阅读说明：本技术 高压套管气压温度在线监测诊断方法、装置及存储介质 (High-voltage bushing air pressure temperature on-line monitoring and diagnosis method and device and storage medium ) 是由 郭晨华 潘晨曦 宁松浩 汪俊 杨志强 于 2020-11-12 设计创作，主要内容包括：本发明提供一种高压套管气压温度在线监测诊断方法、装置及存储介质,该方法包括：采集高压套管内气体压强值和壳体温度值；计算高压套管内的气体分子摩尔密度值；将所述气体分子摩尔密度值转换为预设温度值的等效气压值；对所述等效气压值进行持续监测,并根据设定的诊断阈值,对设备状态做出诊断；另提供了基于移动极差、相间气体分子摩尔密度不均衡度对高压套管设备状态诊断。通过本发明提供的技术方案,实现在线对高压套管内的油气压力值进行24小时不间断监测,能够评估高压套管设备的运行和故障状态,预防事故发生,对设备运行和故障状态的实时监控提供了一种切实可行的手段。(The invention provides a method, a device and a storage medium for online monitoring and diagnosing the air pressure and the temperature of a high-voltage bushing, wherein the method comprises the following steps: collecting a gas pressure value and a shell temperature value in a high-voltage bushing; calculating the molar density value of gas molecules in the high-voltage bushing; converting the gas molecule molar density value into an equivalent gas pressure value of a preset temperature value; continuously monitoring the equivalent air pressure value, and diagnosing the equipment state according to a set diagnosis threshold value; and the diagnosis of the state of the high-voltage bushing equipment based on the extremely poor moving and the molar density imbalance of the gas molecules between phases is also provided. By the technical scheme provided by the invention, the oil gas pressure value in the high-voltage bushing can be continuously monitored for 24 hours on line, the running and fault states of high-voltage bushing equipment can be evaluated, accidents are prevented, and a feasible means is provided for real-time monitoring of the running and fault states of the equipment.)

1. An online monitoring and diagnosing method for the air pressure and temperature of a high-voltage bushing is characterized by comprising the following steps:

collecting a gas pressure value and a shell temperature value in a high-voltage bushing;

calculating the molar density value of gas molecules in the high-voltage bushing;

converting the gas molecule molar density value into an equivalent gas pressure value of a preset temperature value;

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

2. The method for on-line monitoring and diagnosing the pressure and the temperature of the high voltage bushing as claimed in claim 1, wherein the molar density value of the gas molecules in the high voltage bushing is calculated by the following formula:

molar density of gas in the high voltage bushing when the sensor is at the top of the high voltage bushing:

when the sensor is positioned at the bottom of the high-voltage bushing, the molar density value of gas in the high-voltage bushing is as follows:

P_g(t)＝P_o(t)-P_oh(t)

wherein:

P_g(t) the gas pressure in the high-voltage bushing at the moment t;

P_o(t) is the pressure of the oil at the bottom of the high-voltage bushing at the moment t;

P_oh(t) is the equivalent pressure of the oil height in the high-voltage bushing at the moment t;

v (t) is the gas volume in the high-voltage bushing at the time t;

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

T₁(t) is the high-voltage bushing shell temperature at time t;

r is 8314J/kmolK which is the gas universal constant;

d (t) is the molar density value of the gas molecules.

3. The method for on-line monitoring and diagnosing the air pressure and the temperature of the high-voltage bushing as claimed in claim 1, wherein the calculation formula of the equivalent air pressure value of the preset temperature value is as follows:

when the sensor is on top of the high voltage bushing:

when the sensor is at the bottom of the high voltage bushing:

wherein:

P_pr(t) is an equivalent air pressure value of a preset temperature value;

T_pris a preset temperature value.

4. The method for on-line monitoring and diagnosing the air pressure and the temperature of the high-voltage bushing as claimed in claim 1, wherein the status diagnosis is performed in a process statistical control chart mode:

calculating the moving range according to an equivalent air pressure value and an adjacent equivalent air pressure value, wherein the calculation formula is as follows:

MR＝|x_i-x_i+1|(i＝1，2，...，k-1)

wherein: MR is the movement range; | x_i-x_i+1I is the absolute value of the difference between one equivalent air pressure value and the adjacent equivalent air pressure value, and k is the number of the equivalent air pressure values;

calculate the Total mean

Calculating moving range average

Setting an x control limit:

setting the MR control limits:

the lower limit is 0.

5. The method as claimed in claim 4, wherein the continuously monitoring and diagnosing the equivalent air pressure value according to the manner of the process statistical control chart and the set control limit comprises:

continuously presetting a x values outside the x actual control limit: attention is paid to abnormal equipment states;

and continuously presetting b x values, all increasing or all decreasing, and all outside the x actual control limit: early warning of abnormal equipment state;

the continuous preset c x values are all increased or all decreased, and are all on either side of the central line: early warning of abnormal equipment state;

any point of data, exceeding the allowable high-voltage bushing pressure standard range: alarming for abnormal equipment state;

moving the pole difference MR, any 1 point exceeds the upper control line: attention is paid to abnormal equipment states;

moving the pole difference MR, 3 consecutive points exceed the upper control line: and (5) early warning the abnormal state of the equipment.

