Transformer dry-type bushing with current transformer and manufacturing method of transformer dry-type bushing

Abstract

The invention belongs to the technical field of transformer dry-type bushings, particularly relates to a transformer dry-type bushing with a current transformer and a manufacturing method of the transformer dry-type bushing, and solves the problem of high use cost in the prior art. The main sleeve is composed of a large umbrella skirt, a small umbrella skirt, a sleeve installation flange, an in-oil part, a conducting rod, a first pouring layer, a wiring terminal and a second pouring layer, the conducting rod is arranged in the main sleeve, the first pouring layer is arranged on the peripheral face of the conducting rod in a sleeving mode, the second pouring layer is arranged on the peripheral face of the first pouring layer in a sleeving mode, and the wiring terminal is arranged on the second pouring layer in a sleeving mode. The large umbrella skirts and the small umbrella skirts are arranged on one side of the first pouring layer and one side of the second pouring layer in an array and distributed at equal intervals, and a current transformer of the 40.5 kV level dry-type bushing is adopted to replace an independent 40.5 kV level current transformer of a high-voltage chamber of a 35kV boost box-type transformer substation. The purposes of reducing the manufacturing cost, the transportation cost and the installation cost of the box-type substation are achieved; the safety is improved; the maintenance amount is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of transformer dry-type bushings, in particular to a transformer dry-type bushing with a current transformer and a manufacturing method thereof. Background Art

[0002] In order to achieve the goal of "carbon peak and carbon neutrality" as soon as possible, my country is vigorously developing the new energy power generation industry at this stage. With the vigorous development of wind power generation and photovoltaic power generation, 35kV step-up box substations are widely used.

[0003] At present, independent current transformers are installed in the high-voltage room of box-type substations to protect and measure the high-voltage side lines of box-type substations. Due to the large size of current transformers and independent installation, safe insulation distances must be considered during installation, which not only increases the dimensions of the high-voltage room and installation foundation of the box-type substation, but also increases the amount and connection points of the primary circuit leads of the box-type substation, increases the manufacturing, transportation and installation costs of the box-type substation, as well as the equipment failure rate and maintenance, which is not conducive to the safe and stable operation of the equipment. At the same time, the market price of a 40.5kV current transformer is between 3,500 and 5,000 yuan, and each box-type substation needs to install 3, with a total price of between 10,500 and 15,000 yuan, which has a significant impact on the price of the box-type substation.

[0004] In view of the above problems existing in 35kV box-type substations, a 40.5kV dry-type transformer bushing with a current transformer was developed. The current transformer of the 40.5kV dry-type bushing replaced the independent 40.5kV current transformer in the high-voltage room of the 35kV step-up box-type substation, thereby reducing the manufacturing cost, transportation cost and installation cost of the box-type substation, improving safety and reducing maintenance. Summary of the invention

[0005] The purpose of the present invention is to provide a transformer dry-type bushing with a current transformer and a manufacturing method thereof, so as to solve the problem of high use cost.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a transformer dry-type bushing with a current transformer and a manufacturing method thereof, comprising a main bushing, wherein the main bushing is composed of a large shed, a small shed, a bushing mounting flange, an oil-filled portion, a conductive rod, a first casting layer, a wiring terminal, and a second casting layer; a conductive rod is arranged inside the main bushing, the first casting layer is sleeved on the outer circumferential surface of the conductive rod, the second casting layer is sleeved on the outer circumferential surface of the first casting layer, the large shed and the small shed arrays are equidistantly arranged on one side of the first casting layer and the second casting layer, the bushing mounting flange is installed on the other side of the first casting layer and the second casting layer, and a wiring terminal is installed on one side of the bushing mounting flange

[0007] Preferably, the large umbrella skirts and the small umbrella skirts are arranged at equal intervals.

[0008] A method for manufacturing a transformer dry-type bushing with a current transformer, wherein the main bushing (1) is an epoxy resin casting, the casting temperature is 65°C-75°C, the curing temperature is 100°C-130°C, the curing time is greater than 24 hours, and the casting is performed at room temperature; the conductive rod (2) is made of high-purity oxygen-free copper, and the cross-sectional area of ​​the conductive rod is selected according to the current density requirement under the rated working current to meet the temperature limit and temperature rise limit requirements; the current transformer adopts a bushing-type current transformer structure, the conductive rod (2) passes through the center of the current transformer, and the gap between the conductive rod and the current transformer is filled with epoxy resin.

[0009] Compared with the prior art, the present invention has the following beneficial effects:

[0010] 1. The present invention adopts a 40.5kV dry-type bushing built-in current transformer to replace the independent 40.5kV current transformer in the high-voltage room of a 35kV step-up box-type substation, thereby reducing the manufacturing cost, transportation cost, and installation cost of the box-type substation; improving safety; and reducing maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0012] In the figure: 1. Main bushing; 2. Conductive rod; 3. First casting layer; 4. Second casting layer; 5. Bushing mounting flange; 6. Terminal block; 7. Oil-immersed part; 8. Large shed; 9. Small shed. DETAILED DESCRIPTION

[0013] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0014] See also Figure 1, A dry-type bushing for a transformer with a current transformer and its manufacturing method, including a main bushing 1, the main bushing 1 consists of large umbrella skirts 8, small umbrella skirts 9, a bushing installation flange 5, the part in oil 7, a conductive rod 2, a first casting layer 3, a terminal 6, and a second casting layer 4. Inside the main bushing 1, there is a conductive rod 2. The first casting layer 3 is sleeved on the outer peripheral surface of the conductive rod 2, and the second casting layer 4 is sleeved on the outer peripheral surface of the first casting layer 3. The large umbrella skirts 8 and small umbrella skirts 9 are arranged in an array at equal intervals on one side of the first casting layer 3 and the second casting layer 4. The bushing installation flange 5 is installed on the other side of the first casting layer 3 and the second casting layer 4. A terminal 6 is installed on one side of the bushing installation flange 5. The large umbrella skirts 8 and small umbrella skirts 9 are arranged at equal intervals.

