CN110567840A - A Gas Density Transmitter and Monitoring System Against Overvoltage - Google Patents

Abstract

The invention discloses a gas density transmitter. An anti-overvoltage gas density transmitter includes a shell, a pressure sensor, a pressure sensor fixing seat, a temperature sensor, an intelligent processor, a communication module, and a connection joint. The intelligent processor is respectively connected with the temperature sensor, the pressure sensor and the communication module. The intelligent processor collects the pressure signal through the pressure sensor, and the temperature sensor collects the temperature signal. According to the gas pressure-temperature characteristics, the corresponding density value P ₂₀ is obtained through the intelligent processor processing, and the density value P ₂₀ and the pressure value can be transmitted remotely through the communication module. , one or several values in the temperature value, and then realize the online monitoring of the gas of the electrical equipment. The pressure sensor is sealed and fixed on the pressure sensor fixing seat through several insulating pieces, and the shell of the pressure sensor is insulated from the pressure sensor fixing seat. This optimized design greatly improves the anti-overvoltage and anti-interference ability of the gas density transmitter.

Description

A Gas Density Transmitter and Monitoring System Against Overvoltage

technical field

The invention relates to the field of electric power technology, in particular to a high-performance gas density transmitter applied to high-voltage or medium-voltage electrical equipment.

Background technique

At present, SF ₆ (sulfur hexafluoride) electrical equipment has been widely used in the power sector and industrial and mining enterprises, which has promoted the rapid development of the power industry. In recent years, with the rapid economic development, the capacity of China's power system has expanded rapidly, and the amount of SF ₆ electrical equipment has increased. The role of SF ₆ gas in high-voltage electrical equipment is arc extinguishing and insulation. The reduction of the density of SF ₆ gas in high-voltage electrical equipment will seriously affect the safe operation of SF ₆ high-voltage electrical equipment: the reduction of SF ₆ gas density to a certain level will lead to insulation and Loss of arc extinguishing performance.

With the development of unattended substations towards networking and digitalization and the increasing requirements for remote control and telemetry, the on-line monitoring of the gas density and micro-water content of SF ₆ electrical equipment has important practical significance. With the continuous vigorous development of China's smart grid and ubiquitous power Internet of Things, smart high-voltage electrical equipment, as an important part and key node of smart substations, plays a pivotal role in the security of smart grids. At present, most high-voltage electrical equipment is SF ₆ gas-insulated equipment. If the gas density decreases (such as caused by leakage, etc.), it will seriously affect the electrical performance of the equipment and cause serious hidden dangers to safe operation. At present, it is very common to monitor the gas density value in SF ₆ high-voltage electrical equipment online. In particular, the State Grid proposes to build a ubiquitous power Internet of Things. For this reason, the application of the gas density monitoring system (gas density relay) will flourish. The current gas density monitoring system (gas density relay) is basically: 1) The remote SF ₆ gas density relay is used to collect and upload the density, pressure and temperature to realize the online monitoring of gas density. 2) The gas density transmitter is used to collect and upload the density, pressure and temperature to realize online monitoring of gas density. The SF ₆ gas density relay is the core and key component. At present, it is very common to monitor the SF ₆ gas density value in SF ₆ high-voltage electrical equipment online. Therefore, the gas density transmitter is used to realize the collection of density, pressure and temperature. Obviously the gas density transmitter is also the core and key component. However, due to the harsh on-site operation environment of the high-voltage substation, especially when the system is operating, a high overvoltage will be generated, which may cause direct damage to the sensor or electronic components, and then cause the gas density transmitter to fail to work. And the electromagnetic interference on site is very strong, which will also cause the gas density transmitter to not work reliably. In short, the gas density transmitters currently used have the following defects: 1) easy to damage; 2) abnormal signal transmission often occurs. The current products are not suitable for working in harsh outdoor environments, and it is difficult to meet the construction requirements of the ubiquitous power Internet of Things.

Contents of the invention

The present invention aims to solve the above-mentioned defects of the existing problems, and provides an anti-overvoltage gas density transmitter and monitoring system. The invention is used for real-time monitoring of the gas density of gas-insulated or arc-extinguishing electrical equipment, improves efficiency, reduces operation and maintenance costs, and ensures safe operation of a power grid.

