C4F7N / CO2 / O2 ternary mixed gas density relay field calibration device and method

Abstract

The invention relates to a C4F7N / CO2 / O2 ternary mixed gas density relay on-site calibration device and method, belongs to the technical field of density relay calibration, and solves the problem that a contact signal can only be calibrated at a certain group of temperature and pressure in the prior art. A pressure sensing unit, a temperature sensing unit and a verification unit are arranged in a verification chamber in the device. The temperature control assembly comprises a heat preservation cover and a first semiconductor refrigerator. The heat insulation cover is used for wrapping the density relay and the verification chamber during verification; the gas storage assembly comprises a gas storage chamber and a second semiconductor refrigerator; the verification chamber is in gas circuit connection with the density relay and the gas storage chamber. The verification unit simulates working environments with different temperatures and pressures by controlling the temperatures of the first semiconductor cooler and the second semiconductor cooler, calculates an equivalent pressure value of each temperature corresponding to 20 DEG C in real time, and monitors a contact signal of the density relay to complete verification. And accurate verification of the whole temperature range is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of density relay calibration, and particularly relates to a C4F7N / CO2 / O2 ternary mixed gas density relay field calibration device and method. BACKGROUND

[0002] Power systems are gradually promoting the use of environmentally friendly C4F7N / CO2 / O2 ternary mixed gas as an insulating medium in electrical equipment, and installing density relays to monitor the gas density in the equipment chamber to ensure that the insulation performance meets the allowable requirements.

[0003] Density relays mainly include mechanical and digital types, and their basic working principles are based on environmental temperature and gas pressure parameters. The actual pressure value is compensated to 20℃ standard temperature for unified comparison to reflect the gas density state. In actual operation, the alarm and latching contact action reliability of the density relay is crucial. However, due to the aging of components, mechanical wear and tear or drift that may occur during long-term operation, the monitoring results may deviate, resulting in the displayed gas density value (i.e. 20℃ equivalent pressure) not matching the actual value. If this deviation is not discovered in time, it may cause the alarm or latching signal to fail to trigger correctly, and in severe cases, it may even cause an electrical equipment insulation failure.

[0004] Currently, when calibrating the density relay on site, the calibration device and the density relay on the chamber are usually connected into the same gas circuit through a three-way joint, and the gas pressure is changed by means of a piston booster or the like, with the calibration device as a standard device to determine whether the density relay can accurately trigger the alarm or latching signal at a specific pressure point.

[0005] In the existing density relay calibration method, the calibration device and the density relay are at the same environmental temperature, and in the case of a constant density, the pressure required for the alarm or latching contact to conduct is a constant value, that is, the calibration device only calibrates a set of temperature and pressure points corresponding to the gas density when the alarm or latching contact conducts. However, the environmental temperature varies in actual operation, and the gas pressure is not fixed when the gas density drops to the alarm or latching point. At this time, it is not known whether the density relay can compensate the pressure to the correct value according to the temperature, which may cause the density relay to malfunction. SUMMARY

[0006] In view of the above analysis, the embodiments of the present application aim to provide a C4F7N / CO2 / O2 ternary mixed gas density relay field calibration device and method to solve the problem that the existing calibration can only be performed at a certain set of temperature and pressure for the alarm and latching signals.

[0007] In one aspect, the embodiments of the present application provide a C4F7N / CO2 / O2 ternary mixed gas density relay field calibration device, comprising: The calibration chamber is equipped with a pressure sensing unit, a temperature sensing unit, and a calibration unit. Temperature control components include an insulation cover and a first semiconductor cooler disposed within the insulation cover; the insulation cover is used to enclose the density relay and the calibration chamber during calibration. A gas storage assembly includes a gas storage chamber and a second semiconductor cooler disposed inside the gas storage chamber; The calibration chamber is connected to the gas storage chamber via a proportional valve. The calibration unit simulates a full-temperature environment by adjusting the first semiconductor cooler; it changes the pressure in the calibration chamber by adjusting the proportional valve and the second semiconductor cooler; based on the real-time data from the pressure sensing unit and the temperature sensing unit, it dynamically calculates the equivalent pressure value at each temperature during the full-temperature environment simulation, and completes the calibration by receiving the contact signal of the density relay.

[0008] Based on further improvements to the above device, the calibration chamber is connected to the density relay gas circuit via a three-way connector, and the third end of the three-way connector is connected to the gas chamber interface of the electrical equipment via a pipeline with a hand valve.

