High-voltage bushing gas pressure temperature online monitoring and diagnosis method, device and storage medium

Abstract

The present invention provides a method, device and storage medium for online monitoring and diagnosis of gas pressure and temperature of high-voltage bushings. The method includes: collecting gas pressure values ​​and shell temperature values ​​in the high-voltage bushings; calculating gas molecular molar density values ​​in the high-voltage bushings; converting the gas molecular molar density values ​​into equivalent gas pressure values ​​of preset temperature values; continuously monitoring the equivalent gas pressure values, and making a diagnosis of the equipment status according to a set diagnostic threshold; and providing a diagnosis of the high-voltage bushing equipment status based on the moving extreme difference and the imbalance of gas molecular molar density between phases. Through the technical solution provided by the present invention, online 24-hour uninterrupted monitoring of the oil and gas pressure values ​​in the high-voltage bushings is achieved, and the operation and fault status of the high-voltage bushing equipment can be evaluated to prevent accidents, providing a practical means for real-time monitoring of the operation and fault status of the equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of online monitoring and diagnosis of gas pressure and temperature of high-voltage bushings, and in particular to an online monitoring and diagnosis method, device and storage medium for gas pressure and temperature of high-voltage bushings. Background Art

[0002] A large number of oil-filled electrical equipment are running in the existing power system, including transformer high-voltage bushings, current transformers, circuit breakers and other oil-less equipment. During the operation of the substation, the insulation state of the oil-less equipment and the operating state of the internal mechanism are of vital importance to the safe and stable operation of the power system. However, these equipment may cause failures due to improper manufacturing, overhaul, maintenance and oil quality deterioration, and vicious accidents such as explosions and fires occur from time to time, affecting the safe and stable operation of the power grid and the reliability of power supply.

[0003] At present, substations generally use manual inspections for the maintenance of such equipment, and a small number of them will be combined with online insulation monitoring. The manual inspection is to use the inspection of operating personnel and the regular sampling of test personnel. Traditional detection and analysis methods include ultrasonic partial discharge, infrared temperature measurement, oil chromatography analysis, etc. However, in recent years, with the continuous improvement of voltage levels and the increase in equipment capacity, traditional offline preventive test methods can no longer meet the actual needs of the safe operation of modern large-scale power equipment, and it is difficult to truly reflect the insulation status of various types of bushings, current transformers and other equipment under operating conditions. Since preventive tests are carried out according to fixed cycles, they cannot be discovered, tracked, and repaired in a timely manner, which has great limitations.

[0004] Traditional maintenance methods mainly include daily inspection and power failure inspection. Daily inspection includes component inspection and heating inspection; power failure inspection includes insulation resistance measurement, polarization coefficient measurement, capacitance and dielectric loss factor measurement, partial discharge measurement, and transformer oil inspection (current transformers can be powered on to extract oil).

[0005] Component inspections during routine maintenance generally include checking for oil leaks, metal parts corrosion inspection, porcelain sleeve appearance inspection, and grounding condition inspection. For current transformers, the expansion amount of the expander needs to be checked to determine the oil level. Fever detection is very effective in discovering thermal defects and hot spots in equipment with little oil. It can detect overheating caused by poor contact points or excessive temperatures caused by local defects.

[0006] Before commissioning and every few years after operation, low-oil equipment will be shut down regularly for insulation performance testing to determine the insulation condition of the low-oil equipment; at the same time, the gas content and moisture content in the oil will also be measured during the power outage maintenance cycle. Currently, the analysis and detection of dissolved gas in oil is still one of the methods for fault diagnosis of oil-filled electrical equipment.

[0007] Although the conventional methods currently used can detect some faults, the early diagnosis effect of faults is poor, the effect of on-site partial discharge tests is not ideal, and the casing cannot be analyzed by live oil sampling. It is even more difficult when the chromatographic analysis data is abnormal and sampling and tracking are required. At the same time, periodic detection cannot prevent sudden accidents.

[0008] In transformer high-voltage bushings, current transformers and other oil-poor equipment, the insulating oil in a sealed state will decompose during operation due to insulation damage and other reasons, and release a certain amount of gas. The insulating oil of the high-voltage bushing is a mineral oil obtained by distillation and refining of natural petroleum. It is a mixture of many hydrocarbons with different molecular weights, including alkanes, olefins, cycloalkanes, aromatic hydrocarbons, etc.; when there is a discharge or overheating fault inside the equipment, characteristic gases such as H2, CH4, C2H6, C2H4, C2H2, CO and CO2 will be generated. The generated gas is both dissolved in the oil and released on the oil surface. Since the high-voltage bushing is 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. After a long period of accumulation, a certain gas pressure is formed in the cavity, which can cause oil spraying or even explosion in severe cases. At present, there are two main ways to detect characteristic gases: oil and gas spectrum analysis and pressure monitoring. Oil chromatography analysis generally uses manual sampling to regularly monitor the content of acetylene, hydrogen, and total hydrocarbons dissolved in the oil of low-oil equipment. However, this method has a relatively long cycle and cannot detect abnormalities between two detection intervals, posing a safety hazard. Summary of the invention

[0009] The main purpose of the present invention is to provide a method, device and storage medium for online monitoring and diagnosis of gas pressure and temperature of a high-voltage bushing, aiming to solve the problems of existing high-voltage bushing gas pressure and temperature monitoring and fault diagnosis.

