Method for measuring and diagnosing transient temperature of gas in high-pressure bushing

Abstract

The application provides a high-voltage bushing gas transient temperature calculation and state diagnosis method and device and a storage medium. The method comprises the following steps: collecting a high-voltage bushing gas pressure value, a shell temperature value and an ambient temperature value of the device; calculating an ambient temperature influence effective value; calculating a high-voltage bushing gas transient temperature value; calculating a temperature field model parameter; calculating a high-voltage bushing gas transient temperature value; calculating a high-voltage bushing gas molar density value; and performing state diagnosis on the high-voltage bushing according to a set diagnosis threshold value. Through the technical scheme provided by the application, the oil and gas pressure value in the high-voltage bushing can be monitored online for 24 hours without interruption, the running and fault states in the high-voltage bushing can be evaluated, accidents can be prevented, and a feasible means is provided for real-time monitoring of the running and fault states of the device.

Description

Technical Field

[0001] This invention relates to the field of transient temperature measurement and condition diagnosis of gas inside high-pressure bushings, and particularly to a method, apparatus and storage medium for transient temperature measurement and condition diagnosis of gas inside high-pressure bushings. Background Technology

[0002] Existing power systems operate a large number of oil-filled electrical devices, including transformer high-voltage bushings, current transformers, circuit breakers, and other oil-less devices. During substation operation, the insulation condition and internal mechanism operation of these oil-less devices are crucial to the safe and stable operation of the power system. However, these devices are prone to malfunctions due to improper manufacturing, inspection, maintenance, and oil deterioration, leading to frequent serious accidents such as explosions and fires, which affect the safe and stable operation of the power grid and the reliability of power supply.

[0003] Currently, substation maintenance of such equipment generally relies on manual inspections, with a small portion combined with online insulation monitoring. Manual inspections involve both routine checks by operating personnel and periodic spot checks by testing personnel. Traditional detection and analysis methods include ultrasonic partial discharge testing, infrared thermography, and oil chromatography. However, in recent years, with the continuous increase in voltage levels and equipment capacity, traditional offline preventative testing methods can no longer meet the actual needs of safe operation of modern large-scale power equipment, and are difficult to accurately reflect the insulation status of various bushings, current transformers, and other equipment under operating conditions. Because preventative testing is conducted on a fixed schedule, it cannot promptly detect, track, or repair equipment, thus having significant limitations.

[0004] Traditional maintenance methods mainly include routine inspections and power outage inspections. Routine inspections include component checks and overheating tests; power outage inspections include insulation resistance measurements, polarization coefficient measurements, capacitance and dielectric loss factor measurements, partial discharge measurements, and transformer oil checks (current transformers can have their oil sampled while the circuit is energized).

[0005] Routine maintenance component inspections typically include checking for oil leaks, inspecting metal parts for corrosion, visually inspecting porcelain bushings, and checking grounding conditions. For current transformers, the expansion joint's extension and contraction should also be checked to determine the oil level. Heat detection is very effective in identifying thermal defects and overheating points in equipment with low oil levels. It can detect overheating caused by poor contact at contact points or excessively high temperatures due to localized defects.

[0006] Before and every few years after commissioning, oil-filled equipment undergoes regular power outages for insulation performance testing to assess its insulation condition. Simultaneously, during power outage maintenance cycles, the gas and moisture content in the oil is measured. Currently, the analysis and detection of dissolved gases in oil remains one of the methods for diagnosing faults in oil-filled electrical equipment.

[0007] While current conventional methods can detect some faults, they are ineffective for early fault diagnosis. On-site partial discharge tests are also unsatisfactory, and live oil sampling analysis using casing is impossible. Furthermore, sampling for follow-up is even more difficult when chromatographic analysis data is abnormal. At the same time, periodic testing cannot prevent sudden accidents.

[0008] In low-oil equipment such as transformer high-voltage bushings and current transformers, the insulating oil, which is in a sealed state, can decompose during operation due to insulation damage or other reasons, releasing a certain amount of gas. The insulating oil in high-voltage bushings is a mineral oil obtained from natural petroleum through distillation and refining. It is a mixture of hydrocarbons with many different molecular weights, including alkanes, alkenes, cycloalkanes, and aromatics. When there is a discharge or overheating fault inside the equipment, characteristic gases such as H2, CH4, C2H6, C2H4, C2H2, CO, and CO2 are produced. Some of these gases are dissolved in the oil, while others are released onto the oil surface. Because the high-voltage bushing has a sealed structure, the gas on the oil surface gradually accumulates, increasing the gas pressure on the liquid insulating oil. Over time, this buildup creates a certain gas pressure within the cavity, which can, in severe cases, cause oil spraying or even an explosion. Currently, the detection of characteristic gases mainly includes two methods: oil-gas spectroscopy analysis and pressure monitoring. Oil chromatography analysis typically uses manual sampling to periodically monitor the content of dissolved acetylene, hydrogen, and total hydrocarbons in the oil of low-oil equipment. However, this method has a long cycle and cannot detect abnormalities that occur between two detection intervals, posing a safety hazard. Summary of the Invention

[0009] The main objective of this invention is to provide a method, device, and storage medium for calculating the transient temperature of gas inside a high-pressure bushing and for diagnosing its condition, aiming to solve the problems of existing high-pressure bushing condition monitoring and fault diagnosis.