The present invention is realized in this way, an overvoltage resistant gas density transmitter, including a housing, a pressure sensor inside the housing, a pressure sensor fixing seat, a temperature sensor, an intelligent processor, a communication module, a connecting joint and a power supply; The intelligent processor is respectively connected with the temperature sensor, pressure sensor, and communication module; the intelligent processor collects the pressure signal through the pressure sensor, and the temperature sensor collects the temperature signal, and according to the gas pressure-temperature characteristics, the corresponding density value is obtained through the intelligent processor P ₂₀ , and the density value P ₂₀ , or density value, pressure value, temperature value, or pressure value, temperature value is transmitted remotely through the communication module, and then the gas density value, or density value, pressure value, temperature value of the electrical equipment can be monitored online Value, or pressure value, temperature value; The pressure sensor is sealed and fixed on the pressure sensor fixing seat through several insulating parts, and the shell of the pressure sensor is insulated from the pressure sensor fixing seat.

The gas density transmitter with anti-overvoltage further includes an electric field shield, and the electric field shield is arranged outside the pressure sensor and/or the electronic components.

The gas density transmitter with anti-overvoltage further includes a magnetic field shield, and the magnetic field shield is arranged outside the pressure sensor and/or the electronic components.

The gas density transmitter with anti-overvoltage further includes a thermal insulation, and the thermal insulation is arranged at the power supply; or, the temperature sensor is far away from the power supply.

In the above-mentioned gas density transmitter with anti-overvoltage, the intelligent processor is loaded with an embedded system embedded algorithm and control program based on a microprocessor.

The gas density transmitter with anti-overvoltage, the gas density transmitter also includes a value display device, the value display device includes a signal contact, a movement, a pointer and a dial, or includes a digital display device.

In the gas density transmitter with anti-overvoltage, the outside or inside of the casing further includes electromagnetic shielding parts.

In the gas density transmitter with anti-overvoltage, the intelligent processor and/or communication module are provided with a shield.

In the gas density transmitter with anti-overvoltage, the intelligent processor is suitable for gas density transmitters measuring relative pressure and absolute pressure.

The gas density transmitter with anti-overvoltage has a human-computer interaction interface: a data display interface, which refreshes the current data value in real time; and a data input and parameter setting input box.

In the gas density transmitter with anti-overvoltage, the electrical interface of the gas density transmitter has protection functions of anti-misconnection and anti-electromagnetic interference.

In the gas density transmitter with anti-overvoltage, the intelligent processor realizes long-distance transmission of test data and/or results through the communication module; the communication module is arranged on the housing of electronic components or on the housing of the machine .

The overvoltage resistant gas density transmitter also includes a clock loaded on an intelligent processor to record test time.

In the gas density transmitter with anti-overvoltage, the control of the intelligent processor can be controlled through on-site control, background control, or mutual interaction between the two.

The overvoltage-resistant gas density transmitter also includes a micro-water sensor for on-line monitoring of gas micro-water value.

The overvoltage-resistant gas density transmitter also includes a decomposition product sensor, which can monitor gas decomposition products online.

The gas density transmitter with anti-overvoltage, the gas density transmitter also includes an expert management and analysis system, which detects, analyzes and judges the gas density monitoring, gas density transmitter performance, and monitoring components.

The gas density transmitter with anti-overvoltage also includes a plurality of insulating parts, through which the insulation between the pressure sensor, the housing and the connection joint is realized; and the outer casing and the connecting joint of the pressure sensor The housing of the gas density transmitter is insulated between.

A gas density monitoring system composed of the overvoltage-resistant gas density transmitters, comprising: several of the overvoltage-resistant gas density transmitters are sequentially connected to a remote background detection system through a hub and a protocol converter; Wherein, the anti-overvoltage gas density transmitters are respectively arranged on the electrical equipment of the corresponding gas chamber.

In the gas density monitoring system composed of the overvoltage-resistant gas density transmitter, the protocol converter is an IEC61850 or 104 protocol converter.