[0010] To achieve the above object, the present invention provides a method for online monitoring and diagnosis of the gas pressure and temperature of a high-voltage bushing, the method comprising:

[0011] Collect the gas pressure value and shell temperature value in the high-voltage bushing;

[0012] Calculate the molar density of gas molecules in the high-voltage bushing;

[0013] Converting the gas molecule molar density value into an equivalent gas pressure value of a preset temperature value;

[0014] The equivalent gas pressure value is continuously monitored, and the state of the high-voltage bushing equipment is diagnosed according to a set diagnosis threshold.

[0015] Furthermore, the calculation formula of the molar density value of the gas molecules in the high-voltage bushing is: when the sensor is at the top of the high-voltage bushing, the molar density value of the gas in the high-voltage bushing is:

[0016]

[0017] When the sensor is at the bottom of the high-voltage bushing, the molar density of the gas in the high-voltage bushing is:

[0018] P g (t) = P o (t)-P oh (t)

[0019]

[0020] in:

[0021] P g (t) is the gas pressure in the high-voltage bushing at time t;

[0022] P o (t) is the oil pressure at the bottom of the high-pressure casing at time t;

[0023] P oh (t) is the equivalent pressure of the oil in the high-pressure casing at time t;

[0024] V(t) is the gas volume in the high-voltage bushing at time t;

[0025] n(t) is the number of moles of gas molecules in the high-voltage bushing at time t;

[0026] T1(t) is the high voltage bushing shell temperature at time t;

[0027] R = 8314 J / kmolK is the universal gas constant;

[0028] d(t) is the molar density of gas molecules at time t.

[0029] Furthermore, the calculation formula of the equivalent air pressure value of the preset temperature value is:

[0030] When the sensor is on top of the high voltage bushing:

[0031]

[0032] When the sensor is at the bottom of the high voltage bushing:

[0033]

[0034] in:

[0035] P pr (t) is the equivalent pressure value of the preset temperature value at time t;

[0036] T pr is the preset temperature value.

[0037] Furthermore, the state diagnosis method is a process statistical control chart method:

[0038] The moving range is calculated based on an equivalent air pressure value and the adjacent equivalent air pressure value. The calculation formula is as follows:

[0039] MR=|x i -x i+1 |(i=1,2,…,k-1)

[0040] Where: MR is the moving range; |x i -x i+1 | is the absolute value of the difference between an equivalent pressure value and the adjacent equivalent pressure value, and k is the number of equivalent pressure values;

[0041] Calculate the overall average

[0042]

[0043] Calculate the moving average range

[0044]

[0045] Set x control limits:

[0046]

[0047] Setting MR control limits:

[0048]

[0049] Continuously monitoring and diagnosing the equivalent gas pressure value according to the process statistical control chart method and the set control limits includes:

[0050] Continuously preset a x values ​​outside the actual control limit of x: abnormal equipment status is of concern;

[0051] Continuously preset b x values ​​all increase or decrease, and all are outside the actual control limit of x: abnormal equipment status warning;

[0052] Continuously preset c x values, all increasing or all decreasing, and all on either side of the center line: abnormal equipment status warning;

[0053] Any data point exceeds the allowable high-voltage bushing pressure standard range: abnormal equipment status alarm;

[0054] Moving range MR, any one point exceeds the upper control line: equipment status abnormality attention;

[0055] Moving range MR, exceeds the upper control line for 3 consecutive points: abnormal equipment status warning.

[0056] The present invention provides a method for online monitoring and diagnosis of air pressure and temperature of a high-voltage bushing, comprising:

[0057] Collect the gas pressure value and shell temperature value in the high-voltage bushing;

[0058] Calculate the molar density of gas molecules in the high-voltage bushing;

[0059] Calculate the imbalance of molar density of gas molecules between phases;

[0060] The imbalance of the molar density of gas molecules between the phases is continuously monitored, and the state of the high-voltage bushing equipment is diagnosed according to a set diagnostic threshold.

[0061] Furthermore, the calculation of the imbalance degree of molar density of gas molecules between phases is divided into two algorithms: minimum difference and average difference;

[0062] The algorithm for calculating the minimum difference in the imbalance degree of molar density of gas molecules between phases is:

[0063]

[0064] The algorithm for calculating the extreme difference of the imbalance degree of molar density of gas molecules between phases is:

[0065]

[0066] in,

[0067] ε1(t) is the minimum difference in the molar density imbalance of gas molecules between phases;

[0068] ε2(t) is the extreme difference of the imbalance degree of molar density of gas molecules between phases;

[0069] d max (t) = max(d a (t), d b (t), d c (t));

[0070] d min (t) = min(d a (t), d b (t), d c (t));

[0071] d ave (t) = average (d a(t), d b (t), d c (t)).

[0072] Furthermore, the state diagnosis threshold is:

[0073] When ε2(t)≥35%: abnormal equipment status alarm;

[0074] When 35%>ε2(t)≥25%: abnormal equipment status warning;

[0075] When 15%>ε2(t)≥5%: Equipment status is abnormal and attention should be paid.

[0076] In addition, the present invention provides a high-pressure bushing gas pressure and temperature online monitoring and diagnosis device, the high-pressure bushing gas pressure and temperature online monitoring and diagnosis device comprises a memory, a processor, a temperature sensor and a pressure sensor, the memory stores a high-pressure bushing gas pressure and temperature online monitoring and diagnosis program that can be run on the processor, and the high-pressure bushing gas pressure and temperature online monitoring and diagnosis program, when executed by the processor, implements the steps of the high-pressure bushing gas pressure and temperature online monitoring and diagnosis method as described above; the temperature sensor is used to obtain the high-pressure bushing shell temperature value; the pressure sensor is used to obtain the gas pressure value in the high-pressure bushing or the oil pressure value at the bottom of the high-pressure bushing.

