Standard oil sample mixing method and device for checking transformer oil dissolved gas

Abstract

The invention relates to a standard oil sample mixing method and device for transformer oil dissolved gas verification, and the method comprises the following steps: calculating the initial volumes of a saturated oil sample and a blank oil sample and the initial proportion parameter of a proportioning pump according to the gas concentration of a standard oil sample to be prepared; obtaining the temperature and pressure in the oil sample stirring pump, and calculating the actual proportion parameter of the proportioning pump and the actual stirring speed of the oil sample stirring pump according to the initial proportion parameter of the proportioning pump and the temperature and pressure in the oil sample stirring pump; acquiring a saturated oil sample and a blank oil sample with corresponding volume quantities according to actual proportion parameters of a proportioning pump, and stirring the mixed oil sample by an oil sample stirring pump according to an actual stirring speed; the real-time temperature and pressure in the oil sample stirring pump are periodically detected, the corresponding proportional parameters of the proportional pump and the stirring speed of the oil sample stirring pump under the real-time condition are calculated, and the proportional pump and the oil sample stirring pump are adjusted in real time. Compared with the prior art, the device has the advantages of high oil sample mixing efficiency and precision and the like.

Description

Technical Field

[0001] The invention relates to the technical field of preparation of standard oil samples for detection, in particular to a method and a device for mixing standard oil samples for transformer oil dissolved gas verification. Background Art

[0002] The internal defects of oil-immersed electrical equipment (transformers, high-voltage reactors, converter transformers, etc.) can be mainly sensed through the online monitoring device for dissolved gas in oil. Therefore, the accuracy and reliability of the device performance are crucial for monitoring the internal defects of the main equipment. At present, in accordance with management regulations and technical requirements, the online monitoring device for dissolved gas in oil is mainly calibrated on site to grasp the accuracy of its monitoring data. In the calibration work, the preparation of standard oil samples (standard oil) is an important link. The more commonly used methods are gas-matching and oil-matching. The gas-matching method refers to the introduction of a certain amount of characteristic gas into crude oil that does not contain characteristic gas to prepare standard oil containing a certain amount of different characteristic gases. Its basic principle is based on the distribution law of gas in the gas phase and liquid phase. Under certain pressure and temperature conditions, when dynamic equilibrium is reached, there is a fixed distribution coefficient between the content of dissolved gas in the oil and the content of the corresponding components in the gas phase. The standard oil prepared by this oil matching method is not accurate, which will lead to inaccurate final test results. It is rarely used in existing inspection equipment.

[0003] The oil blending method is currently a mainstream method, which mainly involves quantitatively mixing crude oil with different concentrations of characteristic gases under a constant temperature and pressure environment to form a standard oil of a target concentration. For example, the utility model with publication number CN208125682U discloses a standard oil blending unit for an online chromatograph calibration device, including a crude oil tank door, a crude oil tank, a first controller, a standard oil blending mechanism, a second controller, an oil blending tank and a circulation mechanism, wherein the crude oil tank door is arranged on the crude oil tank. The first controller is arranged on the crude oil tank door, and the first controller is used to control the standard oil blending mechanism, the second controller is arranged on the oil blending tank, and the second controller is used to control the circulation mechanism. The standard oil blending mechanism is arranged in the crude oil tank, and the circulation mechanism is arranged in the oil blending tank. The standard oil blending mechanism is connected to the circulation mechanism. The standard oil blending unit for an online chromatograph calibration device provided in the present application replaces the traditional gas blending method and improves the accuracy of standard oil blending. In addition, both the first controller and the second controller are controlled by PLC, which can realize fully automatic oil blending and save manpower.

[0004] And the invention with publication number CN107831298A discloses a method for on-site verification of the performance of a transformer oil dissolved gas monitoring device, including: preparing a first standard oil sample and a second standard oil sample according to the components of the dissolved gas in the oil and the concentration ranges corresponding to the components; using a high-precision gas chromatograph to obtain concentration standard values ​​respectively; connecting with the verification interface of the first oil sample storage device and the second oil sample storage device and the online monitoring device respectively, and obtaining concentration detection values ​​respectively; obtaining concentration measurement values ​​respectively according to the concentration detection values; judging the measurement error of the online monitoring device according to the relative error and the absolute error; selecting the last continuous third preset number threshold concentration detection value of the preset gas in the second standard oil sample as the preset gas concentration measurement value; calculating the relative standard deviation according to the preset gas concentration measurement value, and judging the performance of the online monitoring device according to the relative standard deviation.