[0009] Based on further improvements to the above-mentioned device, the insulation cover of the temperature control component is made of a soft shell material, and when covering the density relay and the calibration chamber, the first semiconductor cooler is positioned between the density relay and the calibration chamber.

[0010] Based on further improvements to the above device, the calibration unit has a built-in temperature-pressure characteristic curve of the C4F7N / CO2 / O2 ternary mixed gas, and is configured to calculate the equivalent pressure value at 20°C for each temperature in real time based on the readings of the pressure sensing unit and the temperature sensing unit; the calibration unit is connected to an operation unit via a data line, and the operation unit includes a touch screen for displaying, setting data and sending commands.

[0011] On the other hand, embodiments of the present invention provide a field calibration method for a C4F7N / CO2 / O2 ternary mixed gas density relay, based on a field calibration device for a C4F7N / CO2 / O2 ternary mixed gas density relay, and perform calibration through the following steps: A ternary mixed gas is introduced into the gas storage chamber of the calibration chamber and the gas storage component. The heat insulation cover of the temperature control component is wrapped around the density relay and the calibration chamber to control the temperature of the first semiconductor cooler and reduce the temperature inside the heat insulation cover to the first target temperature. By adjusting the proportional valve and controlling the temperature of the second semiconductor cooler, the gas in the calibration chamber is transferred to the gas storage chamber until the first target temperature, calculated in real time, corresponds to the equivalent pressure value at 20°C and reaches the preset pressure value. The temperature of the first semiconductor cooler is controlled to gradually raise the temperature inside the insulation cover to the second target temperature. During the temperature rise, the equivalent pressure value at 20°C corresponding to each temperature is calculated in real time, and the contact signal of the density relay is monitored to complete the verification.

[0012] Based on a further improvement of the above method, a ternary mixed gas is introduced into the gas storage chamber of the calibration chamber and the gas storage component, including: Open the manual valve and the proportional valve to control the second semiconductor cooler of the gas storage component to start cooling, so that the ternary mixed gas in the gas chamber of the electrical equipment is transferred to the gas storage chamber of the gas storage component until the temperature of the second semiconductor cooler reaches the first set temperature.

[0013] Based on further improvements to the above method, the equivalent pressure value at 20℃ for each temperature is calculated in real time during the temperature rise process, and the contact signal of the density relay is monitored to complete the verification, including: When the equivalent pressure value is greater than the upper limit of the pressure deviation range of the preset pressure value, but a contact signal of the density relay is received, it indicates that the density relay has acted prematurely. When the density relay receives a contact signal within the pressure deviation range of the preset pressure value, it indicates that the density relay can operate correctly. When the equivalent pressure value is less than the lower limit of the pressure deviation range of the preset pressure value, but no contact signal is received from the density relay, it indicates that the density relay cannot operate correctly.

[0014] Based on the further improvement of the above method, during the temperature rise process, the equivalent pressure value at 20℃ corresponding to each temperature calculated in real time by the calibration unit gradually decreases. When the equivalent pressure value drops to the lower limit of the pressure deviation range of the preset pressure value, the second semiconductor cooler is controlled to heat to the third set temperature, and the proportional valve is adjusted to move the gas in the gas storage chamber to the calibration chamber until the equivalent pressure value gradually rises to the upper limit of the pressure deviation range exceeding the preset pressure value, and then the proportional valve is closed.

[0015] Based on a further improvement of the above method, controlling the temperature of the first semiconductor cooler to gradually raise the temperature inside the insulation cover to the second target temperature includes: Based on the temperature read in real time by the temperature sensing unit of the calibration chamber, the temperature is increased by a set temperature difference to serve as the set temperature of the first semiconductor cooler until the increased temperature reaches the second target temperature.

[0016] Based on further improvements to the above method, the verification method also includes: after the verification is completed, opening the manual valve and the proportional valve, controlling the second semiconductor cooler to heat to the fourth set temperature, so that the ternary mixed gas in the gas storage chamber is driven back to the gas chamber of the electrical equipment.

[0017] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects: 1. By setting up temperature control components with a soft insulation cover and a first semiconductor cooler, a controllable local temperature environment is quickly created around the density relay, simulating various extreme climatic conditions in actual operation. This completely solves the industry problem that traditional calibration methods are limited by natural ambient temperature and cannot complete full-range temperature testing at a single location. Moreover, by continuously controlling the ambient temperature to rise from one target temperature to another, and monitoring the contact signals in real time during this process, a "dynamic scanning" calibration is achieved. This can capture the operation of the density relay at any point in the entire temperature range, making the calibration more comprehensive and realistic.

