Vacuum oil injection system of transformer

Abstract

The invention provides a transformer vacuum oil injection system which comprises a transformer, an oil injection device and a vacuum unit, an oil injection port is formed in the bottom of the transformer, and the oil injection port is communicated with the oil injection device through a pipeline; an extraction opening is formed in the top of the transformer and is communicated with the vacuum unit through a pipeline; a negative pressure tank is arranged on a vacuum pipeline between the transformer and the vacuum unit in series, and the designed negative pressure bearing capacity of the negative pressure tank is not lower than 133 Pa. The safety protection device has the beneficial effects that the high-strength negative pressure tank is connected in series with the vacuum pipeline between the transformer and the vacuum unit, so that a key safety barrier is constructed. And a high-value vacuum unit can be protected from being damaged by oil invasion. In the vacuumizing process, a trace amount of transformer oil possibly volatilized in the transformer or oil liquid generated suddenly can be effectively captured and contained by the negative pressure tank and is prevented from directly entering the vacuum pump, and therefore pump oil pollution and damage to elements in a pump body are prevented.

Description

Technical Field

[0001] This invention relates to the field of transformer technology, and more specifically to a transformer vacuum oil injection system. Background Technology

[0002] Vacuum transformers specifically refer to large power transformers that employ vacuum on-load tap changers, and are key equipment for achieving stable voltage regulation in modern power grids. Their core working principle lies in using a tap changer with a built-in vacuum arc-extinguishing chamber installed within the sealed transformer tank. During the switching of transformer winding taps to change the turns ratio, the superior insulation and arc-extinguishing properties of the high-vacuum environment rapidly extinguish the electric arc. This design effectively avoids the flammable gases and carbon particles produced by the arc decomposition of insulating oil in traditional oil-immersed switches, significantly improving operational reliability and safety, and greatly reducing maintenance requirements. Therefore, vacuum transformers are widely used in power transmission and distribution systems with extremely high requirements for power quality and equipment reliability.

[0003] However, a common and challenging problem encountered during routine maintenance and troubleshooting of this equipment is that vacuum units used for evacuating transformer tanks or tap changer rooms are prone to back-drawing insulating oil from inside the transformer. This problem mainly stems from deviations in operating procedures or abnormal equipment conditions: when the insulating oil level in the transformer tank fails to drop below the vacuum line interface, or when the vacuum unit is shut down in the wrong sequence, the oil will be back-drawn into the internal cavity of the vacuum pump and its associated exhaust pipe due to the pressure difference between the inside and outside of the system. Furthermore, if the oil-gas separator of the vacuum unit is ineffective or malfunctions, failing to effectively separate the entrained oil vapor, liquid oil will also accumulate and infiltrate the pump body.

[0004] Ingesting insulating oil into a vacuum pump unit will trigger a series of serious, cascading negative consequences. First, for the vacuum pump unit itself, the mixing of insulating oil with the vacuum pump oil drastically alters the pump oil's viscosity and saturated vapor pressure, causing a sharp drop in its pumping performance. This results in the inability to achieve the required ultimate vacuum, and may even lead to direct damage such as pump rotor seizure and motor overload burnout. Second, for the transformer being maintained, the contaminated vacuum pump oil will produce oil vapor. These contaminants may diffuse back into the purified oil tank through the vacuum pipeline, causing secondary contamination of the transformer's insulating oil, increasing dielectric loss, and thus jeopardizing the integrity of the entire transformer insulation system. Ultimately, this not only leads to high maintenance costs but also significantly extends transformer downtime for maintenance, severely impacting the reliability and economy of the power grid. Summary of the Invention

[0005] To address the issue that vacuum units used for evacuating transformer tanks are prone to reverse-flowing insulating oil from inside the transformer; This invention provides a transformer vacuum oil injection system, including a transformer, an oil injection device, and a vacuum unit. The transformer has an oil injection port at its bottom, which is connected to the oil injection device via a pipe. The transformer has an air extraction port at its top, which is connected to the vacuum unit via a pipe. A negative pressure tank is connected in series on the vacuum pipeline between the transformer and the vacuum unit. The negative pressure tank is designed to bear a negative pressure of not less than 133 Pa. An air inlet pipe is provided on the side of the negative pressure tank, which is connected to the air extraction port on the top of the transformer through a pipe. An air outlet pipe is provided on the top of the negative pressure tank, which is connected to the air extraction port of the vacuum unit through a pipe.