[0005] However, the above oil preparation method is mainly carried out by stirring, which is achieved by a stirring pump at a certain speed under a constant temperature and pressure environment. It does not consider the influence of different stirring speeds of characteristic gases of different concentrations on the gas solubility under temperature and pressure changes. It also needs to be calibrated multiple times with the help of an external high-precision gas chromatograph analyzer, and the degree of automation is not high. At the same time, the measurement deviation formed is only used for judgment, and no closed-loop control is formed. Therefore, to realize a high-precision oil preparation method, these factors must be considered comprehensively. Summary of the invention

[0006] The purpose of the present invention is to provide a standard oil sample mixing method and device for transformer oil dissolved gas calibration in order to overcome the defects that the above-mentioned prior art does not consider the influence of different stirring speeds on gas solubility under temperature and pressure changing conditions of characteristic gases of different concentrations, and requires multiple calibrations with the aid of an external high-precision gas chromatograph, resulting in low mixing accuracy of the obtained standard oil sample.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] This scheme provides a standard oil sample mixing method for transformer oil dissolved gas calibration, including the following steps:

[0009] According to the gas concentration of the standard oil sample to be configured, the initial volumes of the saturated oil sample and the blank oil sample are calculated to obtain the initial proportional parameters of the proportional pump;

[0010] The temperature and pressure in the oil sample stirring pump are obtained, and the actual proportional parameters of the proportional pump and the actual stirring speed of the oil sample stirring pump are calculated according to the initial proportional parameters of the proportional pump and the temperature and pressure in the oil sample stirring pump;

[0011] According to the actual proportional parameters of the proportional pump, the saturated oil sample and the blank oil sample of corresponding volumes are obtained, and the oil sample stirring pump stirs the mixed oil sample according to the actual stirring speed;

[0012] The real-time temperature and pressure in the oil sample stirring pump are detected periodically, the proportional parameters of the proportional pump and the stirring speed of the oil sample stirring pump corresponding to the real-time conditions are calculated, and the proportional pump and the oil sample stirring pump are adjusted in real time.

[0013] Furthermore, the specific calculation expressions of the actual proportional parameter of the proportional pump and the actual stirring speed of the oil sample stirring pump are:

[0014]

[0015] In the formula, w represents the actual proportional parameter of the proportional pump, w0 represents the initial proportional parameter of the proportional pump, T represents the temperature of the stirring container, P represents the pressure of the stirring container, v represents the actual stirring speed of the oil sample stirring pump; k1~k9 are the control PD parameters, which are constants.

[0016] Furthermore, the actual proportional parameters of the proportional pump and the actual stirring speed of the oil sample stirring pump are solved by digital discretization. The specific expressions are:

[0017]

[0018] In the formula, ▽t represents the discrete time interval, that is, the step time, (v k -v k-1 ) represents the change of stirring speed within the step time, (T k -T k-1 ) represents the temperature change of the stirring container during the step time, (P k -P k-1 ) represents the pressure change of the stirring container during the step time, k is a natural number greater than or equal to 1, and w k represents the scale parameter to be solved, w k-1 Represents the scale parameter of the last calculation, v k represents the stirring speed to be solved, v k-1 Indicates the last calculated stirring speed.

[0019] Furthermore, the blank oil sample is obtained by applying atomization constant temperature vacuum molecular sieve degassing technology.

[0020] Furthermore, the saturated oil sample is prepared by means of saturated dissolution of standard gas at constant temperature and constant pressure.

[0021] The scheme also provides a standard oil sample mixing device for transformer oil dissolved gas calibration, including a proportional pump, a saturated oil sample container, a blank oil sample container, an oil sample stirring pump, a temperature sensor, a pressure sensor and a controller;

[0022] The inlet of the proportional pump is connected to a saturated oil sample container and a blank oil sample container respectively, the outlet of the proportional pump is connected to the inlet of the oil sample stirring pump, and the outlet of the oil sample stirring pump is connected to a standard oil sample container. The temperature sensor and the pressure sensor are used to obtain the temperature and pressure in the oil sample stirring pump. The controller adjusts the stirring speed of the oil sample stirring pump and the proportional parameter of the proportional pump according to the temperature and pressure in the oil sample stirring pump.