The gas density monitoring system consisting of the overvoltage-resistant gas density transmitter is characterized in that the hub adopts an RS485 hub, and the IEC61850 protocol converter or the IEC104 protocol converter is also connected with the network service printer respectively Connect with network data router.

A high-performance gas density transmitter provided by the invention includes a housing, a pressure sensor, a pressure sensor fixing seat, a temperature sensor, an intelligent processor, a communication module, and a connecting joint. The intelligent processor is respectively connected with the temperature sensor, the pressure sensor and the communication module. The intelligent processor collects the pressure signal through the pressure sensor, and the temperature sensor collects the temperature signal. According to the gas pressure-temperature characteristics, the corresponding density value P ₂₀ (that is, the pressure value P ₂₀ at 20°C) is obtained through the processing of the intelligent processor, and through communication The module can remotely transmit the density value P ₂₀ , or the density value, pressure value, temperature value, or pressure value, temperature value, and then realize the online monitoring of the gas density value, or density value, pressure value, temperature value, or pressure value of the electrical equipment , temperature value. In order to improve the anti-overvoltage ability, the pressure sensor is sealed and fixed on the pressure sensor fixing seat through several insulating parts, and the shell of the pressure sensor and the pressure sensor fixing seat are insulated, which can greatly improve the anti-overvoltage ability, anti-electromagnetic Interference ability.

The invention provides a high-performance gas density transmitter for high-voltage electrical equipment. The shell of the pressure sensor is insulated from the fixing seat of the pressure sensor, which can greatly improve the anti-overvoltage and anti-electromagnetic interference capabilities. In addition, a shield is added, and the shield can shield the electric field or the magnetic field, that is, the reflection and/or absorption effect of the material of the shield is used to reduce EMI radiation. The effective addition of shielding materials can reduce or eliminate unnecessary gaps, suppress electromagnetic coupling radiation, and reduce electromagnetic leakage and interference. Materials with high conductivity and magnetic properties can be used as electromagnetic shielding materials (such as iron), and the shielding performance is generally required to reach 40-60dB. Specifically, the electronic components are partially sealed in a housing made of shielding material. Good sealing can well overcome the interference problem caused by electromagnetic leakage due to the conductive discontinuity of the gap.

The electrical equipment includes SF ₆ gas electrical equipment, SF ₆ mixed gas electrical equipment, environment-friendly gas electrical equipment, or other insulating gas electrical equipment. Electrical equipment includes GIS, GIL, PASS, circuit breakers, current transformers, voltage transformers, transformers, inflatable cabinets, ring network cabinets, etc.

Description of drawings

FIG. 1 is a schematic structural view of Embodiment 1 of the present invention;

FIG. 2 is a schematic diagram of a control circuit according to Embodiment 1 of the present invention;

FIG. 3 is a schematic diagram of the system architecture of Embodiment 2 of the present invention;

FIG. 4 is a schematic diagram of the system architecture of Embodiment 3 of the present invention;

FIG. 5 is a schematic diagram of the system architecture of Embodiment 4 of the present invention.

Detailed ways:

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

Figure 1 is a schematic structural diagram of a high-performance gas density transmitter for high-voltage electrical equipment in Embodiment 1 of the present invention. The gas density transmitter includes: pressure sensor 201, temperature sensor 3, intelligent microprocessor 202, equipment connection joint 1010, power supply module 203, insulating parts 204, 205, 206, pressure sensor fixing seat 207, shielding part 208, 209, 2011, transmitter housing 2010, signal line terminal block 2012 and communication module 2013. As shown in FIG. 2 , the intelligent microprocessor 202 is connected with the pressure sensor 201 and the temperature sensor 3 respectively. The pressure P and temperature T signals are collected by the pressure sensor 201 and the temperature sensor 3, and the corresponding density value P ₂₀ (that is, the pressure value P ₂₀ at 20°C) is obtained after processing by the intelligent microprocessor 202 according to the gas pressure-temperature characteristics, and then The online monitoring of the gas density value P ₂₀ (or density value, pressure value, temperature value, or pressure value, temperature value) of the electrical equipment is realized. The monitored information and/or signals are uploaded to the target device through the communication module 2013, and the information includes: gas density value P ₂₀ , or density value, pressure value, temperature value, or pressure value, temperature value, etc. Information, and/or signals are connected to the target device through the signal wire socket 2012 .

