Transformer Monitoring Method

Abstract

The present invention provides a transformer monitoring method. The transformer monitoring method is as follows: the multi-way valve is switched, the pumping unit extracts, and the purging gas sequentially passes through the gas pipeline, the first pipeline, the quantitative loop and the second pipeline and enters the pumping unit. The valves on the first pipeline and the second pipeline are closed, the pumping unit pushes the gas, and the purging gas sequentially passes through the third pipeline and the fourth pipeline. The pumping unit extracts, in the degassing chamber, the gas escapes from the transformer oil and is discharged from the second outlet of the degassing chamber, sequentially passes through the first pipeline, the quantitative loop and the second pipeline, and enters the pumping unit. The multi-way valve is switched, and the carrier gas pushes the gas in the quantitative loop into the gas analyzer, so as to obtain the content of the escaping gas. The present invention has the advantages of accurate detection results and the like.

Description

Technical Field

[0001] The present invention relates to gas detection, and particularly to a transformer monitoring method. Background Art

[0002] Performing predictive maintenance on power transformers is the key to ensuring the safe operation of the national power grid, which requires real-time online monitoring of transformers. When partial discharges, thermal faults, etc. occur inside the transformer, gases will be released and dissolved in the oil through diffusion and convection processes. The types and contents of these gases dissolved in the oil are directly related to the operating state of the transformer and potential latent faults that may exist. Therefore, they are called "fault characteristic gases". By systematically analyzing them, the internal operating state of the transformer can be grasped. Since there is no detection means that can directly analyze trace characteristic gases in the oil, an oil-gas separation device is required to remove the gases from the transformer oil.

[0003] The main oil-gas separation methods in the transformer oil online monitoring system are as follows: The membrane separation method that uses a polymer permeable membrane that is impermeable to oil but permeable to gas to separate oil and gas; The vacuum degassing method that degasses in a vacuum (negative pressure) environment and then compresses back to atmospheric pressure; The headspace degassing method that degasses in an atmospheric pressure environment, which can be further divided into static headspace degassing and dynamic headspace degassing. Among them, the static headspace mainly uses the mechanical oscillation method given in the national standard GB / T 17623-2017; The dynamic headspace degassing, also known as the purge-and-trap method, uses a carrier gas to continuously carry out the gases in the oil and enrich them in the trap. However, the existing technical methods have some problems: The degassing efficiency of the membrane separation method is low and the oil-gas equilibrium time is long; The vacuum degassing requires devices such as a vacuum pump, has high requirements for airtightness, a complex structure, high costs and high failure rates; The mechanical oscillation method has a cumbersome operation process and is not suitable for online systems; The purge-and-trap method cannot recycle the oil sample, the waste oil cannot be directly discharged back to the transformer, and there is a problem of trap failure. Summary of the Invention

[0004] To solve the deficiencies in the above-mentioned existing technical solutions, the present invention provides a transformer monitoring method.

[0005] The object of the present invention is achieved through the following technical solutions:

[0006] A transformer monitoring method, wherein the transformer monitoring method is as follows:

[0007] The multi-way valve is switched, and the pumping unit extracts. The purge gas sequentially passes through the gas pipeline, the first pipeline, the quantitative loop, and the second pipeline and enters the pumping unit:

[0008] The valves on the first pipeline and the second pipeline are closed, and the pumping unit pushes the gas. The purge gas sequentially passes through the third pipeline and the fourth pipeline;

[0009] The pumping unit extracts. In the degassing chamber, gas escapes from the transformer oil and is discharged from the second outlet of the degassing chamber, passing through the first pipeline, the quantitative loop, and the second pipeline in sequence and entering the pumping unit;

[0010] The multi-way valve switches, and the carrier gas pushes the gas in the quantitative loop into the gas analyzer, thereby obtaining the content of the escaped gas.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0012] 1. By adopting the method of full circulation of the oil sample, compared with the non-circulation method, it has a higher gas-phase equilibrium concentration; at the same time, since there is no need to quantify the gas-phase volume and the oil sample volume, there is no need for gas-phase and oil-sample quantification devices, the overall structure is simpler, and the cost is reduced.

[0013] 2. The preheating coil is used to preheat the oil sample in advance, and it can quickly stabilize to the set temperature when entering the oil chamber, so continuous degassing can be carried out without additional heating and temperature control time.

[0014] 3. The heating units in the oil chamber are arranged in a triangular staggered manner, causing the cylinder to flow around when the oil sample flows through, and the vortex shedding caused by the boundary layer separation plays a stirring role. In addition, the hotter surface of the heating unit can be used as a bubble nucleation point, and the formed bubbles quickly rise to the gas-liquid interface and burst under the action of ultrasound.

[0015] 4. The pumping unit plays the role of purging the pipeline and circulating the gas without the need for a circulating gas pump. During degassing, the pumping unit continuously pushes and pulls up and down. During the upward pulling process, the air chamber expands to generate negative pressure, enabling the gas to quickly escape, and finally quickly reaching a dynamic equilibrium with the rich gas oil sample at the bottom.