[0023] Furthermore, a timer is provided in the controller for controlling the temperature sensor and the pressure sensor to periodically obtain the temperature and pressure in the oil sample stirring pump.

[0024] Furthermore, the controller controls the proportional pump and the oil sample stirring pump through a PD regulation method.

[0025] Furthermore, the blank oil sample is obtained by applying atomization constant temperature vacuum molecular sieve degassing technology.

[0026] Furthermore, the saturated oil sample is prepared by means of saturated dissolution of standard gas at constant temperature and constant pressure.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] (1) This scheme uses sensors to periodically detect the temperature and pressure of the oil sample stirring environment, and adjusts the proportional parameters of the proportional pump and the stirring speed of the oil sample stirring pump in real time according to the stirring environment temperature and pressure and the parameters of the standard oil sample. Considering the change in the solubility of the specified gas in the oil sample at different pressures and temperatures, the standard oil sample obtained by this method has higher accuracy, and the coordinated adjustment of the mixing environment and the stirring speed can make the oil sample mix to reach the expected concentration faster, and the mixing efficiency of the standard oil sample is higher.

[0029] (2) This scheme periodically detects the temperature and pressure of the stirring environment, and comprehensively considers the parameters of the proportional pump and the stirring speed of the oil sample stirring pump according to the requirements of the standard oil sample, so that the concentration of the standard oil sample does not directly depend on the calibration of the external chromatograph.

[0030] (3) The present invention uses atomization constant temperature vacuum molecular sieve degassing technology to achieve highly reliable degassing and obtain a more accurate blank oil sample. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A flow chart of the standard oil sample mixing method provided by the present invention;

[0032] Figure 2 This is a structural block diagram of the standard oil sample mixing device provided by the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0034] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0036] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are the directions or positional relationships in which the inventive product is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0037] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0038] In addition, the terms "horizontal", "vertical" and the like do not mean that the components are required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0039] Example 1

[0040] like Figure 1As shown, this embodiment provides a standard oil sample mixing method for transformer oil dissolved gas calibration, comprising the following steps:

[0041] According to the gas concentration of the standard oil sample to be configured, the initial volumes of the saturated oil sample and the blank oil sample are calculated to obtain the initial proportional parameters of the proportional pump;

[0042] The temperature and pressure in the oil sample stirring pump are obtained, and the actual proportional parameters of the proportional pump and the actual stirring speed of the oil sample stirring pump are calculated according to the initial proportional parameters of the proportional pump and the temperature and pressure in the oil sample stirring pump;

[0043] According to the actual proportional parameters of the proportional pump, the saturated oil sample and the blank oil sample of corresponding volumes are obtained, and the oil sample stirring pump stirs the mixed oil sample according to the actual stirring speed;

[0044] The real-time temperature and pressure in the oil sample stirring pump are detected periodically, the proportional parameters of the proportional pump and the stirring speed of the oil sample stirring pump corresponding to the real-time conditions are calculated, and the proportional pump and the oil sample stirring pump are adjusted in real time.

[0045] The temperature and pressure of the oil sample stirring environment are periodically detected by sensors, and the proportional parameters of the proportional pump and the stirring speed of the oil sample stirring pump are adjusted in real time according to the stirring environment temperature and pressure and the parameters of the standard oil sample. Considering the change in solubility of the specified gas in the oil sample at different pressures and temperatures, the standard oil sample obtained by this method has higher accuracy, and the coordinated adjustment of the mixing environment and the stirring speed can make the oil sample mix to reach the expected concentration faster, and the mixing efficiency of the standard oil sample is higher.

[0046] Among them, the specific calculation expressions of the actual proportional parameters of the proportional pump and the actual stirring speed of the oil sample stirring pump are:

[0047]

[0048] In the formula, w represents the actual proportional parameter of the proportional pump, w0 represents the initial proportional parameter of the proportional pump, T represents the temperature of the stirring container, P represents the pressure of the stirring container, v represents the actual stirring speed of the oil sample stirring pump; k1~k9 are the control PD parameters, which are constants.

