Decomposition product detection system based on low-carbon GIS mixed gas

Abstract

The invention discloses a decomposition product detection system based on low-carbon GIS (Gas Insulated Switchgear) mixed gas, relates to the technical field of mixed gas detection, and solves the technical problem that the measurement result is inaccurate due to the fact that the influence of oxygen on a thermal conductivity sensor is not considered in the prior art. Mixed gas is stored through the gas storage module, oxygen detection is conducted on the mixed gas through the electrochemical sensor to obtain the oxygen content, the mixing proportion of the mixed gas is calculated in combination with the influence of the oxygen content in a thermal conductivity detection method, and the mixed gas is decomposed into decomposed gas and pure gas through an electromagnetic decomposition method; deducing and calculating according to a Faraday formula to obtain a flow electron rate, and combining with a mixing ratio of the mixed gas to obtain a decomposition product; the decomposed gas is conveyed to a gas buffer tank, the gas pressure in the gas buffer tank is compared with a preset pressure threshold value, starting of a compressor is controlled according to a comparison result, and tail gas recovery is completed.

Description

Technical Field

[0001] The invention belongs to the field of mixed gas detection, in particular to a decomposition product detection system based on low-carbon GIS mixed gas. Background Art

[0002] SF6 gas is widely used in the power industry due to its excellent insulation and arc extinguishing performance. However, sulfur hexafluoride has a significant greenhouse effect and is one of the six greenhouse gases that are prohibited from being emitted in the Kyoto Protocol. Therefore, it needs to be strictly controlled during use. In order to adapt to the new international environmental protection requirements, mixed insulating gas has begun to be used at home and abroad to replace pure sulfur hexafluoride insulating gas and reduce the use of sulfur hexafluoride gas. The use of mixed insulating gas (SF6 / N2) has become an inevitable trend in the development of electricity.

[0003] The invention patent with application number CN2023107459991 discloses a low-carbon GIS mixed gas detection system, which detects the mixing ratio of sulfur hexafluoride and nitrogen in the mixed gas by infrared detection or thermal conductivity detection, detects the humidity of the mixed gas by a polymer method, and uses an electrochemical method to detect the decomposition products generated during a fault, and recovers the decomposition products; when the invention detects and analyzes the mixing ratio of the mixed gas by thermal conductivity detection, because oxygen may be mixed in the mixed gas, when monitoring temperature changes, the influence of oxygen on the thermal conductivity sensor causes the thermal conductivity of the mixed gas to change, resulting in inaccurate measurement results, which ultimately affects the detection results of the decomposition products.

[0004] The present invention provides a decomposition product detection system based on low-carbon GIS mixed gas to solve the above technical problems. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art; to this end, the present invention proposes a decomposition product detection system based on a low-carbon GIS mixed gas, which is used to solve the technical problem in the prior art that the measurement results are inaccurate due to the failure to consider the influence of oxygen on the thermal conductivity sensor.

[0006] To achieve the above-mentioned object, the first aspect of the present invention provides a decomposition product detection system based on low-carbon GIS mixed gas, comprising: a characteristic detection module, a product detection module and a decomposition gas recovery module;

[0007] Characteristic detection module: used to heat the gas chamber, monitor the temperature of the gas chamber in the characteristic detector through the temperature sensor, and control the switch of the heating unit according to the temperature of the gas chamber; detect the characteristic electrical signal produced by the electrode in the characteristic detector, and analyze the characteristic electrical signal to obtain the mixing ratio of the mixed gas;

[0008] Product detection module: used to perform electromagnetic decomposition on the mixed gas to obtain decomposition gas and pure gas, and to detect the decomposition products contained in the decomposition gas through the electrical signal quantitative analysis method;

[0009] Decomposition gas recovery module: used to collect and store decomposition gas, compress the decomposition gas in the gas tank and monitor the gas pressure in the gas tank, and control the on / off state of the compressor based on the gas pressure.

