CN103366872B - A kind of circular shield isolated bus - Google Patents

Abstract

This invention relates to a circular shielded insulated busbar with high current carrying capacity, good heat dissipation, low temperature rise, strong electrical insulation performance, immunity to environmental interference, and high reliability. It includes a circular conductor and an outer sheath, wherein multiple layers of insulating shielding are provided between the circular conductor and the outer sheath. Each insulating shielding layer consists of an insulating layer and a shielding layer. The insulating layer, from the inside out, includes two layers of polytetrafluoroethylene (PTFE) and a heat-shrinkable sheath. Silicone oil is uniformly coated between the PTFE and the heat-shrinkable sheath.

Description

A circular shielded insulated busbar

technical field

The invention belongs to the field of high-voltage electrical appliances, and in particular relates to a circular shielded insulating bus bar.

Background technique

With the continuous development of the domestic economy, the power load of each substation has increased sharply, the operating current of the system has become larger and larger, the load has become more and more concentrated, and the capacity of the main transformer of the substation has also increased. The connection method of multi-piece rectangular busbars or direct cable connection is no longer suitable for the working method of large current (above 3000A), and at the same time, it causes large additional loss, uneven current distribution, and increased skin effect coefficient resulting in current carrying Phenomena such as capacity decline and contact heating are becoming more and more obvious.

Domestic busbars have been technically improved, so that most of the insulation layers are wrapped with polytetrafluoroethylene. The disadvantage of the insulated busbar is mainly the insulation treatment of the intermediate connection. The insulation of the single pipe mother is done before leaving the factory. The intermediate joint is used for the docking of the single pipe mother and the single pipe mother on site. Insulation treatment of joints, but the humidity and temperature of the surrounding environment are impossible to match, and even impurities may be brought in when wrapping by hand, which greatly reduces the electrical insulation performance of the tube mother.

Contents of the invention

The technical problem to be solved by the present invention is to provide a circular shielded insulated busbar with large carrying capacity, good heat dissipation, low temperature rise, strong electrical insulation performance, no environmental interference and high reliability for the above disadvantages.

In order to solve the problems of the technologies described above, the technical solution of the present invention is:

A circular shielded insulated bus bar, comprising a circular conductor and an outer sheath, wherein a multi-layer insulating shielding layer is arranged between the circular conductor and the outer sheath, and the length of the insulating shielding layer is shorter than that of the circular conductor length.

The above-mentioned circular shielded insulated busbar, wherein the insulating shielding layer is composed of an insulating layer and a shielding layer, and the insulating layer includes two layers of polytetrafluoroethylene and a heat shrinkable sheath from the inside to the outside, and the polytetrafluoroethylene Apply silicone oil evenly between the heat shrinkable sheath.

The above circular shielded insulated bus bar, wherein the length of each insulating shielding layer decreases uniformly from inside to outside.

The above-mentioned circular shielded insulated bus bar, wherein a channel is provided in the circular conductor.

The above-mentioned processing method of a circular shielded insulated busbar is as follows:

1. Leave 20cm at both ends of the circular conductor and wrap a layer of aluminum foil tightly on the surface of the conductor as a shielding layer;

2. After wrapping two layers of polytetrafluoroethylene around the aluminum foil and evenly brushing silicone oil, wrap the heat shrinkable sheath around the polytetrafluoroethylene as an insulating layer;

3. The above steps 1 and 2 can be regarded as the first insulating shielding layer, and then leave 5cm at both ends of each insulating shielding layer, repeat steps 1 and 2 to make the second, third, fourth and other insulating shielding layers , the specific number of layers is subject to actual needs;

4. Wrap the braided copper mesh on the outermost insulating shielding layer for grounding treatment, and then wrap a layer of outer sheath made of polyolefin high polymer.

The beneficial effects of the present invention are:

(1) Large carrying capacity

The bus bar of the insulating tube is a hollow conductor with a large surface area, and the current density distribution on the surface of the conductor is uniform. Therefore, insulated busbars are especially suitable for circuits with large operating currents.