[0010] To achieve the above objectives, the present invention provides a method for calculating and diagnosing the transient temperature of gas inside a high-pressure bushing, the method comprising:

[0011] Collect the gas pressure inside the high-pressure bushing, the shell temperature, and the ambient temperature of the equipment;

[0012] Calculate the effective value of the effect of ambient temperature;

[0013] Calculate the transient temperature of the gas inside the high-pressure bushing;

[0014] Calculate the parameters of the temperature field model;

[0015] Calculate the transient temperature of the gas inside the high-pressure bushing;

[0016] Calculate the molar density of gas molecules inside the high-pressure bushing;

[0017] The high-voltage bushing is subjected to status diagnosis based on the set diagnostic threshold.

[0018] Furthermore, the formula for calculating the effective value of the influence of ambient temperature is as follows:

[0019] ΔT 1e (t)=a·b·e -bt *[T1(t)-T a (t)]

[0020] in,

[0021] t is the sampling time; the value of t is in the range of [0, T], and T is the thermal equilibrium time constant of the equipment affected by the ambient temperature. The units of time t and T are hours.

[0022] ΔT 1e (t) represents the effective value of the influence of ambient temperature at time t;

[0023] T1(t) is the temperature of the high-voltage bushing shell measured at time t;

[0024] T a (t) represents the ambient temperature of the high-pressure bushing at time t;

[0025] * indicates convolution calculation;

[0026] a and b are constant coefficients.

[0027] Furthermore, the formula for calculating the transient temperature of the gas inside the high-pressure bushing is as follows:

[0028]

[0029] in,

[0030] T g (t) represents the transient gas temperature inside the high-pressure bushing at time t;

[0031] A1 is the heat dissipation coefficient between the inside of the high-voltage bushing and the outer casing;

[0032] A2 is the heat dissipation coefficient between the high-voltage bushing casing and the environment;

[0033] B1 is the total heat capacity coefficient from the inside of the high-pressure bushing to the outer shell;

[0034] Furthermore, the calculation formula for the parameters of the temperature field model is as follows:

[0035] Let the transient temperature model parameters of the gas inside the high-pressure bushing be:

[0036]

[0037] but:

[0038] k0~a1T g (t)+a2T1(t)+a3

[0039] in,

[0040] a1, a2, and a3 are constant coefficients, and the values ​​of a1, a2, and a3 are respectively:

[0041] a1=0.0035, a2=-0.0023, a3=0.04.

[0042] Furthermore, the formula for calculating the transient temperature of the gas inside the high-pressure bushing is as follows:

[0043]

[0044] Furthermore, the formula for calculating the molar density of gas molecules inside the high-pressure bushing is as follows:

[0045] When the oil and gas pressure sensor is at the top of the high-pressure bushing, the gas molar density value inside the high-pressure bushing is:

[0046]

[0047] When the oil and gas pressure sensor is at the bottom of the high-pressure bushing, the molar density value of the gas inside the high-pressure bushing is:

[0048]

[0049] in:

[0050] P o (t) represents the hydraulic pressure at the bottom of the high-pressure bushing at time t;

[0051] P oh (t) represents the equivalent pressure of the oil level inside the high-pressure bushing at time t;

[0052] d(t) is the molar density of gas molecules inside the high-pressure bushing at time t.

[0053] Furthermore, the diagnostic threshold is any one or more of the following: gas pressure value inside the high-pressure bushing, movement range, minimum difference in molar density imbalance between phases of gas molecules, and maximum difference in molar density imbalance between phases of gas molecules.

[0054] Furthermore, the present invention provides a device for measuring and diagnosing the transient temperature of gas inside a high-pressure bushing. The device includes a memory and a processor. The memory stores a program for measuring and diagnosing the transient temperature of gas inside a high-pressure bushing that can run on the processor. When the processor executes the program for measuring and diagnosing the transient temperature of gas inside a high-pressure bushing, it implements the steps of the method for measuring and diagnosing the transient temperature of gas inside a high-pressure bushing as described above.

[0055] Furthermore, the transient temperature measurement and condition diagnosis device for the gas inside the high-pressure bushing also includes a temperature sensor and a pressure sensor. The temperature sensor is used to obtain the temperature value of the high-pressure bushing shell; the pressure sensor is used to collect the gas pressure value inside the high-pressure bushing or the hydraulic pressure value of the oil at the bottom of the high-pressure bushing.

[0056] Meanwhile, the present invention provides a storage medium, which is a computer-readable storage medium, storing a program for calculating the transient temperature of gas inside a high-pressure bushing and for diagnosing its condition. The program for calculating the transient temperature of gas inside a high-pressure bushing and for diagnosing its condition can be executed by one or more processors to implement the steps of the method for calculating the transient temperature of gas inside a high-pressure bushing as described above.