6. An online monitoring and diagnosing method for the air pressure and temperature of a high-voltage bushing is characterized by comprising the following steps:

collecting a gas pressure value and a shell temperature value in a high-voltage bushing;

calculating the molar density value of gas molecules in the high-voltage bushing;

calculating the molar density imbalance degree of the gas molecules among the phases;

and continuously monitoring the molar density imbalance of the interphase gas molecules, and diagnosing the state of the high-voltage bushing equipment according to a set diagnosis threshold value.

7. The method for online monitoring and diagnosing the air pressure and the temperature of the high-voltage bushing as claimed in claim 6, wherein the molar density imbalance of the inter-phase gas molecules is divided into an extremely small difference algorithm and an extremely small average difference algorithm;

the algorithm of the small difference of the molar density imbalance of the interphase gas molecules is as follows:

the algorithm of the extremely uniform difference of the molar density imbalance degrees of the gas molecules among the phases is as follows:

wherein the content of the first and second substances,

ε₁(t) the difference of the molar density imbalance of the gas molecules among the phases is small;

ε₂(t) the molar density imbalance of the interphase gas molecules is extremely poor;

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))。

8. the method according to claim 6, wherein the condition diagnosing threshold is:

when epsilon₂(t) is ≥ 35%: alarming for abnormal equipment state;

when 35% is more than epsilon₂(t) not less than 25%: early warning of abnormal equipment state;

when 15% > epsilon₂(t) is not less than 5%: the device status is of abnormal concern.

9. A high-pressure bushing gas pressure temperature online monitoring and diagnosing device, characterized in that the high-pressure bushing gas pressure temperature online monitoring and diagnosing device comprises a memory, a processor, a temperature sensor and a pressure sensor, the memory stores a high-pressure bushing gas pressure temperature online monitoring and diagnosing program which can be run on the processor, the high-pressure bushing gas pressure temperature online monitoring and diagnosing program is executed by the processor to implement the steps of the high-pressure bushing gas pressure temperature online monitoring and diagnosing method as claimed in any one of claims 1 to 8; the temperature sensor is used for acquiring a high-voltage bushing shell temperature value; the pressure sensor is used for acquiring the pressure value of gas in the high-voltage bushing or the pressure value of oil at the bottom of the high-voltage bushing.

10. A storage medium, wherein the storage medium is a computer-readable storage medium, and the storage medium has stored thereon an online monitoring and diagnosing program for pressure and temperature of high-pressure bushing, which is executable by one or more processors to implement the steps of the online monitoring and diagnosing method for pressure and temperature of high-pressure bushing according to any one of claims 1 to 8.

Technical Field

The invention relates to the technical field of high-voltage bushing gas pressure and temperature online monitoring and diagnosis, in particular to a high-voltage bushing gas pressure and temperature online monitoring and diagnosis method, device and storage medium.

Background

A large amount of oil-filled electrical equipment runs in an existing power system, and comprises oil-poor equipment such as a transformer high-voltage bushing, a current transformer and a circuit breaker, and the insulation state of the oil-poor equipment and the running state of an internal mechanism have important significance for safe and stable running of the power system in the running process of a transformer substation. However, these devices may be out of order due to improper manufacturing, maintenance, and oil degradation, and serious accidents such as explosion and fire may occur, which affect the safe and stable operation and power supply reliability of the power grid.

At present, the transformer substation generally adopts manual patrol for maintaining the equipment, and a small part of the equipment can be combined with insulation online monitoring. The manual inspection is that the inspection is performed by using operators and the periodic spot inspection is performed by testers. The traditional detection and analysis method comprises the steps of ultrasonic partial discharge, infrared temperature measurement, oil chromatographic analysis and the like. However, with the continuous improvement of voltage class and the increase of equipment capacity in recent years, the traditional offline preventive test method cannot meet the actual requirement of safe operation of modern large-scale power equipment, and it is difficult to truly reflect the insulation conditions of various types of equipment such as bushings, current transformers and the like under the operation condition. Since the preventive test is carried out according to a fixed period, the preventive test cannot be found, tracked and maintained in time, and has great limitation.

The traditional maintenance method mainly comprises daily detection and power failure detection. Wherein the daily detection comprises component inspection and heating detection; the power failure detection comprises insulation resistance measurement, polarization coefficient measurement, capacitance and dielectric loss factor measurement, partial discharge measurement and transformer oil inspection (a current transformer can be electrified to take oil).

The part inspection in daily maintenance generally detects whether oil leaks, the anticorrosive inspection of metalwork, insulator outward appearance detection, ground connection condition inspection, and for current transformer, still need the flexible volume of inspection expander to confirm the oil level condition. The heating detection is very effective for finding out the thermal defects and hot spots of the oil-poor equipment, and can find out overheating caused by poor contact of contact points or overhigh temperature caused by local defects.

The insulation performance test is carried out by regularly cutting off the power of the oil-less equipment before operation and every few years after operation so as to judge the insulation condition of the oil-less equipment; meanwhile, the gas content and the moisture content in the oil can be measured in the power failure maintenance period, and the analysis and the detection of the dissolved gas in the oil are still one of the methods for fault diagnosis of oil-filled electrical equipment at present.

Although the conventional method adopted at present can detect partial faults, the early diagnosis effect on the faults is poor, the effect of carrying out a partial discharge test on site is not ideal, a sleeve cannot carry out charged oil extraction analysis, and the method is more difficult when chromatographic analysis data is abnormal and sampling and tracking are required. Meanwhile, the periodic detection cannot prevent sudden accidents.

