Special Precision Oil Sampling Valve Device for Multifunctional On-Load Tap Changer of Transformer

Abstract

The present invention discloses a special precise oil sampling valve device for a multi-functional on-load tap-changer of a transformer. The structure of the oil sampling valve device is a valve body with an inlet flange and an outlet flange. A valve is arranged in the valve body on the side of the outlet flange. A valve control handle is arranged on the upper part of the valve body. First and second oil discharge valves are arranged on the front side wall of the valve body chamber, and a protective cap is installed on its outlet. Two bent oil pipes are respectively connected to the inlets of the first and second oil discharge valves. The valve body is connected to the external oil extraction pipe of the tap-changer through its inlet flange. The inlets of the two bent oil pipes are connected to the first and second oil extraction pipes located in the external oil extraction pipe. The first and second oil extraction pipes are arranged in the internal oil extraction pipe through the external oil extraction pipe, and the pipe orifice of the internal oil extraction pipe is located at the bottom of the switch oil chamber. The structure of the present invention is reasonable, the operation is convenient, safe and reliable, which can ensure accurate oil sampling, prevent the mixing of sundries and moisture during sampling, reduce the discharge amount of invalid oil samples, and avoid the waste of oil products.

Description

Technical Field

[0001] The invention belongs to the improvement of the structure of an oil sampling device for a transformer off-load tap-changer oil chamber, and particularly relates to a special precise oil sampling valve device for a multi-functional on-load tap-changer of a transformer. Background Art

[0002] At present, transformer oil is still used as the cooling and insulating medium for on-load tap-changers of transformers. When the on-load tap-changer is in operation, phenomena such as water ingress or oil quality deterioration may occur, which will reduce the insulation level of the tap-changer. In severe cases, it may cause the on-load switch to burn out and even affect the safety of the power grid. Therefore, it is crucial to regularly detect the quality of the transformer oil in the oil chamber of the on-load tap-changer. Article 9.4.4 of the 18 anti-measures of the State Grid clearly stipulates that the on-load tap-changer of the transformer needs to regularly detect the oil sample in the oil chamber, and the detection cycle and items are the same as those of the transformer body to prevent accidents.

[0003] According to the regulations of the 18 anti-measures of the State Grid, the oil of the on-load tap-changer cannot be sampled from the oil inlet. Therefore, at present, the on-load tap-changer samples oil through a drain hole connected to an oil extraction pipe, extracts the oil sample at the bottom of the oil chamber of the on-load tap-changer, the inner pipe of the oil extraction pipe extends deep into the bottom of the switch oil chamber, and the outer pipe of the oil extraction pipe is connected to a ball valve. In order to obtain an effective oil sample, it is necessary to first discharge the invalid oil samples in the inner and outer pipes of the oil extraction pipe of the on-load tap-changer. This method will first cause a large amount of oil waste. The inner diameter of the oil extraction pipe of the on-load tap-changer is about 25 mm, and the total length of the inner and outer pipes is about 2.5 m. Each time an oil sample is extracted, about 1.23 L of invalid oil sample will be generated (V = πr²h). The on-load switch needs to extract oil samples 2 - 3 times a year. After multiple oil samplings, not only will a large amount of oil be wasted, but the switch also needs to be powered off on-site to replenish oil, causing inconvenience in work. Secondly, it has relatively high requirements for the technical level and responsibility of the sampling personnel. Since the oil extraction port and the drain hole are external and the surface is dirty, sundries and moisture will be mixed in during sampling. At the same time, since the inner pipe orifice of the oil extraction pipe of the on-load tap-changer is at the bottom of the oil chamber, only the oil sample at the bottom of the switch oil chamber can be obtained during oil sampling, and the oil sample in the middle of the switch oil chamber cannot be obtained. Therefore, objectively, it is easy to cause inaccurate sampling. Thirdly, if the oil sampling personnel operate irregularly or have weak responsibility, it will not only affect the accuracy of the oil sample, but also cause more oil sample waste. Finally, since transformer oil is harmful to the environment and human health, if the oil sampling personnel handle the invalid oil samples improperly, a large amount of invalid transformer oil may cause serious environmental protection problems. In addition, for the method of sampling oil using an on-line oil sampling device for the on-load tap-changer, there may be safety risks due to the need for on-site live operation. Summary of the Invention

[0004] The object of the present invention is to provide a special precise oil sampling valve device for a multi-functional on-load tap-changer of a transformer, which has a reasonable structure, is convenient, safe and reliable to operate, can ensure accurate and true oil sampling, prevent the mixing of sundries and moisture during sampling, reduce the discharge amount of invalid oil samples, avoid waste of oil products, and reduce the power-off oil replenishment work for the oil chamber of the on-load tap-changer.