[0057] This invention provides a method, device, and storage medium for calculating the transient temperature and diagnosing the condition of gas inside a high-pressure bushing. By collecting the gas pressure, shell temperature, and ambient temperature of the equipment inside the bushing, and calculating the effective value of the influence of ambient temperature and temperature field model parameters, the transient temperature and molar density of the gas molecules inside the bushing are further calculated. Then, equipment condition diagnosis is performed based on a set diagnostic threshold. This method significantly improves the accuracy of gas temperature calculation, appropriately narrowing the allowable deviation of the diagnostic threshold for the calculation results. It enables 24-hour uninterrupted online monitoring of oil and gas pressure values ​​inside the high-pressure bushing, allowing for the assessment of operational and fault conditions within the bushing, preventing accidents, and providing a practical means for real-time monitoring of equipment operation and fault conditions. Attached Figure Description

[0058] Figure 1 This is a flowchart illustrating the method for calculating the transient temperature and diagnosing the condition of gas inside a high-pressure bushing provided in Embodiment 1 of the present invention.

[0059] Figure 2 This is a schematic diagram of the internal structure of a high-pressure bushing gas transient temperature measurement and condition diagnosis device according to an embodiment of the present invention;

[0060] Figure 3This is a schematic diagram of the transient temperature measurement and condition diagnosis program module for gas inside a high-pressure bushing, provided in an embodiment of the present invention. Detailed Implementation

[0061] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0062] Example 1

[0063] Please see Figure 1 Embodiment 1 of the present invention provides a method for calculating and diagnosing the transient temperature of gas inside a high-pressure bushing. The method includes:

[0064] Step S11: Collect the gas pressure inside the high-pressure bushing, the shell temperature, and the ambient temperature of the equipment.

[0065] Step S12: Calculate the effective value of the influence of ambient temperature;

[0066] Step S13: Calculate the transient temperature of the gas inside the high-pressure bushing;

[0067] Step S14: Calculate the temperature field model parameters;

[0068] Step S15: Calculate the transient temperature of the gas inside the high-pressure bushing;

[0069] Step S16: Calculate the molar density of gas molecules inside the high-pressure bushing;

[0070] Step S17: Perform a status diagnosis on the high-voltage bushing according to the set diagnostic threshold.

[0071] Specifically, in this embodiment, the high-voltage bushing is a high-voltage oil-filled bushing at the power input or output terminal of a high-voltage power transformer, with a voltage level greater than or equal to 110kV. The insulating oil of the high-voltage bushing is a mineral oil obtained by distillation and refining of natural petroleum. It is a mixture composed of many hydrocarbons of different molecular weights, including alkanes, alkenes, cycloalkanes, and aromatic hydrocarbons. When there is a discharge or overheating fault inside the equipment, gases such as H2, CH4, C2H6, C2H4, C2H2, CO, and CO2 will be generated. Some of these gases are dissolved in the oil, while others are released onto the oil surface. Since the high-voltage bushing has a sealed structure, the gas on the oil surface gradually accumulates, and the increased gas pressure acts on the liquid insulating oil, causing the oil pressure to gradually increase. Therefore, online monitoring of insulation defects inside the high-voltage bushing can be achieved by acquiring changes in gas pressure.

[0072] The molar quantity of gas inside a high-voltage bushing exists in a dynamic equilibrium state. At any given moment, a certain amount of gas molecules dissolve into the oil, while a certain amount of gas molecules are released from the oil and enter the upper layer of the high-voltage bushing. When the conditions are constant (temperature and pressure are stable), the molar quantity of gas reaches a stable state, i.e., a dynamic equilibrium state. Relevant literature and analysis show that the rate of gas molecule dissolution and release from the insulating oil corresponds to the oil temperature. Generally, the higher the oil temperature, the higher the release rate and the lower the dissolution rate; for high-voltage bushings, this translates to an increase in the molar quantity of gas molecules.

[0073] The physicochemical properties of commonly used mineral transformer oils include:

[0074] The gas density at 20℃ is no greater than 895 kg / m³ 3 ;

[0075] The coefficient of volume expansion of mineral oil is α = 6.4 × 10⁻⁶. -4 (1 / K);

[0076] The coefficient of volumetric expansion for all gases is α = 1 / 273.15 = 3.67 × 10⁻⁶. -3 (1 / K).

[0077] Therefore, the gas inside the high-pressure bushing conforms to the ideal gas law, which refers to a gas that obeys the ideal gas law. Under conditions of moderate pressure and temperature, air, nitrogen, oxygen, helium, hydrogen, and neon all obey the ideal gas law and can be considered ideal gases. Almost all chemically stable gases, when conditions are far from liquefaction or solidification, behave similarly to ideal gases.

[0078] Ideal Gas Law: For an n kilomoles of gas, the relationship between its volume V, absolute pressure P, and absolute temperature T is PV = nRT, where R = 8314 J / kmol·K and R is the universal gas constant.

[0079] After collecting the ambient temperature data of the high-pressure bushing, a temperature gradient model is established using the temperature field distribution law of the high-pressure bushing's heat dissipation process, which can accurately calculate the gas temperature inside the high-pressure bushing. Then, using the aforementioned ideal gas equation, the molar density of the gas inside the high-pressure bushing can be calculated.