The innovation of this technical solution is: the pressure sensor 201 is sealed and fixed on the pressure sensor fixing seat 207 through the insulators 204 , 205 , 206 . Since the pressure sensor 201 is sealed and fixed on the pressure sensor fixing seat 207 through several insulating parts 204, 205, 206, solid insulating parts 204, 205, 206 are added between the shell of the pressure sensor 201 and the pressure sensor fixing seat 207. The pressure sensor 201 can withstand high system overvoltage or lightning strike overvoltage, so that the pressure sensor will not be damaged. It is very important that the insulator 205 is a sealing member with good sealing performance, which can ensure that the pressure sensor 201 is sealed and fixed on the pressure sensor fixing seat 207 to form a well-sealed gas circuit. At the same time, a shield 208 is provided outside the insulator 204 of the housing of the pressure and temperature sensor, and the reflection and/or absorption of the shield 208 is used to reduce EMI electromagnetic radiation, suppress electromagnetic coupling radiation, and reduce electromagnetic leakage and interference. The shielding member 208 can use a material with high conductivity and magnetic permeability as the electromagnetic shielding material, and the shielding performance is generally required to reach 40-60 dB. For example, galvanized sheet, nickel-plated stainless steel can be used, such materials with good magnetic permeability; and copper foil and tin foil with high conductivity; they have good shielding effects on magnetic field and electric field respectively. Specifically, it is also possible to seal the sensor 201 and the remote electronic component part 2 in a casing made of shielding materials 209 and 2011 . Good sealing can well overcome the interference problem caused by electromagnetic leakage due to the conductive discontinuity of the gap, and further improve the anti-interference level of the remote density relay.

It can be seen from Table 1 that the density transmitter using this patented technology has very good anti-overvoltage ability, anti-interference ability and stability, meets the high precision requirements, and can improve the environmental adaptability of the density relay. At the same time, the key is its strong anti-interference ability and very good stability, which greatly improves the reliability and accuracy of the smart grid.

Table 1 Comparison table of contact performance between the density transmitter of this patented technology and the density transmitter of the prior art

The gas density transmitter includes an insulating member, and the pressure sensor is connected to the pressure sensor fixing seat through the insulating member; or the pressure sensor is sealed and fixed on the pressure sensor fixing seat through the insulating member. At the same time, the insulating member 205 is a sealing member with good sealing performance, which not only ensures the sealing, but also improves the anti-overvoltage capability of the transmitter.

A shield 208 is provided outside the sensor housing to improve the anti-interference ability of the density monitor. At the same time, a shielding member 2011 is provided inside (or outside) the housing 2010 of the redensity monitor, and the shielding is to use the reflection and/or absorption effect of the material to reduce EMI radiation. The body is to partially seal the electronic components in a housing made of shielding material. Good sealing can well overcome the interference problem caused by electromagnetic leakage due to the conductive discontinuity of the gap. This can further improve the anti-interference ability of the density transmitter.

The gas density transmitter also includes a thermal insulation, and the thermal insulation is arranged at the power supply (power module); or, the temperature sensor is far away from the heating device. Alternatively, the power source (power module) is located away from the temperature sensor. In this way, the heating of the power supply will not cause measurement errors to the temperature sensor.

The density value P ₂₀ may be a gas density value P ₂₀ monitored in real time; or may be a gas density value P ₂₀ obtained after an average method; or may be a gas density value P ₂₀ obtained after trend value correction. The intelligent microprocessor calculates and processes the gas density values of the electrical equipment using an average method (average method) to obtain an _average value P20 of _the gas density values P20. The average value method is as follows: in the set time interval, the collection frequency is set, and the density values (N) at different time points obtained by all the collections are carried out to the average value calculation process, and the gas density value _P20 is obtained. The average value P _{20 average} is the gas density value P ₂₀ .