[0015] Please refer to Figure 1 , A manufacturing method for a dry-type bushing of a transformer with a current transformer. The main bushing 1 is an epoxy resin casting. Pouring temperature: 65°C - 75°C, curing temperature: 100°C - 130°C, curing time: > 24h, normal temperature pouring; the conductive rod 2 is made of high-purity oxygen-free copper, and the cross-sectional area of the conductive rod is selected according to the current density requirement under the rated working current to meet the temperature limit and temperature rise limit requirements; the current transformer selects a bushing-type current transformer structure, and the conductive rod 2 passes through the center of the current transformer, and the gap between the conductive rod and the current transformer is filled with epoxy resin.

[0016] Its parameter characteristics are:

[0017] Maximum operating voltage of the equipment (kV): 40.5;

[0018] Rated current (A): 100 - 1200;

[0019] Frequency (Hz): 50 / 60;

[0020] Bushing creepage distance (mm): ≥600 (selected according to the pollution level and altitude of the operating environment);

[0021] Dry arc distance (mm): 400 (meeting the requirements for the minimum safety clearance in the altitude and the design code for high-voltage distribution devices);

[0022] Technical parameters of the current transformer: Adopt a bushing-type current transformer structure. According to the technical parameter requirements of the rated current and secondary side protection, determine the transformation ratio, accuracy class, and capacity of the current transformer.

[0023] The performance lies in:

[0024] Operating conditions of the bushing:

[0025] Ambient temperature (transformer oil temperature): -50°C to 110°C; Altitude: ≤4000m;

[0026] Installation method: vertical installation or horizontal installation;

[0027] Power frequency withstand voltage (effective value) (kV): 95 (dry) / 80 (wet);

[0028] Lightning impulse dry withstand voltage (peak) (kV): 200;

[0029] Partial discharge under Um voltage (pC): ≤10;

[0030] Dielectric loss value tanδ under voltage: ≤0.007;

[0031] Cantilever load tolerance (N): ≥1000.

[0032] The specific implementation process of the present invention is as follows: a 40.5kV dry-type transformer bushing with a current transformer is developed, and the independent 40.5kV current transformer in the high-voltage room of a 35kV step-up box-type substation is replaced by the current transformer provided by the 40.5kV dry-type bushing, thereby reducing the external dimensions of the high-voltage room and the installation foundation of the box-type substation, reducing the amount of primary circuit leads and the number of connection points of the box-type substation, reducing the manufacturing, transportation and installation costs of the box-type substation, as well as the equipment failure rate and the amount of overhaul and maintenance, which is beneficial to the safe and stable operation of the equipment, and at the same time effectively reducing the procurement cost of the 40.5kV current transformer, significantly affecting the price of the box-type substation, and effectively improving the economic benefits of producing the box-type substation.

[0033] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A dry-type bushing of a transformer with a current transformer, comprising a main bushing (1), characterized in that: The main bushing (1) consists of a large umbrella skirt (8), a small umbrella skirt (9), a bushing mounting flange (5), a part in oil (7), a conductive rod (2), a first casting layer (3), a terminal (6), and a second casting layer (4). A conductive rod (2) is arranged inside the main bushing (1). The first casting layer (3) is sleeved on the outer peripheral surface of the conductive rod (2). The second casting layer (4) is sleeved on the outer peripheral surface of the first casting layer (3). The large umbrella skirt (8) and the small umbrella skirt (9) are arranged on one side of the first casting layer (3) and the second casting layer (4) at equal intervals in an array. The bushing mounting flange (5) is installed on the other side of the first casting layer (3) and the second casting layer (4). A terminal (6) is installed on one side of the bushing mounting flange (5).

2. The dry bushing of a transformer with a current transformer according to claim 1 and its manufacturing method are characterized in that: The large umbrella skirt (8) and the small umbrella skirt (9) are arranged at equal intervals.

3. The manufacturing method of a dry-type bushing of a transformer with a current transformer according to claim 1, characterized in that: The main bushing (1) is an epoxy resin casting. Pouring temperature: 65°C - 75°C, curing temperature: 100°C - 130°C, curing time: > 24h, normal temperature pouring; the conductive rod (2) is made of high-purity oxygen-free copper, and the cross-sectional area of the conductive rod is selected according to the current density requirement under the rated working current to meet the temperature limit and temperature rise limit requirements; the current transformer uses a bushing type current transformer structure, and the conductive rod (2) passes through the center of the current transformer, and the gap between the conductive rod and the current transformer is filled with epoxy resin.

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