CN101581748B - Zinc oxide arrester on-line monitoring system - Google Patents

Abstract

Zinc oxide surge arrester online monitoring system, including a microprocessor, the microprocessor is respectively connected with the A/D conversion unit, the lightning strike counting module and the GPRS communication module, and the A/D conversion unit is connected with the leakage current sampling module and the voltage sampling module respectively , the structure of the microprocessor includes an input/output interface, a counter and a serial communication interface, the input/output interface is connected with the A/D conversion unit, the counter is connected with the lightning counting module, and the serial communication interface is connected with the GPRS communication module , The microprocessor adopts FPGA chip EP1C6Q240C8. The monitoring system of the invention dynamically monitors the insulation performance of the zinc oxide arrester under the operating voltage, the test result is accurate and reliable, the test process is simple, the test period is short, it is not easily affected by human and external factors, and it can provide the operation and performance of the zinc oxide arrester Deteriorated long-term data have good practical value.

Description

Zinc Oxide Surge Arrester Online Monitoring System

technical field

The invention belongs to the technical field of electrical performance monitoring, and relates to an online monitoring system for the insulation performance of an arrester, in particular to an online monitoring system for a zinc oxide arrester.

Background technique

Surge arrester is one of the important protection devices to ensure the safe operation of the power system, mainly used to limit the lightning overvoltage transmitted from the line or the internal overvoltage caused by operation.

Because of its outstanding advantages in lightning protection performance, silicon carbide arresters are widely used in high-voltage equipment in power systems, but they have the following disadvantages: First, they only have the maximum lightning amplitude voltage limiting protection function, and there is no lightning steep wave protection function. The protection function is incomplete; the second is that there is no continuous lightning impact protection capability; the third is that the stability of the operating characteristics is poor, and it may suffer from transient overvoltage hazards; the fourth is that the operating load is heavy and the service life is short. The above-mentioned shortcomings lead to hidden dangers affecting the safety of the power system in the use of silicon carbide arresters.

Zinc oxide arrester (MOA) has excellent nonlinear volt-ampere characteristics, small size, light weight, large flow capacity, and its protection characteristics are better than silicon carbide valve arresters. The use of zinc oxide arresters can significantly reduce the insulation design level of the protected power equipment, significantly reduce equipment investment, and improve power supply reliability. During use, due to long-term exposure to power frequency voltage, impulse voltage and various external environmental factors, the zinc oxide arrester tends to age, and its insulation properties are destroyed, causing the zinc oxide arrester to lose its function, causing thermal collapse of the power equipment, and even occurrence of explode. Therefore, in order to ensure the normal function of the arrester, it is necessary to regularly detect the performance status of the arrester.

At present, the detection of the performance status of the arrester is carried out by the inspectors who regularly go to the site to conduct on-site inspections, that is, preventive tests on the arrester after regular power outages. This detection method has the following defects:

1) A power outage is required during the test: even a planned power outage will have a certain impact on production. After a power outage, the temperature of the equipment drops, and the test results often cannot reflect the real situation. Studies have shown that about 58.5% of the equipment is difficult to make correct judgments based on low temperature test results.

2) Early report or false report: The test voltage applied by regular power outage maintenance is generally 10KV and below, which is lower than the voltage during the operation of the arrester, and due to the power outage during the test, the reflected situation is quite different from the actual situation, and the operation cannot be reflected in real time The insulation performance and working condition of the arrester under the voltage, so the diagnostic results may not conform to the actual operating state. There have been many cases where the preventive test passed, but the arrester burned out and exploded.

3) High maintenance cost: The material resources, financial resources and manpower invested during the preventive test are relatively large, the test procedure is complicated, the workload is heavy, and the time is concentrated, and the test results are easily affected by human factors.

4) The test cycle is long, and some rapidly developing faults cannot be discovered and diagnosed in time. Therefore, even if the equipment passes the preventive tests, failures still occur from time to time.