[0077] At the same time, the present invention provides a storage medium, which is a computer-readable storage medium, and stores a high-voltage bushing gas pressure and temperature online monitoring and diagnosis program. The high-voltage bushing gas pressure and temperature online monitoring and diagnosis program can be executed by one or more processors to implement the steps of the high-voltage bushing gas pressure and temperature online monitoring and diagnosis method as described above.

[0078] The method, device and storage medium for online monitoring and diagnosis of the gas pressure and temperature of a high-pressure bushing provided by the present invention collect the gas pressure value and the shell temperature value in the high-pressure bushing, calculate the molar density value of the gas molecules in the high-pressure bushing, diagnose the state of the high-pressure bushing equipment based on the equivalent gas pressure value, the moving range, and the imbalance of the molar density of the gas molecules between phases, realize online 24-hour uninterrupted monitoring of the oil and gas pressure value in the high-pressure bushing, evaluate the operation and fault status of the high-pressure bushing equipment, prevent accidents, and provide a practical means for real-time monitoring of the operation and fault status of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0079] Figure 1 A schematic flow chart of a method for online monitoring and diagnosis of high-voltage bushing air pressure and temperature provided in Embodiment 1 of the present invention;

[0080] Figure 2A graph showing the molar density change of the high-voltage bushing gas in the actual monitoring example 1 provided in the first embodiment of the present invention;

[0081] Figure 3 A graph showing the molar density change of the high-voltage bushing gas in the actual monitoring example 2 provided in the first embodiment of the present invention;

[0082] Figure 4 The control diagram of the main transformer A phase gas pressure 20°C (KPa) in the actual monitoring example 1 provided in the second embodiment of the present invention;

[0083] Figure 5 This is a control diagram of the main transformer B phase gas pressure 20°C (KPa) in the actual monitoring example 1 provided in the second embodiment of the present invention;

[0084] Figure 6 This is a control diagram of the main transformer C phase gas pressure 20°C (KPa) in the actual monitoring example 1 provided in the second embodiment of the present invention;

[0085] Figure 7 This is a control diagram of the main transformer A phase gas pressure 20°C (KPa) in the actual monitoring example 2 provided in the second embodiment of the present invention;

[0086] Figure 8 This is a control diagram of the main transformer B phase gas pressure 20°C (KPa) in the actual monitoring example 2 provided in the second embodiment of the present invention;

[0087] Fig. 9 This is a control diagram of the main transformer C phase gas pressure 20°C (KPa) in the actual monitoring example 2 provided in the second embodiment of the present invention;

[0088] Fig.10 A schematic flow chart of a method for online monitoring and diagnosis of high-voltage bushing air pressure and temperature provided in Embodiment 3 of the present invention;

[0089] Fig.11 A graph showing the imbalance degree of the molar density of gas molecules between phases 1 in the actual monitoring example 1 provided in the third embodiment of the present invention;

[0090] Fig.12 A graph showing the imbalance degree of the molar density of gas molecules between phases 2 in the actual monitoring example 1 provided in the third embodiment of the present invention;

[0091] Fig.13 A control diagram of the imbalance degree of the molar density of gas molecules between phases 1 in the actual monitoring example 2 provided in the third embodiment of the present invention;

[0092] Fig.14 This is a control diagram of the imbalance of the molar density of gas molecules between phases 2 in the actual monitoring example 2 provided in the third embodiment of the present invention.

[0093] Fig.15A schematic diagram of the internal structure of a high-voltage bushing gas pressure and temperature online monitoring and diagnosis device provided by an embodiment of the present invention;

[0094] Fig.16 A schematic diagram of a high-voltage bushing gas pressure and temperature online monitoring and diagnosis program module in a high-voltage bushing gas pressure and temperature online monitoring and diagnosis device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0095] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0096] Embodiment 1

[0097] See also Figure 1 Embodiment 1 of the present invention provides a method for online monitoring and diagnosis of the gas pressure and temperature of a high-voltage bushing. The method for online monitoring and diagnosis of the gas pressure and temperature of a high-voltage bushing comprises:

[0098] Step S11: collecting the gas pressure value and shell temperature value in the high-voltage bushing;

[0099] Step S12: Calculate the molar density of gas molecules in the high-voltage bushing;

[0100] Step S13: converting the gas molecule molar density value into an equivalent gas pressure value of a preset temperature value;

[0101] Step S14: continuously monitoring the equivalent air pressure value, and diagnosing the state of the high-voltage bushing equipment according to a set diagnosis threshold.

[0102] Specifically in the first embodiment, the high-voltage bushing is a high-voltage oil-filled bushing at the power input or output end of the high-voltage power transformer, and its voltage level is 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, and is a mixture of many hydrocarbons of different molecular weights, including alkanes, olefins, cycloalkanes, aromatic hydrocarbons, etc. 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. The generated gas is both dissolved in the oil and released on the oil surface. Since the high-voltage bushing is a sealed structure, the gas on the oil surface gradually accumulates, and the gas pressure increases and acts on the liquid insulating oil, causing the oil pressure to gradually increase. Therefore, the online monitoring of the internal insulation defects of the high-voltage bushing can be achieved by obtaining the change of gas pressure.