[0018] 2. A gas storage component is set up through a gas storage chamber and a second semiconductor cooler. By controlling the temperature of the first and second semiconductor coolers and using a proportional valve, the gas is driven to transfer between the gas storage chamber and the calibration chamber, thereby changing the gas pressure and simulating the process of gas leakage or replenishment. Throughout the process, the gas is enclosed in the calibration chamber and the shared pipeline between the calibration chamber and the density relay, without the need to release gas into the atmosphere, resulting in significant economic and environmental benefits.

[0019] 3. By coordinating the control of "ambient temperature" and "gas reserves", an infinite number of "temperature-pressure" combinations are created. All of these combinations correspond to the same "equivalent density", cleverly simulating the working environment of the entire temperature range and realizing the most comprehensive verification of the density relay performance. Operators only need to complete the connection of the verification device and start the program to automatically execute a series of complex operations such as "cooling and gas extraction" → "ambient temperature control" → "alarm point / lock-off point adjustment" → "full temperature range alarm point / lock-off point verification" → "gas return", which greatly reduces human operation error and improves the reliability and consistency of verification results.

[0020] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0021] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts. Figure 1 This is a schematic diagram of the field calibration device for the C4F7N / CO2 / O2 ternary mixed gas density relay in Embodiment 1 of the present invention; Figure 2This is a flowchart of the on-site verification method for the C4F7N / CO2 / O2 ternary mixed gas density relay in Embodiment 2 of the present invention; Figure label: 1-Gas chamber interface; 2-Manual valve; 3-Density relay; 4-Calibration chamber; 5-Signal line; 6-Insulation cover of temperature control component; 7-First semiconductor cooler of temperature control component; 8-Proportional valve; 9-Gas storage chamber of gas storage component; 10-Second semiconductor cooler of gas storage component; 11-T-connector. Detailed Implementation

[0022] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0023] Example 1 A specific embodiment of the present invention discloses a field calibration device for a C4F7N / CO2 / O2 ternary mixed gas density relay, such as... Figure 1 As shown, it includes: Calibration chamber 4 is equipped with a pressure sensing unit, a temperature sensing unit, and a calibration unit. The temperature control component includes an insulation cover 6 and a first semiconductor cooler 7 disposed inside the insulation cover 6; the insulation cover 6 is used to enclose the density relay 3 and the calibration chamber 4 during calibration. The gas storage assembly includes a gas storage chamber 9 and a second semiconductor cooler 10 disposed inside the gas storage chamber 9; The calibration chamber 4 is connected to the gas storage chamber 9 via a proportional valve 8; The calibration unit simulates a full-temperature environment by adjusting the first semiconductor cooler 7; it changes the pressure of the calibration chamber 4 by adjusting the proportional valve 8 and the second semiconductor cooler 10, thus simulating different temperature and pressure working environments for the density relay 3; based on the real-time data from the pressure sensing unit and the temperature sensing unit, it dynamically calculates the equivalent pressure value at 20℃ for each temperature during the full-temperature environment simulation process, and completes the calibration by receiving the contact signal of the density relay 3.

[0024] Furthermore, the calibration chamber 4 is connected to the gas storage chamber 9 via a pipeline with a proportional valve 8; the calibration chamber 4 is connected to the density relay 3 via a three-way connector 11, and the third end of the three-way connector 11 is connected to the gas chamber interface 1 of the electrical equipment via a pipeline with a hand valve 2.

[0025] It should be noted that the gas chamber of the electrical equipment contains an environmentally friendly C4F7N / CO2 / O2 ternary mixed gas. The pipeline between hand valve 2 and calibration chamber 4 and density relay 3 is referred to as the "common pipeline," and it is wrapped with insulation material.

[0026] The calibration unit in calibration chamber 4 is electrically connected to density relay 3, pressure sensing unit, temperature sensing unit, proportional valve 8, first semiconductor cooler 7, and second semiconductor cooler 10. The pressure sensing unit is a pressure sensor, and the temperature sensing unit is a temperature sensor.

[0027] It should be noted that the first semiconductor cooler 7 and the second semiconductor cooler 10 are equipped with temperature measuring components, which provide cooling when energized in the forward direction and heating when energized in the reverse direction; the proportional valve 8 is used to adjust the pipe diameter.

[0028] It should be noted that the pressure sensing unit of the calibration chamber 4 is used to measure the pressure of the C4F7N / CO2 / O2 ternary mixed gas in the calibration chamber 4 and the pipeline connected to it; the temperature sensing unit of the calibration chamber 4 is used to measure the temperature of the temperature-controlled environment formed by the insulation cover 6 of the temperature control component.