In view of the above problems, a live detection method is proposed, that is, the insulation on-line monitoring and diagnosis technology is used to explore the condition-based maintenance system based on on-line monitoring. The so-called insulation on-line monitoring refers to the use of advanced digital signal processing technology and fault diagnosis methods to automatically, continuously or regularly detect and supervise the insulation characteristics of the arrester under the condition that the arrester is not powered off and does not leave the system. Grasp whether the arrester is in normal operation, so as to determine whether the detected arrester needs to be repaired and how to repair it.

Under the operating voltage, monitoring the working status of electrical equipment can truly reflect the operating status of electrical equipment and reduce losses caused by power outages. However, under the operating voltage of the electrical equipment under test, the characteristic quantity of electrical abnormal information is very weak, the range of change is large, and it is susceptible to on-site electromagnetic interference, which makes the collection, transmission, processing and diagnosis of the abnormal information much more complicated than the monitoring of power system operating parameters. , resulting in the slow development of dynamic monitoring of electrical equipment working status.

With the development and application of modern sensor technology, computer technology and information processing technology, the online monitoring technology and diagnosis technology of electrical equipment can be realized. The application in fault diagnosis of power equipment has also been paid more and more attention. The same as the establishment process of the preventive test system, through use, promotion, summary and improvement, the power equipment condition-based maintenance standard based on online monitoring will be formulated, and a complete power system condition-based maintenance system will be gradually established.

Contents of the invention

The purpose of the present invention is to provide an online monitoring system for zinc oxide arresters, which can dynamically monitor the insulation performance of the arrester under the operating voltage. The test results are accurate and reliable, and the test process is simple, the test period is short, and it is not easily affected by human and external factors. .

The technical scheme adopted in the present invention is that the on-line monitoring system for zinc oxide lightning arresters includes a microprocessor, and the microprocessor is connected with the A/D conversion unit, the lightning strike counting module and the GPRS communication module respectively, and the A/D conversion unit is respectively connected with the leakage The current sampling module is connected with the voltage sampling module, and the structure of the microprocessor is provided with an input/output interface, a counter and a serial communication interface, the input/output interface is connected with the A/D conversion unit, and the counter is connected with the lightning strike counting module , the serial communication interface is connected with the GPRS communication module, and the microprocessor adopts the FPGA chip EP1C6Q240C8.

The monitoring system of the present invention utilizes the advantages of wireless transmission of GPRS to convert the monitoring information into digital signals and transmit them to the server-side database of the monitoring center through the GPRS module, so that managers can conveniently query the resistive current component value and the number of lightning strikes of MOA on the client side , Real-time understanding of the operation status information of MOA. Combining the advantages of the fundamental harmonic method and the double "AT" method, the accurate detection of the resistive leakage current during the live operation of the MOA is realized, and the detection result is displayed on the liquid crystal display, and the monitored information is converted into a digital signal and transmitted through the GPRS module to the In the server-side database of the monitoring center, managers can easily query the MOA resistive current component value and the number of lightning strikes on the client side to understand the operation status of the MOA. The whole system is easy to operate, convenient and quick to monitor, overcomes the shortcomings of bulky and inconvenient operation of existing testing instruments, and can provide long-term data on the operation and performance degradation of zinc oxide arresters, which has good practical value.

Description of drawings

Fig. 1 is the structural representation of a kind of embodiment of detection system of the present invention;

Fig. 2 is the structural representation of the voltage sampling module in the monitoring system of the present invention;

Fig. 3 is a schematic structural diagram of a leakage current sampling module in the monitoring system of the present invention;

Fig. 4 is the structural representation of the lightning strike counting module in the monitoring system of the present invention;

Fig. 5 is a flow chart of the main program of the monitoring system of the present invention.

In the figure, 1. Microprocessor, 2. A/D conversion unit, 3. Leakage current sampling module, 4. Voltage sampling module, 5. Lightning counting module, 6. GPRS communication module, 7. Liquid crystal display, 8. Random Memory, 9. Zinc oxide arrester.

