CN106841953B - Partial discharge test terminations for cable accessories for measuring prefabricated defects - Google Patents

Abstract

The invention discloses a partial discharge test terminal for cable accessories for measuring prefabricated defects. The cable body includes a wire core and a protective layer covering the wire core. The upper end of the wire core of the cable body is fixedly connected with a copper nose, and the copper nose is connected with a high-voltage lead wire; The bottom of the metal bottom plexiglass oil cup is made of metal; the bottom is provided with a plexiglass cup wall; the metal bottom plexiglass oil cup is filled with silicone oil; the bottom of the metal bottom plexiglass oil cup is set on an epoxy resin pad The epoxy resin block is fixed on the insulating base, and the insulating base is located on the side of the epoxy resin block, and the resin is fixed with an epoxy resin support rod; the cable body is fixed on the epoxy resin support rod through two copper clips, and the cable body is fixed on the epoxy resin support rod. The lower end extends into the metal bottom plexiglass oil cup, and the lower end of the wire core of the cable body contacts the metal bottom of the metal bottom plexiglass oil cup. The invention patent effectively avoids the problem of partial discharge that may occur at the cable test terminal, and effectively guarantees the accuracy of the test.

Description

Partial discharge test terminations for cable accessories for measuring prefabricated defects

technical field

The invention relates to the technical field of high voltage and insulation, in particular to a partial discharge test terminal for cable accessories used for measuring prefabricated defects.

Background technique

Cross-linked polyethylene (XLPE) insulated cables have been widely used in the development of urban power grids due to their excellent electrical properties. It is of great significance to study the characteristics of insulation defects of XLPE cables to improve the reliability of urban electric energy and power supply.

Partial discharge is a discharge phenomenon that can occur in any electrical equipment due to excessive electrical stress. Since the discharge occurs in a small area and cannot generate a continuous current, it is called partial discharge. It will eventually lead to the collapse of the entire insulation system through continuous erosion of the surrounding insulating medium, which is the main cause of insulation degradation and an important symptom and manifestation of insulation degradation. During the test, a detection impedance is used to pick up the high-frequency pulse signal generated by the partial discharge at the defect, and its duration is short enough to ensure the required pulse resolution.

Therefore, when measuring the partial discharge at the prefabricated defect, the pulse signal picked up by the detection impedance must be generated by the prefabricated defect, otherwise the accuracy of the test result will be affected.

Contents of the invention

The purpose of the present invention is to provide a partial discharge test terminal for cable accessories for measuring prefabricated defects, considering the influence of partial discharges that may be generated by the rest of the cable terminal on the test results of prefabricated defects when measuring partial discharges. The clamping device is combined with a simple and reusable test terminal to solve the above technical problems.

To achieve the above object, the present invention adopts the following technical solutions:

Partial discharge test terminal of cable accessories for measuring prefabricated defects, including cable body, metal bottom plexiglass oil cup, epoxy resin spacer, insulating base, epoxy resin support rod and oil cup bottom joint; cable body includes wire core and The protective layer wrapping the wire core, the upper end of the wire core of the cable body is fixedly connected with a copper nose, and the copper nose is connected with a high-voltage lead; the lower end of the wire core of the cable body is exposed outside the protective layer; the bottom of the metal bottom plexiglass oil cup is made of metal The bottom of the oil cup is equipped with the bottom joint of the oil cup and the wall of the plexiglass cup, and the plexiglass cup wall surrounds the bottom joint of the oil cup; the metal bottom plexiglass oil cup is filled with silicone oil; the bottom joint of the oil cup is located on the metal bottom plexiglass oil The bottom of the cup; the bottom of the plexiglass oil cup with a metal bottom is set on an epoxy resin pad, and the epoxy resin pad is fixed on the insulating base, and the insulating base is located on the side of the epoxy resin pad. The resin is fixed with an epoxy resin support rod ;The cable body is fixed on the epoxy resin support rod through copper clips, the lower end of the cable body extends into the metal bottom plexiglass oil cup, the lower end of the cable core is fixed by the base joint, and is in good contact with the base.