In oil-less equipment such as a high-voltage bushing of a transformer, a current transformer and the like, insulating oil in a sealed state can be decomposed to release a certain amount of gas due to the influence of insulation damage and other reasons in the operation process, the insulating oil of the high-voltage bushing is mineral oil obtained by distilling and refining natural petroleum, is a mixture consisting of a plurality of hydrocarbons with different molecular weights, and comprises alkane, alkene, cycloalkane, aromatic hydrocarbon and the like; when discharge or overheating faults exist in the equipment, characteristic gases such as H2, CH4, C2H6, C2H4, C2H2, CO and CO2 can be generated, the generated gases are dissolved in oil and released to the oil surface, the gases on the oil surface are gradually accumulated due to the fact that the high-voltage sleeve is of a sealing structure, the gas pressure is increased to act on the liquid insulating oil, oil pressure is gradually increased and accumulated for a long time, certain gas pressure is formed in the cavity, and oil injection and even explosion can be caused in severe cases. Currently, the detection of characteristic gas mainly comprises two modes: oil gas spectrum analysis and pressure monitoring. Generally, the oil chromatographic analysis is carried out by adopting a manual sampling mode to regularly monitor the content of acetylene, hydrogen and total hydrocarbon dissolved in oil of the oil-less equipment, but the method has a long period, and cannot find the abnormity appearing between two detection intervals, so that potential safety hazards exist.

Disclosure of Invention

The invention mainly aims to provide a method, a device and a storage medium for online monitoring and diagnosis of the air pressure and temperature of a high-voltage bushing, and aims to solve the problems of monitoring the air pressure and temperature of the existing high-voltage bushing and fault diagnosis.

In order to achieve the above object, the present invention provides an online monitoring and diagnosing method for the air pressure and temperature of a high voltage bushing, which comprises:

collecting a gas pressure value and a shell temperature value in a high-voltage bushing;

calculating the molar density value of gas molecules in the high-voltage bushing;

converting the gas molecule molar density value into an equivalent gas pressure value of a preset temperature value;

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

Further, the calculation formula of the molar density value of the gas molecules in the high-voltage bushing is as follows: molar density of gas in the high voltage bushing when the sensor is at the top of the high voltage bushing:

when the sensor is positioned at the bottom of the high-voltage bushing, the molar density value of gas in the high-voltage bushing is as follows:

P_g(t)＝P_o(t)-P_oh(t)

wherein:

P_g(t) the gas pressure in the high-voltage bushing at the moment t;

P_o(t) is the pressure of the oil at the bottom of the high-voltage bushing at the moment t;

P_oh(t) is the equivalent pressure of the oil height in the high-voltage bushing at the moment t;

v (t) is the gas volume in the high-voltage bushing at the time t;

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

T₁(t) is the high-voltage bushing shell temperature at time t;

r is 8314J/kmolK which is the gas universal constant;

d (t) is the molar density value of the gas molecules at the time t.

Further, the calculation formula of the equivalent air pressure value of the preset temperature value is as follows:

when the sensor is on top of the high voltage bushing:

when the sensor is at the bottom of the high voltage bushing:

wherein:

P_pr(t) an equivalent air pressure value of a preset temperature value at the moment t;

T_pris a preset temperature value.

Further, the state diagnosis mode is a process statistical control chart mode:

calculating the moving range according to an equivalent air pressure value and an adjacent equivalent air pressure value, wherein the calculation formula is as follows:

MR＝|x_i-x_i+1|(i＝1,2,…,k-1)

wherein: MR is the movement range; | x_i-x_i+1I is the absolute value of the difference between one equivalent air pressure value and the adjacent equivalent air pressure value, and k is the number of the equivalent air pressure values;

calculate the Total mean

Calculating moving range average

Setting an x control limit:

setting the MR control limits:

the continuous monitoring and diagnosis of the equivalent air pressure value according to the mode of the process statistical control chart and the set control limit comprises the following steps:

continuously presetting a x values outside the x actual control limit: attention is paid to abnormal equipment states;

and continuously presetting b x values, all increasing or all decreasing, and all outside the x actual control limit: early warning of abnormal equipment state;

the continuous preset c x values are all increased or all decreased, and are all on either side of the central line: early warning of abnormal equipment state;

any point of data, exceeding the allowable high-voltage bushing pressure standard range: alarming for abnormal equipment state;

moving the pole difference MR, any 1 point exceeds the upper control line: attention is paid to abnormal equipment states;

moving the pole difference MR, 3 consecutive points exceed the upper control line: and (5) early warning the abnormal state of the equipment.

The invention provides a high-voltage bushing air pressure temperature on-line monitoring and diagnosis method, which comprises the following steps:

collecting a gas pressure value and a shell temperature value in a high-voltage bushing;

calculating the molar density value of gas molecules in the high-voltage bushing;

calculating the molar density imbalance degree of the gas molecules among the phases;

and continuously monitoring the molar density imbalance of the interphase gas molecules, and diagnosing the state of the high-voltage bushing equipment according to a set diagnosis threshold value.