[0010] Preferably, the switching of the heating unit is controlled according to the air chamber temperature, comprising:

[0011] A1: Extraction of gas chamber temperature and corresponding temperature time;

[0012] A2: Setting a preset temperature; the preset temperature is set according to the standard operating temperature of the thermal sensor; the oxygen content is obtained by detecting the oxygen content of the mixed gas in the gas chamber through the electrochemical sensor;

[0013] A3: Determine whether the air chamber temperature is equal to the preset temperature; if yes, control the heating unit to switch to the heat preservation state and jump to A4; if no, jump to A5;

[0014] A4: Determine whether the current air chamber temperature is the same as the previous air chamber temperature; if yes, mark the air chamber temperature state as being in a heat preservation state; if no, continue to detect the air chamber temperature and mark the air chamber temperature state as being not in a heat preservation state;

[0015] A5: Determine whether the current air chamber temperature is greater than the preset temperature; if yes, mark the temperature state of the air chamber as over-temperature state, control the heating unit to start lowering the temperature until the preset temperature is reached and the insulation state is turned on; if no, mark the temperature state of the air chamber as low-temperature state, control the heating unit to continue heating until the preset temperature is reached and the insulation state is turned on.

[0016] Preferably, the oxygen content is obtained by performing oxygen detection on the mixed gas in the gas chamber by an electrochemical sensor, comprising:

[0017] B1: Delivers the mixed gas to the high-range electrochemical sensor;

[0018] B2: Determine whether the high-range electrochemical sensor generates a high-concentration electrical signal; if yes, mark the high-concentration electrical signal as a mixed gas electrical signal; if no, deliver the mixed gas to the low-range electrochemical sensor and jump to B3;

[0019] B3: Determine whether the low-range electrochemical sensor generates an electrical signal; if so, the low-concentration electrical signal is marked as a mixed gas electrical signal; if not, it means that there is no oxygen in the mixed gas;

[0020] The mixed gas electrical signal is matched with the electrical signal-oxygen content comparison table to obtain the oxygen content of the mixed gas.

[0021] Preferably, the step of analyzing the characteristic electrical signal to obtain the mixing ratio of the mixed gas includes:

[0022] Extract the oxygen content in the mixed gas;

[0023] The mixed gas is transported to the electrochemical gas sensor for oxidation-reduction, an oxidation-reduction electrical signal is generated at the electrode, and the oxidation-reduction electrical signal is converted into a characteristic digital signal;

[0024] The effect of oxygen content on the thermal conductivity sensor is marked as f(Co 2 ); the oxygen signal Io of the oxygen in the characteristic digital signal of the mixed gas is calculated by the formula Io=K×Co; wherein k is the proportional coefficient corresponding to the working condition of the electrochemical gas sensor, and Co represents the concentration of oxygen;

[0025] By the formula Cq = [K × f (Co 2 )] / (Iq-Io) to calculate the mixing ratio Cq of type q gas in the mixed gas; wherein Iq represents the gas signal occupied by gas q.

[0026] Preferably, the detecting of the decomposition products contained in the decomposition gas by means of an electrical signal quantitative analysis method comprises:

[0027] The number of electrons generated at the electrode during the redox process, the electrical signal and the mixing ratio of the mixed gas are extracted, and the formula PT = n × f / i is obtained based on the Faraday's law of electrolysis, and the flow electron rate PT is calculated, where i represents the amount of electrical signal, n is the number of electrons transferred per mole of substance during the redox process, and f is the Faraday constant;

[0028] The decomposition products are obtained by matching the number of mobile electrons and the mixing ratio with the product comparison table.