The intelligent processor is based on the microprocessor-based embedded system embedded algorithm and control program to automatically control the entire monitoring process, including all peripherals, logic and input and output. The gas density transmitter also includes a signal contact, a movement, a pointer, and a dial, and has an indication display; or, includes a digital display device, and has an indication display. Digital display, convenient and intuitive reading. The outside or inside of the casing of the gas density transmitter further includes a shielding member, which can shield the electric field, or the magnetic field, or the electric field and the magnetic field. The pressure sensor is provided with a shield. The intelligent processor or the communication module is provided with a shield; or both the intelligent processor and the communication module are provided with a shield. In this way, the anti-interference ability of the transmitter is further improved.

The intelligent processor can measure relative pressure and absolute pressure type gas density transmitter. The gas density transmitter has a human-computer interaction function: it has a data display interface and can refresh the current data value in real time; it has a data input function and can input parameter setting values; the intelligent processor has an interface and can complete test data storage; And/or test data export; and/or test data can be printed; and/or can carry out data communication with the host computer; and/or can input analog and digital information. The electrical interface of the gas density transmitter has a protection function, and the interface will not be damaged if misconnected; or/and will not be disturbed by electromagnetic fields. The intelligent processor also includes a communication module, through which information such as test data and/or results can be transmitted remotely. The communication module can be arranged on the housing of electronic components or on the housing of the machine. It can also include a clock, which is set on the intelligent processor and can record the test time. The control of the intelligent processor can be controlled through on-site control, background control, or the interaction between the two. The gas density transmitter has the functions of real-time online density value, pressure value, temperature value and other data display, change trend analysis, historical data query, real-time alarm and other functions.

The gas density transmitter also includes a micro-water sensor, which can monitor the gas micro-water value online. The gas density transmitter also includes a decomposition product sensor, which can monitor gas decomposition products online. In this way, the function of the transmitter is more complete, and the protection of electrical equipment is safer.

The gas density transmitter has a self-diagnostic function and can report abnormalities in time. Such as disconnection, short circuit alarm, sensor damage and other notices. When the density of the gas density transmitter is monitored online and the gas pressure has a rising trend, an abnormal notice should be raised in time.

Using edge computing, the density transmitter can input events such as gas supplementation and/or deflation tests, and can perform new calculations of _the gas density value P20 according to events such as corresponding gas supplementation and/or deflation tests. or adjust. If the density transmitter monitors that the gas density value _P20 gradually increases within a certain short period of time, it can be judged as an air supply event, and it can be judged based on the maximum gas density value _P20 monitored at that time. For the end of the refilling event, a new calculation or adjustment of the gas density value P ₂₀ is performed. If the density transmitter detects that the gas density value _P20 gradually drops slightly within a certain short period of time, it can be judged as an outgassing test (micro water or decomposition) event, and can be based on the minimum gas density monitored at that time. When the value is _P20 , it is judged that the outgassing test event is over, and a new calculation or adjustment of _the gas density value P20 is performed. The density transmitter can record events such as gas supplementation and/or gas deflation testing, such as time, or/and times, or/and gas quality.

The gas density transmitter also includes an analysis system (expert management analysis system), which detects, analyzes and judges gas density monitoring, gas density transmitter performance, and monitoring components. The gas density transmitter has data analysis and data processing functions, and can perform corresponding fault diagnosis and prediction on electrical equipment and the gas density transmitter itself.

Figure 3 shows a gas density monitoring system composed of high-performance gas density transmitters, as shown in Figure 3, including: several high-voltage or medium-voltage electrical equipment with gas chambers, several high-performance gas density transmitters The transmitters are connected to the remote background detection system through a hub and a protocol converter in turn; among them, the high-performance gas density transmitters are respectively set on the high-voltage or medium-voltage electrical equipment corresponding to the gas chamber.

A gas density monitoring system composed of high-performance gas density transmitters, including: several high-voltage electrical equipment equipped with sulfur hexafluoride gas chambers, and several high-performance gas density transmitters, all of which pass through the hub and IEC61850 protocol converter in turn It is connected with the remote background detection system; among them, the high-performance gas density transmitter is respectively set on the high-voltage electrical equipment of the corresponding sulfur hexafluoride gas chamber.