[0103] The molar quantity of gas inside the high-voltage bushing is in a dynamic equilibrium state. At the same time, a certain amount of gas molecules dissolve into the oil, and at the same time a certain amount of gas molecules are resolved from the oil and enter the upper layer of the high-voltage bushing. When the state is certain (temperature and pressure are stable), the molar quantity of gas reaches a stable state, that is, a dynamic equilibrium state. Through relevant literature and analysis, it is found that the speed at which insulating oil dissolves and resolves gas molecules has a corresponding relationship with the oil temperature. Generally, the higher the oil temperature, the faster the resolution speed and the slower the dissolution speed. For high-voltage bushings, the molar quantity of gas molecules increases.

[0104] The physical and chemical indicators of commonly used mineral transformer oils include:

[0105] Gas density at 20°C is not more than 895kg / m 3 ;

[0106] The volume expansion coefficient of mineral oil is α = 6.4 × 10 -4 (1 / K);

[0107] The volume expansion coefficient of all gases is α = 1 / 273.15 = 3.67 × 10 -3 (1 / K).

[0108] The gas in the high-voltage bushing conforms to the ideal gas state equation, which refers to the gas that obeys the ideal gas law. When the pressure is not high and the temperature is not too low, air, nitrogen, oxygen, helium, hydrogen, neon, etc., all obey the ideal gas law, and such gases can be regarded as ideal gases. Almost all chemically stable gases behave similarly to ideal gases when the conditions are far from liquefaction or solidification.

[0109] Ideal gas law: For n kilomoles of gas, the relationship between its volume V, absolute pressure P and absolute temperature T is PV=nRT, where R=8314J / kmol.K, and R is the universal gas constant.

[0110] Therefore, by collecting the gas pressure value and shell temperature value in the high-voltage bushing, the gas molecular molar density value in the high-voltage bushing is calculated, and the calculation formula is:

[0111] When the sensor is at the top of the high-voltage bushing, the molar density of the gas in the high-voltage bushing is:

[0112]

[0113] When the sensor is at the bottom of the high-voltage bushing, the molar density of the gas in the high-voltage bushing is:

[0114] P g (t) = P o (t)-Poh (t)

[0115]

[0116] in:

[0117] P g (t) is the gas pressure in the high-voltage bushing at time t;

[0118] P o (t) is the oil pressure at the bottom of the high-pressure casing at time t;

[0119] P oh (t) is the equivalent pressure of the oil in the high-pressure casing at time t;

[0120] V(t) is the gas volume in the high-voltage bushing at time t;

[0121] n(t) is the number of moles of gas molecules in the high-voltage bushing at time t;

[0122] T1(t) is the high voltage bushing shell temperature at time t;

[0123] R = 8314 J / kmolK is the universal gas constant;

[0124] d(t) is the molar density of gas molecules.

[0125] The calculated gas molecule molar density value d(t) is used as the basic indicator value for status monitoring and diagnosis of gas pressure and temperature in the high-voltage bushing.

[0126] Furthermore, the gas molecule molar density value is converted into an equivalent gas pressure value of a preset temperature value; the calculation formula for the equivalent gas pressure value of the preset temperature value is:

[0127] When the sensor is on top of the high voltage bushing:

[0128]

[0129] When the sensor is at the bottom of the high voltage bushing:

[0130]

[0131] in:

[0132] P pr (t) is the equivalent air pressure value of the preset temperature value;

[0133] T pr is the preset temperature value;

[0134] P o (t) is the oil pressure at the bottom of the high-pressure casing at time t;

[0135] P oh (t) is the equivalent pressure of the oil height in the high-pressure casing at time t.

[0136] When the sensor is at the top of the high-pressure bushing to monitor the oil temperature and pressure at the top of the high-pressure bushing, the molar density of the gas in the high-pressure bushing is:

[0137]

[0138] The algorithm using 20°C pressure is:

[0139]

[0140] Where: T 20 =293.15K, where K is the thermodynamic temperature unit.

[0141] When the sensor is at the bottom of the high-pressure bushing to monitor the oil temperature and pressure at the bottom of the high-pressure bushing, the molar density of the gas in the high-pressure bushing is:

[0142]

[0143] In order to obtain the most accurate calculation results, P oh (t) Take the given empirical value P oh (t)≈75kPa.

[0144] The algorithm using 20°C pressure is:

[0145]

[0146] P 20 (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.

[0147] Under normal conditions, the gas molecular molar density value of the gas in the high-voltage bushing is maintained within a certain range, and fluctuates accordingly with the fluctuation of the gas state quantity (P / T). When the gas molecular molar density value changes greatly, it is usually caused by some abnormal situation. For example: internal local overheating, local discharge, abnormal oil quality deterioration, etc., will increase the gas molecular molar density value; gas and oil leakage in the high-voltage bushing will cause a decrease in the gas molecular molar density value. Therefore, by tracking the gas molecular molar density value, a preliminary judgment can be made on the above fault state. Because the gas molecular molar density value, under normal circumstances, the fluctuation of the data conforms to the normal probability distribution.

[0148] Therefore, the equivalent air pressure value is continuously monitored, and the device status is diagnosed according to the set diagnosis threshold. Specifically, the status diagnosis threshold is set as:

[0149] When the sensor is at the top of the high-voltage bushing, the state diagnosis threshold is 60 kPa to 180 kPa; when the sensor is at the bottom of the high-voltage bushing, the state diagnosis threshold is 120 kPa to 230 kPa.