[0029] The calibration unit in calibration chamber 4 has a built-in temperature-pressure characteristic curve of the C4F7N / CO2 / O2 ternary mixed gas, and is configured to calculate the equivalent pressure value of each temperature corresponding to the 20℃ standard temperature in real time based on the readings of the pressure sensing unit and the temperature sensing unit.

[0030] The calibration unit of the calibration chamber 4 is connected to the contact circuit of the density relay 3 via a signal line 5, which is used to monitor the contact signal of the density relay 3 during the calibration process. The calibration unit is connected to an operation unit via a data line. The operation unit includes a touch screen for displaying, setting data and sending instructions.

[0031] Specifically, the data displayed by the operation unit is sent by the verification unit, including but not limited to: the readings of the pressure sensing unit and the temperature sensing unit, the temperatures of the first semiconductor cooler 7 and the second semiconductor cooler 10, the status of the proportional valve 8, the equivalent pressure value calculated in real time at the corresponding 20°C standard temperature, and the verification results obtained by monitoring the contact signal of the density relay, including: the density relay operates prematurely, the density relay operates normally, and the density relay fails to operate.

[0032] The instructions sent by the operation unit are received by the verification unit, including but not limited to: starting verification, adjusting the diameter of the proportional valve 8, and controlling the temperature of the first semiconductor cooler 7 and the second semiconductor cooler 10 for cooling and heating.

[0033] The data set by the operation unit is stored in the verification unit, including: alarm point pressure value, lockout point pressure value, pressure deviation value, first target temperature, second target temperature, temperature difference value, and multiple set temperatures.

[0034] Among them, the alarm point pressure value P 20,1 Greater than the locking point pressure value P 20,2All of these are set according to the pressure value corresponding to the density of the ternary gas mixture as indicated by the density relay 3 at the rated temperature (usually 20℃).

[0035] The pressure deviation value is set according to the characteristics of the C4F7N / CO2 / O2 ternary gas mixture. In this embodiment, it is set to 0.008 MPa, so the pressure deviation range of the alarm point is P. 20,1 ±0.008MPa, that is The pressure deviation range of the locking point is P. 20,2 ±0.008MPa, that is .

[0036] The first and second target temperatures are set according to the operating environment temperature of the electrical equipment. In this embodiment, the operating environment temperature of the C4F7N / CO2 / O2 ternary mixed gas electrical equipment is between -10℃ and 50℃, therefore the first target temperature is set to -10℃ and the second target temperature is set to 50℃.

[0037] The temperature difference is used to control the stable temperature rise of the first semiconductor cooler 7 during the calibration process, and is exemplarily set to 10°C.

[0038] Multiple set temperatures are used to control the temperature to be reached by the first semiconductor cooler 7 and the second semiconductor cooler 10 during the calibration process.

[0039] Furthermore, the insulation cover 6 of the temperature control component is made of soft shell material, and when covering the density relay 3 and the calibration chamber 4, the first semiconductor cooler 7 is placed between the density relay 3 and the calibration chamber 4. The space formed after covering does not exceed 30cm×30cm×30cm, which facilitates on-site calibration.

[0040] For example, the soft shell material is made of rubber and plastic insulation cotton.

[0041] Compared with existing technologies, this embodiment discloses a field calibration device for a C4F7N / CO2 / O2 ternary mixed gas density relay. This is an independent, external field calibration device that is temporarily connected to an existing density relay on-site via a tee connector and hand valve. It can be disassembled after calibration, making it a universal and portable calibration tool. By using a soft insulation cover and a first semiconductor cooler to set up a temperature control component, a controllable local temperature environment is quickly created around the density relay, simulating various extreme climatic conditions in actual operation. This completely solves the industry problem that traditional calibration methods are limited by natural ambient temperature and cannot complete full-range temperature testing at a single location. Furthermore, by continuously controlling the ambient temperature to rise from one target temperature to another, and monitoring the contact signals in real time during this process, a "dynamic scanning" calibration is achieved. This captures the operation of the density relay at any point within the entire temperature range, resulting in a more comprehensive and realistic calibration. A gas storage component is set up by a gas storage chamber and a second semiconductor cooler. The gas is driven to transfer between the gas storage chamber and the calibration chamber by temperature control of the first and second semiconductor coolers and proportional valves, thereby changing the gas pressure and simulating the process of gas leakage or replenishment. Throughout the process, the gas is sealed in the calibration chamber and in the shared pipeline between the calibration chamber and the density relay, without the need to release gas into the atmosphere, resulting in significant economic and environmental benefits.