[0080] Therefore, by collecting the gas pressure inside the high-pressure bushing, the shell temperature, and the ambient temperature, the molar density of the gas molecules inside the high-pressure bushing is calculated. Specifically, the effective value of the influence of ambient temperature is first calculated. Because the high-pressure bushing is filled with oil, its relative heat capacity is relatively large, and the influence of ambient temperature changes on the oil and gas temperature is cumulative and delayed, which is a slow accumulation process. Therefore, an equivalent algorithm is used to calculate the effective value ΔT of the influence of ambient temperature. 1e (t). ΔT 1e (t) is directly related to the equilibrium time of the casing equipment under environmental influence. The equilibrium time constant of the casing equipment under environmental influence is T≈5 hours. This is equivalent to the constant environmental temperature value at time t, representing the cumulative effect of environmental temperature changes over time T.

[0081] The formula for calculating the effective value of the influence of ambient temperature is as follows:

[0082] ΔT 1e (t)=a·b·e -bt *[T1(t)-T a (t)]

[0083] in,

[0084] t is the sampling time; the value of t is in the range of [0, T], and T is the thermal equilibrium time constant of the equipment affected by the ambient temperature. The units of time t and T are hours.

[0085] ΔT 1e (t) represents the effective value of the influence of ambient temperature at time t;

[0086] T1(t) is the temperature of the high-voltage bushing shell measured at time t;

[0087] T a (t) represents the ambient temperature of the high-pressure bushing at time t;

[0088] * indicates convolution calculation;

[0089] a and b are constant coefficients, determined by the monitoring data sampling period and the equipment thermal balance time constant. Recommended coefficients are shown in Table 1.

[0090] Table 1:

[0091] Monitoring data sampling duration Monitoring data sampling period constant coefficient a constant coefficient b 1 hour / time 10 hours 0.78 0.56 1 hour / time (default) 5 hours 0.61 1.11 1 hour / time 2.5 hours 0.405 2.22 0.5 hours / time 5 hours 0.78 1.11 2 hours / time 5 hours 0.405 1.11

[0092] Furthermore, based on the calculated effective value of the environmental temperature influence and the temperature field model parameters, the transient temperature value of the gas inside the high-pressure bushing is calculated, and the calculation formula is as follows:

[0093]

[0094] in,

[0095] T g (t) represents the transient gas temperature inside the high-pressure bushing at time t;

[0096] A1 is the heat dissipation coefficient between the inside of the high-voltage bushing and the outer casing;

[0097] A2 is the heat dissipation coefficient between the high-voltage bushing casing and the environment;

[0098] B1 is the total heat capacity coefficient from the inside of the high-pressure bushing to the outer shell;

[0099] By analyzing the actual operating conditions of the thermal system, the algorithm model is simplified. Then, dynamic equivalent calculations are performed on the main variables in the equations, thus achieving accurate results from dynamic calculations through static equations.

[0100] make: And for high-pressure bushing equipment It is a very small number;

[0101] To simplify calculations, If we ignore the null terminology, the equation transforms into:

[0102] T g (t)=k0ΔT 1e (t)+T1(t)

[0103] k0 is the temperature field model parameter corresponding to the sensor installed on the high-voltage bushing, which is treated as an approximation constant, with a default empirical value of k0 = 0.5.

[0104] Furthermore, the temperature field model parameter k0 is calculated. The physical meaning of k0 is the ratio of the heat dissipation coefficient from the high-pressure bushing shell to the environment to the heat dissipation coefficient from the gas inside the high-pressure bushing to the high-pressure bushing shell. Under a specific state, the heat dissipation performance of each part of the equipment is stable, and the heat dissipation coefficient is constant. That is, the temperature field model parameter k0 corresponding to the sensor installed on the high-pressure bushing is also constant. Therefore, roughly, k0 can be treated as a constant coefficient in the diagnostic calculation process.

[0105] When considering k0 in a dynamic process, k0 is treated as a variable. A calculation function for k0 is designed for accurate calculation. The heat dissipation coefficient A2 from the high-pressure bushing shell to the environment increases with increasing equipment temperature and temperature difference; the heat dissipation coefficient A1 from the gas inside the high-pressure bushing to the high-pressure bushing shell decreases with increasing equipment temperature. k0(t) is approximately linearly related to both the gas temperature and the ambient temperature, and its calculation formula is:

[0106] k0(t)=a1T g (t)+a2T1(t)+a3

[0107] in,

[0108] k0(t) is the model parameter of the temperature field inside the high-pressure bushing;

[0109] a1, a2, and a3 are constant coefficients; specifically, the coefficients a1, a2, and a3 are obtained through test data from normal equipment, and the values ​​of a1, a2, and a3 are given here as follows:

[0110] a1=0.0035, a2=-0.0023, a3=0.04

[0111] Furthermore, based on the calculated effective value of the environmental temperature influence and the calculated temperature field model parameters, the transient temperature value of the gas inside the high-pressure bushing is calculated using the following formula:

