program code may include individual program code for implementing the various steps in the above method, respectively. The program code can be read from or written to one or more computer program products. These computer program products comprise a program code carrier such as a hard disk, a Compact Disc (CD), a memory card or a floppy disk. The program code may be compressed, for example, in a suitable form. The codes, when executed by a computing processing device, cause the computing processing device to perform the steps in the power device partial discharge detection method described above.
The embodiment of the application also provides a computer readable storage medium, on which a computer program is stored, which when executed by a processor, implements the method for detecting partial discharge of an electrical device according to any of the embodiments above.
It will be clearly understood by those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, systems and units may refer to the corresponding processes in the foregoing method embodiments, which are not repeated herein.
In the several embodiments provided herein, it should be understood that the disclosed systems, and methods may be implemented in other ways. For example, the system embodiments described above are merely illustrative, e.g., the partitioning of elements is merely a logical functional partitioning, and there may be additional partitioning in actual implementation, e.g., multiple elements or components may be combined or integrated into another system, or some features may be omitted, or not implemented. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be through some interface, system or unit indirect coupling or communication connection, which may be in electrical, mechanical or other form.
The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed over a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
In addition, each functional unit in the embodiments of the present application may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in software functional units.
The integrated units, if implemented in the form of software functional units and sold or used as stand-alone products, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application may be embodied in essence or a part contributing to the prior art or all or part of the technical solution in the form of a software product stored in a storage medium, including several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods of the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a random access Memory (RAM, random Access Memory), a magnetic disk, or an optical disk, or other various media capable of storing program codes.
The above embodiments are only for illustrating the technical solution of the present application, and are not limiting; although the application 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 scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present application.
Claims (10)
1. A power equipment partial discharge detection system, comprising: the device comprises a partial discharge pulse current detection device, an ultrahigh frequency sensor device, a signal processing module and a partial discharge positioning module;
the partial discharge pulse current detection device is used for acquiring high-frequency pulse current of the power equipment, carrying out signal identification by adopting the high-frequency pulse current and generating initial partial discharge data;
the ultrahigh frequency sensor device is used for detecting ultrahigh frequency electromagnetic wave signals according to the initial partial discharge data and generating a plurality of ultrahigh frequency electromagnetic wave signals;
the signal processing module is used for performing signal conversion on the ultrahigh frequency electromagnetic wave signal to generate intermediate partial discharge data;
the partial discharge positioning module is used for performing positioning calculation by adopting the ultrahigh frequency electromagnetic wave signals and updating the intermediate partial discharge data to generate target partial discharge data corresponding to the power equipment.
2. The electrical equipment partial discharge detection system according to claim 1, wherein the partial discharge pulse current detection means performs the steps of:
acquiring high-frequency pulse current of the power equipment;
converting the high-frequency pulse current into a corresponding voltage signal to generate an initial voltage signal;
amplifying and filtering the initial voltage signal to generate a target voltage signal;
carrying out digital processing on the target voltage signal through a digital signal processor, extracting spectrum characteristics, and generating spectrum characteristics corresponding to the high-frequency pulse current;
and when the frequency spectrum characteristic is larger than a preset frequency spectrum threshold value, generating initial partial discharge data corresponding to the power equipment.
3. The electrical equipment partial discharge detection system of claim 1, wherein the ultra-high frequency sensor device comprises a reference sensor and a plurality of positioning sensors; the ultra-high frequency sensor device performs the steps of:
when the initial partial discharge data is received, starting the reference sensor and the positioning sensor to acquire ultrahigh frequency electromagnetic wave signals corresponding to the power equipment, and generating a plurality of ultrahigh frequency electromagnetic wave signals;
the ultra-high frequency electromagnetic wave signal includes sensor coordinates and a signal arrival time.