[0029] Preferably, the controlling the on / off state of the compressor based on the gas pressure comprises:

[0030] The decomposed gas is transported to the decomposed gas buffer tank, and a pressure threshold is set, and the gas pressure in the decomposed gas buffer tank is collected in real time through a pressure sensor; the pressure threshold is set according to the size of the buffer tank and the volume of the mixed gas;

[0031] Determine whether the gas pressure is greater than or equal to the pressure threshold; if yes, close the air inlet and start the compressor to compress the decomposed gas; if no, continue to intake air.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. The present invention stores the mixed gas through the gas storage module and connects it with the characteristic detection module through the flow meter. The volume of the mixed gas can be measured during the transportation process, and the gas chamber is heated to a suitable temperature for the thermal conductivity sensor to work and is kept warm, thereby ensuring the measurement accuracy of the thermal conductivity sensor; the mixed gas is detected by the electrochemical sensor to effectively avoid the oxygen 2 Damage to low-range sensors due to excessive concentration and 2 The accident of inaccurate detection of high-range sensors due to low concentration can be avoided, and the oxygen content can be obtained, which can eliminate the influence of oxygen on the electrochemical gas sensor and make the result more accurate. The temperature of the thermal conductivity sensor is kept constant through the thermal effect of current, and an electrical signal is generated at the electrode. The mixing ratio of each gas in the mixed gas is calculated in combination with the influence of oxygen on the thermal conductivity sensor, which reduces the influence of temperature fluctuations on the detection results and improves the accuracy and repeatability of the detection. By correcting the influence of oxygen, the concentration of other gases can be determined more accurately. The mixed gas is decomposed into decomposition gas and pure gas by electromagnetic decomposition, and the decomposition products in the decomposition gas are detected by electrical signal quantitative analysis. The flow electron rate is derived and calculated according to the Faraday formula, and the decomposition products are obtained in combination with the mixing ratio of the mixed gas. Multiple gas components can be detected at the same time to provide comprehensive gas composition information. The decomposed gas is transported to the gas buffer tank, and the gas pressure in the buffer tank is detected. The gas pressure is compared with the preset pressure threshold, and the start of the compressor is controlled according to the comparison result, which can complete the exhaust gas recovery more automatically and reduce the workload and work risks of the staff.

[0034] 2. The present invention analyzes the electrical signals generated during the oxidation and reduction of the mixed gas by an electrical signal quantitative analysis method. Since the electrons are analyzed, the gas with very small concentration can be detected, and the detection sensitivity and accuracy are higher and the speed is faster. When obtaining the gas type in the mixed gas, the influence coefficient is set according to the influence of oxygen on the thermal conductivity sensor, so that the result can be better calculated and the result is more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 The following is a flowchart of an embodiment of the present invention.

[0037] Figure 2 It is a system composition diagram of the present invention.

[0038] Figure 3 A complete flow chart for obtaining the temperature state of the gas chamber in one embodiment of the present invention. DETAILED DESCRIPTION

[0039] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] See also Figure 1-Figure 3 , the first aspect of the present invention provides a decomposition product detection system based on low-carbon GIS mixed gas, including: a gas storage module, a characteristic detection module, a product detection module and a decomposition gas recovery module;

[0041] Characteristic detection module: used to heat the gas chamber, monitor the temperature of the gas chamber in the characteristic detector through the temperature sensor, and control the switch of the heating unit according to the temperature of the gas chamber; detect the characteristic electrical signal produced by the electrode in the characteristic detector, and analyze the characteristic electrical signal to obtain the mixing ratio of the mixed gas.

[0042] Exemplarily, the characteristic detection module is connected to the gas storage module via a flow meter to deliver the mixed gas to the characteristic detector, control the delivery rate of the mixed gas during the delivery process, and calculate the volume of the mixed gas by the delivery rate and delivery time.