[0042] Example 2 Another embodiment of the present invention discloses a field calibration method for a C4F7N / CO2 / O2 ternary mixed gas density relay, such as... Figure 2 As shown, the verification is performed using the field verification device of Example 1 through the following steps: S1. Fill the calibration chamber 4 and the gas storage chamber 9 of the gas storage component with a ternary mixed gas, wrap the density relay 3 and the calibration chamber 4 with the heat insulation cover 6 of the temperature control component, control the temperature of the first semiconductor cooler 7, and reduce the temperature inside the heat insulation cover 6 to the first target temperature. S2. By adjusting the proportional valve 8 and controlling the temperature of the second semiconductor cooler 10, the gas in the calibration chamber is transferred to the gas storage chamber until the first target temperature calculated in real time corresponds to the equivalent pressure value at 20°C and reaches the preset pressure value. S3. Control the temperature of the first semiconductor cooler 7 so that the temperature inside the heat insulation cover 6 gradually rises to the second target temperature. During the temperature rise process, calculate the equivalent pressure value at 20°C for each temperature in real time and monitor the contact signal of the density relay to complete the verification.

[0043] It should be noted that step S1 is used to control the ambient temperature at the minimum operating temperature of the C4F7N / CO2 / O2 ternary mixed gas electrical equipment; step S2 is used to adjust the alarm point or the interlocking point at the minimum temperature; and step S3 is used to verify the alarm contact action or the interlocking contact action within the entire temperature range as the ambient temperature is gradually increased to the maximum temperature.

[0044] In practice, the verification methods for alarm points and interlocking points are the same, only the corresponding preset pressure values ​​are different. Typically, the alarm point is verified first, followed by the interlocking point. That is: first, based on the preset alarm point pressure value, the alarm point and alarm contact actions are adjusted and verified according to steps S2 and S3 respectively; then, based on the preset interlocking point pressure value, the interlocking point and interlocking contact actions are adjusted and verified according to steps S2 and S3 respectively.

[0045] It should be noted that before performing step S1, cooling and gas extraction are also included, specifically: S0. Open the hand valve 2 and the proportional valve 8 to control the second semiconductor cooler 10 of the gas storage component to start cooling, so that the ternary mixed gas in the gas chamber of the electrical equipment is transferred to the gas storage chamber 9 of the gas storage component until the temperature of the second semiconductor cooler 10 reaches the first set temperature.

[0046] It should be noted that, first close the hand valve 2, then install the calibration device, including: connecting the calibration chamber 4 in the calibration device to the density relay 3 via the three-way connector 11, and establishing an electrical connection between the density relay 3 and the calibration unit of the calibration chamber 4 via the signal line 5. After the connection is completed, open the hand valve 2 and the proportional valve 8.

[0047] Based on the pressure value corresponding to the density reached at 20℃ indicated by density relay 3, the pressure value (alarm point pressure value and lockout point pressure) and threshold values ​​such as the first target temperature, the second target temperature, the pressure deviation value, and the temperature difference value are set using the operation unit of the verification unit.

[0048] Furthermore, the second semiconductor cooler 10 is controlled to start cooling, so that the environmentally friendly C4F7N / CO2 / O2 ternary mixed gas in the gas chamber is transferred to the gas storage chamber 9. When the first set temperature is reached, the manual valve 2 and the proportional valve 8 are closed.

[0049] Specifically, the calibration unit controls the second semiconductor cooler 10 to start cooling, for example, setting the cooling temperature to 0℃. During the cooling process, the pressure of the C4F7N / CO2 / O2 ternary mixed gas continuously decreases, and the gas in the gas chamber continuously moves towards the gas storage chamber 9. When the temperature drops to the first set temperature, for example -20℃, the manual valve 2 and the proportional valve 8 are closed. At this time, the gas density inside the gas storage chamber 9 is higher than that inside the common pipeline.

[0050] In the environmental temperature control of step S1, the density relay 3 and the calibration chamber 4 are first wrapped with a soft heat insulation cover 6, and then the first semiconductor cooler 7 is controlled to cool to the first target temperature and maintain it to simulate a low temperature environment.

[0051] Specifically, the insulation cover 6 of the temperature control component is made of a soft shell material with poor thermal conductivity, which can effectively isolate external temperature interference. The first target temperature is set to -10℃. After the first semiconductor cooler 7 cools to the first target temperature, it maintains this temperature for 5 minutes to stabilize the internal temperature of the insulation cover 6 at -10℃, simulating a low-temperature working environment and ensuring the accuracy of subsequent pressure measurement and compensation.