[0112] T g (t)=k0ΔT 1e (t)+T1(t)

[0113] Furthermore, based on the calculated transient gas temperature T inside the high-pressure bushing... g (t) can be used to calculate the molar density of gas molecules inside the high-pressure bushing. Specifically, the formula for calculating the molar density of gas molecules inside the high-pressure bushing is as follows:

[0114] When the oil and gas pressure sensor is at the top of the high-pressure bushing, the gas molar density value inside the high-pressure bushing is:

[0115]

[0116] When the oil and gas pressure sensor is at the bottom of the high-pressure bushing, the molar density value of the gas inside the high-pressure bushing is:

[0117]

[0118] in:

[0119] P g (t) represents the gas pressure inside the high-pressure bushing at time t;

[0120] Po (t) represents the hydraulic pressure at the bottom of the high-pressure bushing at time t;

[0121] P oh (t) represents the equivalent pressure of the oil level inside the high-pressure bushing at time t;

[0122] d(t) is the molar density of gas molecules inside the high-pressure bushing at time t.

[0123] The calculated gas molecule molar density value d(t) is used as a basic index value for monitoring and diagnosing the gas pressure and temperature in the high-pressure bushing.

[0124] Further, the gas molecule molar density value is converted into an equivalent gas pressure value at a preset temperature; the formula for calculating the equivalent gas pressure value at the preset temperature is:

[0125] When the high-voltage bushing sensor is at the top of the high-voltage bushing:

[0126]

[0127] When the high-voltage bushing sensor is at the bottom of the high-voltage bushing:

[0128]

[0129] in:

[0130] P pr (t) represents the equivalent pressure at a preset temperature value;

[0131] T pr The preset temperature value;

[0132] When the preset temperature is 20℃, the calculation method for the equivalent pressure is:

[0133] When the high-voltage bushing sensor is at the top of the high-voltage bushing:

[0134]

[0135] When the high-voltage bushing sensor is at the bottom of the high-voltage bushing:

[0136]

[0137] Wherein: T 20 = 293.15K, where K is the unit of thermodynamic temperature.

[0138] P oh (t) Take the given empirical value P oh (t)≈75kPa.

[0139] P 20d(t) and d(t) are fixed multiples of T. 20 Therefore, in terms of diagnostic function, the molar density of gas molecules and the pressure at 20°C are equivalent diagnostic indicators.

[0140] Under normal conditions, the molar density of gas molecules in the high-pressure bushing remains within a certain range, fluctuating accordingly with changes in the gas state quantity (P / T). Significant changes in the molar density are usually caused by some abnormal condition. For example, internal localized overheating, partial discharge, or abnormal oil deterioration can increase the molar density; while gas or oil leaks in the high-pressure bushing can decrease it. Therefore, tracking the molar density can provide a preliminary assessment of these fault conditions. Under normal circumstances, the fluctuations in the molar density data conform to a normal probability distribution.

[0141] Therefore, the equivalent air pressure value is continuously monitored according to a set diagnostic threshold. Specifically, the diagnostic threshold is set as follows:

[0142] When the high-pressure bushing sensor is at the top of the high-pressure bushing, the diagnostic threshold is 60 kPa to 180 kPa; when the high-pressure bushing sensor is at the bottom of the high-pressure bushing, the diagnostic threshold is 120 kPa to 230 kPa.

[0143] Example 2

[0144] Compared with Embodiment 1 above, the main difference of Embodiment 2 lies in the diagnostic method and effect. In Embodiment 2 provided by the present invention, the diagnostic method is as follows:

[0145] The moving range is calculated based on an equivalent pressure value and its adjacent equivalent pressure values, using the following formula:

[0146] MR=|x i -x i+1 |(i=1,2,…,k-1)

[0147] Where: MR is the moving range; |x i -x i+1 | represents the absolute value of the difference between an equivalent pressure value and its adjacent equivalent pressure values, and k represents the number of equivalent pressure values;

[0148] Calculate the overall average

[0149]

[0150] Calculate the moving range mean

[0151]

[0152] Set x control limits:

[0153]

[0154] Set MR control limits:

[0155]

[0156] The continuous monitoring and diagnosis of the equivalent air pressure value based on the diagnostic method and the set control limits includes:

[0157] If *a* consecutively preset *x* values ​​are outside the actual control limit of *x*, the device status is considered abnormal.

[0158] If b consecutive preset x values ​​are all increased or all decreased, and all are outside the actual control limit of x: Equipment status abnormality warning;

[0159] If c consecutive preset x values ​​all increase or all decrease, and all are on either side of the center line: Equipment status abnormality warning;

[0160] If any data point exceeds the permissible high-pressure bushing pressure standard range, an abnormal equipment status alarm will be triggered.

[0161] If the moving range (MR) exceeds the upper control line at any point, the equipment status is abnormal and should be monitored.

[0162] The moving range (MR) exceeds the upper control line for 3 consecutive points, triggering an equipment status abnormality warning.