[0005] The object of the present invention is achieved as follows: A special precise oil sampling valve device for a multi-functional on-load tap-changer of a transformer includes a tap-changer arranged on the transformer. The tap-changer is provided with a switch oil chamber. An inner oil extraction pipe arranged in the switch oil chamber is connected to an outer oil extraction pipe located outside the switch oil chamber and the transformer. The structure of the oil sampling valve device is a valve body with an inlet flange and an outlet flange. A valve is arranged in the valve body on the side of the outlet flange. A valve control handle is arranged on the upper part of the valve body. First and second drain valves are arranged on the front side wall of the valve body chamber on the side of the inlet flange, and protective caps are respectively installed on their outlets. The inlets of the first and second drain valves are respectively connected to two bent oil pipes located in the valve body chamber. The valve body is connected to the outer oil extraction pipe of the tap-changer through its inlet flange. The inlets of the two bent oil pipes are respectively connected to first and second oil extraction pipes located in the outer oil extraction pipe. The first and second oil extraction pipes are respectively arranged in the inner oil extraction pipe through the outer oil extraction pipe. The pipe orifice of the inner oil extraction pipe is located at the bottom of the switch oil chamber. Among them, the pipe orifices of the first and second oil extraction pipes located in the inner oil extraction pipe are respectively located in the middle and at the bottom of the inner oil extraction pipe.

[0006] A ball valve is arranged on one side of the valve body of the oil sampling valve device of the present invention. Two drain valves and two oil extraction pipes are arranged in the chamber on the other side of the valve body. The two drain valves are arranged on the side of the oil inlet of the ball valve and are equipped with protective caps. The two oil extraction pipes respectively connected to the two drain valves penetrate into the oil extraction pipe of the on-load tap-changer and extend to the bottom and middle of the inner pipe of the oil extraction pipe in the oil chamber of the on-load tap-changer. Since the oil in the on-load tap-changer is always in a positive pressure environment, when taking an oil sample, the protective cap is removed and the drain valve is opened, and the oil in the switch can flow out through the oil extraction pipe with an inner diameter of 3 mm, avoiding the entry of external moisture and impurities and ensuring the accuracy of the oil sample; since the positions of the two oil extraction pipes are respectively at the bottom and middle of the switch oil chamber, the taken oil sample can more truly reflect the state of the oil in the switch oil chamber; since the total volume of the oil extraction pipes is much smaller than that of the oil extraction pipe, the discharge amount of invalid oil samples can be greatly reduced, avoiding a large amount of waste of oil products and on-site environmental protection risks; reducing the technical requirements for oil sampling personnel and avoiding inaccurate oil samples, waste of oil products and environmental protection risks caused by non-standard operations; avoiding safety risks brought by on-site power connection; at the same time, the present invention is installed once and maintenance-free for life, and can retain the original functions of the oil extraction pipe and the ball valve of the on-load tap-changer.

[0007] The present invention is designed with an oil drain valve. The oil extraction pipe connected to the oil drain valve extends into the middle and bottom of the oil extraction pipe of the on-load tap-changer, which can solve problems existing in the prior art such as the accuracy of oil samples, waste of oil products, environmental protection, safety, and high technical requirements for oil sampling technology.

[0008] Since the oil chamber of the on-load tap-changer is always in a positive pressure environment, when the oil drain valve on the valve body is opened, the oil sample can flow out through the oil extraction pipe to achieve the function of oil sampling, that is, the oil sample valve switch on the valve body is only opened to immediately obtain the oil sample, reducing the operation difficulty of technicians.