[0052] Since step S0 involves directly drawing gas from the gas chamber of the electrical equipment, the gas density in the shared pipeline is the same as the gas chamber density, initially higher than the density at the alarm point and the lockout point. Therefore, in step S2, by lowering the temperature of the gas storage chamber 9 and increasing the pressure difference, the gas is slowly transferred from the calibration chamber 4 to the gas storage chamber 9, reducing the gas pressure in the calibration chamber 4. Using the built-in temperature-pressure characteristic curve, the measured pressure is compensated to the pressure under standard conditions of 20°C, ensuring consistency with the alarm point pressure / lockout point pressure.

[0053] Specifically, the calibration unit controls the second semiconductor cooler 10 to cool to a second set temperature, such as -40℃. The pressure inside the calibration chamber 4 continuously decreases, and under the pressure difference, the gas slowly transfers into the storage chamber 9. The gas pressure in the shared pipeline slowly decreases, and the pressure value read by the pressure sensing unit in the calibration chamber 4 also continuously decreases. Based on the built-in temperature-pressure characteristic curve of the C4F7N / CO2 / O2 ternary mixed gas, and based on the readings from the pressure and temperature sensing units, the calibration unit compensates the gas pressure to the pressure at 20℃, calculates the equivalent pressure value at 20℃, and determines whether the preset pressure value is the alarm point pressure value or the lockout point pressure value according to the current calibration target. When the equivalent pressure value reaches the preset pressure value, the adjustment ends, and the proportional valve 8 is closed. At this time, the gas density in the shared pipeline is set to the critical value at which the density relay should theoretically operate. Subsequently, when the ambient temperature changes, the subtle changes between "operation" and "non-operation" of the density relay can be observed more accurately, thereby determining whether its performance is accurate.

[0054] In the full temperature range verification in step S3, the contact signal of the density relay is monitored under continuously increasing temperature to verify whether the density relay can operate correctly in different temperature and pressure environments.

[0055] It should be noted that controlling the temperature of the first semiconductor cooler 7 to gradually raise the temperature inside the insulation cover 6 to the second target temperature includes: Based on the temperature read in real time by the temperature sensing unit of the calibration chamber 4, the temperature is increased by a set temperature difference to serve as the set temperature of the first semiconductor cooler 7, until the increased temperature reaches the second target temperature.

[0056] For example, the temperature difference is set to 10°C, and the temperature read by the temperature sensing unit in real time is T. c Then the set temperature T of the first semiconductor cooler 7 b For T c +10℃.

[0057] When the temperature control component is continuously heating the first semiconductor cooler 7, the temperature inside the insulation cover 6 rises at a relatively stable rate. Since the common pipeline is wrapped with insulation material, the gas temperature inside the common pipeline rises slowly and can be considered constant. At this time, the equivalent pressure value P after temperature compensation... 20 As the pressure continues to decrease, the equivalent pressure value is displayed in real time on the operating unit of the verification unit.

[0058] The pressure deviation range corresponding to the verification target is obtained, that is, the pressure deviation range of the alarm point is P. 20,1 ±0.008MPa, the pressure deviation range of the locking point is P 20,2 ±0.008MPa.

[0059] As the equivalent pressure value continues to decrease, the contact signal of the density relay 3 is monitored in real time based on the comparison results of the pressure deviation range between the equivalent pressure value and the preset pressure value to identify whether the density relay 3 can operate correctly.

[0060] Specifically, this includes: when the equivalent pressure value is greater than the upper limit of the pressure deviation range of the preset pressure value, but a contact signal of density relay 3 is received, it indicates that density relay 3 is activated too early, causing the alarm / lockout to be triggered too early; When the equivalent pressure value is within the pressure deviation range of the preset pressure value, the contact signal of the density relay 3 is received, indicating that the density relay 3 can operate correctly. When the equivalent pressure value is less than the lower limit of the pressure deviation range of the preset pressure value, but no contact signal is received from the density relay 3, it indicates that the density relay 3 cannot operate correctly.

[0061] It should be noted that as the temperature continues to rise, the equivalent pressure value P... 20 It will further decrease to the lower limit of the pressure deviation range. It is necessary to actively replenish gas into the shared pipeline to increase the equivalent pressure value.

[0062] At this time, the second semiconductor cooler 10 is controlled to heat to the third set temperature. The proportional valve 8 is adjusted so that the equivalent pressure value gradually rises to the upper limit of the pressure deviation range exceeding the preset pressure value, and then the proportional valve 8 is closed.

