Method for detecting dissolved gas in transformer oil

Abstract

The invention relates to the technical field of transformer fault detection, in particular to a method for detecting dissolved gas in transformer oil. The method comprises the following steps: collecting corresponding oil samples at different oil sampling points of the transformer; stirring and mixing the oil sample; detecting dissolved gas in oil in the mixed oil sample; and correcting the gas content of the dissolved gas in the oil according to the external influence factors. In order to solve the problems that a transformer is large in size and gas dissolved in oil at each collection point is not uniformly distributed, a multi-point collection and mixed detection mode is adopted for optimization; in the multi-point acquisition and mixed detection process, the problem that the gas dissolved in the oil overflows inevitably is solved, the overflow problem can be corrected according to the specific conditions of external influence factors, and the detection accuracy of the gas dissolved in the oil is improved.

Description

Technical Field

[0001] The invention relates to the technical field of transformer fault detection, and in particular to a method for detecting dissolved gas in transformer oil. Background Art

[0002] As my country's power level continues to improve, the power Internet is also constantly developing and improving. It is particularly important to accurately and reliably monitor the stability of power transformer operation. In the power system, the healthy operation of the transformer is the key to ensuring the smooth operation of the power grid. Such a large-scale power system has brought huge challenges to this work. For a long time, the power equipment maintenance strategy has mainly adopted regular maintenance based on time. Although regular maintenance can generally detect defects in the equipment during maintenance, it plays a significant role in ensuring the safety and economic operation of the equipment. However, there are also cases where regular maintenance is not timely, resulting in a decrease in equipment reliability.

[0003] Most large transformers use insulating oil for insulation. When a transformer fails during operation, the insulating oil and solid insulating materials in the transformer will age and decompose under the combined effects of discharge, high temperature, oxidation and other factors, and produce some gases, such as low molecular hydrocarbon gases such as CH4, C2H6, C2H4 and C2H2, as well as gases such as CO, CO2 and H2.

[0004] At present, the transformer fault online monitoring device samples transformer oil in a single-point sampling method, and the single-point sampling method has obvious defects: temperature has a direct impact on the concentration of dissolved gas in transformer oil, that is, the concentration of dissolved gas will be different at different oil temperatures. Due to the large volume of the transformer, the oil temperature in different parts of the transformer is different during operation, resulting in different concentrations of dissolved gas in the oil in different parts. Single-point sampling can only extract oil from a certain part. Therefore, the analysis results obtained by single-point sampling cannot well reflect the overall dissolved gas concentration in the transformer oil, affecting the accuracy of subsequent fault diagnosis. Summary of the invention

[0005] The present invention discloses a method for detecting dissolved gas in transformer oil, and the specific method is as follows:

[0006] Collect corresponding oil samples at different oil sampling points of the transformer;

[0007] Stir and mix the oil sample;

[0008] Detection of dissolved gas in oil in mixed oil samples;

[0009] Correct the dissolved gas content in the oil according to external influencing factors.

[0010] The advantage of this embodiment is that, in view of the large size of the transformer and the uneven distribution of dissolved gas in the oil at each collection point, a multi-point collection and mixed detection method is adopted for optimization; in the process of multi-point collection and mixed detection, the dissolved gas in the oil will inevitably overflow. The present invention can correct the overflow problem according to the specific circumstances of the external influencing factors, thereby improving the accuracy of dissolved gas detection in the oil.

[0011] Furthermore, the external influencing factors include:

[0012] Ambient temperature, pressure, temperature or oil sample model from oil sample collection to detection of dissolved gas in oil.

[0013] The advantage of this embodiment is that, through observation and analysis, the biggest external factors affecting the spillage of dissolved gas in oil are determined, which are ambient temperature, pressure, temperature or oil sample model.

[0014] Furthermore, before correcting the gas content of dissolved gas in oil according to external influencing factors, the influence of ambient temperature, pressure, temperature or oil sample type on dissolved gas in oil is quantified experimentally;

[0015] Correct the content of dissolved gas in the oil based on the quantitative impact.