[0006] As a preferred embodiment, the negative pressure tank is equipped with a level gauge for real-time monitoring of the liquid accumulation height inside the tank.

[0007] As a preferred embodiment, a solenoid valve is installed on the air intake pipe. The solenoid valve is electrically connected to the level gauge via a signal line, receives its signal, and automatically opens or closes the air intake passage accordingly.

[0008] As a preferred embodiment, an air filter is installed at the front end of the vacuum unit's air extraction port to prevent impurities from being drawn into the vacuum unit.

[0009] As a preferred embodiment, the lowest point of the negative pressure tank is provided with an oil drain pipe and equipped with a valve for draining any accumulated oil or purging the system during maintenance.

[0010] As a preferred embodiment, the top of the negative pressure tank is also provided with a vacuum test port for connecting an external vacuum gauge to accurately detect the vacuum level inside the tank.

[0011] As a preferred embodiment, the oil injection device employs a high-vacuum oil filter, which can operate normally in a high-vacuum environment and simultaneously perform precise filtration and oil injection operations on the insulating oil.

[0012] The beneficial effects of this invention are as follows: 1. This invention constructs a critical safety barrier by connecting a high-strength negative pressure tank in series on the vacuum pipeline between the transformer and the vacuum unit. This protects the high-value vacuum unit from damage caused by oil intrusion. During the vacuuming process, trace amounts of transformer oil that may evaporate from the transformer or suddenly generated oil are effectively captured and contained by the negative pressure tank, preventing them from directly entering the vacuum pump. This prevents pump oil contamination, damage to internal pump components, and a sharp decline in performance, significantly extending the service life of the vacuum unit and reducing maintenance costs.

[0013] 2. The level gauge installed inside the negative pressure tank in this invention can monitor the accumulated oil level in real time. When the liquid level reaches a preset warning value, the level gauge will immediately send a signal to automatically close the solenoid valve on the air inlet pipeline. This action quickly disconnects the negative pressure tank from the transformer, effectively preventing more oil from entering the tank while also isolating the vacuum unit, allowing it to continue operating safely or shut down under safe conditions. This represents a leap from passive acceptance to active interception, greatly improving the automation level and safety reliability of the entire system. Attached Figure Description

[0014] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein... Figure 1 This is a schematic diagram of the structure of the present invention.

[0015] Figure 2 This is a schematic diagram of the negative pressure tank of the present invention.

[0016] The numbers in the attached diagram are: 1. Transformer; 11. Oil inlet; 12. Air outlet; 2. Oil filling device; 3. Vacuum unit; 4. Negative pressure tank; 41. Air inlet pipe; 42. Air outlet pipe; 43. Oil drain pipe; 44. Liquid level gauge; 45. Solenoid valve; 46. Vacuum test port; 47. Sight glass. Detailed Implementation

[0017] To illustrate the features of the present invention, the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0018] Example: Please see Figures 1 to 2 This embodiment provides a transformer vacuum oil injection system, the specific structure of which is described below: The system includes a transformer 1, an oil filling device 2, and a vacuum unit 3. An oil filling port 11 is located at the bottom of the transformer 1, and this port is connected to the oil filling device 2 via a pipe. In this embodiment, the oil filling device 2 is a high-vacuum oil filter, which can operate normally in a high-vacuum environment and simultaneously perform precise filtration and oil filling operations on the insulating oil. An air extraction port 12 is located at the top of the transformer 1, and this port is connected to the vacuum unit 3 via a pipe.