Further, calculating the molar density imbalance of the gas molecules between phases, wherein the molar density imbalance of the gas molecules between phases is divided into an extremely small difference algorithm and an extremely small difference algorithm;

the algorithm of the small difference of the molar density imbalance of the interphase gas molecules is as follows:

the algorithm of the extremely uniform difference of the molar density imbalance degrees of the gas molecules among the phases is as follows:

wherein the content of the first and second substances,

ε₁(t) the difference of the molar density imbalance of the gas molecules among the phases is small;

ε₂(t) the molar density imbalance of the interphase gas molecules is extremely poor;

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))。

further, the state diagnostic threshold is:

when epsilon₂(t)≥35％: alarming for abnormal equipment state;

when the content is 35 percent>ε₂(t) not less than 25%: early warning of abnormal equipment state;

when the content is 15 percent>ε₂(t) is not less than 5%: the device status is of abnormal concern.

In addition, the present invention provides an online monitoring and diagnosing apparatus for pressure and temperature of high-pressure bushing gas, which includes a memory, a processor, a temperature sensor and a pressure sensor, wherein the memory stores an online monitoring and diagnosing program for pressure and temperature of high-pressure bushing gas, which is executable on the processor, and the online monitoring and diagnosing program for pressure and temperature of high-pressure bushing gas, when executed by the processor, implements the steps of the online monitoring and diagnosing method for pressure and temperature of high-pressure bushing gas; the temperature sensor is used for acquiring a high-voltage bushing shell temperature value; the pressure sensor is used for acquiring the pressure value of gas in the high-voltage bushing or the pressure value of oil at the bottom of the high-voltage bushing.

Meanwhile, the present invention provides a storage medium, which is a computer-readable storage medium, and the storage medium stores thereon an online monitoring and diagnosing program for pressure and temperature of high-pressure bushing, which can be executed by one or more processors to implement the steps of the online monitoring and diagnosing method for pressure and temperature of high-pressure bushing as described above.

According to the method, the device and the storage medium for online monitoring and diagnosing the air pressure and the temperature of the high-voltage bushing, provided by the invention, the condition of the high-voltage bushing equipment is diagnosed on the basis of the equivalent air pressure value, the movement range and the molar density imbalance of interphase gas molecules by acquiring the air pressure value and the shell temperature value in the high-voltage bushing according to the calculation of the molar density value of the gas molecules in the high-voltage bushing, so that the uninterrupted monitoring of the oil-gas pressure value in the high-voltage bushing for 24 hours is realized, the running and fault conditions of the high-voltage bushing equipment can be evaluated, the occurrence of accidents is prevented, and a feasible practical means is provided for the real-time monitoring of the.

Drawings

Fig. 1 is a schematic flow chart of a method for online monitoring and diagnosing a pressure and a temperature of a high voltage bushing according to an embodiment of the present invention;

FIG. 2 is a graph showing a transition of a molar density of a gas in a high-pressure liner according to a first practical monitoring embodiment of the present invention;

FIG. 3 is a graph illustrating a transition of molar density of a gas in a high-pressure liner according to a second embodiment of the present invention;

FIG. 4 is a control chart of the main transformer A phase air pressure 20 ℃ (KPa) in the first practical monitoring embodiment according to the second embodiment of the present invention;

FIG. 5 is a control chart of the main transformer B-phase air pressure 20 ℃ (KPa) in the first practical monitoring embodiment according to the second embodiment of the present invention;

FIG. 6 is a control chart of the main transformer C-phase air pressure 20 ℃ (KPa) in the first practical monitoring embodiment according to the second embodiment of the present invention;

FIG. 7 is a control chart of the main transformer A-phase air pressure 20 ℃ (KPa) in the second practical monitoring embodiment provided by the second embodiment of the present invention;

fig. 8 is a control diagram of the main transformer B-phase air pressure 20 ℃ (KPa) in the second practical monitoring example provided by the second embodiment of the present invention;

FIG. 9 is a control chart of the main transformer C-phase air pressure 20 ℃ (KPa) in the second practical monitoring embodiment provided by the second embodiment of the present invention;

fig. 10 is a schematic flow chart of a method for online monitoring and diagnosing the pressure and temperature of the high-voltage bushing according to a third embodiment of the present invention;

FIG. 11 is a graph showing the variation of the molar density imbalance of the gas molecules between phases No. 1 in the first practical monitoring example provided in the third embodiment of the present invention;

FIG. 12 is a graph showing the variation of the molar density imbalance of the gas molecules between phases No. 2 in the first practical monitoring example provided by the third embodiment of the present invention;

fig. 13 is a control diagram of the degree of imbalance in the molar density of phase-1 gas molecules in the second practical monitoring example provided in the third embodiment of the present invention;

fig. 14 is a control diagram of the imbalance degree of the molar density of the phase 2 gas molecules in the second practical monitoring example provided in the third embodiment of the present invention.

Fig. 15 is a schematic view of an internal structure of an online monitoring and diagnosing apparatus for gas pressure and temperature of a high-voltage bushing according to an embodiment of the present invention;

fig. 16 is a schematic diagram of a high-pressure bushing gas pressure temperature online monitoring and diagnosing program module in the high-pressure bushing gas pressure temperature online monitoring and diagnosing apparatus according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example one

Referring to fig. 1, an embodiment of the present invention provides an online monitoring and diagnosing method for the air pressure and temperature of a high voltage bushing, where the online monitoring and diagnosing method for the air pressure and temperature of a high voltage bushing includes:

step S11: collecting a gas pressure value and a shell temperature value in a high-voltage bushing;

step S12: calculating the molar density value of gas molecules in the high-voltage bushing;

step S13: converting the gas molecule molar density value into an equivalent gas pressure value of a preset temperature value;

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

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 the voltage level of the high-voltage bushing is greater than or equal to 110 kV. The insulating oil of high-voltage bushing is a mineral oil obtained by distilling and refining natural petroleum, and is a mixture of many hydrocarbons with different molecular weights, including alkane, alkene, cyclane, aromatic hydrocarbon, etc. When discharge or overheating faults exist in the equipment, gases such as H2, CH4, C2H6, C2H4, C2H2, CO and CO2 can be generated, the generated gases are dissolved in oil and released to the oil surface, the gases on the oil surface are gradually accumulated due to the fact that the high-voltage bushing is of a sealing structure, the gas pressure is increased to act on the liquid insulating oil, oil pressure is gradually increased, and therefore online monitoring of insulation defects in the high-voltage bushing can be achieved by obtaining changes of the gas pressure.