[0150] See also Figure 2 , Figure 2 The casing gas molar density transition diagram in the actual monitoring example 1 provided in the embodiment 1 of the present invention shows the pressure change trend of phase A, phase B and phase C at 20°C. All data of the three phases change within the allowable range, and the change trends of the three-phase data are almost completely consistent. Therefore, it can be considered that the equipment is in a normal state.

[0151] See also Figure 3 , Figure 3 In the casing gas molar density change diagram in the actual monitoring example 2 provided in the embodiment 1 of the present invention, all the data of the three phases change within the allowable limits, and the equipment is normal; but the change trends of the three-phase data are quite different, among which the C phase gas pressure value is the largest, and it is recommended to pay attention to the C phase casing equipment.

[0152] Embodiment 2

[0153] Compared with the above-mentioned embodiment 1, the main difference of embodiment 2 is that the diagnosis method and effect are different. In embodiment 2 provided by the present invention, the state diagnosis method is:

[0154] The moving range is calculated based on an equivalent air pressure value and the adjacent equivalent air pressure value. The calculation formula is as follows:

[0155] MR=|x i -x i+1 |(i=1,2,…,k-1)

[0156] Where: MR is the moving range; |x i -x i+1 | is the absolute value of the difference between an equivalent pressure value and the adjacent equivalent pressure value, and k is the number of equivalent pressure values;

[0157] Calculate the overall average

[0158]

[0159] Calculate the moving average range

[0160]

[0161] Set x control limits:

[0162]

[0163] Setting MR control limits:

[0164]

[0165] The continuous monitoring and diagnosis of the equivalent air pressure value according to the diagnosis method and the set control limit includes:

[0166] Continuously preset a x values ​​outside the actual control limit of x: abnormal equipment status is of concern;

[0167] Continuously preset b x values ​​all increase or decrease, and all are outside the actual control limit of x: abnormal equipment status warning;

[0168] Continuously preset c x values, all increasing or all decreasing, and all on either side of the center line: abnormal equipment status warning;

[0169] Any data point exceeds the allowable high-voltage bushing pressure standard range: abnormal equipment status alarm;

[0170] Moving range MR, any one point exceeds the upper control line: equipment status abnormality attention;

[0171] Moving range MR, exceeds the upper control line for 3 consecutive points: abnormal equipment status warning.

[0172] Specifically, in combination with the characteristics of the high-voltage bushing power equipment in this embodiment, the statistical process control (SPC) control chart diagnostic index is designed as follows:

[0173] 1) The equivalent pressure value (x) of 20℃ gas, data for 3 consecutive days, is outside the control limit: the equipment status is abnormal and attention should be paid;

[0174] 2) The equivalent pressure value (x) of gas at 20°C, data for 15 consecutive days, all increase or all decrease, and all are outside the control limit: abnormal equipment status warning;

[0175] 3) Equivalent gas pressure value (x) at 20°C, data for 22 consecutive days, all increasing or all decreasing, and all on either side of the center line: abnormal equipment status warning;

[0176] 4) 20℃ gas equivalent pressure value (x), any point data exceeds the allowable pressure standard range: abnormal equipment status alarm;

[0177] 5) Moving range MR, any one point exceeds the upper control line: equipment status is abnormal and attention should be paid;

[0178] 6) Moving range MR, 3 consecutive points exceeding the upper control line: abnormal equipment status warning.

[0179] Please also read Figure 4 , Figure 5 and Figure 6 , which are respectively the air pressure 20°C (KPa) control diagrams of the main transformer phase A, phase B and phase C in the actual monitoring example 1 provided in the second embodiment of the present invention. The diagnosis result: the data of the three phases A / B / C are all within the normal control limits, and the equipment is in normal state.

[0180] Please also read Figure 7 , Figure 8 and Fig. 9 , which are respectively the air pressure 20℃ (KPa) control diagrams of the main transformer phase A, phase B and phase C in the actual monitoring example 2 provided in the second embodiment of the present invention. The diagnosis result: a small amount of sample data of the phase C data exceeds the upper limit, but does not exceed the allowable range of the equipment. The equipment is in a state of concern.

[0181] Embodiment 3

[0182] See also Fig.10 Specifically in the third embodiment, the online monitoring and diagnosis method of the high-voltage bushing gas pressure and temperature includes:

[0183] Step S21: collecting the gas pressure value and shell temperature value in the high-voltage bushing;

[0184] Step S22: Calculate the molar density of gas molecules in the high-voltage bushing;

[0185] Step S23: Calculate the imbalance degree of molar density of gas molecules between phases;

[0186] Step S24: continuously monitoring the imbalance of the molar density of gas molecules between the phases, and diagnosing the state of the high-voltage bushing equipment according to a set diagnosis threshold.

[0187] Specifically, steps S21 and S22 are the same as steps S11 and S12 in the above embodiment, and are not described in detail here.

[0188] In step S23, the molar density imbalance of gas molecules between phases is calculated, and the molar density imbalance of gas molecules between phases is divided into two algorithms: extremely small difference and extremely average difference.

[0189] The algorithm for calculating the minimum difference in the imbalance degree of molar density of gas molecules between phases is:

[0190]

[0191] The algorithm for calculating the extreme difference of the imbalance degree of molar density of gas molecules between phases is:

[0192]

[0193] in,

[0194] ε1(t) is the minimum difference in the molar density imbalance of gas molecules between phases;

[0195] ε2(t) is the extreme difference of the imbalance degree of molar density of gas molecules between phases;

[0196] d max (t) = max(d a (t), d b (t), d c (t));

[0197] d min (t) = min(d a (t), d b (t), d c (t));

[0198] d ave (t) = average (d a (t), d b (t), d c (t)).

