Gas taking device and method for aluminum sheath of high-voltage cable

Abstract

The invention relates to a high-voltage cable aluminum sheath gas taking device and method.The high-voltage cable aluminum sheath gas taking device comprises an installation base with a valve body installation cavity, a sealing gasket, a valve body base, a valve core provided with a plunger spring and an inflating valve body provided with a core rod, the valve core is installed on the valve body base, and the valve body base is connected to the valve body installation cavity in a threaded mode and sealed through the sealing gasket; the inflating valve body is connected to the valve body base, and the core rod makes contact with the valve core. The valve core is driven to be opened and closed through the core rod, and opening and closing of the gas collection guide pipe are controlled. Drilling and gas extraction are performed on the body near the high-voltage cable joint, operation is performed under the condition that a cable buffer layer is not damaged, characteristic gas generated by insulation defects in the cable is extracted, the reliability is high, and the field practicability is good. By adopting the gas taking method disclosed by the invention, gas taking in a proper gas taking period can be ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of high-voltage cable detection, and in particular to a high-voltage cable aluminum sheath air extraction device and method. Background Art

[0002] Since the insulation design margin of high-voltage cables, especially at the joints, is large and there are few effective detection methods, potential defects generated during the installation process are usually difficult to detect through power outage tests such as insulation resistance and AC withstand voltage. Existing high-voltage cable live detection technologies, such as partial discharge detection, sheath circulation monitoring and infrared temperature measurement, are not sensitive to common problems such as water ingress and early insulation defects, and have limitations such as low defect detection rate and large interference from the electromagnetic environment. Electrical equipment fault monitoring technology based on escaping gas analysis has been widely used in transformer status detection, and its reliability and sensitivity have been confirmed, but there is currently little research on the gas generation characteristics and detection methods of cable-type solid insulation equipment. Under conditions of moisture, water ingress, heat generation, abnormal discharge, etc., various typical materials inside high-voltage cables will undergo reactions such as decomposition of organic polymer materials and corrosion of metal materials, thereby generating a large amount of escaping gas derivatives. By analyzing the key parameters such as the composition and concentration of the escaping gas inside the cable, the difference between the characteristic gas and the normal operating state can be extracted, which can provide new ideas for the rapid detection of high-voltage cable defects, but there is currently no effective gas extraction device. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and propose a high-voltage cable aluminum sheath gas extraction device and method. By drilling holes and extracting gas from the body near the high-voltage cable joint, the operation is performed without damaging the cable buffer layer, and the characteristic gas generated by insulation defects inside the cable is extracted. The reliability is strong and the field practicability is good. The gas extraction method of the present invention can ensure that gas extraction is performed within a suitable gas extraction cycle.

[0004] The present invention solves the technical problem by adopting the following technical solutions:

[0005] A high-voltage cable aluminum sheath air extraction device comprises a mounting base with a valve body mounting cavity, a sealing gasket, a valve body base, a valve core equipped with a plunger spring and a valve mouth body equipped with a core rod, the valve core is mounted on the valve body base, the valve body base is threadedly connected to the valve body mounting cavity and sealed by the sealing gasket, the valve mouth body is connected to the valve body base, and the core rod is in contact with the valve core; the opening and closing of the valve core is driven by the core rod to control the opening and closing of the gas collecting duct.

[0006] Moreover, it also includes an air collecting conduit, and the mounting base is provided with an air collecting conduit which is in communication with the mounting cavity of the valve body.

[0007] Moreover, in the initial state, the valve core of the air extraction device closes the air passage of the valve body base; when the core rod is pressed down, the valve core can be driven to move downward, open the air passage, and connect the air collecting duct with the valve body. When the core rod rises and resets, the valve core resets under the action of the plunger spring, closes the air passage of the valve body base, and closes the air collecting duct.

[0008] A gas extraction method for a high-voltage cable aluminum sheath gas extraction device comprises the following steps:

[0009] Step 1: Find the crest position on the outer sheath of the high-voltage cable, remove the outer sheath after baking with an open flame, and expose the crest position of the aluminum sheath, which is used to install the mounting base of the gas extraction device;

[0010] Step 2: Use non-woven cloth to dip in diesel and wipe off the asphalt on the surface of the aluminum sheath;

[0011] Step 3: Select a suitable installation position at the crest of the aluminum sheath, and polish the aluminum sheath with a file to increase adhesion;

[0012] Step 4, select the drill bit 10, the drilling depth is limited by the stopper on the drill bit, and then drill the aluminum sheath at the selected suitable installation position;

[0013] Step 5: After the drilling is completed, the mounting base is fixedly connected to the aluminum sheath, and the gas collecting duct is inserted into the drilled hole;

[0014] Step 6. After the mounting base is bonded and fixed, apply casting glue on the aluminum sheath around the mounting base. After drying, cover the two sides of the air extraction device with PVC self-adhesive tape extending within a length of 10 cm; permanently install the air extraction device on the high-voltage cable for subsequent air pressure monitoring and air extraction inside the high-voltage cable.