The molar amount of the gas inside the high-voltage bushing is in a dynamic equilibrium state. At the same time, a certain amount of gas molecules are dissolved into the oil, and simultaneously a certain amount of gas molecules are resolved out of the oil and enter the upper layer of the high-voltage bushing. When the state is constant (temperature and pressure are stable), the molar quantity of the gas reaches a stable state, namely a dynamic equilibrium state. Obtained by relevant literature and analysis: the speed of dissolving and desorbing gas molecules in insulating oil has a corresponding relation with the oil temperature, generally, the higher the oil temperature is, the higher the analysis speed is, the dissolution speed is reduced, and for a high-voltage bushing, the molar quantity of the gas molecules is increased.

The physical and chemical indexes of the common mineral transformer oil comprise:

the gas density is not more than 895kg/m at 20 DEG C³；

The volume expansion coefficient alpha of mineral oil is 6.4X 10^-4(1/K)；

The volume expansion coefficient alpha of all gases is 1/273.15-3.67X 10^-3(1/K)。

The gas within the high pressure bushing conforms to the equation of state for an ideal gas, which refers to a gas that obeys the laws of an ideal gas. In the case of low pressure and low temperature, air, nitrogen, oxygen, helium, hydrogen, neon and the like all obey the law of ideal gases, and such gases can be regarded as ideal gases. Almost all chemically stable gases behave similarly to ideal gases when conditions are far from liquefaction or solidification.

Ideal gas law: the relationship among the volume V, the absolute pressure P and the absolute temperature T of n thousand moles of gas is PV ═ nRT, wherein R is 8314J/kmol.K, and R is a gas universal constant.

Therefore, by collecting the gas pressure value and the shell temperature value in the high-voltage bushing, the molar density value of the gas molecules in the high-voltage bushing is calculated, and the calculation formula is as follows:

molar density of gas in the high voltage bushing when the sensor is at the top of the high voltage bushing:

when the sensor is positioned at the bottom of the high-voltage bushing, the molar density value of gas in the high-voltage bushing is as follows:

P_g(t)＝P_o(t)-P_oh(t)

wherein:

P_g(t) the gas pressure in the high-voltage bushing at the moment t;

P_o(t) is the pressure of the oil at the bottom of the high-voltage bushing at the moment t;

P_oh(t) is the equivalent pressure of the oil height in the high-voltage bushing at the moment t;

v (t) is the gas volume in the high-voltage bushing at the time t;

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

T₁(t) is the high-voltage bushing shell temperature at time t;

r is 8314J/kmolK which is the gas universal constant;

d (t) is the molar density value of the gas molecules.

And calculating the obtained index value which is used as the basis for the gas molecular molar density value d (t) to be used for monitoring and diagnosing the states of the gas pressure and the gas temperature in the high-pressure sleeve.

Further, converting the molar density value of the gas molecules into an equivalent gas pressure value of a preset temperature value; the calculation formula of the equivalent air pressure value of the preset temperature value is as follows:

when the sensor is on top of the high voltage bushing:

when the sensor is at the bottom of the high voltage bushing:

wherein:

P_pr(t) is an equivalent air pressure value of a preset temperature value;

T_pris a preset temperature value;

P_o(t) is the pressure of the oil at the bottom of the high-voltage bushing at the moment t;

P_ohand (t) is the equivalent pressure of the oil height in the high-voltage bushing at the time t.

When the sensor is positioned at the top of the high-voltage bushing to monitor the oil temperature and the oil pressure at the top of the high-voltage bushing, the molar density value of gas in the high-voltage bushing is as follows:

the algorithm using the 20 ℃ pressure is:

wherein: t is₂₀293.15K, where K is the thermodynamic temperature unit.

When the sensor is positioned at the bottom of the high-voltage bushing to monitor the oil temperature and the oil pressure at the bottom of the high-voltage bushing, the molar density value of gas in the high-voltage bushing is as follows:

to obtain as accurate a calculation as possible, P_oh(t) givenEmpirical value P_oh(t)≈75kPa。

The algorithm using the 20 ℃ pressure is:

P₂₀(T) and d (T) are fixed multiples of T₂₀So that the molar density of gas molecules and the 20 ℃ pressure are equivalent diagnostic indicators in terms of diagnostic function.

Under normal conditions, the molar density value of gas molecules of the gas in the high-pressure sleeve is maintained within a certain range, and the value fluctuates along with the fluctuation of the gas state quantity (P/T). When the molar density of the gas molecules is greatly changed, the change is usually caused by some abnormal condition. For example: internal local overheating, local discharge, abnormal degradation of oil, etc., which can increase the molar density value of gas molecules; the leakage of gas from the high-pressure bushing causes the molar density value of gas molecules to be reduced. Therefore, by tracking the molar density value of the gas molecules, a preliminary judgment can be made on the fault state. Due to the molar density value of the gas molecules, the fluctuation of the data is changed under normal conditions, and the normal probability distribution is met.