Among them, 1-1. Input/output interface, 1-2. Universal input/output port, 1-3. Counter, 1-4. Serial communication interface, 3-1. Leakage current sensor, 3-2. Pressure sensitive Resistor, 3-3. Operational amplifier A, 3-4. Operational amplifier B, 4-1. First transformer, 4-2. Active operational amplifier, 5-1. Second transformer, 5-2. ACAC Converter, 5-3. Optical coupler, 5-4. Inverting tube.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

The structure of an embodiment of the monitoring system of the present invention is shown in FIG. 1 . Including microprocessor 1, letter microprocessor 1 is respectively connected with A/D conversion unit 2, lightning strike counting module 5, GPRS communication module 6, liquid crystal display 7 and RAM 8, A/D conversion unit 2 is connected with leakage current The sampling module 3 is connected with the voltage sampling module 4 . The structure of microprocessor 1 is provided with input/output interface 1-1, general input/output port 1-2, counter 1-3 and serial communication interface 1-4; Input/output interface 1-1 and A/D The conversion unit 2 is connected, the general input/output port 1-2 is connected with the liquid crystal display 7 and the RAM 8 respectively, the counter 1-3 is connected with the lightning counting module 5, and the serial communication interface 1-4 is connected with the GPRS communication module 6 connected.

Microprocessor 1 uses FPGA chip EP1C6Q240C8 to receive the signal input by A/D converter 2, process and store the received signal, display the processing result, and send the processed data to GPRS communication Module 6 is used to receive the instruction transmitted by GPRS communication module 6, and send the received instruction to A/D converter 2 and lightning strike counting module 5;

The A/D converter 2 is used to receive the signals sent by the leakage current sampling module 3 and the voltage sampling module 4, and perform A/D conversion on the received signals and input them to the microprocessor 1, and is used to receive the signals transmitted by the microprocessor 1. instructions, and transmit the received instructions to the leakage current sampling module 3 and the voltage sampling module 4 respectively;

The leakage current sampling module 3 adopts the BCT-2 type electromagnetic core-through small current sensor based on the active zero-flux technology, which is used to receive the instructions input by the A/D converter 2, and collect the leakage current of the arrester according to the received instructions signal, inputting the collected leakage current signal into the A/D converter 2;

The voltage sampling module 4 is used to receive the instruction input by the A/D converter 2, and collect the voltage signal of the arrester according to the received instruction, and input the collected voltage signal into the A/D converter 2;

The lightning strike counting module 5 adopts the principle of pulse counting, and is used to collect information on the number of times the arrester is struck by lightning, and transmit the information to the microprocessor 1;

The GPRS communication module 6 is used for dial-up Internet access, transparent data transmission and protocol conversion according to the ETSI GSM Phase 2+ standard, for receiving the data delivered by the microprocessor 1, and sending the received data to the remote monitoring center for use in Receive instructions from the remote monitoring center, and transmit the received instructions to the microprocessor 1.

The structure of the voltage sampling module 4 in the monitoring system of the present invention is shown in FIG. 2 . The first transformer 4-1 is included, and the first transformer 4-1 adopts a miniature current-type voltage transformer. The upper end of the primary winding of the first transformer 4-1 is connected in series with the resistor R1, and a phase voltage is applied between the resistor R1 and the lower end of the primary winding of the first transformer 4-1, and the resistor R1 is a current limiting resistor. The first transformer 4- 1 The upper end of the secondary winding is connected to the positive input end of the active operational amplifier 4-2, the lower end of the secondary winding of the first transformer 4-1 is connected to the negative input end of the active operational amplifier 4-2, Between the first transformer 4-1 and the active operational amplifier 4-2, from the first transformer 4-1 to the active operational amplifier 4-2, a diode D1 and a diode D2 are connected in parallel in sequence, and the anode of the diode D1 is connected to the first The upper end of the secondary winding of the transformer 4-1 is connected, the negative pole of the diode D1 is connected with the lower end of the secondary winding of the first transformer 4-1, and the negative pole of the diode D2 is connected with the upper end of the secondary winding of the first transformer 4-1 The anode of the diode D2 is connected to the lower end of the secondary winding of the first transformer 4-1, and a resistor R2 is connected in series between the positive input terminal and the output terminal of the active operational amplifier 4-2, and the active operational amplifier 4 The output end of -2 is also connected to one end of the capacitor C, and the other end of the capacitor C is grounded.