[0015] Moreover, the area of ​​the outer sheath removed in step 1 is a circular area not less than 25 cm in diameter.

[0016] Moreover, the depth of the drilling in step 4 is adjusted by a limiter, and the limit depth is required to be less than the sum of the thickness of the aluminum sheath and the thickness of the air gap to avoid damaging the insulating outer shield.

[0017] Moreover, the specific implementation method of step 5 is: the mounting base is fixedly connected to the aluminum sleeve by bonding or welding; after the mounting base and the aluminum sleeve are completely bonded, the valve body base, the valve core and the valve mouth body are installed in sequence.

[0018] The advantages and positive effects of the present invention are:

[0019] The present invention includes a mounting base with a valve body mounting cavity, a sealing gasket, a valve body base, a valve core equipped with a plunger spring, and a valve body equipped with a core rod. The valve core is mounted on the valve body base, the valve body base is threadedly connected to the valve body mounting cavity and sealed by a sealing gasket, the valve body is connected to the valve body base, and the core rod is in contact with the valve core; the opening and closing of the valve core is driven by the core rod to control the opening and closing of the gas collecting duct. The present invention performs drilling and gas extraction on the body near the high-voltage cable connector without damaging the cable buffer layer, and extracts characteristic gases generated by insulation defects inside the cable, with high reliability and good on-site practicality. The gas extraction method of the present invention can ensure gas extraction within a suitable gas extraction cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a front view of the device of the present invention;

[0021] Figure 2 It is a perspective view of the device of the present invention.

[0022] Description of labels:

[0023] 1-Mounting base, 2-Sealing gasket, 3-Valve body base, 4-Valve core, 5-Core rod, 6-Valve mouth body, 7-Gas collecting duct. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below with reference to the accompanying drawings.

[0025] A high voltage cable aluminum sheath gas extraction device, such as Figure 1 and Figure 2 As shown, it includes a mounting base 1 with a valve body mounting cavity, a sealing gasket 2, a valve body base 3, a valve core 4 equipped with a plunger spring, and a valve mouth body 6 equipped with a core rod 5. Among them, an air collecting duct 7 connected to the valve body mounting cavity is provided on the mounting base. The valve core is mounted on the valve body base, the valve body base is threadedly connected to the valve body mounting cavity and sealed by a sealing gasket, the valve mouth body is connected to the valve body base, and the core rod is in contact with the valve core; the opening and closing of the valve core is driven by the core rod to control the opening and closing of the air collecting duct. The air extraction device of the present invention can be permanently installed on a high-voltage cable. When air extraction is required, the valve is opened and air can be pumped by an air pump; when air extraction is not required, the air pressure of the buffer layer can be monitored by connecting a barometer, which is convenient for determining the air extraction cycle. The air extraction method of the present invention can ensure that air extraction is performed within a suitable air extraction cycle.

[0026] In the initial state of the air extraction device, the valve core closes the air passage of the valve body base; when the core rod is pressed down, the valve core can be driven downward to open the air passage, so that the air collecting duct is connected with the valve body. When the core rod rises and resets, the valve core is reset under the action of the plunger spring, closing the air passage of the valve body base and the air collecting duct.

[0027] A gas extraction method for a high-voltage cable aluminum sheath gas extraction device comprises the following steps:

[0028] Step 1: Find the crest position on the outer sheath of the high-voltage cable, remove the outer sheath after baking with an open flame, and expose the crest position of the aluminum sheath, which is used to install the mounting base of the gas extraction device. The area removed from the outer sheath is a circular area with a diameter of not less than 25 cm.

[0029] Step 2: Use a non-woven cloth dipped in diesel to wipe off the asphalt on the surface of the aluminum sheath.

[0030] Step 3: Select a suitable installation position at the peak of the aluminum sheath, and polish the aluminum sheath with a file to increase adhesion.

[0031] Step 4: Select a drill bit 10, and limit the drilling depth by the stopper on the drill bit, and then drill the aluminum sheath at the selected suitable installation position. The limit of the drilling depth can be adjusted by the stopper, and the limit depth is required to be less than the sum of the thickness of the aluminum sheath and the thickness of the air gap to avoid damaging the insulation outer shield.