Therefore, the equivalent air pressure value is continuously monitored, and the state of the equipment is diagnosed according to the set diagnosis threshold value, and specifically, the state diagnosis threshold value is set as follows:

when the sensor is positioned at the top of the high-voltage bushing, the state diagnosis threshold value is 60 kPa-180 kPa; when the sensor is positioned at the bottom of the high-voltage bushing, the state diagnosis threshold value is 120 kPa-230 kPa.

Referring to fig. 2, fig. 2 is a molar density transition diagram of the casing gas in a first practical monitoring example provided by the first embodiment of the present invention, which shows the pressure variation trends of the phase a, the phase B and the phase C at 20 ℃, all three-phase data are varied within an allowable range, and the three-phase data variation trends are almost completely consistent, so that the apparatus can be considered to be in a normal state.

Referring to fig. 3, fig. 3 is a graph showing a molar density transition of a casing gas in a second practical monitoring example provided by the first embodiment of the present invention, all three-phase data are changed within an allowable limit, and the equipment is normal; but the variation trend difference of the three-phase data is large, wherein the C-phase air pressure value is the largest, and C-phase sleeve equipment is recommended to be concerned.

Example two

Compared with the first embodiment, the second embodiment has the main difference that the diagnosis method and the effect are different, and in the second embodiment provided by the invention, the state diagnosis method is as follows:

calculating the moving range according to an equivalent air pressure value and an adjacent equivalent air pressure value, wherein the calculation formula is as follows:

MR＝|x_i-x_i+1|(i＝1,2,…,k-1)

wherein: MR is the movement range; | x_i-x_i+1I is the absolute value of the difference between one equivalent air pressure value and the adjacent equivalent air pressure value, and k is the number of the equivalent air pressure values;

calculate the Total mean

Calculating moving range average

Setting an x control limit:

setting the MR control limits:

the continuously monitoring and diagnosing the equivalent air pressure value according to the diagnosis mode and the set control limit comprises the following steps:

continuously presetting a x values outside the x actual control limit: attention is paid to abnormal equipment states;

and continuously presetting b x values, all increasing or all decreasing, and all outside the x actual control limit: early warning of abnormal equipment state;

the continuous preset c x values are all increased or all decreased, and are all on either side of the central line: early warning of abnormal equipment state;

any point of data, exceeding the allowable high-voltage bushing pressure standard range: alarming for abnormal equipment state;

moving the pole difference MR, any 1 point exceeds the upper control line: attention is paid to abnormal equipment states;

moving the pole difference MR, 3 consecutive points exceed the upper control line: and (5) early warning the abnormal state of the equipment.

Specifically, in combination with the characteristics of the high-voltage bushing power device in this embodiment, the Statistical Process Control (SPC) Control chart diagnosis index is designed as follows:

1) gas equivalent pressure value (x) at 20 ℃, data for 3 consecutive days, outside the control limits: attention is paid to abnormal equipment states;

2) gas equivalent pressure value (x) at 20 ℃, data for 15 consecutive days, all increasing or all decreasing, and all outside the control limits: early warning of abnormal equipment state;

3) gas equivalent pressure value (x) at 20 ℃, data for 22 consecutive days, all increasing or all decreasing, and all on either side of the centerline: early warning of abnormal equipment state;

4) the equivalent gas pressure value (x) of the gas at 20 ℃, the data of any point exceeds the allowable pressure standard range: alarming for abnormal equipment state;

5) moving the pole difference MR, any 1 point exceeds the upper control line: attention is paid to abnormal equipment states;

6) moving the pole difference MR, 3 consecutive points exceed the upper control line: and (5) early warning the abnormal state of the equipment.

Referring to fig. 4, fig. 5 and fig. 6, which are control charts of the atmospheric pressure 20 ℃ (KPa) of the main transformer in the first practical monitoring example provided by the second embodiment of the present invention, respectively, the diagnosis results are: the A/B/C three-phase data are all within the normal control limit, and the equipment is in a normal state.

Referring to fig. 7, fig. 8 and fig. 9, the control charts of the air pressures 20 ℃ (KPa) of the main transformer phase a, the phase B and the phase C in the second practical monitoring example according to the second embodiment of the present invention are shown, respectively, and the diagnosis results are: and C-phase data small amount of sample data exceeds the upper limit, but does not exceed the allowable range of the equipment, and the equipment is in the attention state.

EXAMPLE III

Referring to fig. 10, in a third embodiment, an online monitoring and diagnosing method for the pressure and temperature of a high voltage bushing includes:

step S21: collecting a gas pressure value and a shell temperature value in a high-voltage bushing;

step S22: calculating the molar density value of gas molecules in the high-voltage bushing;

step S23: calculating the molar density imbalance degree of the gas molecules among the phases;

step S24: and continuously monitoring the molar density imbalance of the interphase gas molecules, and diagnosing the state of the high-voltage bushing equipment according to a set diagnosis threshold value.

Specifically, steps S21 and S22 are the same as steps S11 and S12 in the above embodiment, and are not repeated herein.

In step S23, the molar density imbalance of the gas molecules between phases, which is an algorithm of minimum difference and maximum difference, is calculated.