[0009] The two oil extraction pipes provided in the present invention penetrate into the oil extraction pipe of the on-load tap-changer and respectively extend into the middle and bottom of the oil chamber of the on-load tap-changer, and can respectively obtain the oil samples in the middle and bottom of the oil chamber, ensuring the comprehensiveness and accuracy of the oil samples. The two oil extraction pipes are nylon pipes, with a diameter of only 3 mm and a maximum length of about 2.5 m (taking a 110 kV transformer as an example). Each time, for each 110 kV transformer, the oil samples extracted through the two oil extraction pipes will only produce about 0.04 L of invalid oil samples (V = πr²h × 2). Compared with the traditional oil sampling method (the inner diameter of the oil extraction pipe is 25 mm, and the invalid oil sample reaches 1.23 L per unit), 1.19 L of invalid oil samples can be saved each time (the actual amount saved during actual operation will be 2 - 3 times this amount). Currently, about 200,000 transformers are newly put into operation in the country every year. According to the traditional oil sampling method, about 440.34 tons of oil products are wasted every year (0.895 oil density × 1.23 L × 200,000 units × 2 times / year). The present invention can reduce the emission of 426.02 tons of invalid oil samples every year (0.895 oil density × 1.19 L × 200,000 units × 2 times / year), greatly reducing the waste of oil products and environmental protection problems caused by improper treatment of invalid oil samples. It reduces the technical requirements for oil sampling personnel, avoiding inaccurate oil samples, waste of oil products, and environmental protection risks caused by non-standard operations; avoiding safety risks brought by on-site power connection. In addition to being able to reduce the emission of transformer oil to achieve energy-saving and environmental protection effects, it also avoids the power outage oil replenishment work increased due to the reduction of oil in the oil chamber of the on-load tap-changer.

[0010] The oil drain valve is equipped with a protective cap, which can protect the valve orifice of the oil drain valve from pollution, ensuring the authenticity and accuracy of the extracted oil sample. The installation and maintenance method of the 25 ball valve is simple, and it can be installed once and maintained for life. And it can retain the original functions of the oil extraction pipe of the on-load tap-changer and the ball valve.

[0011] The oil extraction pipe is made of nylon material, with good flexibility, anti-twisting, can withstand heavy pressure, does not break, does not deform, and can quickly recover. At the same time, it also has the characteristics of being acid-resistant, resistant to transformer oil, coolant, etc., and is applicable to an ambient temperature of -40°C to +120°C. Nylon materials are also widely used for the accessories in the oil chamber of the on-load tap-changer to ensure oil resistance and safety, without any impact on the safe operation of the on-load tap-changer.

[0012] The structure of the present invention is reasonable, easy to operate, safe and reliable, ensuring accurate and real oil sampling, preventing the mixing of impurities and moisture during sampling, reducing the discharge of invalid oil samples, avoiding waste of oil products, and reducing the power-off oil replenishment work for the on-load tap-changer oil chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present invention will be further described below in conjunction with the drawings. Figure 1 It is a schematic structural diagram of the oil sampling valve device. Figure 2 It is a front view structural schematic diagram of the oil sampling valve. Figure 3 It is Figure 2 a partial top view sectional structural schematic diagram of Figure 4 It is Figure 3 an enlarged structural schematic diagram of the oil drain valve in Figure 5 It is a schematic structural diagram of the present invention installed on a transformer. Figure 6 It is Figure 5 a top view structural schematic diagram of DETAILED DESCRIPTION OF THE EMBODIMENTS