[0032] Step 5: After the drilling is completed, the mounting base is fixedly connected to the aluminum sleeve, and the gas collecting duct is inserted into the drilled hole. Specifically, in the actual operation, the mounting base can be fixedly connected to the aluminum sleeve by bonding or welding. After the mounting base is completely bonded to the aluminum sleeve, the valve body base, the valve core and the valve body are installed in sequence.

[0033] Step 6. After the mounting base is bonded and fixed, apply cast glue on the aluminum sheath around the mounting base. After drying, cover the PVC self-adhesive tape on both sides of the air extraction device within a length of 10 cm. The air extraction device is permanently installed on the high-voltage cable for subsequent air pressure monitoring and air extraction inside the high-voltage cable.

[0034] The present invention extracts characteristic gas generated by insulation defects inside the cable by drilling holes and extracting gas from the body near the high-voltage cable joint without damaging the cable buffer layer, and has high reliability and good on-site practicality. The gas extraction method of the present invention can ensure that gas extraction is performed within a suitable gas extraction cycle.

[0035] It should be emphasized that the embodiments described in the present invention are illustrative rather than restrictive. Therefore, the present invention includes but is not limited to the embodiments described in the specific implementation manner. Any other implementation manners derived by those skilled in the art based on the technical solution of the present invention also fall within the scope of protection of the present invention.

Claims

1. A high voltage cable aluminum sheath air extraction device, characterized in that: It includes a mounting base with a valve body mounting cavity, a sealing gasket, a valve body base, a valve core equipped with a plunger spring and a valve mouth body equipped with a core rod. The valve core is mounted on the valve body base, the valve body base is threadedly connected to the valve body mounting cavity and sealed by the sealing gasket, the valve mouth body is connected to the valve body base, and the core rod is in contact with the valve core; the opening and closing of the valve core is driven by the core rod to control the opening and closing of the gas collecting duct.

2. A high voltage cable aluminum sheath air extraction device according to claim 1, characterized in that: It also includes an air collecting conduit, and the mounting base is provided with an air collecting conduit that is in communication with the valve body mounting cavity.

3. A high voltage cable aluminum sheath air extraction device according to claim 1, characterized in that: In the initial state, the valve core of the air extraction device closes the air passage of the valve body base; when the core rod is pressed down, the valve core can be driven to move downward, open the air passage, and connect the air collecting conduit with the valve body. When the core rod rises and resets, the valve core resets under the action of the plunger spring, closes the air passage of the valve body base, and closes the air collecting conduit.

4. A gas extraction method for a high voltage cable aluminum sheath gas extraction device as claimed in any one of claims 1 to 3, characterized in that: The following steps are involved: Step 1: Find the crest position on the outer sheath of the high-voltage cable, remove the outer sheath after baking with an open flame, and expose the crest position of the aluminum sheath, which is used to install the mounting base of the gas extraction device; Step 2: Use non-woven cloth to dip in diesel and wipe off the asphalt on the surface of the aluminum sheath; Step 3: Select a suitable installation position at the crest of the aluminum sheath, and polish the aluminum sheath with a file to increase adhesion; Step 4, select the drill bit 10, the drilling depth is limited by the stopper on the drill bit, and then drill the aluminum sheath at the selected suitable installation position; Step 5: After the drilling is completed, the mounting base is fixedly connected to the aluminum sheath, and the gas collecting duct is inserted into the drilled hole; Step 6. After the mounting base is bonded and fixed, apply casting glue on the aluminum sheath around the mounting base. After drying, cover the two sides of the air extraction device with PVC self-adhesive tape extending within a length of 10 cm; permanently install the air extraction device on the high-voltage cable for subsequent air pressure monitoring and air extraction inside the high-voltage cable.

5. The gas extraction method of the high-voltage cable aluminum sheath gas extraction device according to claim 4 is characterized in that: The area of ​​the outer sheath removed in step 1 is a circular area not less than 25 cm in diameter.

6. The gas extraction method of the high-voltage cable aluminum sheath gas extraction device according to claim 4, characterized in that: The depth of the drilling in step 4 is adjusted by a limiter, and the limit depth is required to be less than the sum of the thickness of the aluminum sheath and the thickness of the air gap to avoid damaging the insulating outer shield.

7. The gas extraction method of the high-voltage cable aluminum sheath gas extraction device according to claim 4, characterized in that: The specific implementation method of step 5 is: the mounting base is fixedly connected to the aluminum sleeve by bonding or welding; after the mounting base and the aluminum sleeve are completely bonded, the valve body base, the valve core and the valve mouth body are installed in sequence.

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