[0163] Specifically, considering the characteristics of the high-voltage bushing power equipment in this embodiment, the diagnostic indicators for the Statistical Process Control (SPC) control chart are designed as follows:

[0164] 1) Equivalent gas pressure (x) at 20℃, data for 3 consecutive days, outside the control limits: abnormal equipment status requires attention;

[0165] 2) The equivalent gas pressure value (x) at 20℃, for 15 consecutive days, all of which either increase or decrease and are all outside the control limits: Equipment abnormality warning;

[0166] 3) Equivalent gas pressure (x) at 20℃, data for 22 consecutive days, all increasing or all decreasing, and all on either side of the centerline: Equipment abnormality warning;

[0167] 4) The equivalent gas pressure value (x) at 20℃, if any data point exceeds the allowable pressure standard range, will trigger an alarm indicating abnormal equipment status.

[0168] 5) If the moving range (MR) exceeds the upper control line at any point, the equipment status is abnormal and should be monitored.

[0169] 6) If the moving range (MR) exceeds the upper control line for 3 consecutive points, an abnormal equipment status warning will be issued.

[0170] Example 3

[0171] Compared with the above embodiment one, the main difference of embodiment three is that the diagnostic indicators are different. In embodiment three provided by the present invention, the design of the diagnostic indicators is: the unevenness of the molar density of gas molecules between phases, which can be divided into two different algorithms: the minimum difference and the maximum average difference.

[0172] The algorithm for minimizing the difference in the molar density disequilibrium of interphase gas molecules is as follows:

[0173]

[0174] The algorithm for the mean difference of the molar density disequilibrium of interphase gas molecules is as follows:

[0175]

[0176] in,

[0177] ε1(t) represents the minimum difference in the molar density imbalance of interphase gas molecules;

[0178] ε2(t) represents the difference in the uniformity of the molar density disequilibrium of gas molecules between phases;

[0179] d max (t)=max(d a (t), d b (t), d c (t));

[0180] d min (t)=min(d a (t), d b (t), d c (t));

[0181] d ave (t) = average(d) a (t), d b (t), d c (t)).

[0182] Furthermore, the state diagnosis threshold is:

[0183] When ε2(t) ≥ 35%: Equipment status abnormal alarm;

[0184] When 35% > ε2(t) ≥ 25%: Equipment status abnormality warning;

[0185] When 15% > ε2(t) ≥ 5%: Pay attention to abnormal equipment status.

[0186] The imbalance degree minimum difference algorithm is sensitive to small data and should be used if there are many oil or gas leaks.

[0187] The unevenness mean difference algorithm is sensitive to large data, such as those with internal overheating, partial discharge, and abnormal oil quality deterioration, and is therefore suitable for use.

[0188] The minimum difference algorithm or the maximum mean difference algorithm for imbalance can be selected for diagnosis based on the actual engineering situation. For example, the diagnostic threshold set for the maximum mean difference algorithm for imbalance can be:

[0189] When ε2(t) ≥ 35%: Equipment status abnormal alarm;

[0190] When 35% > ε2(t) ≥ 25%: Equipment status abnormality warning;

[0191] When 15% > ε2(t) ≥ 5%: Pay attention to abnormal equipment status.

[0192] In addition, the present invention also provides a device for measuring and diagnosing the transient temperature of gas inside a high-pressure bushing.

[0193] Please see Figure 2 This is a schematic diagram of the internal structure of a device for measuring and diagnosing the transient temperature of gas inside a high-pressure bushing, provided in an embodiment of the present invention. The device includes at least a memory 11, a processor 12, a communication bus 13, a network interface 14, a temperature sensor 15, and a pressure sensor 16.

[0194] The memory 11 includes at least one type of readable storage medium, including flash memory, hard disk, multimedia card, card-type memory (e.g., SD or DX memory), magnetic memory, magnetic disk, optical disk, etc. In some embodiments, the memory 11 can be an internal storage unit of the high-pressure bushing gas transient temperature measurement and condition diagnosis device, such as the hard disk of the high-pressure bushing gas transient temperature measurement and condition diagnosis device. In other embodiments, the memory 11 can also be an external storage device of the high-pressure bushing gas transient temperature measurement and condition diagnosis device, such as a plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, etc., equipped on the high-pressure bushing gas transient temperature measurement and condition diagnosis device. Furthermore, the memory 11 can also include both internal storage units and external storage devices of the high-pressure bushing gas transient temperature measurement and condition diagnosis device. The memory 11 can be used not only to store the application software and various data of the gas transient temperature measurement and condition diagnosis device installed in the high-pressure bushing, such as the code of the gas transient temperature measurement and condition diagnosis program in the high-pressure bushing, but also to temporarily store data that has been output or will be output.

[0195] In some embodiments, processor 12 may be a central processing unit (CPU), controller, microcontroller, microprocessor or other data processing chip, used to run program code stored in memory 11 or process data, such as executing transient temperature measurement and status diagnosis programs for gas inside high-pressure bushings.

[0196] Communication bus 13 is used to enable communication between these components.

[0197] The network interface 14 may optionally include a standard wired interface or a wireless interface (such as a WI-FI interface), which is typically used to establish a communication connection between the gas transient temperature measurement and condition diagnosis device in the high-pressure bushing and other electronic devices.