The algorithm of the small difference of the molar density imbalance of the interphase gas molecules is as follows:

the algorithm of the extremely uniform difference of the molar density imbalance degrees of the gas molecules among the phases is as follows:

wherein the content of the first and second substances,

ε₁(t) the difference of the molar density imbalance of the gas molecules among the phases is small;

ε₂(t) the molar density imbalance of the interphase gas molecules is extremely poor;

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))。

the imbalance degree minimum difference algorithm is sensitive to smaller data, and is suitable for being adopted if oil leakage and air leakage phenomena occur more;

the imbalance extreme mean-error algorithm is sensitive to larger data, and is suitable for being adopted due to more phenomena such as internal overheating, partial discharge, abnormal oil degradation and the like;

the imbalance degree minimum difference algorithm or the imbalance degree maximum average difference algorithm can be selected according to the actual engineering situation for diagnosis, for example, the diagnosis threshold set by the imbalance degree maximum average difference algorithm is selected as follows:

when epsilon₂(t) is ≥ 35%: alarming for abnormal equipment state;

when the content is 35 percent>ε₂(t) not less than 25%: early warning of abnormal equipment state;

when the content is 15 percent>ε₂(t) is not less than 5%: the device status is of abnormal concern.

Referring to fig. 11 and 12 together, fig. 11 and 12 are graphs showing the transition of the molar density imbalance of the interphase gas molecules No. 1 and No. 2 in the first practical monitoring example provided in the third embodiment, respectively, and the results of the diagnosis of the transition graphs are as follows:

1) the molar density imbalance of the gas molecules between the main transformer phases No. 1 is within an allowable range, and the equipment is in a normal state.

2) In a certain period of time in the later stage of the unbalance degree of the molar density of the gas molecules between the phases of the No. 2 main transformer, a small amount of sample data exceeds the attention upper limit, and the equipment is in an attention state.

Referring to fig. 13 and 14 together, fig. 13 and 14 are a control chart of the imbalance of the molar density of the interphase gas molecules No. 1 and No. 2 in the practical monitoring example two provided in the third embodiment, respectively, and the diagnosis result is:

1) the molar density imbalance of the gas molecules between the main transformer phases No. 1 is within an allowable range, and the equipment is in a normal state.

2) In a certain period of time in the later stage of the control chart of the mole density imbalance of the molecules of the gas between the phases of the No. 2 main transformer, a small amount of sample data exceeds the attention upper limit, and the equipment is in an attention state; in a certain period of time in the control chart, a small amount of sample data continuously rises and exceeds the attention upper limit, and the equipment is in an attention state.

In addition, the invention also provides an online monitoring and diagnosing device for the gas pressure and temperature of the high-voltage bushing.

Referring to fig. 15, an internal structure diagram of a high-pressure bushing gas pressure temperature online monitoring and diagnosing apparatus according to an embodiment of the present invention is provided, where the high-pressure bushing gas pressure temperature online monitoring and diagnosing apparatus 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.

The memory 11 includes at least one type of readable storage medium, which includes a flash memory, a hard disk, a multimedia card, a card type memory (e.g., SD or DX memory, etc.), a magnetic memory, a magnetic disk, an optical disk, and the like. The memory 11 may be an internal storage unit of the high-voltage bushing gas pressure temperature online monitoring and diagnosing apparatus in some embodiments, for example, a hard disk of the high-voltage bushing gas pressure temperature online monitoring and diagnosing apparatus. The memory 11 may also be an external storage device of the online monitoring and diagnosing apparatus for pressure and temperature of air in the high-pressure bushing in other embodiments, such as a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash Card (Flash Card), and the like, which are equipped on the online monitoring and diagnosing apparatus for pressure and temperature of air in the high-pressure bushing. Further, the memory 11 may also include both an internal storage unit of the high-pressure bushing gas pressure temperature online monitoring and diagnosing apparatus and an external storage device. The memory 11 may be used to store not only application software installed in the high-voltage bushing gas pressure temperature online monitoring and diagnosing apparatus and various data, such as codes of a high-voltage bushing gas pressure temperature online monitoring and diagnosing program, but also temporarily store data that has been output or will be output.

The processor 12 may be, in some embodiments, a Central Processing Unit (CPU), controller, microcontroller, microprocessor or other data Processing chip, and is used for executing program codes stored in the memory 11 or Processing data, such as executing a high-pressure-sleeve gas pressure and temperature online monitoring and diagnosing program.

The communication bus 13 is used to realize connection communication between these components.

The network interface 14 may optionally include a standard wired interface, a wireless interface (e.g., WI-FI interface), and is typically used to establish a communication link between the high-voltage bushing gas pressure temperature online monitoring and diagnosis device and other electronic devices.

The temperature sensor 15 and the pressure sensor 16 are connected with the processor 12, and the temperature sensor 15 is used for acquiring a temperature value in the high-voltage bushing; the pressure sensor 16 is used for acquiring a pressure value of gas in the high-voltage bushing or a pressure value of oil at the bottom of the high-voltage bushing.

Optionally, the online monitoring and diagnosing apparatus for pressure, temperature and gas pressure of the high-pressure bushing may further include a user interface, the user interface may include a Display (Display), an input unit such as a Keyboard (Keyboard), and the optional user interface may further include a standard wired interface and a wireless interface. Alternatively, in some embodiments, the display may be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, an OLED (Organic Light-Emitting Diode) touch device, or the like. The display, which may also be referred to as a display screen or display unit, is used to display information processed in the high-pressure bushing gas pressure temperature online monitoring and diagnosis device and to display a visual user interface.