[0043] The mixed gas is transported to the characteristic monitor, and the preset temperature is set to 25 degrees in this embodiment; the temperature in the gas chamber is monitored in real time by a temperature sensor set in the characteristic monitor; the mixed gas is transported to the trace oxygen detection unit in the characteristic detector, and the electrical signal generated when the mixed gas passes through the high-range electrochemical sensor in the trace oxygen detection unit is monitored; it is determined whether the high-range electrochemical sensor generates an electrical signal. If an electrical signal is generated, it means that oxygen is mixed in the mixed gas and the oxygen concentration is high, and the high-concentration electrical signal is marked as a mixed gas electrical signal; if the high-range electrochemical sensor does not generate an electrical signal, the mixed gas continues to be transported to the low-range electrochemical sensor, and the electrical signal generation of the low-range electrochemical sensor is monitored. If an electrical signal is generated, it means that oxygen is mixed in the mixed gas and the oxygen concentration is low, and the low-concentration electrical signal is marked as a mixed gas electrical signal. If no electrical signal is generated, it means that no oxygen is mixed in the mixed gas.

[0044] A comparison table of the electrical signal of the mixed gas and the corresponding oxygen content is constructed based on the historical electrical signals of the mixed gas and the corresponding oxygen content. The electrical signals of the mixed gas are matched with the table to obtain the corresponding oxygen content. In this embodiment, the oxygen content in the mixed gas is 1%.

[0045] It should be noted that when detecting a mixed gas by the thermal conductivity detection method, if the mixed gas contains air, the thermal conductivity of the mixed gas will change, affecting the final measurement result of the mixed gas concentration. When detecting oxygen in the mixed gas, different electrochemical sensors are used successively to detect oxygen. This can effectively avoid damage to low-range sensors due to excessively high oxygen concentrations, and accidents such as inaccurate detection of high-range sensors due to excessively low oxygen concentrations.

[0046] Detect the air chamber temperature in the characteristic detector and determine whether the air chamber temperature is equal to the preset temperature. In this embodiment, the air chamber temperature at this time is 22 degrees. If it is determined that the air chamber temperature is not equal to the preset temperature, then continue to determine whether the air chamber temperature at the current time is greater than the preset temperature. If it is determined that the air chamber temperature at the current time is less than the preset temperature, then mark the air chamber temperature state as a low temperature state, control the heating unit to continue heating, and start the insulation state when the air chamber temperature reaches 25 degrees to keep the air chamber temperature at 25 degrees.

[0047] The temperature of the sensor is kept at 25 degrees through the thermal effect of current, and a characteristic electrical signal is generated at the electrode. The sampled voltage value is mapped to a 10-bit discrete level and encoded into a binary digital signal to obtain a characteristic digital signal.

[0048] The effect of oxygen concentration on the thermal conductivity sensor in this embodiment 2 )=10+2×Co, set the proportional coefficient k to 5, and calculate the oxygen signal Io=5 by the formula Io=K×Co. In this embodiment, the gas signal of sulfur hexafluoride in the mixed gas measured at the electrode is 3. Combined with the effect of oxygen on the thermal conductivity sensor, the formula Cq=[K×f(Co 2 )] / Iq-Io is used to calculate the mixing ratio of sulfur hexafluoride in the mixed gas, Cq=65%.

[0049] It should be noted that the oxygen concentration has a certain influence on the thermal conductivity sensor. In this embodiment, the thermal conductivity of sulfur hexafluoride is lower than that of oxygen, so the higher the oxygen concentration, the higher the thermal conductivity of the mixed gas.

[0050] Product detection module: used to perform electromagnetic decomposition on the mixed gas to obtain decomposition gas and pure gas, and obtain the decomposition products contained in the decomposition gas through electrical signal quantitative analysis method and mixing ratio detection.

[0051] For example, the electron transfer in the redox process generates an electrical signal. The number of electrons transferred in the redox process is marked as n. The total electrical signal generated is 10 amperes. The redox time is 60 seconds. The formula PT=n×f / i is derived by Faraday's formula. The mobile electron rate PT=10.36×10 -4 Mole per second; the flow electron rate and the mixing ratio of the mixed gas are matched with the product comparison table to obtain the decomposition products including sulfur dioxide, carbon monoxide and hydrogen sulfide.

[0052] It should be noted that after electromagnetic decomposition, the pure gas is sulfur hexafluoride and nitrogen, and the decomposed gas is the product of oxidation and reduction. Different gases have different electron flow rates during the oxidation and reduction process, and the gas concentration will also affect the product of electromagnetic decomposition.