[0016] Furthermore, the effect of ambient temperature on dissolved gas in oil is quantified by experiments. The specific experimental method is as follows:

[0017] Design a closed experimental device that can control the temperature and realize the circulation and ventilation of oil samples and air samples. Set temperature sensors and gas concentration sensors in the experimental device to monitor the changes of temperature and gas concentration.

[0018] Place the sample transformer oil into the experimental apparatus;

[0019] Record the baseline temperature and gas concentration at the beginning of the experiment;

[0020] By controlling the heating or cooling function of the experimental device, the temperature is gradually changed;

[0021] Real-time monitoring and recording of experimental data on the concentration of dissolved gas in sample transformer oil and gas leaking out of space as a function of temperature;

[0022] Construct a temperature-space spillover gas relationship table based on experimental data;

[0023] When correcting the dissolved gas content in the oil according to the temperature, the corresponding spatial overflow gas content is obtained by querying the temperature-space overflow gas relationship table, and the correction is completed by adding the dissolved gas content in the oil to the corresponding spatial overflow gas content.

[0024] The advantage of this embodiment is that it is found that as the temperature increases, the concentration of the fault gas dissolved in the transformer oil decreases, while the concentration released into the air inside the transformer increases.

[0025] Furthermore, the effect of pressure on dissolved gas in oil is quantified by experiments. The specific experimental method is as follows:

[0026] Design a closed experimental device that can control the internal pressure and realize the circulation ventilation of oil samples and air samples. Set up a pressure sensor and a gas concentration sensor in the experimental device to monitor the changes in pressure and gas concentration.

[0027] Place the sample transformer oil into the experimental apparatus;

[0028] Record the baseline pressure and gas concentration at the beginning of the experiment;

[0029] The pressure can be gradually changed by increasing or decreasing the pressure function of the experimental device;

[0030] Real-time monitoring and recording of experimental data on the concentration of dissolved gas in sample transformer oil and gas leaking out of space as a function of pressure;

[0031] Construct a table of pressure-space overflow gas relationship based on experimental data;

[0032] When correcting the dissolved gas content in the oil according to the pressure, the corresponding spatial overflow gas content is obtained by querying the pressure-space overflow gas relationship table, and the correction is completed by adding the dissolved gas content in the oil to the corresponding spatial overflow gas content.

[0033] The advantage of this embodiment is that it is found that as the pressure increases, the concentration of the fault gas dissolved in the transformer oil decreases, while the concentration released into the air inside the transformer increases;

[0034] Furthermore, the effect of humidity on dissolved gas in oil was quantified by experiments. The specific experimental method is as follows:

[0035] Design a closed experimental device that can control the internal humidity and realize the circulation ventilation of oil samples and air samples. Set humidity sensors and gas concentration sensors in the experimental device to monitor the changes of humidity and gas concentration.

[0036] Place the sample transformer oil into the experimental apparatus;

[0037] Record the baseline humidity and gas concentration at the beginning of the experiment;

[0038] By controlling the experimental device to increase or decrease the humidity function, the humidity is gradually changed;

[0039] Real-time monitoring and recording of experimental data on the concentration of dissolved gas in sample transformer oil and gas leaking out of space as it changes with humidity;

[0040] Construct a humidity-space escape gas relationship table based on experimental data;

[0041] When correcting the dissolved gas content in the oil according to humidity, the corresponding spatial overflow gas content is obtained by querying the humidity-space overflow gas relationship table, and the correction is completed by adding the dissolved gas content in the oil to the corresponding spatial overflow gas content.

[0042] The advantage of this embodiment is that it is found that as the humidity increases, the concentration of the fault gas dissolved in the transformer oil decreases, while the concentration released into the air inside the transformer increases.