[0063] Specifically, the verification unit sets the third set temperature to 20℃, and the second semiconductor cooler 10 starts heating, causing the pressure in the gas storage chamber 9 of the gas storage assembly to be higher than the pressure in the common pipeline. The gas in the gas storage chamber 9 continuously moves towards the common pipeline, causing the gas pressure in the common pipeline to rise. The diameter of the proportional valve 8 is adjusted to adjust the real-time calculated equivalent pressure value P. 20 The pressure rises to the upper limit of the pressure deviation range exceeding the preset pressure value, such as P. 20,1 +0.01MPa or P 20,2 +0.01MPa, then close proportional valve 8.

[0064] Furthermore, the first semiconductor cooler 7 inside the insulation cover 6 continues to generate heat, and the temperature inside the insulation cover 6 continues to rise, with the equivalent pressure value P... 20 If the pressure drops again, the contact signal of the density relay will continue to be monitored in real time when the equivalent pressure value is within the pressure deviation range. When the pressure drops to the lower limit of the pressure deviation range again, the process of replenishing gas into the common pipeline is repeated by adjusting the proportional valve 8 and the second semiconductor cooler 10 until the temperature inside the insulation cover 6 rises to the second target temperature of 50°C. This completes the verification of the same 20°C alarm point / lock-off point under different temperature and pressure combinations.

[0065] After completing the alarm point and interlock point verifications in steps S2-S3, the process also includes: gas return, specifically referring to: After the calibration is completed, the second semiconductor cooler 10 is heated to the fourth set temperature, such as 100°C, by opening the manual valve 2 and the proportional valve 8, so that the ternary mixed gas in the gas storage chamber 9 is driven back to the gas chamber of the electrical equipment, reducing gas loss in the gas chamber.

[0066] Since the field verification method for the C4F7N / CO2 / O2 ternary mixed gas density relay in this embodiment can be mutually referenced with the aforementioned field verification device for the C4F7N / CO2 / O2 ternary mixed gas density relay, this is a repetition and will not be repeated here.

[0067] This method embodiment not only possesses the corresponding technical effects of the aforementioned device embodiments, but also, by coordinating the control of "ambient temperature" and "gas reserves," the entire verification method creates an infinite number of "temperature-pressure" combinations. All these combinations correspond to the same "equivalent density," cleverly simulating a full-temperature-range working environment and achieving the most comprehensive verification of the density relay's performance. Operators only need to connect the verification device and start the program to automatically execute a series of complex operations such as "cooling and gas extraction" → "ambient temperature control" → "alarm point / lock-off point adjustment" → "full-temperature-range alarm point / lock-off point verification" → "gas return," greatly reducing human error and improving the reliability and consistency of the verification results.

[0068] Those skilled in the art will understand that all or part of the processes of the methods described in the above embodiments can be implemented by a computer program instructing related hardware, and the program can be stored in a computer-readable storage medium. The computer-readable storage medium may be a disk, optical disk, read-only memory, or random access memory, etc.

[0069] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A C4F7N / CO2 / O2 ternary mixed gas density relay field calibration device, characterized in that, The application relates to a C4F7N / CO2 / O2 ternary mixed gas density relay field calibration device, which comprises the following parts: a calibration chamber, which is internally provided with a pressure sensing unit, a temperature sensing unit and a calibration unit; a temperature control assembly, which comprises a heat preservation cover and a first semiconductor refrigerator arranged in the heat preservation cover; the heat preservation cover is used for wrapping the density relay and the calibration chamber during calibration; a gas storage assembly, which comprises a gas storage chamber and a second semiconductor refrigerator arranged in the gas storage chamber; the calibration chamber is connected with the gas storage chamber through a proportional valve; the calibration unit simulates a full-temperature-range environment by adjusting the first semiconductor refrigerator; the pressure of the calibration chamber is changed by adjusting the proportional valve and the second semiconductor refrigerator; based on real-time data of the pressure sensing unit and the temperature sensing unit, equivalent pressure values of each temperature in the full-temperature-range environment simulation process are dynamically calculated, and calibration is completed by receiving a contact signal of the density relay.

2. The C4F7N / CO2 / O2 ternary gas density relay field calibration device according to claim 1, characterized by The calibration chamber is connected with the density relay through a tee joint, and a third end of the tee joint is connected with a gas chamber interface of an electrical equipment through a pipeline with a hand valve.