[0053] Decomposition gas recovery module: used to collect and store decomposition gas, compress the decomposition gas in the gas tank and monitor the gas pressure in the gas tank, and control the on / off state of the compressor based on the gas pressure.

[0054] Exemplarily, the decomposition gas is collected and stored in a gas buffer tank. In this embodiment, the pressure threshold is set to 500 Newtons, and the gas pressure in the decomposition gas buffer tank is collected in real time through a pressure sensor; it is determined whether the gas pressure is greater than or equal to the pressure threshold; if so, the air inlet is closed and the compressor is started to compress the decomposition gas; if not, the air intake continues. In this embodiment, the current gas pressure is 500 Newtons, indicating that the gas in the buffer tank has reached the process requirement at this time, and the compressor is started to compress the decomposition gas, and the compressed gas is purified by a purifier and stored in a recovery bottle.

[0055] The exhaust gas produced by low-carbon mixed gases has serious harmful effects on the atmosphere and human safety. If it is discharged directly into the atmosphere, it will cause serious air pollution and damage. In addition, the exhaust gas itself is toxic, and workers are also at risk of exposure to toxic gases when working or recycling.

[0056] Part of the data in the above formula is calculated by removing the dimension and taking its numerical value. The formula is a formula closest to the actual situation obtained by software simulation of a large amount of collected data; the preset parameters and preset thresholds in the formula are set by technical personnel in this field according to actual conditions or obtained through simulation of a large amount of data.

[0057] Working principle of the present invention:

[0058] The present invention stores mixed gas through a gas storage module, and connects it with a characteristic detection module through a flow meter, detects oxygen in the mixed gas through an electrochemical gas sensor to obtain the oxygen content, heats and insulates the gas chamber in the characteristic detector, transports the mixed gas to the gas chamber, keeps the temperature of the gas chamber unchanged through the thermal effect of the current, generates a characteristic electrical signal, analyzes the characteristic electrical signal, and calculates the mixing ratio of the gas in combination with the influence of oxygen in the mixed gas on the thermal conductivity sensor; decomposes the mixed gas through electromagnetic decomposition, and detects and calculates the flow electron rate during oxidation and reduction through an electrical signal quantitative analysis method, and obtains the decomposition product in combination with the mixing ratio of the mixed gas; transports the decomposed gas to a gas buffer tank, monitors the gas pressure in the buffer tank in real time, and compares it with a preset pressure threshold, controls the start of the compressor according to the comparison result, and completes the recovery of the decomposed gas.

[0059] The above embodiments are only used to illustrate the technical method of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical method of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical method of the present invention.

Claims

1. A decomposition product detection system based on low-carbon GIS mixed gas, characterized in that: include: Characteristic detection module, product detection module and decomposition gas recovery module; Characteristic detection module: used to heat the gas chamber, monitor the temperature of the gas chamber in the characteristic detector through the temperature sensor, and control the switch of the heating unit according to the temperature of the gas chamber; Detecting characteristic electrical signals generated by electrodes in the characteristic detector, and analyzing the characteristic electrical signals to obtain the mixing ratio of the mixed gas; Product detection module: used to perform electromagnetic decomposition on the mixed gas to obtain decomposed gas and pure gas, and obtain the decomposition products contained in the decomposed gas through the electrical signal quantitative analysis method and the mixed ratio detection; Decomposition gas recovery module: used to collect and store decomposition gas, compress the decomposition gas in the gas tank and monitor the gas pressure in the gas tank, and control the on / off state of the compressor based on the gas pressure.