(2) Low skin effect and low power loss

The skin effect coefficient of the insulating tube busbar is low, Kf≤1, and the AC resistance is small, so the power loss of the busbar is small. If multiple pieces of rectangular conductors are used, as the number of pieces increases, the skin effect coefficient will increase continuously, the effective carrying capacity per unit section will decrease, the current distribution between pieces will be uneven, the additional loss will increase, and the heat dissipation conditions will be poor.

(3) Good heat dissipation conditions and low temperature rise

The insulating pipe busbar is a hollow conductor, and the inner diameter air duct of the busbar can naturally form hot air convection. The difference in air pressure between indoor and outdoor can naturally form hot air convection, and the heat dissipation conditions are good, thus greatly improving the power supply efficiency.

(4) Large allowable stress [σ] and high mechanical strength

The allowable stress of the insulating tube busbar is 4 times that of the rectangular busbar. It can withstand a large short-circuit current and has high mechanical strength, which increases the supporting span of the busbar. Under the condition of 50KA short-circuit current, the suspended span of Φ100×5mm insulated busbar can reach 9 meters. With the support of the busbar bracket, the span of the busbar can reach 13 meters. Due to the large span of the busbar, it can directly enter the high-voltage room and indoor Current-limiting reactor or 10 kV switchgear connection, reducing the corresponding post insulators, busbar fittings, and civil structures

Base.

(5) Strong electrical insulation performance

The insulating pipe busbar adopts the sealing and shielding insulation method, and the grounding potential of the shell is zero. Because the electrical shielding has the following functions: a. Make the electric field evenly distributed; b. Control the potential and limit the electric field; c. Avoid partial discharge on the insulating surface; d. Conduct leakage current and charging current; e. Protect against dangerous contact voltage and other characteristics, so the electric field distribution of this shielded insulated tubular busbar is uniform and the electrical insulation performance is strong.

(6) High heat resistance coefficient of insulating materials

The main insulating material of the insulating pipe busbar is polytetrafluoroethylene, which can work at -250°C ~ +250°C, has excellent electrical properties and chemical stability, small dielectric loss, flame retardancy, aging resistance, and a service life of ≥40 years.

(7) Strong resistance to electrical vibration

Directly fix the insulating pipe busbar on the steel frame or concrete support, cancel the wall bushing and post insulator, and have strong anti-vibration ability.

(8) No environmental interference, high reliability

Each phase of the insulating tube busbar is sealed, shielded and insulated, there is no condensation inside, and the grounding and phase-to-phase short-circuit faults caused by external moisture, dust and foreign objects are eliminated, and the operation has a high degree of reliability.

Description of drawings

Fig. 1 is the front view of the present invention

Fig. 2 is a sectional view of the present invention

detailed description

The present invention will be further described below in conjunction with the accompanying drawings.

Example one

As shown in the figure, a 10KV circular shielded insulated busbar includes a circular conductor 1 and an outer sheath 2. There is a circular channel 4 inside the circular conductor 1. Leave 20cm at both ends of the circular conductor 1 and place it on the The surface of the conductor is tightly surrounded by a layer of insulating shielding layer 3, wherein the insulating shielding layer 3 is composed of an insulating layer 31 and a shielding layer 32, and the insulating layer 31 includes two layers of polytetrafluoroethylene 311 and a heat shrinkable sheath 312 from the inside to the outside. Silicone oil is evenly applied between the tetrafluoroethylene 311 and the heat-shrinkable sheath 312 . Afterwards, respectively stay 5cm at each insulating shielding layer 3 two ends, carry out the making of the second, the 3rd, the 4th insulating shielding layer, take polyolefin high polymer as material to do outer layer protection outside the 4th insulating shielding layer Set 2, and do grounding treatment on the fourth insulation shielding layer wrapped braided copper mesh 5.

Its production method is as follows:

1. Leave 20cm at both ends of the circular conductor and wrap a layer of aluminum foil tightly on the surface of the conductor as a shielding layer;

2. After wrapping two layers of polytetrafluoroethylene around the aluminum foil and evenly brushing silicone oil, wrap the heat shrinkable sheath around the polytetrafluoroethylene as an insulating layer;

3. The above steps 1 and 2 can be regarded as the first insulating shielding layer, and then leave 5cm at both ends of each insulating shielding layer, and repeat steps 1 and 2 to make the second, third and fourth insulating shielding layers;

4. Wrap the braided copper mesh on the fourth layer of insulating shielding layer for grounding treatment, and then wrap a layer of outer sheath made of polyolefin polymer as material.