[0043] Furthermore, the effect of oil sample type on dissolved gas in oil was quantified through experiments. The specific experimental method is as follows:

[0044] Design a closed experimental device and set a gas concentration sensor in the experimental device to monitor the changes in gas concentration;

[0045] Sample transformer oils of different oil sample types are placed in the experimental device respectively;

[0046] Record the gas concentration of transformer oil spills from different oil sample types as experimental data;

[0047] Construct an oil sample model-space spill gas relationship table based on experimental data;

[0048] When correcting the dissolved gas content in the oil according to the oil sample model, the corresponding space overflow gas content is obtained by querying the oil sample model-space overflow gas relationship table, and the correction is completed by adding the dissolved gas content in the oil to the corresponding space overflow gas content.

[0049] The advantage of this embodiment is that it is found that as the viscosity of the transformer oil increases, the solubility of the gas dissolved in the oil decreases, resulting in a relatively low concentration of the fault gas dissolved in the oil.

[0050] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The accompanying drawings of the present invention are as follows:

[0052] Figure 1 This is a schematic diagram of the process of detecting the concentration of dissolved gas in oil according to the present invention;

[0053] Figure 2 Schematic diagram of the dissolved gas detection device in transformer oil. DETAILED DESCRIPTION

[0054] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0055] A method for detecting dissolved gas in transformer oil, such as Figure 1 As shown, the specific steps are as follows:

[0056] S1. Collect corresponding oil samples at different oil sampling points of the transformer.

[0057] Dissolved gas detection device in transformer oil Figure 2 As shown, it includes multiple oil sample collection modules, a front oil sample mixing module, a rear oil sample detection module and an oil sample post-processing module.

[0058] Among them, the oil sample collection module is used to be installed at the oil collection point of the transformer, collect oil samples from the corresponding oil collection point, and transmit them to the front oil sample mixing module connected to itself; the front oil sample mixing module is used to mix the oil samples, and divide the mixed oil samples into multiple parts and transmit them to multiple rear oil sample detection modules respectively; the rear oil sample detection module is used to perform mixed gas detection on the mixed oil sample, obtain the gas type and content information in the mixed oil sample, and perform fault analysis on the transformer based on the obtained detection results; the oil sample post-processing module is used to recover all oil samples detected by the rear oil sample detection module and transmit them to the transformer.

[0059] This embodiment takes oil from multiple different places, and after taking the oil, it is output to the front oil mixing device, which mixes the oil taken from all points, and then sends the mixed oil to multiple independent mixed gas post-oil sample detection units for detection.

[0060] The concentration of gas dissolved in the oil at different positions of the transformer is not very uniform. Especially when an abnormality occurs in a certain part, the gas concentration in that part will change quickly, and the change in gas concentration in other places will be delayed. Through this oil mixing method, problems can be discovered more promptly.

[0061] The post-oil sample detection module includes: an oil-gas separation unit, a gas detection unit and a data acquisition and control unit. The oil-gas separation unit is used to separate the mixed oil sample into oil and gas, and transmit the separated gas to be detected to the gas detection unit; the gas detection unit is used to detect the gas to be detected, and send the detected gas type and content to the data acquisition and control unit; the data acquisition and control unit is used to compare the gas content with the preset threshold value to perform fault analysis on the transformer.

[0062] S2. Stir and mix the oil sample.

[0063] S3. Detect dissolved gas in the oil sample after mixing.

[0064] S4. Correct the dissolved gas content in the oil according to external influencing factors.

[0065] In this embodiment, the external influencing factors include: ambient temperature, pressure, temperature or oil sample type during the process from collecting the oil sample to detecting the dissolved gas in the oil.

[0066] This embodiment quantifies the effect of ambient temperature on dissolved gas in oil through experiments. The specific experimental method is as follows:

[0067] Design a closed experimental device that can control the temperature and realize the circulation and ventilation of oil samples and air samples. Set temperature sensors and gas concentration sensors in the experimental device to monitor the changes of temperature and gas concentration.