[0199] The algorithm of minimum difference of imbalance degree is sensitive to small data. It is suitable to be used if there are many oil and gas leakage phenomena.

[0200] The extreme mean difference algorithm of imbalance degree is sensitive to large data, such as internal overheating, partial discharge, abnormal oil quality degradation, etc., and should be adopted;

[0201] The imbalance minimum difference algorithm or imbalance extreme average difference algorithm can be selected for diagnosis according to the actual project situation. For example, the diagnosis threshold set by the imbalance extreme average difference algorithm is:

[0202] When ε2(t)≥35%: abnormal equipment status alarm;

[0203] When 35%>ε2(t)≥25%: abnormal equipment status warning;

[0204] When 15%>ε2(t)≥5%: Equipment status is abnormal and attention should be paid.

[0205] Please also read Fig.11 and Fig.12 , Fig.11 and Fig.12 They are respectively the shift diagrams of the imbalance degree of the molar density of gas molecules between phases 1 and 2 in the actual monitoring example 1 provided in the third embodiment, and the diagnostic results of the shift diagrams:

[0206] 1) The imbalance of gas molecule molar density between phases of No. 1 main transformer is within the allowable range and the equipment is in normal condition.

[0207] 2) During a certain period of time in the later stage of the imbalance of gas molecule molar density between the No. 2 main transformer phases, a small amount of sample data exceeded the upper limit of attention, and the equipment was in a state of attention.

[0208] Please also read Fig.13 and Fig.14 , Fig.13 and Fig.14 They are the control diagrams of the unbalanced degree of the molar density of gas molecules between phases 1 and 2 in the actual monitoring example 2 provided in the third embodiment, and the diagnosis results are:

[0209] 1) The imbalance of gas molecule molar density between phases of No. 1 main transformer is within the allowable range and the equipment is in normal condition.

[0210] 2) During a certain period in the later stage of the control chart of the imbalance degree of gas molecule molar density between the phases of main transformer No. 2, a small amount of sample data exceeded the upper limit of attention, and the equipment was in a state of concern; during a certain period in the middle stage of the control chart, a small amount of sample data continued to rise and exceeded the upper limit of attention, and the equipment was in a state of concern.

[0211] In addition, the present invention also provides a high-voltage bushing gas pressure and temperature online monitoring and diagnosis device.

[0212] See also Fig.15 , is a schematic diagram of the internal structure of a high-pressure bushing gas pressure and temperature online monitoring and diagnosis device provided by an embodiment of the present invention, wherein the high-pressure bushing gas pressure and temperature online monitoring and diagnosis device at least includes a memory 11, a processor 12, a communication bus 13, a network interface 14, a temperature sensor 15 and a pressure sensor 16.

[0213] Among them, the memory 11 includes at least one type of readable storage medium, and the readable storage medium includes flash memory, hard disk, multimedia card, card-type memory (for example, SD or DX memory, etc.), magnetic memory, disk, optical disk, etc. In some embodiments, the memory 11 can be an internal storage unit of the high-voltage bushing gas pressure temperature online monitoring and diagnosis device, such as the hard disk of the high-voltage bushing gas pressure temperature online monitoring and diagnosis device. In other embodiments, the memory 11 can also be an external storage device of the high-voltage bushing gas pressure temperature online monitoring and diagnosis device, such as a plug-in hard disk equipped on the high-voltage bushing gas pressure temperature online monitoring and diagnosis device, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), etc. Further, the memory 11 can also include both the internal storage unit of the high-voltage bushing gas pressure temperature online monitoring and diagnosis device and an external storage device. The memory 11 can not only be used to store application software and various types of data installed in the high-voltage bushing gas pressure temperature online monitoring and diagnosis device, such as the code of the high-voltage bushing gas pressure temperature online monitoring and diagnosis program, but also can be used to temporarily store data that has been output or is to be output.

[0214] In some embodiments, the processor 12 may be a central processing unit (CPU), a controller, a microcontroller, a microprocessor or other data processing chip, and is used to run program codes or process data stored in the memory 11, such as executing an online monitoring and diagnosis program for the pressure and temperature of the high-pressure casing gas.

[0215] The communication bus 13 is used to realize the connection and communication between these components.

[0216] The network interface 14 may optionally include a standard wired interface, a wireless interface (such as a WI-FI interface), and is generally used to establish a communication connection between the high-voltage bushing gas pressure and temperature online monitoring and diagnosis device and other electronic devices.

[0217] 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 inside the high-pressure casing; the pressure sensor 16 is used to obtain the gas pressure value inside the high-pressure casing or the oil pressure value at the bottom of the high-pressure casing.

[0218] Optionally, the high-voltage bushing gas pressure and temperature online monitoring and diagnosis device may further include a user interface, which may include a display (Display), an input unit such as a keyboard (Keyboard), and the optional user interface may also include a standard wired interface and a wireless interface. Optionally, in some embodiments, the display may be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, and an OLED (Organic Light-Emitting Diode) touch device, etc. Among them, the display may also be appropriately referred to as a display screen or a display unit, which is used to display information processed in the high-voltage bushing gas pressure and temperature online monitoring and diagnosis device and to display a visualized user interface.