3. The C4F7N / CO2 / O2 ternary gas density relay field calibration device according to claim 2, characterized by The heat preservation cover of the temperature control assembly adopts a soft shell material, and when the density relay and the calibration chamber are wrapped, the first semiconductor refrigerator is arranged at a position between the density relay and the calibration chamber.

4. The C4F7N / CO2 / O2 ternary gas density relay field calibration device according to claim 2, characterized by The calibration unit is internally provided with a temperature-pressure characteristic curve of C4F7N / CO2 / O2 ternary mixed gas, and is configured to calculate equivalent pressure values of each temperature corresponding to 20 DEG C in real time according to readings of the pressure sensing unit and the temperature sensing unit; the calibration unit is externally connected with an operation unit through a data line, and the operation unit comprises a touch screen for displaying, setting data and sending instructions.

5. A method for field calibration of a C4F7N / CO2 / O2 ternary gas density relay, characterized by, The C4F7N / CO2 / O2 ternary mixed gas density relay field calibration device according to any one of claims 1-4 is calibrated through the following steps: the calibration chamber and the gas storage chamber of the gas storage assembly are filled with ternary mixed gas, the heat preservation cover of the temperature control assembly is wrapped around the density relay and the calibration chamber, the temperature of the first semiconductor refrigerator is controlled, and the temperature in the heat preservation cover is lowered to a first target temperature; the gas in the calibration chamber is transferred to the gas storage chamber by adjusting the proportional valve and controlling the temperature of the second semiconductor refrigerator, and the equivalent pressure value of the first target temperature corresponding to 20 DEG C is calculated in real time until the preset pressure value is reached; the temperature of the first semiconductor refrigerator is controlled, the temperature in the heat preservation cover is gradually increased to a second target temperature, the equivalent pressure value of each temperature corresponding to 20 DEG C is calculated in real time during the temperature increasing process, and the contact signal of the density relay is monitored to complete the calibration.

6. The C4F7N / CO2 / O2 ternary gas density relay field calibration method according to claim 5, characterized by, The calibration chamber and the gas storage chamber of the gas storage assembly are filled with ternary mixed gas, including: the hand valve and the proportional valve are opened, the second semiconductor refrigerator of the gas storage assembly is controlled to start refrigeration, the ternary mixed gas in the gas chamber of the electrical equipment is transferred to the gas storage chamber of the gas storage assembly, and the temperature of the second semiconductor refrigerator reaches a first set temperature.

7. The C4F7N / CO2 / O2 ternary gas density relay field calibration method according to claim 5, characterized by, The equivalent pressure value of each temperature corresponding to 20 DEG C is calculated in real time during the temperature increasing process, and the contact signal of the density relay is monitored to complete the calibration, including: When the equivalent pressure value is greater than the upper limit of the pressure deviation range of the preset pressure value, but the contact signal of the density relay is received, it indicates that the density relay is prematurely activated; When the equivalent pressure value is within the pressure deviation range of the preset pressure value, and the contact signal of the density relay is received, it indicates that the density relay can be correctly activated; When the equivalent pressure value is less than the lower limit of the pressure deviation range of the preset pressure value, but the contact signal of the density relay is not received, it indicates that the density relay cannot be correctly activated.

8. The C4F7N / CO2 / O2 ternary gas density relay field calibration method according to claim 5, characterized by, During the temperature rising process, the equivalent pressure value corresponding to each temperature calculated by the verification unit in real time gradually decreases, when the equivalent pressure value decreases to the lower limit of the pressure deviation range of the preset pressure value, the second semiconductor refrigerator is controlled to heat to a third set temperature, and the proportional valve is adjusted to move the gas in the gas storage chamber to the verification chamber until the equivalent pressure value gradually increases to exceed the upper limit of the pressure deviation range of the preset pressure value, and then the proportional valve is closed.

9. The C4F7N / CO2 / O2 ternary gas density relay field calibration method according to claim 5, characterized by, The temperature of the first semiconductor refrigerator is controlled to gradually increase the temperature in the heat preservation cover to a second target temperature, including: The temperature read by the temperature sensing unit of the verification chamber in real time is increased by a set temperature difference value as the set temperature of the first semiconductor refrigerator until the increased temperature reaches the second target temperature.

10. The C4F7N / CO2 / O2 ternary gas density relay field calibration method according to claim 6, characterized by, The verification method further includes: after the verification is completed, the hand valve and the proportional valve are opened, and the second semiconductor refrigerator is controlled to heat to a fourth set temperature, so that the ternary mixed gas in the gas storage chamber is driven back to the gas chamber of the electrical equipment.

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