The gas density monitoring system is composed of high-performance gas density transmitters. The gas density transmitter has the functions of real-time online density value, pressure value, temperature value and other data display, trend analysis, historical data query, real-time alarm and other functions. With data analysis and data processing functions, it can perform corresponding fault diagnosis and prediction on electrical equipment, and provide technical support for condition-based maintenance of electrical equipment.

As shown in Figures 3 and 4, PC is the online monitoring background host and system, Gateway is the network switch, Server is the comprehensive application server, ProC is the protocol converter/online monitoring intelligent unit, HUB is the hub, and Z is the high-performance gas Density transmitter. On-line monitoring system architecture: Detailed system diagrams such as simple architecture (Figure 3), conventional architecture (Figure 4), and complex architecture. System architecture diagram and brief description: 1. Background software platform: based on Windows, Linux and others, or VxWorks, Android, Unix, UCos, FreeRTOS, RTX, embOS, MacOS. 2. Key business modules and basic functions of background software: such as authority management, device management, data storage and query, etc.; and user management, alarm management, real-time data, historical data, real-time curves, historical curves, configuration management, data acquisition, data Parsing, recording conditions, exception handling. 3. Interface configuration: such as Form interface, Web interface, configuration interface, etc. The monitoring system can also be an architecture system diagram of the wireless transmission mode, as shown in Figure 5. The wireless module and the high-performance gas density transmitter can be integrated or separated, and the specific scheme can be flexible.

This monitoring system can monitor the temperature, pressure, density, micro-water and other physical quantities of SF6 gas inside the circuit breaker, GIS and other electrical equipment in real time and its change trend, and has a communication interface to upload the data to the background system to realize circuit breaker, GIS, etc. On-line monitoring function of electrical equipment SF6 gas density, micro water and other physical quantities, and can flexibly set the alarm limit, query historical data on the spot, accurately analyze and judge the leakage trend and leakage rate of the equipment, and detect abnormalities in the equipment in advance, so as to ensure Safe operation of electrical equipment and the whole system of substation. Really realize the online monitoring of electrical equipment in substations, especially unattended stations. It plays an important role in improving the safe operation and operation management level of the power grid system, carrying out expected diagnosis and trend analysis, and reducing unplanned power outage maintenance.

A gas density monitoring system composed of high-performance gas density transmitters, the communication mode of the several high-performance gas density transmitters is wired or wireless. Wired communication methods are RS232, RS485, CAN-BUS and other industrial buses, optical fiber Ethernet, 4-20mA, Hart, IIC, SPI, Wire, coaxial cable, PLC power carrier, etc.; wireless communication methods are sensor built-in 5G/NB -IOT communication modules (such as 5G, NB-IOT), 2G/3G/4G/5G, WIFI, Bluetooth, Lora, Lorawan, Zigbee, infrared, ultrasonic, sound wave, satellite, light wave, quantum communication, sonar, etc. The sensor data is uploaded to the IoT cloud platform. The hub adopts RS485 hub, and the IEC61850 protocol converter is connected with the network service printer and the network data router respectively.

The invention provides a high-performance gas density transmitter for high-voltage and medium-voltage electrical equipment, or a monitoring system composed of it, which can overcome the inability of mechanical SF6 gas density relays to accurately monitor SF ₆ gas in electrical equipment The problem of density can be solved, and the problems of large investment and inconvenient construction on site can be overcome. It can inform the operation and maintenance personnel of the accurate information of air leakage in time, deal with the air leakage problem in time, improve safety performance, reduce operation and maintenance costs, and ensure the safe operation of the power grid. At the same time, it can greatly reduce the emission of SF ₆ gas and protect the environment.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the present invention. scope.