[0016] 5. The gas detection result is accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Referring to the accompanying drawings, the disclosure of the present invention will become easier to understand. It is easy for those skilled in the art to understand that these drawings are only used to illustrate the technical solutions of the present invention and are not intended to limit the protection scope of the present invention. In the drawings:

[0018] Figure 1 is a schematic flow chart of the transformer monitoring method according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] Figure 1The following description and the accompanying drawings illustrate alternative embodiments of the present invention to teach those skilled in the art how to implement and reproduce the present invention. To explain the technical solutions of the present invention, some conventional aspects have been simplified or omitted. Those skilled in the art should understand that variations or substitutions derived from these embodiments will fall within the scope of the present invention. Those skilled in the art should understand that the following features can be combined in various ways to form multiple variations of the present invention. Thus, the present invention is not limited to the following alternative embodiments, but is defined only by the claims and their equivalents.

[0020] Embodiment 1:

[0021] The transformer monitoring method according to an embodiment of the present invention, as shown in the figure, the transformer monitoring method is as follows:

[0022] The multi-way valve is switched, and the pumping unit extracts. The purge gas sequentially passes through the gas pipeline, the first pipeline, the quantitative loop, and the second pipeline, and enters the pumping unit:

[0023] The valves on the first pipeline and the second pipeline are closed, and the pumping unit pushes the gas. The purge gas sequentially passes through the third pipeline and the fourth pipeline;

[0024] The pumping unit extracts. In the degassing chamber, the gas escapes from the transformer oil, discharges from the second outlet of the degassing chamber, and sequentially passes through the first pipeline, the quantitative loop, and the second pipeline, and enters the pumping unit;

[0025] The multi-way valve is switched, and the carrier gas pushes the gas in the quantitative loop into the gas analyzer, thereby obtaining the content of the escaping gas.

[0026] In order to average the content of the escaping gas, further, the pumping unit extracts, and the gas escaping from the degassing chamber enters the pumping unit; the pumping unit pushes the extracted gas, and the gas enters the second pipeline and the quantitative loop; at the same time, the gas escaping from the degassing chamber enters the pumping unit through the third pipeline in the forward direction; the pumping unit pushes the extracted gas in the reverse direction into the third pipeline.

[0027] In order to achieve pressure balance, further, when the gas escapes from the degassing chamber, the pressure in the first pipeline or the third pipeline is detected;

[0028] If the pressure is less than the atmospheric pressure, gas is injected into the degassing chamber through the gas pipeline so that the pressure in the first pipeline or the third pipeline reaches the atmospheric pressure;

[0029] If the pressure is greater than the atmospheric pressure, the fourth pipeline is connected to the outside so that the pressure in the first pipeline or the third pipeline reaches the atmospheric pressure.

[0030] In order to achieve continuous detection, further, the transformer oil circulates between the degassing chamber and the transformer, enters the degassing chamber from the first inlet, and is discharged from the first outlet, and the liquid level in the degassing chamber remains stable.

[0031] In order to improve the accuracy of gas detection, further, the calculation method of the gas content C in the transformer oil is as follows:

[0032] k is a coefficient, λ is the degree of equilibrium, G is the volume of the pipeline connected to the second outlet and the quantitative loop, L is the volume of the transformer oil in the degassing chamber, q is the flow rate of the transformer oil entering the degassing chamber, t is the time required for the pumping unit to extract and push out the escaped gas once, C0 is the gas content output by the gas analyzer, and the way to obtain λ is:

[0033] Perform degassing equilibrium on the standard transformer oil with a known concentration C under the condition that the parameters G, L, q, and t are determined, and obtain the degree of equilibrium λ according to the gas content C0 output by the gas analyzer.

[0034] In order to increase the gas escape speed, further, use heating and / or ultrasonic vibration to promote the escape of gas from the transformer oil; multiple heaters are vertically arranged at the bottom of the degassing chamber and are arranged in a triangular staggered pattern; the transformer oil is preheated before entering the degassing chamber.

[0035] Embodiment 2:

[0036] An application example of the transformer monitoring method according to Embodiment 1 of the present invention.

[0037] In this application example, as Figure 1 shown, the transformer monitoring method is:

[0038] Under the action of the first pump and the second pump, the oil in the transformer flows through the heater, the first pump, the degassing chamber, and the second pump in sequence, and then returns to the transformer; the degassing chamber includes a container, a heating rod, and an ultrasonic vibrator. The cylindrical heating rod is vertically arranged at the bottom of the container and is arranged in a triangular staggered pattern; the ultrasonic vibrator is arranged on the lower side outside the container; a liquid level sensor is arranged in the container, and by adjusting the first pump and the second pump, the liquid level in the container is made stable;

[0039] The multi-way valve is switched, and the pumping unit extracts. The purge gas sequentially passes through the gas pipeline, the first pipeline, the quantitative loop, and the second pipeline and enters the pumping unit, realizing the cleaning of the quantitative loop: the pumping unit includes a cylinder, a piston, and a driving module, and the driving module drives the piston to move bidirectionally in the cylinder;

