Contact anti-oxidation sulfur hexafluoride gas density relay

Abstract

The utility model provides a contact anti-oxidation sulfur hexafluoride gas density relay, which comprises a machine core, a spring tube, a temperature compensating plate, an electric contact and a sealing shell, and is characterized in that the machine core, the spring tube, the temperature compensating plate and the electric contact are positioned in the sealing shell; the pressure interface end is communicated with the interior of the spring tube and the exterior of the sealing shell; and industrial high-purity nitrogen is filled in a cavity outside the spring tube in the sealed shell. The sulfur hexafluoride gas density relay solves the problems that in the prior art, after a sulfur hexafluoride gas density relay runs for several years, the contact resistance of an electric contact is increased, and moisture condensation occurs in a sealed cavity in a low-temperature environment.

Description

Technical Field

[0001] The utility model relates to the technical field of UHV power transmission and transformation equipment, in particular to a sulfur hexafluoride gas density relay with anti-oxidation contacts. Background Art

[0002] Sulfur hexafluoride gas density relays are widely used in sulfur hexafluoride high-voltage and extra-high-voltage electrical equipment such as circuit breakers, instrument transformers, transformers, and pipe busbars. The density value is an important indicator of the insulating and arc-extinguishing performance of sulfur hexafluoride gas. How to accurately and reliably monitor on-site and online is related to the safety and maintenance of the operation of high-voltage power grids and involves the protection of the natural environment on which humans depend for survival.

[0003] The mechanical unit of the existing sulfur hexafluoride gas density relay consists of four major components: a bellows, a temperature compensation piece, a movement, and electrical contacts. Among them: a) The function of the movement is to convert the displacement of the end of the bellows into an angular displacement, so that the pointer assembled on the movement indicates the measured sulfur hexafluoride gas density value P20. The performance and state of the electrical contact hairspring in the movement directly affect the measurement accuracy of the sulfur hexafluoride gas density relay; b) The function of the electrical contacts is to send a switch signal for contact conduction when the sulfur hexafluoride gas density P20 drops to a set value. The size of the contact resistance of the electrical contact conductive needle will affect the transmission of the switch signal of the density relay.

[0004] The medium filled in the cavity of the existing sulfur hexafluoride gas density relay is the air in nature. a) Since the oxygen content in the air is 21%, an oxide layer will form on the surface of the electrical contact conductive needle in the normally open state exposed to the air over time, increasing the surface resistance. When the sulfur hexafluoride gas density P20 drops to the set value, a small current passing through the two already contacted conductive needles will show a non-conductive phenomenon; b) The enclosed air in the cavity is formed during the assembly and calibration process at a temperature of 20 ± 1°C and a relative humidity of 40 - 50% rh. When the ambient temperature is lower than a certain temperature value, the air in the cavity begins to condense. When the dew drops condense between the electrical contact conductive needles, it will affect the output of the electrical contact signal; when the dew drops fall on the hairspring of the movement or the hairspring of the electrical contacts, it will reduce the indication and control accuracy of the sulfur hexafluoride gas density relay; when the dew drops adsorb on the glass window, it will prevent people from observing the indicated value.

[0005] Therefore, it is urgent to solve the problems of increased contact resistance of electrical contacts and condensation in the cavity under low-temperature environments after the sulfur hexafluoride gas density relay has been in operation for several years. Summary of the Utility Model

[0006] The purpose of the present utility model is to provide a sulfur hexafluoride gas density relay with anti-oxidation contacts, mainly to solve the problems existing in the above-mentioned prior art, that is, after the sulfur hexafluoride gas density relay operates for several years, the contact resistance of the electrical contacts increases and condensation appears in the cavity under low-temperature environments.

[0007] To achieve the above purpose, the technical solution adopted by the present utility model is: a sulfur hexafluoride gas density relay with anti-oxidation contacts, including a movement, a bourdon tube, a temperature compensation piece and electrical contacts, characterized in that: the sulfur hexafluoride gas density relay with anti-oxidation contacts further includes a sealed housing, the movement, the bourdon tube, the temperature compensation piece and the electrical contacts are located inside the sealed housing, the sealed housing is sealingly connected to the pressure interface end, and the pressure interface end communicates with the inside of the bourdon tube and the outside of the sealed housing;

[0008] The cavity inside the sealed housing and outside the bourdon tube is filled with a gas with extremely low oxygen content and water content.

[0009] Further, the oxygen content of the gas in the cavity is 3×10 -6 V / V, and the water content is 5×10 -6 V / V industrial high-purity nitrogen.

[0010] Further, the air pressure of the gas in the cavity is 101.32±3 kPa abs. industrial high-purity nitrogen.

[0011] Further, an air inlet is provided on the sealed housing, and the air inlet is sealed by a screw with a sealing ring.

[0012] In view of the above technical features, the present utility model has the following beneficial effects:

[0013] For the sulfur hexafluoride gas density relay with anti-oxidation contacts of the present utility model, since the cavity of the sealed housing is filled with a gas with extremely low oxygen content and water content, it can effectively prevent the contact resistance of the electrical contacts from increasing due to oxidation, and avoid condensation in the cavity of the sealed housing under low-temperature environments. Description of the Drawings

[0014] Figure 1 is the front view of a sulfur hexafluoride gas density relay with anti-oxidation contacts in Embodiment 1;

[0015] In the figure:

[0016] 1 - sealed housing, 11 - cavity, 12 - nitrogen inlet, 13 - glass window;

[0017] 2 - movement, 21 - movement hairspring;

[0018] 3 - bourdon tube;

[0019] 4 - electrical contacts, 41 - electrical contact conducting pin, 42 - electrical contact hairspring;

