Switchboard copper busbar insulation treatment measures

This paper introduces several methods of insulating the copper row of the switchgear, which are tube-type shielded insulated busbar method, fluidized bed coating method, and development of new insulating materials. The characteristics and advantages of the insulating treatment method are expounded, and the future is pointed out. A new method of insulation treatment.

Switchboard copper busbar insulation treatment measures
1. Tube type shielded insulation bus method

With the continuous increase of residential electricity consumption, the main transformer capacity of the substation continues to increase, and the rated current of the low-voltage outlet side busbar of the transformer is continuously increasing (more than 3000A), which leads to a series of problems. The multiple rectangular conventional busbars used in the power system have not been able to meet the needs of the work. With the increasing power consumption, the busbars are due to their own structural aspects.
Because it will cause heat problems and electric power problems, which will affect the safety and reliability of substation power supply. In order to solve the above problems, the tubular shielded insulated busbar is used instead of the open rectangular busbar to improve the utilization of the busbar and enhance the mechanical performance of the busbar. It has been well applied in practical engineering and played a positive role in the safe and reliable operation of the substation.

The advantages of tubular shielded insulated busbars instead of open rectangular busbars are: (1) low skin effect and low power loss. The tubular shielded insulated busbar replaces a plurality of rectangular conductor busbars, the skin effect coefficient is low, the power loss of the busbar is small, and the heat dissipation condition is improved, and there is substantially no eddy loss; (2) current carrying capacity
Big. The tubular shielded insulated busbar replaces the rectangular conductor busbars, which changes the shape of the outer surface of the tube, so that the current density distribution on the surface of the conductor is uniform, avoiding the phenomenon of charge accumulation, thereby avoiding local heating of the busbar; (3) Allowing large stress and span Large, high mechanical strength. Tube type shielded insulated busbar generation
For a plurality of rectangular conductor busbars, the copper tube replaces the rectangular copper row, which improves the tensile strength of the busbar and improves the short-circuit current that the busbar can withstand; (4) good heat dissipation and low temperature rise. The tubular shielded insulated busbar replaces multiple rectangular conductor busbars, which changes the structure of the busbar and improves the heat dissipation conditions.
More obvious than multiple rectangular conductor busbars.

2. Fluidized bed coating

At present, the busbar coated flame retardant insulating powder has been 10. O~40.5kV switchgear has been applied. Some foreign companies have used this technology to insulate the busbars in high-voltage switchgear, such as ABB in Switzerland and Mitsubishi in Japan. The principle of fluidized bed coating. The fluidized bed works by loading the powder coating into a fluidization tank with a perforated plate, which is a uniformly distributed air flowing through the layer to drive the powder to flow, so that it is in a flowing state.
After the airflow and the powder reach equilibrium, reach a certain height. After preheating the workpiece to be treated, the powder is then passed through to adhere the powder to the workpiece, and finally heat cured to form a uniform coating. The insulating powder is composed of a binder and a filler, and is added with a flame retardant, a curing agent and a leveling agent, and is produced through a special process. The base material is epoxy resin, the filler is silicon micropowder or alumina, and the flame retardant is dodecyl bromide. technological design. Fluidized bed process: Busbar punching, bending, pretreatment, masking, preheating, first-class bed coating, cleaning of busbar lap joints and fixtures---Jm heat curing, cooling, and busbar cleaning.

    Process influence factors. (1) Melting temperature, heat of dissolution and heat capacity of the powder coating. The physical properties of the powder have a great influence on the quality of the coating, and also determine the preheating temperature, so it is necessary to choose the appropriate material; (2) The melt index of the powder coating. When measuring this index, special attention should be paid to the test conditions. It should be tested at the appropriate temperature and pressure by the corresponding national standard method, and then used for g/10min table.
Show. This index represents the fluidity of the coating powder under current conditions, thereby controlling the thickness of the coating; (3) Preheating temperature of the workpiece. This is a very important factor, which has a great influence on the quality of the coating. It is necessary to choose the right temperature to ensure the quality of the coating. The preheating temperature is determined by the coating and the workpiece. (4) Immersion time. It has no effect on the quality of the coating of the workpiece, but has a certain influence on the thickness of the coating; (5)
The material of the material to be coated has a matrix coefficient K. This is a very important factor, which has little effect on the coating of the workpiece, but has a great influence on the thickness of the coating. The K value, the immersion time and the preheating temperature together determine the thickness of the coating, and can also change A factor to change the thickness of the coating.

3. Develop new insulation materials

With the development of science and technology, a new type of heat-shrinkable insulating material has emerged. Through years of exploration and use, it proves that this material has high use value in anti-aging performance and insulation protection. When a heat-shrinkable insulating material is used, in consideration of its peculiar properties, it must be heated to adhere to the surface of the conductor to achieve an insulating effect. Heat shrinkable material, also known as polymer shape memory material, mainly uses the knot
The crystalline polymer material is treated by high-energy ray treatment or chemical initiator to generate a new bond between the polymer chains to form a crosslinked network structure polymer. The external force can be stretched or expanded within a certain temperature range. This is the "memory effect" of crosslinked polymers. The main properties of heat-shrinkable materials: (1) heat-shrinkable insulation materials have good insulation properties; (2) heat-shrinkable insulation materials for substation busbars
The edge protection does not reduce the current carrying capacity of the busbar; (3) The heat-shrinkable insulating material has good flame retardancy. Field tests show that the test sample does not burn at 960 °C ignition test: (4) Heat-shrinkable insulation material, because of the cross-linked structure of the internal network, its anti-aging performance is better than other insulating materials; (5) heat-shrinkable insulation material has good Temperature resistance.