[0198] The temperature sensor 15 and the pressure sensor 16 are connected to the processor 12. The temperature sensor 15 is used to obtain the temperature value of the high-pressure bushing shell; the pressure sensor 16 is used to collect the gas pressure value inside the high-pressure bushing or the oil pressure value at the bottom of the high-pressure bushing.

[0199] Optionally, the transient gas temperature measurement and condition diagnosis device inside the high-pressure bushing may further include a user interface. The user interface may include a display, an input unit such as a keyboard, and optionally, a standard wired interface or a wireless interface. Optionally, in some embodiments, the display may be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, or an OLED (Organic Light-Emitting Diode) touchscreen, etc. The display may also be appropriately referred to as a screen or display unit, used to display information processed in the transient gas temperature measurement and condition diagnosis device inside the high-pressure bushing and to display a user interface for visualization.

[0200] Figure 2 Only the high-pressure bushing gas transient temperature measurement and condition diagnosis device with components 11-16 and the high-pressure bushing gas transient temperature measurement and condition diagnosis program is shown. Those skilled in the art will understand that... Figure 2 The structure shown does not constitute a limitation on the device for measuring and diagnosing transient gas temperature inside the high-pressure bushing. It may include fewer or more components than shown, or combine certain components, or have different component arrangements.

[0201] exist Figure 2 In the embodiment of the high-pressure bushing gas transient temperature measurement and status diagnosis device shown, the memory 11 stores a high-pressure bushing gas transient temperature measurement and status diagnosis program; when the processor 12 executes the high-pressure bushing gas transient temperature measurement and status diagnosis program stored in the memory 11, it performs the following steps:

[0202] Step S11: Collect the gas pressure inside the high-pressure bushing, the shell temperature, and the ambient temperature of the equipment.

[0203] Step S12: Calculate the effective value of the influence of ambient temperature;

[0204] Step S13: Calculate the transient temperature of the gas inside the high-pressure bushing;

[0205] Step S14: Calculate the temperature field model parameters;

[0206] Step S15: Calculate the transient temperature of the gas inside the high-pressure bushing;

[0207] Step S16: Calculate the molar density of gas molecules inside the high-pressure bushing;

[0208] Step S17: Perform a status diagnosis on the high-voltage bushing according to the set diagnostic threshold.

[0209] Reference Figure 3The diagram shown is a schematic diagram of the program modules for the transient temperature measurement and status diagnosis of gas inside a high-pressure bushing according to an embodiment of the device for transient temperature measurement and status diagnosis of gas inside a high-pressure bushing of the present invention. In this embodiment, the transient temperature measurement and status diagnosis program of gas inside a high-pressure bushing can be divided into a monitoring module 10, a calculation module 20, a setting module 30, and a diagnosis module 40, as exemplarily:

[0210] Monitoring module 10 is used to collect the gas pressure value inside the high-pressure bushing, the shell temperature value, and the ambient temperature value of the equipment.

[0211] Calculation module 20 is used to calculate the molar density value of gas molecules, the equivalent gas pressure value, the minimum difference of the unevenness of the molar density of gas molecules between phases, and the maximum difference of the unevenness of the molar density of gas molecules between phases.

[0212] Setting module 30 is used to set diagnostic thresholds;

[0213] The diagnostic module 40 is used for online monitoring and diagnosis of gas pressure and temperature inside the high-pressure bushing.

[0214] The functions or operation steps implemented by the above-mentioned monitoring module 10, calculation module 20, setting module 30 and diagnosis module 40 when they are executed are largely the same as those in the above embodiments, and will not be repeated here.

[0215] Furthermore, this invention also proposes a storage medium, which is a computer-readable storage medium, storing a transient temperature measurement and status diagnosis program for the gas inside the high-pressure bushing. This program can be executed by one or more processors to perform the following operations:

[0216] Step S11: Collect the gas pressure inside the high-pressure bushing, the shell temperature, and the ambient temperature of the equipment.

[0217] Step S12: Calculate the effective value of the influence of ambient temperature;

[0218] Step S13: Calculate the transient temperature of the gas inside the high-pressure bushing;

[0219] Step S14: Calculate the temperature field model parameters;

[0220] Step S15: Calculate the transient temperature of the gas inside the high-pressure bushing;

[0221] Step S16: Calculate the molar density of gas molecules inside the high-pressure bushing;

[0222] Step S17: Perform a status diagnosis on the high-voltage bushing according to the set diagnostic threshold.

[0223] The specific implementation of the storage medium of the present invention is basically the same as the embodiments of the above-described method and apparatus for calculating the transient temperature and diagnosing the state of gas inside the high-pressure bushing, and will not be repeated here.