[0219] Fig.15 Only the high-voltage bushing gas pressure and temperature online monitoring and diagnosis device having components 11-16 and the high-voltage bushing gas pressure and temperature online monitoring and diagnosis program is shown. It can be understood by those skilled in the art that Fig.15 The structure shown does not constitute a limitation on the high-voltage bushing gas pressure and temperature online monitoring and diagnosis device, and may include fewer or more components than shown in the figure, or a combination of certain components, or a different arrangement of components.

[0220] exist Fig.15 In the embodiment of the high-voltage bushing gas pressure and temperature online monitoring and diagnosis device shown, the memory 11 stores a high-voltage bushing gas pressure and temperature online monitoring and diagnosis program; when the processor 12 executes the high-voltage bushing gas pressure and temperature online monitoring and diagnosis program stored in the memory 11, the following steps are implemented:

[0221] Step S11: collecting the gas pressure value and shell temperature value in the high-voltage bushing;

[0222] Step S12: Calculate the molar density of gas molecules in the high-voltage bushing;

[0223] Step S13: converting the gas molecule molar density value into an equivalent gas pressure value of a preset temperature value;

[0224] Step S14: continuously monitoring the equivalent air pressure value, and diagnosing the state of the high-voltage bushing equipment according to a set diagnosis threshold.

[0225] Or the following steps:

[0226] Step S21: collecting the gas pressure value and shell temperature value in the high-voltage bushing;

[0227] Step S22: Calculate the molar density of gas molecules in the high-voltage bushing;

[0228] Step S23: Calculate the imbalance degree of molar density of gas molecules between phases;

[0229] Step S24: continuously monitoring the imbalance of the molar density of gas molecules between the phases, and diagnosing the state of the high-voltage bushing equipment according to a set diagnosis threshold.

[0230] Reference Fig.16 FIG. 1 is a schematic diagram of a program module of a high-pressure bushing gas pressure and temperature online monitoring and diagnosis program in an embodiment of a high-pressure bushing gas pressure and temperature online monitoring and diagnosis device of the present invention. In this embodiment, the high-pressure bushing gas pressure and temperature online monitoring and diagnosis program can be divided into a monitoring module 10, a calculation module 20, a setting module 30 and a diagnosis module 40. For example:

[0231] Monitoring module 10, used to collect the gas pressure value and shell temperature value in the high-voltage bushing;

[0232] The calculation module 20 is used to calculate the gas molecule molar density value, the equivalent gas pressure value, the minimum difference of the imbalance degree of the gas molecule molar density between phases, and the average difference of the imbalance degree of the gas molecule molar density between phases;

[0233] A setting module 30, used for setting a diagnosis threshold;

[0234] The diagnosis module 40 is used for online monitoring and diagnosis of the pressure and temperature of the high-pressure bushing gas.

[0235] The functions or operation steps implemented when the program modules such as the monitoring module 10, the calculation module 20, the setting module 30 and the diagnosis module 40 are executed are substantially the same as those in the above-mentioned embodiment and will not be described in detail herein.

[0236] In addition, an embodiment of the present invention further provides a storage medium, which is a computer-readable storage medium, and stores a high-voltage bushing gas pressure and temperature online monitoring and diagnosis program, and the high-voltage bushing gas pressure and temperature online monitoring and diagnosis program can be executed by one or more processors to implement the following operations:

[0237] Step S11: collecting the gas pressure value and shell temperature value in the high-voltage bushing;

[0238] Step S12: Calculate the molar density of gas molecules in the high-voltage bushing;

[0239] Step S13: converting the gas molecule molar density value into an equivalent gas pressure value of a preset temperature value;

[0240] Step S14: continuously monitoring the equivalent air pressure value, and diagnosing the state of the high-voltage bushing equipment according to a set diagnosis threshold.

[0241] Or the following steps:

[0242] Step S21: collecting the gas pressure value and shell temperature value in the high-voltage bushing;

[0243] Step S22: Calculate the molar density of gas molecules in the high-voltage bushing;

[0244] Step S23: Calculate the imbalance degree of molar density of gas molecules between phases;

[0245] Step S24: continuously monitoring the imbalance of the molar density of gas molecules between the phases, and diagnosing the state of the high-voltage bushing equipment according to a set diagnosis threshold.

[0246] The specific implementation of the storage medium of the present invention is basically the same as the above-mentioned high-voltage bushing gas pressure temperature online monitoring and diagnosis method and device embodiments, and will not be repeated here.

[0247] Compared with the prior art, the method, device and storage medium for online monitoring and diagnosis of the gas pressure and temperature of the high-pressure bushing provided by the present invention collect the gas pressure value and the shell temperature value in the high-pressure bushing, calculate the molar density value of the gas molecules in the high-pressure bushing, diagnose the status of the high-pressure bushing equipment based on the equivalent gas pressure value, the moving range, and the imbalance of the molar density of the gas molecules between phases, and realize 24-hour uninterrupted online monitoring of the oil and gas pressure value in the high-pressure bushing, which can evaluate the operation and fault status of the high-pressure bushing equipment, prevent accidents, and provide a practical means for real-time monitoring of the operation and fault status of the equipment.

[0248] It should be noted that the serial numbers of the above-mentioned embodiments of the present invention are only for description and do not represent the advantages and disadvantages of the embodiments. And the terms "including", "comprising" or any other variants thereof in this article are intended to cover non-exclusive inclusion, so that a process, device, article or method including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, device, article or method. In the absence of further restrictions, an element defined by the sentence "including one..." does not exclude the presence of other identical elements in the process, device, article or method including the element.