[0020] 5 - Temperature compensation piece;

[0021] 6 - Pressure interface end;

[0022] 7 - Sealing ring;

[0023] 8 - Screw. Specific implementation manner

[0024] The present utility model will be further described below in conjunction with specific implementation manners. It should be understood that these embodiments are only used to illustrate the present utility model and not to limit the scope of the present utility model. In addition, it should be understood that after reading the content taught by the present utility model, those skilled in the art can make various changes or modifications to the present utility model, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0025] See Figure 1 , Specific Embodiment 1. This Embodiment 1 provides a contact antioxidant sulfur hexafluoride gas density relay, which includes a movement 2, a bourdon tube 3, a temperature compensation piece 5, and an electrical contact 4. This contact antioxidant sulfur hexafluoride gas density relay further includes a sealed housing 1. The movement 2, the bourdon tube 3, the temperature compensation piece 5, and the electrical contact 4 are located inside the sealed housing 1. The sealed housing 1 is sealingly connected to the pressure interface end 6, and the pressure interface end 6 communicates the inside of the bourdon tube 3 and the outside of the sealed housing 1; the cavity 11 inside the sealed housing 1 and outside the bourdon tube 3 is filled with industrial high-purity nitrogen. The inside of the bourdon tube 3 communicates with the outside of the sealed housing 1 through the pressure interface end 6 to form a channel where the gas to be measured (such as sulfur hexafluoride gas) is located. The cavity 11 is a space filled with industrial high-purity nitrogen, and the two are separated.

[0026] The electrical contact 4 includes an electrical contact conductive pin 41 and an electrical contact hairspring 42.

[0027] Based on the mechanism of metal surface oxidation and gas low-temperature condensation, a dry, clean and oxygen element-free stable gas, such as industrial high-purity nitrogen, is filled into the cavity 11 inside the sealed housing 1 and outside the bourdon tube 3.

[0028] The oxygen content of the industrial high-purity nitrogen in the cavity 11 is 3×10 -6 V / V, and the water content of the industrial high-purity nitrogen is 5×10 - 6V / V. The industrial high-purity nitrogen gas has extremely low oxygen content, which can prevent the electric contact 4 from being oxidized and increasing the contact resistance; the industrial high-purity nitrogen gas has extremely low water content, and there will be no condensation in the cavity 11 under low-temperature environment, which can prevent the conductive needle 41 of the electric contact from being affected by condensation and affecting the output of the contact signal, prevent the hairspring 21 of the movement and the hairspring 42 of the electric contact from being affected by condensation and reducing the accuracy of indication and control, and can also prevent dew drops from adsorbing on the glass window 13 of the sealed housing 1. After the sulfur hexafluoride gas density relay has been operating for several years, the contact resistance of the electric contact 4 will not increase and there will be no condensation in the cavity 11 under low-temperature environment.

[0029] The air pressure of the industrial high-purity nitrogen gas in the cavity 11 reaches 101.32 ± 3 kPa abs., that is, 101.32 kilopascals (absolute pressure).

[0030] The sealed housing 1 is provided with a nitrogen gas inlet 12, and the nitrogen gas inlet 12 is sealed by a screw 8 with a sealing ring 7.

[0031] Specific operation steps: a) evacuate the cavity 11 to -94 kPa; b) fill in 2 - 5 kPa of industrial high-purity nitrogen gas (oxygen content 3×10 -6 V / V, water content 5×10 -6 V / V) to ensure that the outside air does not enter the cavity 11; c) after the nitrogen gas in the cavity 11 overflows and the air pressure reaches 101.32 kPa abs., screw on the screw 8 with the sealing ring 7 to seal the nitrogen gas inlet 12, so that the cavity 11 in the sealed housing 1 remains in a sealed state and prevents the industrial high-purity nitrogen gas from overflowing.

[0032] Through physical verification, for a sulfur hexafluoride gas density relay with anti-oxidation contacts in this Embodiment 1, all technical indicators have met the standards and usage requirements of the electric power industry, and have passed the special inspection by a third party and the installation test by users.

[0033] The above are only the preferred embodiments of the present utility model, and do not limit the patent scope of the present utility model accordingly. Any equivalent structural or equivalent process transformation made by using the description and drawings of the present utility model, or directly or indirectly applied in other related technical fields, shall be similarly included in the patent protection scope of the present utility model.

Claims

1. A contact anti-oxidation sulfur hexafluoride gas density relay, comprising a movement (2), a spring tube (3), a temperature compensation sheet (5) and an electric contact (4), characterized in that: The contact oxidation-resistant sulfur hexafluoride gas density relay also includes a sealed housing (1), a movement (2), a spring tube (3), a temperature compensation sheet (5) and an electric contact (4) are located inside the sealed housing (1), the sealed housing (1) is sealedly connected to a pressure interface end (6), the pressure interface end (6) communicates with the inside of the spring tube (3) and the outside of the sealed housing (1), and a cavity (11) inside the sealed housing (1) and outside the spring tube (3) is filled with industrial high-purity nitrogen.

2. A contact oxidation-resistant sulfur hexafluoride gas density relay according to claim 1, characterized in that: The oxygen content of the gas in the cavity (11) is 3×10 -6 V / V, water content is 5×10 -6 V / V industrial high purity nitrogen.

3. The contact anti-oxidation sulfur hexafluoride gas density relay according to claim 1, characterized in that: The gas pressure in the cavity (11) is 101.32±3 kPa abs. industrial high-purity nitrogen.

4. The contact oxidation-resistant sulfur hexafluoride gas density relay according to claim 1, characterized in that: The sealed housing (1) is provided with an air inlet (12), which is sealed by a screw (8) with a sealing ring (7).

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