[0068] Place the sample transformer oil into the experimental apparatus;

[0069] Record the baseline temperature and gas concentration at the beginning of the experiment;

[0070] By controlling the heating or cooling function of the experimental device, the temperature is gradually changed;

[0071] Real-time monitoring and recording of experimental data on the concentration of dissolved gas in sample transformer oil and gas leaking out of space as a function of temperature;

[0072] Construct a temperature-space spillover gas relationship table based on experimental data;

[0073] When correcting the dissolved gas content in the oil according to the temperature, the corresponding spatial overflow gas content is obtained by querying the temperature-space overflow gas relationship table, and the correction is completed by adding the dissolved gas content in the oil to the corresponding spatial overflow gas content.

[0074] This embodiment quantifies the effect of pressure on dissolved gas in oil through experiments. The specific experimental method is as follows:

[0075] Design a closed experimental device that can control the internal pressure and realize the circulation ventilation of oil samples and air samples. Set up a pressure sensor and a gas concentration sensor in the experimental device to monitor the changes in pressure and gas concentration.

[0076] Place the sample transformer oil into the experimental apparatus;

[0077] Record the baseline pressure and gas concentration at the beginning of the experiment;

[0078] The pressure can be gradually changed by increasing or decreasing the pressure function of the experimental device;

[0079] Real-time monitoring and recording of experimental data on the concentration of dissolved gas in sample transformer oil and gas leaking out of space as a function of pressure;

[0080] Construct a table of pressure-space overflow gas relationship based on experimental data;

[0081] When correcting the dissolved gas content in the oil according to the pressure, the corresponding spatial overflow gas content is obtained by querying the pressure-space overflow gas relationship table, and the correction is completed by adding the dissolved gas content in the oil to the corresponding spatial overflow gas content.

[0082] This embodiment quantifies the effect of humidity on dissolved gas in oil through experiments. The specific experimental method is as follows:

[0083] Design a closed experimental device that can control the internal humidity and realize the circulation ventilation of oil samples and air samples. Set humidity sensors and gas concentration sensors in the experimental device to monitor the changes of humidity and gas concentration.

[0084] Place the sample transformer oil into the experimental apparatus;

[0085] Record the baseline humidity and gas concentration at the beginning of the experiment;

[0086] By controlling the experimental device to increase or decrease the humidity function, the humidity is gradually changed;

[0087] Real-time monitoring and recording of experimental data on the concentration of dissolved gas in sample transformer oil and gas leaking out of space as it changes with humidity;

[0088] Construct a humidity-space escape gas relationship table based on experimental data;

[0089] When correcting the dissolved gas content in the oil according to humidity, the corresponding spatial overflow gas content is obtained by querying the humidity-space overflow gas relationship table, and the correction is completed by adding the dissolved gas content in the oil to the corresponding spatial overflow gas content.

[0090] This embodiment quantifies the effect of oil sample type on dissolved gas in oil through experiments. The specific experimental method is as follows:

[0091] Design a closed experimental device and set a gas concentration sensor in the experimental device to monitor the changes in gas concentration;

[0092] Put the sample transformer oils of different oil sample types, such as 10#, 25#, and 45#, into the experimental device respectively;

[0093] Record the gas concentration of transformer oil spills from different oil sample types as experimental data;

[0094] Construct an oil sample model-space spill gas relationship table based on experimental data;

[0095] When correcting the dissolved gas content in the oil according to the oil sample model, the corresponding space overflow gas content is obtained by querying the oil sample model-space overflow gas relationship table, and the correction is completed by adding the dissolved gas content in the oil to the corresponding space overflow gas content.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for detecting dissolved gas in transformer oil, characterized in that: The specific method is as follows: Collect corresponding oil samples at different oil sampling points of the transformer; Stir and mix the oil sample; Detection of dissolved gas in oil in mixed oil samples; Correct the dissolved gas content in the oil according to external influencing factors.

2. The method for detecting dissolved gas in transformer oil according to claim 1, wherein: The external influencing factors include: Ambient temperature, pressure, temperature or oil sample model from oil sample collection to detection of dissolved gas in oil.