[0249] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, disk, optical disk) as described above, and includes a number of instructions for a terminal device (which can be a drone, mobile phone, computer, server, or network device, etc.) to execute the methods described in each embodiment of the present invention.

[0250] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A method for online monitoring and diagnosis of high-voltage bushing gas pressure and temperature, characterized in that: include: Collect the gas pressure value and shell temperature value in the high-voltage bushing; Calculate the molar density of gas molecules in the high-voltage bushing; The calculation formula of the molar density of gas molecules in the high-voltage bushing is: When the sensor is at the top of the high-voltage bushing, the molar density of the gas in the high-voltage bushing is: When the sensor is at the bottom of the high-voltage bushing, the molar density of the gas in the high-voltage bushing is: P g (t)=P o (t)-P oh (t) in: 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-pressure casing at time t; P oh (t) is the equivalent pressure of the oil in the high-pressure casing at time t; V(t) is the gas volume in the high-voltage bushing at time t; n(t) is the number of moles of gas molecules in the high-voltage bushing at time t; T1(t) is the high voltage bushing shell temperature at time t; R = 8314 J / kmolK is the universal gas constant; d(t) is the molar density of gas molecules; Converting the gas molecule molar density value into an equivalent gas pressure value of a preset temperature value; The calculation formula for the equivalent air pressure value of the preset temperature value is: When the sensor is on top of the high voltage bushing: When the sensor is at the bottom of the high voltage bushing: in: P pr (t) is the equivalent air pressure value of the preset temperature value; T pr is the preset temperature value; Continuously monitoring the equivalent gas pressure value, and diagnosing the state of the high-voltage bushing equipment according to a set diagnostic threshold; The state diagnosis method is the process statistical control chart method: The moving range is calculated based on an equivalent air pressure value and the adjacent equivalent air pressure value. The calculation formula is as follows: MR=|x i -x i+1 |(i=1,2,…,k-1) Where: MR is the moving range; |x i -x i+1 | is the absolute value of the difference between an equivalent pressure value and the adjacent equivalent pressure value, and k is the number of equivalent pressure values; Calculate the overall average Calculate the moving average range Set x control limits: Setting MR control limits: Lower limit = 0; Continuously monitoring and diagnosing the equivalent gas pressure value according to the process statistical control chart method and the set control limits includes: Continuously preset a x values ​​outside the x control limit: abnormal equipment status is of concern; Continuously preset b x values ​​all increase or all decrease, and all are outside the x control limit: abnormal equipment status warning; Continuously preset c x values, all increasing or all decreasing, and all on either side of the center line: abnormal equipment status warning; Any data point exceeds the allowable high-voltage bushing pressure standard range: abnormal equipment status alarm; Moving range MR, any one point exceeds the upper control line: equipment status abnormality attention; Moving range MR, exceeds the upper control line for 3 consecutive points: abnormal equipment status warning.

2. A method for online monitoring and diagnosis of high-voltage bushing gas pressure and temperature, characterized in that: include: Collect the gas pressure value and shell temperature value in the high-voltage bushing; Calculate the molar density of gas molecules in the high-voltage bushing; Calculate the imbalance of molar density of gas molecules between phases; The molar density imbalance of gas molecules between phases is divided into two algorithms: the minimum difference and the average difference; The algorithm for calculating the minimum difference in the imbalance degree of molar density of gas molecules between phases is: The algorithm for calculating the extreme difference of the imbalance degree of molar density of gas molecules between phases is: in, ε1(t) is the minimum difference in the molar density imbalance of gas molecules between phases; ε2(t) is the extreme difference of the imbalance degree of molar density of gas molecules between phases; d max (t)=max(d a (t),d b (t),d c (t)); d min (t)=min(d a (t),d b (t),d c (t)); d ave (t)=average(d a (t),d b (t),d c (t)); Continuously monitoring the imbalance of the molar density of gas molecules between the phases, and diagnosing the state of the high-voltage bushing equipment according to a set diagnostic threshold; The status diagnostic thresholds are: When ε2(t)≥35%: abnormal equipment status alarm; When 35%>ε2(t)≥25%: abnormal equipment status warning; When 15%>ε2(t)≥5%: Equipment status is abnormal and attention should be paid.

3. A high-voltage bushing gas pressure and temperature online monitoring and diagnosis device, characterized in that: The high-pressure bushing gas pressure and temperature online monitoring and diagnosis device comprises a memory, a processor, a temperature sensor and a pressure sensor. The memory stores a high-pressure bushing gas pressure and temperature online monitoring and diagnosis program that can be run on the processor. When the high-pressure bushing gas pressure and temperature online monitoring and diagnosis program is executed by the processor, the steps of the high-pressure bushing gas pressure and temperature online monitoring and diagnosis method as described in any one of claims 1 to 2 are implemented; the temperature sensor is used to obtain the high-pressure bushing shell temperature value; the pressure sensor is used to obtain the gas pressure value in the high-pressure bushing or the oil pressure value at the bottom of the high-pressure bushing.

4. A storage medium, characterized in that: The storage medium is a computer-readable storage medium, and a high-voltage bushing gas pressure and temperature online monitoring and diagnosis program is stored on the storage medium. The high-voltage bushing gas pressure and temperature online monitoring and diagnosis program can be executed by one or more processors to implement the steps of the high-voltage bushing gas pressure and temperature online monitoring and diagnosis method according to any one of claims 1 to 2.

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