2. A decomposition product detection system based on low-carbon GIS mixed gas according to claim 1, characterized in that: The method of controlling the switch of the heating unit according to the temperature of the air chamber comprises: A1: Extraction of gas chamber temperature and corresponding temperature time; A2: Setting a preset temperature; the preset temperature is set according to the standard operating temperature of the thermal sensor; the oxygen content is obtained by detecting the oxygen content of the mixed gas in the gas chamber through the electrochemical sensor; A3: Determine whether the air chamber temperature is equal to the preset temperature; if yes, control the heating unit to switch to the heat preservation state and jump to A4; if no, jump to A5; A4: Determine whether the current air chamber temperature is the same as the previous air chamber temperature; if yes, mark the air chamber temperature state as being in a heat preservation state; if no, continue to detect the air chamber temperature and mark the air chamber temperature state as being not in a heat preservation state; A5: Determine whether the current air chamber temperature is greater than the preset temperature; if yes, mark the temperature state of the air chamber as over-temperature state, control the heating unit to start lowering the temperature until the preset temperature is reached and the insulation state is turned on; if no, mark the temperature state of the air chamber as low-temperature state, control the heating unit to continue heating until the preset temperature is reached and the insulation state is turned on.

3. A decomposition product detection system based on low-carbon GIS mixed gas according to claim 2, characterized in that: The method of detecting oxygen in the mixed gas in the gas chamber by an electrochemical sensor to obtain the oxygen content includes: B1: Delivers the mixed gas to the high-range electrochemical sensor; B2: Determine whether the high-range electrochemical sensor generates a high-concentration electrical signal; if yes, mark the high-concentration electrical signal as a mixed gas electrical signal; if no, deliver the mixed gas to the low-range electrochemical sensor and jump to B3; B3: Determine whether the low-range electrochemical sensor generates an electrical signal; if so, the low-concentration electrical signal is marked as a mixed gas electrical signal; if not, it means that there is no oxygen in the mixed gas; The mixed gas electrical signal is matched with the electrical signal-oxygen content comparison table to obtain the oxygen content of the mixed gas.

4. A decomposition product detection system based on low-carbon GIS mixed gas according to claim 1, characterized in that: The step of analyzing the characteristic electrical signal to obtain the mixing ratio of the mixed gas includes: Extract the oxygen content in the mixed gas; The mixed gas is transported to the electrochemical gas sensor for oxidation-reduction, an oxidation-reduction electrical signal is generated at the electrode, and the oxidation-reduction electrical signal is converted into a characteristic digital signal; The influence of oxygen content on the thermal conductivity sensor is marked as f(Co2); the oxygen signal Io, which is the proportion of oxygen in the characteristic digital signal of the mixed gas, is calculated by the formula Io=K×Co; where k is the proportional coefficient corresponding to the working condition of the electrochemical gas sensor, and Co represents the concentration of oxygen; The mixing ratio Cq of the gas type q in the mixed gas is calculated by the formula Cq=[K×f(Co2)] / (Iq-Io); wherein Iq represents the gas signal occupied by gas q.

5. The decomposition product detection system based on low-carbon GIS mixed gas according to claim 1 is characterized in that: The decomposition products contained in the decomposition gas are obtained by the electric signal quantitative analysis method and the mixed ratio detection, including: The number of electrons generated at the electrode during the redox process, the electrical signal and the mixing ratio of the mixed gas are extracted, and the formula PT = n × f / i is obtained based on the Faraday's law of electrolysis, and the flow electron rate PT is calculated, where i represents the amount of electrical signal, n is the number of electrons transferred per mole of substance during the redox process, and f is the Faraday constant; The decomposition products are obtained by matching the number of mobile electrons and the mixing ratio with the product comparison table.

6. A decomposition product detection system based on low-carbon GIS mixed gas according to claim 1, characterized in that: The method of controlling the on / off state of the compressor based on the gas pressure comprises: The decomposed gas is transported to the decomposed gas buffer tank, and a pressure threshold is set, and the gas pressure in the decomposed gas buffer tank is collected in real time through a pressure sensor; the pressure threshold is set according to the size of the buffer tank and the volume of the mixed gas; Determine whether the gas pressure is greater than or equal to the pressure threshold; if yes, close the air inlet and start the compressor to compress the decomposed gas; if no, continue to intake air.

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