[0019] A negative pressure tank 4 is connected in series in the vacuum pipeline between transformer 1 and vacuum unit 3. The negative pressure tank 4 is designed to withstand a negative pressure of not less than 133 Pa. An air inlet pipe 41 is provided on the side of the negative pressure tank 4, which is connected to the air extraction port 12 on the top of transformer 1 via a pipe. An air outlet pipe 42 is provided on the top of the negative pressure tank 4, which is connected to the air extraction port of vacuum unit 3 via a pipe. An air filter is installed at the front end of the air extraction port of vacuum unit 3 to prevent impurities from being drawn into the vacuum unit.

[0020] The negative pressure tank 4 is equipped with a level gauge 44 for real-time monitoring of the liquid accumulation level inside the tank. A solenoid valve 45 is installed on the air inlet pipe 41, which is electrically connected to the level gauge 44 via a signal line, receiving its signal and automatically opening or closing the air inlet passage accordingly. An oil drain pipe 43 is located at the lowest point of the bottom of the negative pressure tank 4. This drain pipe 43 is equipped with a valve for draining any accumulated oil or purging the system during maintenance. A vacuum test port 46 is also provided at the top of the negative pressure tank 4 for connecting an external vacuum gauge to accurately detect the vacuum level inside the tank, and an observation mirror 47 for observing the liquid level is provided on the side.

[0021] The system provides additional negative pressure buffer and oil collection function during the transformer vacuum oil injection process through the setting of negative pressure tank 4. With the automatic control of level gauge 44 and solenoid valve 45, it effectively prevents oil from entering the vacuum unit and ensures the safe and stable operation of the system.

[0022] The above embodiments and accompanying drawings are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. The present invention has been described in detail with reference to preferred embodiments. Those skilled in the art should understand that any changes, modifications, additions, or substitutions made by those skilled in the art within the scope of the present invention do not depart from the spirit of the present invention and should also fall within the protection scope of the claims of the present invention. Other related technical structures not disclosed in detail in the present invention are existing technologies in the art.

Claims

1. A transformer vacuum oil injection system, comprising a transformer (1), an oil injection device (2), and a vacuum unit (3), wherein the transformer (1) has an oil injection port (11) at its bottom, which is connected to the oil injection device (2) via a pipe; and the transformer (1) has an air extraction port (12) at its top, which is connected to the vacuum unit (3) via a pipe; characterized in that: A negative pressure tank (4) is connected in series on the vacuum pipeline between the transformer (1) and the vacuum unit (3). The negative pressure tank (4) is designed to bear a negative pressure of not less than 133 Pa. An air inlet pipe (41) is provided on the side of the negative pressure tank (4). The air inlet pipe (41) is connected to the air extraction port (12) on the top of the transformer (1) through a pipe. An air outlet pipe (42) is provided on the top of the negative pressure tank (4). The air outlet pipe (42) is connected to the air extraction port of the vacuum unit (3) through a pipe.

2. The transformer vacuum oil injection system according to claim 1, characterized in that: The negative pressure tank (4) is equipped with a level gauge (44) for real-time monitoring of the liquid accumulation height inside the tank.

3. The transformer vacuum oil injection system according to claim 2, characterized in that: A solenoid valve (45) is installed on the air intake pipe (41). The solenoid valve (45) is electrically connected to the liquid level gauge (44) through a signal line, receives its signal, and automatically opens or closes the air intake passage accordingly.

4. The transformer vacuum oil injection system according to claim 1, characterized in that: The vacuum unit (3) is equipped with an air filter at the front end of the air extraction port to prevent impurities from being drawn into the vacuum unit.

5. The transformer vacuum oil injection system according to claim 1, characterized in that: The lowest point of the negative pressure tank (4) is provided with an oil drain pipe (43) and a valve, which is used to drain any possible oil accumulation or to drain the system during maintenance.

6. The transformer vacuum oil injection system according to claim 1, characterized in that: The top of the negative pressure tank (4) is also provided with a vacuum test port (46) for connecting an external vacuum gauge to accurately detect the vacuum level inside the tank; an observation mirror (47) for observing the liquid level is provided on the side.

7. The transformer vacuum oil injection system according to claim 1, characterized in that: The oil injection device (2) uses a high vacuum oil filter to simultaneously perform precision filtration and oil injection operations on the insulating oil.

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