Claims (21)

1. An overvoltage-resistant gas density transmitter is characterized by comprising a shell, a pressure sensor fixing seat, a temperature sensor, an intelligent processor, a communication module, a connecting joint and a power supply, wherein the pressure sensor, the pressure sensor fixing seat, the temperature sensor, the intelligent processor, the communication module, the connecting joint and the power supply are arranged in the shell; the intelligent processor is respectively connected with the temperature sensor, the pressure sensor and the communication module; the intelligent processor collects pressure signals through the pressure sensor and collects temperature through the temperature sensorThe signal is processed by an intelligent processor according to the gas pressure-temperature characteristic to obtain a corresponding density value P₂₀and remotely transmitting the density value P through the communication module₂₀Or the density value, the pressure value and the temperature value, or the pressure value and the temperature value, so as to realize online monitoring of the gas density value, or the density value, the pressure value and the temperature value, or the pressure value and the temperature value of the electrical equipment; the pressure sensor is characterized in that the pressure sensor is fixed on the pressure sensor fixing seat in a sealing mode through a plurality of insulating parts, and the shell of the pressure sensor is insulated from the pressure sensor fixing seat.

2. An overvoltage resistant gas density transmitter as claimed in claim 1 further including an electric field shield disposed outside the pressure sensor and/or electronic component portion.

3. The overvoltage resistant gas density transmitter of claim 1, further comprising a magnetic field shield disposed outside the pressure sensor and/or electronics portion.

4. The overvoltage resistant gas density transmitter of claim 1 further including insulation disposed at the power supply; alternatively, the temperature sensor is remote from the power source.

5. The overvoltage resistant gas density transmitter of claim 1 wherein the intelligent processor carries embedded microprocessor based algorithms and control programs.

6. An overvoltage resistant gas density transmitter as claimed in claim 1 further including an indication display including signal contacts, a movement, a pointer and a dial or including a digital display device.

7. The overvoltage resistant gas density transmitter of claim 1 wherein the housing further includes electromagnetic shielding on the outside or inside.

8. The overvoltage resistant gas density transmitter of claim 1, wherein the smart processor and/or communication module is provided with shielding.

9. The overvoltage resistant gas density transmitter of claim 1, wherein the intelligent processor is adapted to measure both relative pressure and absolute pressure types of gas density transmitters.

10. The overvoltage resistant gas density transmitter of claim 1, wherein the gas density transmitter has a human machine interface: the method comprises the steps of providing a data display interface, and refreshing a current data value in real time; has data input and parameter set value input boxes.

11. the overvoltage resistant gas density transmitter of claim 1 wherein the electrical interface of the gas density transmitter is provided with protection against misconnection and electromagnetic interference.

12. The overvoltage resistant gas density transmitter of claim 1 wherein the intelligent processor enables remote transmission of test data and/or results via the communication module; the communication module is arranged on the electronic component shell or the mechanical shell.

13. The overvoltage resistant gas density transmitter of claim 1 further including a clock, the clock being loaded on the intelligent processor to record the test time.

14. The overvoltage resistant gas density transmitter of claim 1 wherein the intelligent processor is controlled by either field control or background control or both.

15. The overvoltage resistant gas density transmitter of claim 1 further including a micro water sensor for on-line monitoring of gas micro water values.

16. The overvoltage resistant gas density transmitter of claim 1 further including a analyte sensor capable of on-line monitoring of gas analytes.

17. The overvoltage resistant gas density transmitter of claim 1 further including an expert management analysis system for detecting, analyzing and evaluating the gas density monitoring, gas density transmitter performance, and monitoring components.

18. The overvoltage resistant gas density transmitter of claim 1 further including a plurality of insulators through which said pressure sensor is insulated from said housing and said connector; and the housing of the pressure sensor and the housing of the gas density transmitter are insulated from each other.

19. A gas density monitoring system comprised of the overvoltage resistant gas density transmitter, comprising: the overvoltage-resistant gas density transmitters are connected with a remote background detection system sequentially through the concentrator and the protocol converter; the overvoltage-resistant gas density transmitters are respectively arranged on the electrical equipment of the corresponding gas chambers.

20. The gas density monitoring system of claim 19, wherein the protocol converter is an IEC61850 or 104 protocol converter.

21. A gas density monitoring system consisting of said overvoltage resistant gas density transmitter according to claim 19, wherein the hub is an RS485 hub and the IEC61850 protocol converter or 104 protocol converter is further connected to the network service printer and the network data router, respectively.