Fig. 15 only shows the on-line monitoring and diagnosing apparatus for pressure and temperature of high-pressure bushing having the components 11-16 and the on-line monitoring and diagnosing program for pressure and temperature of high-pressure bushing, and it will be understood by those skilled in the art that the structure shown in fig. 15 does not constitute a limitation of the on-line monitoring and diagnosing apparatus for pressure and temperature of high-pressure bushing, and may include fewer or more components than those shown, or some components in combination, or a different arrangement of components.

In the embodiment of the online monitoring and diagnosing apparatus for pressure and temperature of high-pressure bushing shown in fig. 15, the memory 11 stores an online monitoring and diagnosing program for pressure and temperature of high-pressure bushing; the processor 12 implements the following steps when executing the high-voltage bushing gas pressure temperature online monitoring and diagnosing program stored in the memory 11:

step S11: collecting a gas pressure value and a shell temperature value in a high-voltage bushing;

step S12: calculating the molar density value of gas molecules in the high-voltage bushing;

step S13: converting the gas molecule molar density value into an equivalent gas pressure value of a preset temperature value;

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

Or the following steps:

step S21: collecting a gas pressure value and a shell temperature value in a high-voltage bushing;

step S22: calculating the molar density value of gas molecules in the high-voltage bushing;

step S23: calculating the molar density imbalance degree of the gas molecules among the phases;

step S24: and continuously monitoring the molar density imbalance of the interphase gas molecules, and diagnosing the state of the high-voltage bushing equipment according to a set diagnosis threshold value.

Referring to fig. 16, a schematic diagram of program modules of an online monitoring and diagnosing program for pressure and temperature of high-pressure bushing in an embodiment of the online monitoring and diagnosing apparatus for pressure and temperature of high-pressure bushing according to the present invention is shown, in this embodiment, the online monitoring and diagnosing program for pressure and temperature of high-pressure bushing may be divided into a monitoring module 10, a calculating module 20, a setting module 30, and a diagnosing module 40, which exemplarily:

the monitoring module 10 is used for acquiring a gas pressure value and a shell temperature value in the high-voltage bushing;

the calculating module 20 is configured to calculate a molar density value of the gas molecules, an equivalent gas pressure value, a minimum difference between molar density imbalances of the interphase gas molecules, and a maximum difference between molar density imbalances of the interphase gas molecules;

a setting module 30 for setting a diagnostic threshold;

and the diagnosis module 40 is used for monitoring and diagnosing the pressure and the temperature of the high-voltage bushing on line.

The functions or operation steps of the monitoring module 10, the calculating module 20, the setting module 30, and the diagnosing module 40 when executed are substantially the same as those of the above embodiments, and are not described herein again.

Furthermore, an embodiment of the present invention further provides a storage medium, which is a computer-readable storage medium, and the storage medium stores thereon an online monitoring and diagnosing program for high-pressure bushing gas pressure and temperature, which is executable by one or more processors to implement the following operations:

step S11: collecting a gas pressure value and a shell temperature value in a high-voltage bushing;

step S12: calculating the molar density value of gas molecules in the high-voltage bushing;

step S13: converting the gas molecule molar density value into an equivalent gas pressure value of a preset temperature value;

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

Or the following steps:

step S21: collecting a gas pressure value and a shell temperature value in a high-voltage bushing;

step S22: calculating the molar density value of gas molecules in the high-voltage bushing;

step S23: calculating the molar density imbalance degree of the gas molecules among the phases;

step S24: and continuously monitoring the molar density imbalance of the interphase gas molecules, and diagnosing the state of the high-voltage bushing equipment according to a set diagnosis threshold value.

The embodiment of the storage medium of the present invention is substantially the same as the embodiments of the above-mentioned method and apparatus for online monitoring and diagnosing the pressure and temperature of the high-voltage bushing, and will not be described herein in detail.

Compared with the prior art, the method, the device and the storage medium for online monitoring and diagnosing the air pressure and the temperature of the high-voltage bushing provided by the invention have the advantages that the online monitoring of the oil-gas pressure value in the high-voltage bushing for 24 hours is realized by acquiring the air pressure value and the shell temperature value in the high-voltage bushing, calculating the molar density value of the gas molecules in the high-voltage bushing and diagnosing the state of the high-voltage bushing equipment based on the equivalent air pressure value, the movement range and the molar density imbalance degree of the interphase gas molecules, the running and fault states of the high-voltage bushing equipment can be evaluated, accidents are prevented, and a feasible means is provided for real-time monitoring of the running and fault states of the equipment.

It should be noted that the above-mentioned numbers of the embodiments of the present invention are merely for description, and do not represent the merits of the embodiments. And the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, apparatus, article, or method that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, apparatus, article, or method. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, apparatus, article, or method that comprises the element.

Through the above description of the embodiments, those skilled in the art will clearly understand that the method of the above embodiments can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware, but in many cases, the former is a better implementation manner. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium (e.g., ROM/RAM, magnetic disk, optical disk) as described above, and includes instructions for enabling a terminal device (e.g., a drone, a mobile phone, a computer, a server, or a network device) to execute the method according to the embodiments of the present invention.

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.