[0049] Optionally, the actual proportional parameter of the proportional pump and the actual stirring speed of the oil sample stirring pump are solved by digital discretization. The specific expressions are:

[0050]

[0051] In the formula, ▽t represents the discrete time interval, that is, the step time, (v k -v k-1 ) represents the change of stirring speed within the step time, (Tk -T k-1 ) represents the temperature change of the stirring container during the step time, (P k -P k-1 ) represents the pressure change of the stirring container during the step time, k is a natural number greater than or equal to 1, and w k represents the scale parameter to be solved, w k-1 Represents the scale parameter of the last calculation, v k represents the stirring speed to be solved, v k-1 Indicates the last calculated stirring speed.

[0052] Among them, k1~k9 control PD parameters can be implemented by using different algorithms, such as artificial intelligence, neural network, etc., so this embodiment does not elaborate on the method of determining these nine parameters in detail.

[0053] Specifically, the blank oil sample is obtained by using the atomization constant temperature vacuum molecular sieve degassing technology. The saturated oil sample is prepared by the saturated dissolution of the standard gas at constant temperature and constant pressure.

[0054] like Figure 2 As shown, this embodiment also provides a standard oil sample mixing device for transformer oil dissolved gas calibration, including a proportional pump, a saturated oil sample container, a blank oil sample container, an oil sample stirring pump, a temperature sensor, a pressure sensor and a controller;

[0055] The inlet of the proportional pump is connected to the saturated oil sample container and the blank oil sample container respectively, the outlet of the proportional pump is connected to the inlet of the oil sample stirring pump, the outlet of the oil sample stirring pump is connected to the standard oil sample container, the temperature sensor and the pressure sensor are used to obtain the temperature and pressure in the oil sample stirring pump, and the controller adjusts the stirring speed of the oil sample stirring pump and the proportional parameter of the proportional pump according to the temperature and pressure in the oil sample stirring pump.

[0056] Among them, the controller is connected to a temperature control system and a pressure control system, which can detect the temperature and pressure of the stirring environment and transmit them to the controller. The controller calculates and solves the proportional parameters and stirring speed, and the controller adjusts the oil sample stirring pump and the proportional pump according to the calculation results.

[0057] Optionally, a timer is provided in the controller for controlling the temperature sensor and the pressure sensor to periodically obtain the temperature and pressure in the oil sample stirring pump. The controller controls the proportional pump and the oil sample stirring pump by PD regulation.

[0058] Specifically, the blank oil sample is obtained by using the atomization constant temperature vacuum molecular sieve degassing technology. The saturated oil sample is prepared by the saturated dissolution of the standard gas at constant temperature and constant pressure.

[0059] In combination with the above standard oil sample mixing method and the device for implementing the corresponding method, this embodiment also provides a more specific implementation method, such as Figure 1 and Figure 2 As shown, the following steps are included:

[0060] Step 1: Prepare the standard oil sample with the specified gas concentration according to the requirements, calculate the initial volumes w1 and w2 of the saturated oil sample and the blank oil sample, and then get the initial proportional parameter of the proportional pump, which is recorded as w0;

[0061] Step 2: Detect the initial temperature T0 of the oil sample stirring environment through the temperature control system, and detect the initial pressure P0 of the oil sample stirring environment in conjunction with the pressure control system;

[0062] Step 3: Solve the expression for the actual proportional parameter of the proportional pump and the actual stirring speed of the oil sample stirring pump by digital discretization to calculate the actual proportional parameter W k and the actual stirring speed v k ;

[0063] Step 4: The controller adjusts the proportional parameters of the proportional pump and the stirring speed of the stirring pump according to the proportional parameters and the stirring speed obtained in Steps 2 and 3 to mix the oil sample;

[0064] Step 5: Use the timer inside the controller to periodically obtain the real-time temperature T in the stirring container. k and pressure P k According to the actual proportional parameters of the proportional pump and the calculation formula of the actual stirring speed of the oil sample stirring pump, the W that meets the conditions is solved. k and v k , and make real-time adjustments;

[0065] By real-time monitoring of the temperature and pressure of the oil sample stirring environment, and by adjusting the concentration of the mixed gas specified by the standard oil sample, the stirring speed and the parameters of the proportional pump can be adjusted in real time, the efficiency of oil sample mixing can be improved while improving the accuracy of the obtained standard oil sample.