3. The method for detecting dissolved gas in transformer oil as claimed in claim 2, characterized in that: Before correcting the gas content of dissolved gas in oil according to external influencing factors, the influence of ambient temperature, pressure, temperature or oil sample type on the dissolved gas in oil is quantified experimentally; Correct the content of dissolved gas in the oil based on the quantitative impact.

4. The method for detecting dissolved gas in transformer oil according to claim 3, characterized in that: The effect of ambient temperature on dissolved gas in oil is quantified by experiments. The specific experimental method is as follows: Design a closed experimental device that can control the temperature and realize the circulation and ventilation of oil samples and air samples. Set temperature sensors and gas concentration sensors in the experimental device to monitor the changes of temperature and gas concentration. Place the sample transformer oil into the experimental apparatus; Record the baseline temperature and gas concentration at the beginning of the experiment; By controlling the heating or cooling function of the experimental device, the temperature is gradually changed; Real-time monitoring and recording of experimental data on the concentration of dissolved gas in sample transformer oil and gas leaking out of space as a function of temperature; Construct a temperature-space spillover gas relationship table based on experimental data; When correcting the dissolved gas content in the oil according to the temperature, the corresponding spatial overflow gas content is obtained by querying the temperature-space overflow gas relationship table, and the correction is completed by adding the dissolved gas content in the oil to the corresponding spatial overflow gas content.

5. The method for detecting dissolved gas in transformer oil according to claim 4, characterized in that: The effect of pressure on dissolved gas in oil is quantified by experiments. The specific experimental method is as follows: Design a closed experimental device that can control the internal pressure and realize the circulation ventilation of oil samples and air samples. Set up a pressure sensor and a gas concentration sensor in the experimental device to monitor the changes in pressure and gas concentration. Place the sample transformer oil into the experimental apparatus; Record the baseline pressure and gas concentration at the beginning of the experiment; The pressure can be gradually changed by increasing or decreasing the pressure function of the experimental device; Real-time monitoring and recording of experimental data on the concentration of dissolved gas in sample transformer oil and gas leaking out of space as a function of pressure; Construct a table of pressure-space overflow gas relationship based on experimental data; When correcting the dissolved gas content in the oil according to the pressure, the corresponding spatial overflow gas content is obtained by querying the pressure-space overflow gas relationship table, and the correction is completed by adding the dissolved gas content in the oil to the corresponding spatial overflow gas content.

6. The method for detecting dissolved gas in transformer oil according to claim 4, characterized in that: The effect of humidity on dissolved gas in oil was quantified experimentally. The specific experimental method is as follows: Design a closed experimental device that can control the internal humidity and realize the circulation ventilation of oil samples and air samples. Set humidity sensors and gas concentration sensors in the experimental device to monitor the changes of humidity and gas concentration. Place the sample transformer oil into the experimental apparatus; Record the baseline humidity and gas concentration at the beginning of the experiment; By controlling the experimental device to increase or decrease the humidity function, the humidity is gradually changed; Real-time monitoring and recording of experimental data on the concentration of dissolved gas in sample transformer oil and gas leaking out of space as it changes with humidity; Construct a humidity-space escape gas relationship table based on experimental data; When correcting the dissolved gas content in the oil according to humidity, the corresponding spatial overflow gas content is obtained by querying the humidity-space overflow gas relationship table, and the correction is completed by adding the dissolved gas content in the oil to the corresponding spatial overflow gas content.

7. The method for detecting dissolved gas in transformer oil according to claim 4, characterized in that: The effect of oil sample type on dissolved gas in oil is quantified through experiments. The specific experimental method is as follows: Design a closed experimental device and set a gas concentration sensor in the experimental device to monitor the changes in gas concentration; Sample transformer oils of different oil sample types are placed in the experimental device respectively; Record the gas concentration of transformer oil spills from different oil sample types as experimental data; Construct an oil sample model-space spill gas relationship table based on experimental data; When correcting the dissolved gas content in the oil according to the oil sample model, the corresponding space overflow gas content is obtained by querying the oil sample model-space overflow gas relationship table, and the correction is completed by adding the dissolved gas content in the oil to the corresponding space overflow gas content.

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