Example two

As shown in the figure, a 35KV circular shielded insulated busbar includes a circular conductor 1 and an outer sheath 2. There is a circular channel 4 inside the circular conductor 1. Leave 20cm at both ends of the circular conductor 1 and place it in the The surface of the conductor is tightly surrounded by a layer of insulating shielding layer 3, wherein the insulating shielding layer 3 is composed of an insulating layer 31 and a shielding layer 32, and the insulating layer 31 includes two layers of polytetrafluoroethylene 311 and a heat shrinkable sheath 312 from the inside to the outside. Silicone oil is evenly applied between the tetrafluoroethylene 311 and the heat-shrinkable sheath 312 . Leave 5cm respectively at each insulating shielding layer 3 two ends afterwards, carry out the making of the second, third, fourth, fifth, sixth, seventh and eighth insulating shielding layers, outside the eighth insulating shielding layer The outer sheath 2 is made of polyolefin high polymer, and the eighth insulation shielding layer is wrapped around the braided copper mesh 5 for grounding treatment.

Its production method is as follows:

1. Leave 20cm at both ends of the circular conductor and wrap a layer of aluminum foil tightly on the surface of the conductor as a shielding layer;

2. After wrapping two layers of polytetrafluoroethylene around the aluminum foil and evenly brushing silicone oil, wrap the heat shrinkable sheath around the polytetrafluoroethylene as an insulating layer;

3. The above steps 1 and 2 can be regarded as the first insulation shielding layer, and then leave 5cm at both ends of each insulation shielding layer, repeat steps 1 and 2 for the second, third, fourth, fifth, and sixth , Production of the seventh and eighth insulation shielding layers;

4. Wrap the braided copper mesh on the eighth layer of insulating shielding layer for grounding treatment, and then wrap a layer of outer sheath made of polyolefin high polymer.

In summary, the beneficial effects of the present invention are:

(1) Large carrying capacity

The bus bar of the insulating tube is a hollow conductor with a large surface area, and the current density distribution on the surface of the conductor is uniform. Therefore, insulated busbars are especially suitable for circuits with large operating currents.

(2) Low skin effect and low power loss

The skin effect coefficient of the insulating tube busbar is low, Kf≤1, and the AC resistance is small, so the power loss of the busbar is small. If multiple pieces of rectangular conductors are used, as the number of pieces increases, the skin effect coefficient will increase continuously, the effective carrying capacity per unit section will decrease, the current distribution between pieces will be uneven, the additional loss will increase, and the heat dissipation conditions will be poor.

(3) Good heat dissipation conditions and low temperature rise

The insulating pipe busbar is a hollow conductor, and the inner diameter air duct of the busbar can naturally form hot air convection. The difference in air pressure between indoor and outdoor can naturally form hot air convection, and the heat dissipation conditions are good, thus greatly improving the power supply efficiency.

(4) Large allowable stress [σ] and high mechanical strength

The allowable stress of the insulating tube busbar is 4 times that of the rectangular busbar. It can withstand a large short-circuit current and has high mechanical strength, which increases the supporting span of the busbar. Under the condition of 50KA short-circuit current, the suspended span of Φ100×5mm insulated busbar can reach 9 meters. With the support of the busbar bracket, the span of the busbar can reach 13 meters. Due to the large span of the busbar, it can directly enter the high-voltage room and indoor Current-limiting reactor or 10 kV switchgear connection, reducing the corresponding post insulators, busbar fittings, and civil structures

Base.

(5) Strong electrical insulation performance

The insulating pipe busbar adopts the sealing and shielding insulation method, and the grounding potential of the shell is zero. Because the electrical shielding has the following functions: a. Make the electric field evenly distributed; b. Control the potential and limit the electric field; c. Avoid partial discharge on the insulating surface; d. Conduct leakage current and charging current; e. Protect against dangerous contact voltage and other characteristics, so the electric field distribution of this shielded insulated tubular busbar is uniform and the electrical insulation performance is strong.