The secondary side of the high-voltage line in the power system has formed a standard AC (alternating current) 100V voltage and 5A current, but the 100V AC voltage signal obtained from the PT secondary side wiring is not suitable for subsequent comparison and collection. According to the monitoring principle, it is necessary to collect the phase voltage of the zinc oxide arrester 9 during operation, and the resistor R1 in the voltage sampling module 4 limits the current of the standard AC100V voltage, and inputs the current-limited voltage signal into the first transformer 4-1, The first mutual inductor 4-1 isolates and filters the received voltage signal, so that the linearity and angle difference of the voltage signal meet the accuracy requirements of the system, and then inputs the processed voltage signal into the front active operational amplifier 4- 2. The active operational amplifier 4-2 amplifies the received voltage signal and outputs it. At this time, by adjusting the feedback resistor R2 of the active operational amplifier 4-2, the required voltage can be obtained at the output terminal of the active operational amplifier 4-2. voltage output.

Fig. 3 shows the structure of the leakage current sampling module 3 in the monitoring system of the present invention. Including the leakage current sensor 3-1, the leakage current sensor 3-1 adopts the BCT-2 type electromagnetic core-through small current sensor based on the active zero magnetic flux technology. The leakage current sensor 3-1 is connected in parallel with the piezoresistor 3-2 to form a parallel circuit, one end of the parallel circuit is connected to one end of the resistor R1, and the other end of the parallel circuit is grounded; the other end of the resistor R1 is connected to the operational amplifier A3-3 The reverse input terminal of the operational amplifier A3-3 is also connected with one end of the resistor R2 and the output terminal of the operational amplifier A3-3 respectively, and the positive input terminal of the operational amplifier A3-3 is connected with the resistor R3 series, resistor R3 is grounded; the output terminal of operational amplifier A3-3 is connected to one terminal of resistor R5, the other terminal of resistor R5 is connected to the inverting input terminal of operational amplifier B3-4, and the reverse input terminal of operational amplifier B3-4 A resistor R7 is connected in series between the input terminal and the output terminal of the operational amplifier B3-4, the positive input terminal of the operational amplifier B3-4 is connected in series with the resistor R6, and the resistor R6 is grounded; the two bypasses of the output terminal of the operational amplifier B3-4 are respectively connected with diodes D1 and diode D2, the cathode of diode D1 and the anode of diode D2 are respectively connected to the output terminal of operational amplifier B3-4, the anode of diode D1 is connected to DGND, and the cathode of diode D2 is connected to VCC. The leakage current sensor 3-1 is connected in series with the ground wire of the zinc oxide arrester 9.

In the field of data acquisition, the acquisition and processing methods of medium and large signals are relatively mature, but there is no fixed mode for the acquisition and data processing of small signals. The small signal itself is relatively weak, and is often submerged in external interference and self-generated noise, making it very difficult to collect and separate small signals. The leakage current of the zinc oxide arrester 9 is a small current of the milliampere level or even microampere level. In order to accurately reflect the leakage current of the zinc oxide arrester 9, the basic requirements for the small current sensor are as follows: (1) It can be adapted to measure the small current (milliampere safety level), high sensitivity, and the secondary signal should be as large as possible; (2) within the measurement range, the linearity is good, the output waveform is not distorted, and the ratio difference and angle difference between the output signal and the measured signal are small , and its difference is stable and does not change with other factors; (3) Good working stability, small and stable temperature coefficient, simple structure, small size, electromagnetic shielding function, and good electromagnetic compatibility. Therefore, the leakage current sensor 3-1 in the leakage current sampling module 3 of this monitoring system adopts the BCT-2 type electromagnetic type core-through small current sensor based on active zero magnetic flux technology, and installs it on the ground wire of the zinc oxide arrester 9 Above, the leakage current of the zinc oxide arrester 9 is sampled. An operational amplifier is used for signal conditioning. The non-inverting input terminal of the operational amplifier (that is, the input terminal of the resistor R2) is a 2.5V voltage provided by a precision voltage source as a reference voltage for boosting the level. Diode D1 and diode D2 play a protective role, and it is necessary to ensure that the voltage is limited within 3.3V, and 1N4001 can be selected. The voltage at the clamp input terminal of the varistor 3-2 cannot exceed a given value.