[0066] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A method for mixing standard oil samples for transformer oil dissolved gas calibration, characterized in that: The following steps are involved: According to the gas concentration of the standard oil sample to be configured, the initial volumes of the saturated oil sample and the blank oil sample are calculated to obtain the initial proportional parameters of the proportional pump; The temperature and pressure in the oil sample stirring pump are obtained, and the actual proportional parameters of the proportional pump and the actual stirring speed of the oil sample stirring pump are calculated according to the initial proportional parameters of the proportional pump and the temperature and pressure in the oil sample stirring pump; According to the actual proportional parameters of the proportional pump, the saturated oil sample and the blank oil sample of corresponding volumes are obtained, and the oil sample stirring pump stirs the mixed oil sample according to the actual stirring speed; The real-time temperature and pressure in the oil sample stirring pump are detected periodically, the proportional parameters of the proportional pump and the stirring speed of the oil sample stirring pump corresponding to the real-time conditions are calculated, and the proportional pump and the oil sample stirring pump are adjusted in real time.

2. A standard oil sample mixing method for transformer oil dissolved gas calibration according to claim 1, characterized in that: The specific calculation expressions for the actual proportional parameters of the proportional pump and the actual stirring speed of the oil sample stirring pump are: In the formula, w represents the actual proportional parameter of the proportional pump, w0 represents the initial proportional parameter of the proportional pump, T represents the temperature of the stirring container, P represents the pressure of the stirring container, v represents the actual stirring speed of the oil sample stirring pump; k1~k9 are the control PD parameters, which are constants.

3. A standard oil sample mixing method for transformer oil dissolved gas calibration according to claim 2, characterized in that: The actual proportional parameters of the proportional pump and the actual stirring speed of the oil sample stirring pump are solved by digital discretization. The specific expressions are: In the formula, represents a discrete time interval, i.e., the step time, (v k -v k-1 ) represents the change of stirring speed within the step time, (T k -T k-1 ) represents the temperature change of the stirring container during the step time, (P k -P k-1 ) represents the pressure change of the stirring container during the step time, k is a natural number greater than or equal to 1, and w k represents the scale parameter to be solved, w k-1 Represents the scale parameter of the last calculation, v k represents the stirring speed to be solved, v k-1 Indicates the last calculated stirring speed.

4. A method for mixing standard oil samples for transformer oil dissolved gas calibration according to claim 1, characterized in that: The blank oil sample is obtained by using atomization constant temperature vacuum molecular sieve degassing technology.

5. A method for mixing standard oil samples for transformer oil dissolved gas calibration according to claim 1, characterized in that: The saturated oil sample is prepared by saturated dissolution of the standard gas at constant temperature and constant pressure.

6. A standard oil sample mixing device for transformer oil dissolved gas calibration, characterized in that: It includes a proportional pump, a saturated oil sample container, a blank oil sample container, an oil sample stirring pump, a temperature sensor, a pressure sensor and a controller; The inlet of the proportional pump is connected to a saturated oil sample container and a blank oil sample container respectively, the outlet of the proportional pump is connected to the inlet of the oil sample stirring pump, and the outlet of the oil sample stirring pump is connected to a standard oil sample container. The temperature sensor and the pressure sensor are used to obtain the temperature and pressure in the oil sample stirring pump. The controller adjusts the stirring speed of the oil sample stirring pump and the proportional parameter of the proportional pump according to the temperature and pressure in the oil sample stirring pump.

7. A standard oil sample mixing device for transformer oil dissolved gas calibration according to claim 6, characterized in that: The controller is provided with a timer for controlling the temperature sensor and the pressure sensor to periodically obtain the temperature and pressure in the oil sample stirring pump.

8. A standard oil sample mixing device for transformer oil dissolved gas calibration according to claim 6, characterized in that: The controller controls the proportional pump and the oil sample stirring pump through a PD regulation method.

9. A standard oil sample mixing device for transformer oil dissolved gas calibration according to claim 6, characterized in that: The blank oil sample is obtained by using atomization constant temperature vacuum molecular sieve degassing technology.

10. A standard oil sample mixing device for transformer oil dissolved gas calibration according to claim 6, characterized in that: The saturated oil sample is prepared by saturated dissolution of the standard gas at constant temperature and constant pressure.

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