4. The electrical device partial discharge detection system of claim 1, wherein the signal processing module comprises a switching unit, a differential amplification circuit, a digital-to-analog converter, and a signal amplification circuit;
the switch unit is used for controlling the acquisition circuit to transmit voltage data corresponding to the ultrahigh frequency electromagnetic wave signal to the differential amplification circuit;
the differential amplifying circuit is used for inputting the voltage data into an amplifier for gain amplification to generate an amplified signal;
the digital-to-analog converter is used for carrying out digital-to-analog conversion on the amplified signal and carrying out current calculation to generate initial partial discharge current;
and the signal amplifying circuit is used for carrying out fitting calibration on the initial partial discharge current and corresponding data multimeter data to generate intermediate partial discharge data.
5. The electrical equipment partial discharge detection system according to claim 4, wherein the switching unit performs the steps of:
the control acquisition circuit applies partial discharge pulse current corresponding to the ultrahigh frequency electromagnetic wave signal to a power resistor to generate voltage drop data;
and transmitting voltage data corresponding to the voltage drop data to the differential amplifying circuit.
6. The electrical device partial discharge detection system of claim 4 wherein the digital-to-analog converter performs the steps of:
performing digital-to-analog conversion on the amplified signal to generate an initial digital-to-analog sampling value;
calculating the ratio of the initial digital-analog sampling value to the corresponding gain multiple to generate a target digital-analog sampling value;
and calculating the target digital-analog sampling value and the corresponding power resistor resistance value to generate an initial partial discharge current.
7. The electrical device partial discharge detection system of claim 3 wherein the partial discharge positioning module performs the steps of:
substituting the sensor coordinates corresponding to the ultrahigh frequency electromagnetic wave signals into a preset partial discharge distance formula to perform coordinate calculation, and generating partial discharge power coordinates;
the preset partial discharge distance formula is as follows:
wherein r is i Representing the distance between each sensor and the partial discharge source, the coordinates of the partial discharge source are P (x, y, z), and the coordinates of each sensor are S i (x i ,y i ,z i ) The method comprises the steps of carrying out a first treatment on the surface of the v represents the propagation speed of the ultrahigh frequency electromagnetic wave in the current space and medium; t represents the time required for the ultrahigh frequency electromagnetic wave signal released by the partial discharge source to propagate to the reference sensor; t (T) 1i Representing the time difference between the ultra-high frequency electromagnetic wave signal to the reference sensor and the ultra-high frequency electromagnetic wave signal to the positioning sensor;
and updating the intermediate partial discharge data by adopting the partial discharge source coordinates to generate target partial discharge data corresponding to the power equipment.
8. A power equipment partial discharge detection method, characterized by being applied to the power equipment partial discharge detection system according to any one of claims 1 to 7, the power equipment partial discharge detection system comprising: the device comprises a partial discharge pulse current detection device, an ultrahigh frequency sensor device, a signal processing module and a partial discharge positioning module; the method comprises the following steps:
the high-frequency pulse current of the power equipment is obtained through the partial discharge pulse current detection device, and signal identification is carried out by adopting the high-frequency pulse current, so that initial partial discharge data are generated;
detecting ultrahigh frequency electromagnetic wave signals according to the initial partial discharge data by the ultrahigh frequency sensor device to generate a plurality of ultrahigh frequency electromagnetic wave signals;
the ultrahigh frequency electromagnetic wave signal is subjected to signal conversion through the signal processing module, and intermediate partial discharge data are generated;
and carrying out positioning calculation by adopting the ultrahigh frequency electromagnetic wave signal through the partial discharge positioning module, updating the intermediate partial discharge data, and generating target partial discharge data corresponding to the power equipment.
9. An electronic device comprising a memory and a processor, wherein the memory stores a computer program that, when executed by the processor, causes the processor to perform the steps of the method for detecting partial discharge of an electrical device of claim 8.
10. A computer-readable storage medium, on which a computer program is stored, characterized in that the computer program, when executed, implements the method for detecting partial discharge of an electrical device according to claim 8.
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