The structure of the lightning strike counting module 5 in the monitoring system of the present invention, as shown in FIG. The cathode of the diode D1 is connected in series with the capacitor C1, the cathode of the diode D2 is respectively connected with the capacitor C2, one end of the resistor R1 and one end of the resistor R2, and the other end of the resistor R2 is respectively connected with the pin 3 of the ACAC converter 5-2 and the diode D3 The positive pole of the diode D3 is connected to the negative pole of the diode D4, the positive pole of the diode D4, the other end of the resistor R1, the capacitor C2, the capacitor C1 and the other end of the second transformer 5-1 are respectively connected to the ACAC converter 5 The pin 2 of -2 is connected, the capacitor C1 adopts a capacitor with a high withstand voltage value, and the diode D1 and diode D2 adopt fast recovery diodes. Resistor R1 is a varistor, and resistor R2 is a cement resistor.

The pin 1 of the ACAC converter 5-2 is respectively connected with the negative pole of the capacitor C3, the negative pole of the Zener diode VD1, the negative pole of the Zener diode VD2, and one end of the resistor R3, and the other end of the resistor R3 is connected with the photocoupler 5-3 respectively. The anode of light-emitting diode is connected with the cathode of diode D5; -2 pin 4 is connected.

The base of the phototransistor in the optocoupler 5-3 is connected to a voltage of 5V, the emitters of the phototransistor are grounded respectively to capacitor C4, the capacitor C4 is connected in parallel with resistor R4, and the resistor R4 is connected to the collector of the phototransistor in the photocoupler 5-3 , the collector of the light-emitting transistor is also connected to the pin 1 of the inverting tube 5-4, and the pin 2 of the inverting tube 5-4 is respectively connected to the capacitor C5, the negative pole of the diode D6, the positive pole of the diode D7 and the Zener diode The negative poles of VD3 are connected, the positive poles of the capacitor C5 and the Zener diode VD3 are respectively connected to the positive pole of the diode D6 to DGND, and the negative pole of the diode D7 is connected to the 3.3 V voltage.

The lightning strike high voltage acts on the zinc oxide arrester 9, and a current is generated in the zinc oxide arrester 9, and the current flows into the lightning strike counting module 5, and the lightning strike counting module 5 performs rectification and limiting processing on the incoming current, and the processed current signal is sent by the photoelectric The coupler 5-3 transmits, and the optocoupler 5-3 plays the role of isolation protection while transmitting the current signal, and the current signal output by the optocoupler 5-3 is sent to the microprocessor 1 through the inverter 5-4 The counters 1-3 count as interrupt pulses. When the count input pulse has a high-to-low negative transition (that is, a falling edge trigger), the counter 1-3 adds "1". The number of times is sent to the microprocessor 1, and the microprocessor 1 accumulates the number of lightning strikes on the original basis.

The GPRS communication module 6 transmits information such as the monitored leakage current and lightning count pulses through the GPRS/GSM network over a long distance. GPRS is a standardized packet switching data service based on the traditional GSM network. It can provide packet data services at a rate of up to 115kbt/s, making the transmission of multimedia services including pictures, voice and video in wireless networks a reality. . It also adopts packet switching technology, no need to establish and maintain circuits during the communication process, which conforms to the bursty characteristics of data communication, and the call establishment time is very short, which can meet the requirements of wireless communication of this system.