(6) High heat resistance coefficient of insulating materials

The main insulating material of the insulating pipe busbar is polytetrafluoroethylene, which can work at -250°C ~ +250°C, has excellent electrical properties and chemical stability, small dielectric loss, flame retardancy, aging resistance, and a service life of ≥40 years.

(7) Strong resistance to electrical vibration

Directly fix the insulating pipe busbar on the steel frame or concrete support, cancel the wall bushing and post insulator, and have strong anti-vibration ability.

(8) No environmental interference, high reliability

Each phase of the insulating tube busbar is sealed, shielded and insulated, there is no condensation inside, and the grounding and phase-to-phase short-circuit faults caused by external moisture, dust and foreign objects are eliminated, and the operation has a high degree of reliability.

Claims (2)

1. A circular shielded insulated bus bar, characterized in that it includes a circular conductor and an outer sheath, a circular channel is provided in the circular conductor, and 20cm is left at each end of the circular conductor to wrap tightly on the surface of the conductor A layer of insulating shielding layer, wherein the insulating shielding layer is composed of an insulating layer and a shielding layer. The insulating layer includes two layers of polytetrafluoroethylene and a heat-shrinkable sheath from the inside to the outside, and the coating between the polytetrafluoroethylene and the heat-shrinkable sheath is uniform Brush silicone oil; after that, leave 5cm at both ends of each insulating shielding layer to make the second, third, and fourth insulating shielding layers, and use polyolefin polymer as the material outside the fourth insulating shielding layer. layer sheath, and do grounding treatment on the fourth insulating shielding layer wrapped around the braided copper mesh; the manufacturing method of the circular shielded insulating busbar is as follows: (1). After leaving 20cm at both ends of the round conductor, tightly wrap a layer of aluminum foil on the surface of the conductor as a shielding layer; (2). After the aluminum foil is wrapped with two layers of polytetrafluoroethylene and evenly coated with silicone oil, the heat-shrinkable sheath is wrapped around the polytetrafluoroethylene as an insulating layer; (3). The above steps 1 and 2 can be regarded as the first insulating shielding layer, and then leave 5cm at both ends of each insulating shielding layer, repeat steps 1 and 2 to carry out the second, third and fourth insulating shielding layers make; (4). Wrap the braided copper mesh on the outside of the fourth insulating shielding layer for grounding treatment, and then wrap a layer of outer sheath made of polyolefin high polymer. 2. A circular shielded insulated bus bar, characterized in that it includes a circular conductor and an outer sheath, a circular channel is arranged in the circular conductor, and 20cm is left at each end of the circular conductor, and then it is tightly wrapped on the surface of the conductor A layer of insulating shielding layer, wherein the insulating shielding layer is composed of an insulating layer and a shielding layer. The insulating layer includes two layers of polytetrafluoroethylene and a heat-shrinkable sheath from the inside to the outside, and the coating between the polytetrafluoroethylene and the heat-shrinkable sheath is uniform Brush silicone oil; after that, leave 5cm at both ends of each insulating shielding layer to make the second, third, fourth, fifth, sixth, seventh, and eighth insulating shielding layers, and make the eighth insulating shielding layer The outer layer is made of polyolefin polymer as the outer sheath, and the eighth insulating shielding layer is wrapped with braided copper mesh for grounding treatment; the manufacturing method of the circular shielded insulating busbar is as follows: (1). After leaving 20cm at both ends of the round conductor, tightly wrap a layer of aluminum foil on the surface of the conductor as a shielding layer; (2). After the aluminum foil is wrapped with two layers of polytetrafluoroethylene and evenly coated with silicone oil, the heat-shrinkable sheath is wrapped around the polytetrafluoroethylene as an insulating layer; (3). The above steps 1 and 2 can be regarded as the first insulating shielding layer, and then leave 5cm at both ends of each insulating shielding layer, repeat steps 1 and 2 for the second, third, fourth, fifth, Production of the sixth, seventh and eighth insulating shielding layers; (4). Wrap the braided copper mesh on the eighth layer of insulating shielding layer for grounding treatment, and then wrap a layer of outer sheath made of polyolefin high polymer.