[0014] A special precise oil sampling valve device for a transformer multi-functional on-load tap-changer, as shown in Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6As shown in the figure, it includes a tap changer provided on a transformer 1. The tap changer is provided with a switch oil chamber 2. An oil extraction inner pipe 5 provided in the switch oil chamber 2 is connected to an oil extraction outer pipe 4 located outside the switch oil chamber 2 and the transformer 1. The structure of the oil sampling valve device 3 is a valve body 8 with an inlet flange 9 and an outlet flange 10. A valve is provided in the valve body 8 on the side of the outlet flange 10. A valve control handle 11 is provided on the upper part of the valve body 8. First and second drain valves 12, 13 are provided on the front side wall of the valve body chamber on the side of the inlet flange 9. Protective caps 15 are respectively installed on their outlets. Two bent oil pipes 14 located in the valve body chamber are respectively connected to the inlets of the first and second drain valves 12, 13. The valve body 8 is connected to the tap changer oil extraction outer pipe 4 through its inlet flange 9. The inlets of the two bent oil pipes 14 are respectively connected to the first and second oil extraction pipes 6, 7 located in the oil extraction outer pipe 4. The first and second oil extraction pipes 6, 7 are respectively arranged in the oil extraction inner pipe 5 through the oil extraction outer pipe 4. The pipe orifice of the oil extraction inner pipe 5 is located at the bottom of the switch oil chamber 2. Among them, the pipe orifices of the first and second oil extraction pipes 6, 7 located in the oil extraction inner pipe 5 are respectively located in the middle and at the bottom of the oil extraction inner pipe 5. When the protective cap 15 is removed and the drain valve handle 16 is opened, since the switch oil chamber is always in a positive pressure environment, the oil sample will flow out through the oil extraction pipe, achieving the purpose of taking the oil sample. After discharging about 0.02 L of invalid oil sample (taking a 110 kV transformer as an example, the discharged invalid oil sample is slightly different for different transformer voltage levels), the accuracy of the obtained oil sample can be ensured. After taking the oil sample, close the drain valve handle 16 and cover the protective cap 15 to avoid contamination of the valve orifice of the drain valve and ensure the accuracy of the oil sample when taking the oil sample next time. Drain valve handles 16 are respectively provided on the first and second drain valves 12, 13. The first and second oil extraction pipes 6, 7 are both composed of nylon pipes. The outer diameter of the nylon pipe is 4 mm and the inner diameter is 3 mm. The connection flange of the inlet flange 9 of the valve body and the tap changer oil extraction outer pipe 4 is connected by 4 bolts with a diameter of φ12 mm. The valve provided in the valve body 8 is a ball valve with a diameter of 25 mm.

[0015] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claimed rights.

Claims

1. A special precise oil sampling valve device for a multi-functional on-load tap-changer of a transformer, comprising a tap-changer arranged on the transformer (1), the tap-changer being provided with a switch oil chamber (2), an inner oil extraction pipe (5) arranged in the switch oil chamber (2) being connected to an outer oil extraction pipe (4) located outside the switch oil chamber (2) and the transformer (1), a valve control handle (11) being arranged on the upper part of the valve body (8), characterized in that: The structure of the oil sampling valve device (3) is a valve body (8) with an inlet flange (9) and an outlet flange (10). A valve is arranged inside the valve body (8) on the side of the outlet flange (10). The first and second oil drain valves (12, 13) are arranged on the front side wall of the valve body chamber on the side of the inlet flange (9), and protective caps (15) are respectively installed on their outlets. The inlets of the first and second oil drain valves (12, 13) are respectively connected to two bent oil pipes (14) located inside the valve body chamber. The valve body (8) is connected to the tapping switch oil extraction outer pipe (4) through its inlet flange (9). The inlets of the two bent oil pipes (14) are respectively connected to the first and second oil extraction pipes (6, 7) located inside the oil extraction outer pipe (4). The first and second oil extraction pipes (6, 7) are respectively arranged inside the oil extraction inner pipe (5) through the oil extraction outer pipe (4). The pipe orifice of the oil extraction inner pipe (5) is located at the bottom of the switch oil chamber (2). Among them, the pipe orifices of the first and second oil extraction pipes (6, 7) located inside the oil extraction inner pipe (5) are respectively located in the middle and at the bottom of the oil extraction inner pipe (5). The first and second oil extraction pipes (6, 7) are both made of nylon pipes. The outer diameter of the nylon pipe is 4 mm, and the inner diameter is 3 mm. The valve arranged inside the valve body (8) is a ball valve, and its diameter is 25 mm.

2. The special precise oil sampling valve device for the multi-functional on-load tap-changer of a transformer according to claim 1, characterized in that: Oil drain valve handles (16) are respectively arranged on the first and second oil drain valves (12, 13).

3. The special precise oil sampling valve device for the multi-functional on-load tap-changer of a transformer according to claim 1, characterized in that: The connection flange between the inlet flange (9) of the valve body and the tapping switch oil extraction outer pipe (4) is connected by 4 bolts of φ12 mm.

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