The main program flowchart of the monitoring system of the present invention, as shown in Figure 5, the current signal measured by the leakage current sensor 3-1 is sent to the A/D conversion unit 2 after I/V conversion, amplification and filtering for sampling conversion; The phase difference signal is sent to the microprocessor 1 for calculation and processing to obtain the cosine value of the angle, and the A/D conversion result is also sent to the microprocessor 1 for calculation and processing, and then the two calculation results are multiplied to obtain the resistive For the current value, due to the interference between the phases, the software phase shifting method is used for phase shifting, and the phase is fine-tuned. When the lightning pulse signal is input to the microprocessor 1, the calculation process of the resistive current is stopped under the control of the piezoresistor 3-2, and at this time, the counting of the lightning pulse is performed.

The working process of the monitoring system of the present invention:

The microprocessor 1 outputs the received acquisition instruction through the input/output interface 1-1, starts the leakage current sampling module 3, the voltage sampling module 4 and the lightning strike counting module 5, and collects the leakage current signal and the voltage signal of the zinc oxide arrester 9 on site , and record the lightning counting pulse information, and simultaneously input the collected signal and recorded information into the microprocessor 1, and the microprocessor 1 displays the received signal and information through the liquid crystal display 7, and stores them in the random access memory 8, and at the same time, The microprocessor 1 processes the received signals and information, and after collecting the data of one power frequency cycle, transmits the processed data to the remote monitoring center through the GPRS communication module 6 .

The monitoring system dynamically monitors the insulation performance of the zinc oxide arrester 9 under the operating voltage, the test result is accurate and reliable, the test process is simple, the test period is short, and it is not easily affected by human and external factors. The whole system is easy to operate, convenient and quick to monitor, overcomes the shortcomings of bulky and inconvenient operation of existing testing instruments, and can provide long-term data on the operation and performance degradation of zinc oxide arresters, which has good practical value.

Claims (5)