Further, the protective layer sequentially includes an inner semiconductive layer, a cross-linked polyethylene insulating layer, an outer semiconductive layer, a copper shielding layer and an outer sheath from inside to outside; the copper shielding layer is grounded through a ground wire.

Further, the epoxy resin support rod is composed of two movably connected sections, which can be adjusted in height.

Further, there are prefabricated defects in the cross-linked polyethylene insulating layer of the cable body.

Furthermore, the bottom edge of the plexiglass oil cup with a metal bottom is smooth, and the base joint ensures good contact between the cable core and the base, reducing the possibility of the lower end of the body being discharged in the oil under high voltage.

Further, the cable body is fixed on the epoxy resin support rod through two copper clips; the distance between the two copper clips can be adjusted, and the adjustment range is 20 to 60 centimeters.

Further, the bottom joint of the oil cup is composed of several elastic steel contacts arranged in a ring, and the inner diameter of the annular space formed by the inner surrounding of the several elastic steel contacts in a natural state is smaller than the diameter of the cable core.

Compared with the prior art, the present invention has the following beneficial effects:

1) The bottom of the plexiglass oil cup is made of metal, and the metal edges are polished and smooth. The base connector ensures that the cable core is in good contact with the base, reducing the possibility of the lower end of the body being discharged in the oil under high voltage.

2) The oil cup and the cable sample wire core are fixed together through the oil cup base joint. After the test, just pull out the cable. The repeated use of the oil cup terminal is realized.

3) The distance between the copper clips is flexible and adjustable, and the adjustment range is 20 to 60 centimeters.

Description of drawings

Fig. 1 is the structural representation of the cable accessory partial discharge test terminal used for measuring prefabricated defects of the present invention;

Figure 2 is a sectional view of the cable body;

Fig. 3 is a schematic structural diagram of the base of the oil cup;

Fig. 4 is a sectional view of the oil cup base connector contact.

Detailed ways

The content of the patent of the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Please refer to Fig. 1, Fig. 2, Fig. 3 and Fig. 4, a partial discharge test terminal for cable accessories of the present invention for measuring prefabricated defects, including a cable body 3, a metal bottom plexiglass oil cup 4, and an epoxy resin pad Block 5, insulating base 7 and epoxy resin support rod 8, oil cup base joint 10.

The cable body 3 includes a wire core 31 and a protective layer wrapping the wire core 31. The protective layer includes an inner semiconductive layer 32, a cross-linked polyethylene insulating layer 33, an outer semiconductive layer 34, a copper shielding layer 35 and an outer semiconductive layer from the inside to the outside. Sheath 36. The inner and outer semiconducting layers play the role of uniform electric field and phase-to-phase shielding. The cross-linked polyethylene insulating layer is the main insulation of the cable. The current-carrying wire core is generally copper or aluminum.

The oil cup base joint 10 is made of 16 elastic steel contacts 41, and the inner diameter is slightly smaller than the cable core.

The upper end of the wire core 31 of the cable body 3 is fixedly connected with the copper nose 2, and the copper nose 2 is connected with the high-voltage lead wire 1; the lower end of the wire core 31 of the cable body 3 is exposed outside the protective layer, and the copper shielding layer 35 of the cable body 3 passes through the ground wire grounded.

The bottom of the metal bottom plexiglass oil cup 4 is made of metal, and the metal edges have been polished and smoothed to reduce the possibility of partial discharge at the sample terminal; the bottom is provided with a plexiglass cup wall and joints, and the base joints ensure The cable core is in good contact with the base. Silicone oil is housed in the plexiglass oil cup 4 at the metal bottom.

The bottom of the metal bottom plexiglass oil cup 4 is provided with an epoxy resin pad 5, and the epoxy resin pad 5 is fixed on an insulating base 7, and the insulating base 7 is located on the side of the epoxy resin pad 5, and the resin is fixed with epoxy resin Support rod 8. Epoxy resin support bar 8 is the support bar that can adjust height, is made up of two joints.