[0224] Compared with existing technologies, the present invention provides a method, device, and storage medium for calculating the transient temperature and condition diagnosis of gas inside a high-pressure bushing. By collecting the gas pressure, shell temperature, and ambient temperature of the equipment inside the high-pressure bushing, and calculating the effective value of the influence of ambient temperature and the parameters of the temperature field model, the transient temperature and molar density of gas molecules inside the high-pressure bushing are further calculated. Then, equipment condition diagnosis is performed based on a set diagnostic threshold. This method significantly improves the accuracy of gas temperature calculation, appropriately narrows the allowable deviation of the diagnostic threshold for the corresponding calculation results, and enables 24-hour uninterrupted online monitoring of oil and gas pressure values ​​inside the high-pressure bushing. It can assess the operating and fault conditions within the high-pressure bushing, prevent accidents, and provides a practical means for real-time monitoring of equipment operation and fault conditions.

[0225] It should be noted that the sequence numbers of the above embodiments of the present invention are merely for descriptive purposes and do not represent the superiority or inferiority of the embodiments. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, apparatus, article, or method that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, apparatus, article, or method. Without further limitations, an element defined by the phrase "comprising a…" does not exclude the presence of other identical elements in the process, apparatus, article, or method that includes that element.

[0226] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device (which may be a drone, mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0227] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A method for calculating and diagnosing the state of gas transient temperature in a high-voltage bushing, characterized by, Comprising: S1, collect the gas pressure value in the high-voltage sleeve, the shell temperature value (T1(t)), and the ambient temperature value (T a (t)); S2, calculate the effective value of environmental temperature influence (ΔT 1e (t)), the calculation formula is: ΔT 1e (t) = a • b • e -bt *[T1(t) - T a (t)] Wherein, t is the sampling time; t is in the range of [0, T], T is the thermal equilibrium time constant of the device environment temperature influence, the unit of time t, T is hour; ΔT 1e (t) is the effective value of the ambient temperature influence at time t; T1(t) is the measured high-voltage sleeve shell temperature at t; T a (t) is the temperature value of the external environment in which the high-voltage bushing is located at time t; * is a convolution calculation; a, b are constant coefficients, a is the environmental temperature influence coefficient, b is the time constant, which is obtained by fitting the historical temperature data of the device; S3, calculate the transient temperature value (T g (t)) of the gas in the high-pressure sleeve, the initial calculation formula is: Wherein, T g (t) is the transient gas temperature value in the high-voltage bushing at time t; A1 is the heat dissipation coefficient between the high-voltage sleeve inside and the shell; A2 is the heat dissipation coefficient between the high-voltage sleeve shell and the environment; B1 is the total heat capacity coefficient of the high-voltage sleeve inside to the shell; S4, calculate the temperature field model parameter (k0), let The function relationship is: k0 = a1T g (t) + a2T1(t) + a3 Wherein, a1, a2, a3 are constant coefficients, the values of a1, a2, a3 are respectively: a1=0.0035, a2=-0.0023, a3=0.04; S5, the transient temperature value of the gas in the high-voltage sleeve is calculated again, and the calculation formula is: S6, the gas molar density value (d(t)) in the high-voltage sleeve is calculated, when the oil and gas pressure sensor is at the top of the high-voltage sleeve, the gas molar density value in the high-voltage sleeve is: When the oil and gas pressure sensor is at the bottom of the high-voltage sleeve, the gas molar density value in the high-voltage sleeve is: Wherein: P g (t) is the gas pressure in the high-voltage bushing at time t; P o (t) is the oil pressure at the bottom of the high-voltage bushing at time t; P oh (t) is the equivalent pressure of the oil height in the high-voltage bushing at time t; d(t) is the gas molar density value in the high-voltage sleeve at t; S7, according to the set diagnostic threshold, the state of the high-voltage sleeve is diagnosed, and the diagnostic threshold includes any one or more of the gas pressure value in the high-voltage sleeve, the moving range, the minimum difference (ε1(t)) of the inter-phase gas molar density imbalance, and the maximum difference (ε2(t)) of the inter-phase gas molar density imbalance.

2. The method of claim 1, wherein, The calculation formula of the moving range is: MR = |x i - x i+1 (i = 1, 2,..., k - 1) Wherein: MR is the moving range, x is the equivalent gas pressure value, and k is the number of equivalent gas pressure values; Total average: Moving range average: X control limit: MR control limit: Lower limit = 0 3. The method of claim 1, wherein, The minimum difference of the inter-phase gas molar density imbalance is: The maximum difference of the inter-phase gas molar density imbalance is: where d max (t), d min (t), d ave (t) are the maximum, minimum and average molar density values between phases, respectively.

4. A device for calculating and diagnosing the state of gas transient temperature in a high-voltage bushing, characterized by The storage medium is a computer readable storage medium, and a program is stored thereon, and the program can be executed by the processor to realize the method steps of any one of claims 1-3.

5. The apparatus of claim 4, wherein, Also included are a temperature sensor for acquiring a high-pressure bushing shell temperature value (T1(t)) and an ambient temperature value (T a o (t)); and a pressure sensor for acquiring a high-pressure bushing internal gas pressure value (P9(t)) or a high-pressure bushing internal bottom oil liquid pressure value (P​ 6. A storage medium, characterized by The storage medium is a computer readable storage medium, and a program is stored thereon, and the program can be executed by the processor to realize the method steps of any one of claims 1-3.

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