1. The on-line monitoring system for zinc oxide lightning arresters is characterized in that it includes a microprocessor (1), and the microprocessor (1) communicates with the A/D conversion unit (2), the lightning strike counting module (5) and the GPRS communication module (6) respectively. ), the A/D conversion unit (2) is respectively connected with the leakage current sampling module (3) and the voltage sampling module (4), and the structure of the microprocessor (1) is provided with an input/output interface (1 -1), counter (1-3) and serial communication interface (1-4), input/output interface (1-1) is connected with A/D conversion unit (2), counter (1-3) is connected with lightning The counting module (5) is connected, the serial communication interface (1-4) is connected with the GPRS communication module (6), and the microprocessor (1) adopts FPGA chip EP1C6Q240C8, The structure of the leakage current sampling module (3): the leakage current sensor (3-1) and the piezoresistor (3-2) form a parallel circuit, one end of the parallel circuit is connected to one end of the resistor R1, and the parallel circuit The other end is grounded, and the other end of the resistor R1 is connected to the inverting input terminal of the operational amplifier A (3-3), and the inverting input terminal of the operational amplifier A (3-3) is respectively connected to one end of the resistor R2 and the operational amplifier A ( 3-3) is connected to the output terminal, the positive input terminal of the operational amplifier A (3-3) is connected in series with the resistor R3, the resistor R3 is grounded, and the output terminal of the operational amplifier A (3-3) is connected to one end of the resistor R5 , the other end of the resistor R5 is connected to the inverting input terminal of the operational amplifier B (3-4), between the inverting input terminal of the operational amplifier B (3-4) and the output terminal of the operational amplifier B (3-4) Resistor R7 is connected in series, the positive input terminal of operational amplifier B (3-4) is connected in series with resistor R6, resistor R6 is grounded, and the two bypasses of the output terminal of operational amplifier B (3-4) are respectively connected with diode D1 and diode D2, diode D1 The cathode of the diode and the anode of the diode D2 are respectively connected to the output terminal of the operational amplifier B (3-4), the anode of the diode D1 is connected to DGND, the cathode of the diode D2 is connected to VCC, The structure of the lightning strike counting module (5) includes: one end of the second transformer (5-1) is respectively connected to the anode of the diode D1 and the anode of the diode D2, the cathode of the diode D1 is connected in series with the capacitor C1, and the diode D2 The negative pole is respectively connected to the capacitor C2, one end of the resistor R1 and one end of the resistor R2, and the other end of the resistor R2 is respectively connected to the pin 3 of the ACAC converter (5-2) and the positive pole of the diode D3, and the negative pole of the diode D3 is connected to The cathode of the diode D4 is connected, and the anode of the diode D4, the other end of the resistor R1, the capacitor C2, the capacitor C1 and the other end of the second transformer (5-1) are respectively connected to the pin 2 of the ACAC converter (5-2). connected, The pin 1 of the ACAC converter (5-2) is respectively connected to the capacitor C3, the negative pole of the Zener diode VD1, the negative pole of the Zener diode VD2 and one end of the resistor R3, and the other end of the resistor R3 is respectively connected to the optocoupler The anode of the light-emitting diode in (5-3) is connected to the cathode of the diode D5, the capacitor C3, the anode of the Zener diode VD1, the anode of the Zener diode VD2, the anode of the diode D5 and the light-emitting diode in the optocoupler (5-3) The negative electrodes of the ACAC converter (5-2) are respectively connected to pin 4, The base of the phototransistor in the optocoupler (5-3) is connected to 5V voltage, the emitter of the phototransistor in the optocoupler (5-3) is grounded respectively to capacitor C4, capacitor C4 is connected in series with resistor R4, and resistor R4 is connected to The collector of the phototransistor in the optocoupler (5-3), the collector of the light emitting transistor in the optocoupler (5-3) is also connected to pin 1 of the inverting tube (5-4), and the inverting tube ( 5-4) Pin 2 is respectively connected to the capacitor C5, the cathode of the diode D6, the anode of the diode D7 and the cathode of the Zener diode VD3, the anode of the capacitor C5 and the Zener diode VD3 are respectively grounded, and the anode of the diode D6 is connected to DGND , the cathode of diode D7 is connected to 3.3 V voltage. 2. The monitoring system according to claim 1, characterized in that, the structure of the microprocessor (1) also includes a general input/output port (1-2), and the general input/output port (1-2) is respectively It is connected with liquid crystal display (7) and RAM (8). 3. The monitoring system according to claim 1, characterized in that the leakage current sensor (3-1) adopts a BCT-2 type electromagnetic core-through small current sensor based on active zero-flux technology. 4. The monitoring system according to claim 1, characterized in that the structure of the voltage sampling module (4) includes a first transformer (4-1), a primary winding of the first transformer (4-1) A phase voltage is applied between the upper and lower ends of the first transformer (4-1), the upper end of the primary winding of the first transformer (4-1) is connected in series with a resistor R1, and the upper end of the secondary winding of the first transformer (4-1) is connected to the active operational amplifier (4 -2) is connected to the positive input terminal, the lower end of the secondary winding of the first transformer (4-1) is connected to the negative input terminal of the active operational amplifier (4-2), the first transformer (4- 1) Between the active operational amplifier (4-2), from the first transformer (4-1) to the active operational amplifier (4-2), a diode D1 and a diode D2 are connected in parallel in sequence, and the anode of the diode D1 is connected to the first The upper end of the secondary winding of a transformer (4-1) is connected, the cathode of the diode D1 is connected to the lower end of the secondary winding of the first transformer (4-1), the cathode of the diode D2 is connected to the first transformer (4-1) 1) The upper end of the secondary winding is connected, the anode of the diode D2 is connected to the lower end of the secondary winding of the first transformer (4-1), and the positive input terminal and output terminal of the active operational amplifier (4-2) A resistor R2 is connected in series between them, and the output terminal of the active operational amplifier (4-2) is also connected to one end of the capacitor C, and the other end of the capacitor C is grounded. 5. The monitoring system according to claim 4, characterized in that the first transformer (4-1) is a miniature current-type voltage transformer.

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