The cable body 3 is fixed on the epoxy resin support rod 8 by two copper clips 6, the lower end of the cable body 3 extends into the metal bottom plexiglass oil cup 4, and the lower end of the wire core of the cable body 3 is inserted into the base joint 10, so that The elastic steel contacts spread outward to clamp the lower end of the wire core.

When the partial discharge test terminal of a cable accessory used for measuring prefabricated defects of the present invention is used, a sample is made first, and in the process of making the sample, the outer sheath of the cable body, the copper shield of a specified length, and the copper shield of a specified length are peeled off in sequence. outer semiconducting layer. Make prefabricated defects in the exposed main insulation layer, and connect the ground wire on the exposed copper shielding layer, and finally put on the cable terminal accessories. The partial discharge test for measuring cable terminal samples includes the following steps:

1) Adjust the two copper clips 6 to the appropriate position, pour silicone oil into the oil cup 4 to two-thirds of the height of the oil cup;

2) Insert the cable body sample into the metal bottom plexiglass oil cup 4, insert the lower end of the wire core of the cable body 3 into the base joint 10, and fix the outer sheath of the cable body 3 with copper clips;

3) Connect the high-voltage lead wire and the ground wire, and perform a pressure test.

Claims (4)

1. A cable accessory partial discharge test terminal for measuring prefabricated defects, characterized in that it includes a cable body (3), a metal-bottomed plexiglass oil cup (4), an epoxy resin pad (5), and an insulating base (7) , epoxy resin support rod (8) and oil cup bottom joint (10); The cable body includes a wire core (31) and a protective layer covering the wire core (31). The upper end of the wire core of the cable body is fixedly connected with a copper nose (2), and the copper nose is connected with a high-voltage lead wire (1); the lower end of the wire core of the cable body is Partially exposed outside the protective layer; the bottom of the organic glass oil cup with a metal bottom is made of metal; the bottom is provided with an oil cup bottom joint (10) and an organic glass cup wall, and the organic glass cup wall surrounds the oil cup bottom joint (10) Among them; the metal bottom plexiglass oil cup is filled with silicone oil; The bottom of the metal bottom plexiglass oil cup is set on the epoxy resin pad, and the epoxy resin pad is fixed on the insulating base; the side of the epoxy resin pad is provided with an epoxy resin support rod fixed on the insulating base; The cable body is fixed on the epoxy resin support rod through the copper clip (6), the lower end of the cable body extends into the metal-bottomed plexiglass oil cup, the lower end of the cable core is fixed by the bottom joint (10) of the oil cup, and is connected with Good contact with the bottom of the metal bottom plexiglass oil cup; The oil cup bottom joint (10) is composed of 16 elastic steel contacts arranged in a ring, and the inner diameter of the annular space formed by the inner surrounding of the 16 elastic steel contacts in a natural state is smaller than the diameter of the cable core; The protective layer sequentially includes an inner semiconductive layer (32), a cross-linked polyethylene insulating layer (33), an outer semiconductive layer (34), a copper shielding layer (35) and an outer sheath (36); the copper shielding layer Layer (35) is grounded by ground wire; There are prefabricated defects in the cross-linked polyethylene insulation layer of the cable body. 2. The cable accessory partial discharge test terminal for measuring prefabricated defects according to claim 1, wherein the epoxy resin support rod is composed of two movably connected sections, and the height can be adjusted. 3. The cable accessory partial discharge test terminal for measuring prefabricated defects according to claim 1, characterized in that, the bottom edge of the metal bottom plexiglass oil cup is smooth, and the bottom joint of the oil cup ensures that the cable core and the metal bottom plexiglass The bottom of the oil cup is in good contact, reducing the possibility of the lower end of the body being discharged in the oil under high pressure. 4. The cable accessory partial discharge test terminal for measuring prefabricated defects according to claim 1, wherein the cable body is fixed on the epoxy resin support rod by two copper clips (6); The distance between the clips can be adjusted, and the adjustment range is 20 to 60 centimeters.