[0040] Close the valves on the first pipeline and the second pipeline, and the pumping unit pushes the gas. The purge gas sequentially passes through the third pipeline and the fourth pipeline and is discharged to the outside from the fourth pipeline;

[0041] The pumping unit extracts. Inside the degassing chamber, the heating rod heats and the ultrasonic oscillator operates. Gas escapes from the transformer oil and is discharged from the second outlet of the degassing chamber, passing through the first pipe, the sampling loop, and the second pipe in sequence, and through the third pipe. The two flow paths enter the pumping unit;

[0042] The pumping unit pumps repeatedly for multiple times;

[0043] The pressure sensor detects the pressure in the first pipe. If the pressure is lower than the atmospheric pressure, the gas pipe is opened to introduce purging nitrogen, and it is closed after reaching the atmospheric pressure. If the pressure is higher than the atmospheric pressure, part of the gas is discharged through the fourth pipe, and it is closed after reaching the atmospheric pressure, so as to achieve pressure balance;

[0044] After the pressure balance, the multi-way valve is switched. The carrier gas pushes the gas in the sampling loop into the chromatographic column for separation, and finally it is sent to the detector for detection, so as to obtain the content C of the escaped gas 0 ;

[0045] The calculation method of the content C of the gas in the transformer oil is as follows:

[0046] k is a coefficient, λ is the degree of equilibrium, G is the volume of the pipe connected to the second outlet and the sampling loop, L is the volume of the transformer oil in the degassing chamber, q is the flow rate of the transformer oil entering the degassing chamber, t is the time required for the pumping unit to extract and push the escaped gas once. The way to obtain λ is:

[0047] The standard transformer oil with a known concentration C is degassed and balanced under the condition that the parameters G, L, q, and t are determined, and the gas content C output by the gas analyzer is used 0 to obtain the degree of equilibrium λ.

Claims

1. Transformer monitoring method, the transformer monitoring method is as follows: The multi-way valve is switched, and the pumping unit extracts. The purge gas sequentially passes through the gas pipeline, the first pipeline, the quantitative loop, and the second pipeline and enters the pumping unit: The valves on the first pipeline and the second pipeline are closed, and the pumping unit pushes the gas. The purge gas sequentially passes through the third pipeline and the fourth pipeline; The pumping unit extracts. In the degassing chamber, the gas escapes from the transformer oil and is discharged from the second outlet of the degassing chamber, sequentially passes through the first pipeline, the quantitative loop, and the second pipeline, and enters the pumping unit; The multi-way valve is switched, and the carrier gas pushes the gas in the quantitative loop into the gas analyzer, so as to obtain the content C of the evolved gas 0 ; The content C of the gas in the transformer oil is: , where k is a coefficient, λ is the degree of balance, G is the volume of the pipeline connected to the second outlet and the quantitative loop, L is the volume of transformer oil in the degassing chamber, q is the flow rate of the transformer oil entering the degassing chamber, and t is the time required for the pumping unit to extract and push out the escaped gas once.

2. The transformer monitoring method according to claim 1, characterized in that the pumping unit extracts, and the gas escaping from the degassing chamber enters the pumping unit; the pumping unit pushes the extracted gas, and the gas enters the second pipeline and the quantitative loop.

3. The transformer monitoring method according to claim 2, characterized in that the pumping unit extracts, and the gas escaping from the degassing chamber enters the pumping unit in the forward direction through the third pipeline; the pumping unit pushes the extracted gas and enters the third pipeline in the reverse direction.

4. The transformer monitoring method according to claim 1, characterized in that when the gas escapes in the degassing chamber, the pressure in the first pipeline or the third pipeline is detected; if the pressure is less than the atmospheric pressure, the gas pipeline is used to inject gas into the degassing chamber so that the pressure in the first pipeline or the third pipeline reaches the atmospheric pressure; if the pressure is greater than the atmospheric pressure, the fourth pipeline is used to communicate with the outside so that the pressure in the first pipeline or the third pipeline reaches the atmospheric pressure.

5. The transformer monitoring method according to claim 1, characterized in that the transformer oil circulates between the degassing chamber and the transformer, enters the degassing chamber from the first inlet, and is discharged from the first outlet, and the liquid level in the degassing chamber remains stable.

6. The transformer monitoring method according to claim 1, characterized in that the way to obtain λ is: Degas and balance a standard transformer oil with a known concentration C under the condition that parameters G, L, q, and t are determined, and obtain the equilibrium degree λ according to the gas content C output by the gas analyzer. 0 , and obtain the equilibrium degree λ.

7. The transformer monitoring method according to claim 1, characterized in that the gas in the transformer oil is promoted to escape by means of heating and / or ultrasonic vibration.

8. The transformer monitoring method according to claim 1, characterized in that a plurality of heaters are vertically arranged at the bottom of the degassing chamber and are arranged in a triangular staggered pattern.

9. The transformer monitoring method according to claim 1, characterized in that the transformer oil is preheated before entering the degassing chamber.

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