Insulating Sleeve
The insulating sleeve is a kind of insulating material and is a general term. Among the electrical materials are glass fiber insulation sleeves, PVC sleeves, heat shrink sleeves, and the like.
Single type
Insulated with pure porcelain or resin, often made into wall bushings for voltage levels of 35 kV and below. The insulating member is tubular, and the middle portion is fitted or glued to be fixed on the perforated wall. The flange is generally gray cast iron. When the working current is greater than 1500 amps, non-magnetic materials are commonly used to reduce heat generation. The insulation structure of a single insulating sleeve is divided into two types: air chamber and air chamber short circuit. The air cavity casing is used for voltage levels of 10 kV and below. An air cavity is provided between the conductor and the porcelain sleeve as auxiliary insulation, which can reduce the casing capacitance and increase the corona voltage and the sliding voltage of the casing. When the voltage level is high (20 to 30 kV), corona will occur inside the air chamber to disable the above action. At this time, the air cavity short circuit structure is adopted. The inner wall of the porcelain sleeve of the porcelain sleeve is coated with a semiconductor glaze, and the spring sheet is connected to the conductor to short-circuit the air chamber to eliminate the internal corona. Corona and slip can still occur near the flange. Usually, a large umbrella skirt is arranged on both sides of the porcelain sleeve near the flange, and a semi-conductive layer is coated near the flange to evenly distribute the electric field, thereby improving the discharge characteristics of the sleeve.
complex
Oil or gas is used as the insulating medium, generally made of transformer bushing or circuit breaker bushing, which is commonly used for voltage levels below 35 kV. The inner cavity between the conductor of the composite insulating sleeve and the porcelain sleeve is filled with transformer oil to provide radial insulation. When the voltage exceeds 35 kV, an insulating tube or a covered cable is sheathed on the conductor to enhance the insulation. The conductor structure of the composite insulating sleeve has two types: a cable-through type and a guide rod type. The cable-through cable that uses the transformer directly passes through the casing for easy installation. When the working current is greater than 600 amps, it is difficult to install the cable-through structure, and a guide rod structure is generally adopted. The capacitive bushing consists of a capacitor core, a porcelain sleeve, a metal attachment and a conductor. Mainly used for ultra high voltage transformers and circuit breakers. The upper part works in the tank in the atmosphere and in the lower part. The capacitor core of the capacitor sleeve is used as the inner insulation, and the porcelain sleeve is used as the outer insulation to protect the capacitor core. The electric field on the surface of the porcelain sleeve is evenly distributed by the pressure equalization of the internal capacitor core, thereby improving the electrical insulation performance of the sleeve. The metal attachment has an intermediate connecting sleeve (flange), an end cap, a pressure equalizing ball, and the like. The conductor is a cable or a hard steel pipe.
Capacitive bushing
When the capacitor core is made of adhesive tape, it has high mechanical strength, can be installed at any angle, has good moisture resistance, simple structure and maintenance, and can be turned into a short tail type to reduce the size without the need for casing. The disadvantage is that at high voltage levels, the material and process requirements are higher, and the air gap is not easily eliminated in the core, resulting in a low partial discharge voltage. Tapeline capacitive bushings have gradually been replaced by oil-paper capacitive bushings due to high dielectric loss and low partial discharge voltage. Oil paper is used as the capacitor core. Generally, there is a porcelain sleeve. The lower part has a larger size, is sensitive to moisture, and has high sealing requirements. The advantage is that the insulating material and the process are easy to solve, the dielectric loss is small, and the partial discharge performance is good. Since the 1970s, 110-500 kV ultra-high pressure oil-paper capacitive casing has been widely used in China. In the 1980s, China also developed a plastic-impregnated paper sleeve, in which the capacitor core was made into a heart with an insulating paper roll, vacuum impregnated with a synthetic resin, and then thermally cured. Its performance combines the advantages of tape and oil-paper capacitive bushings.
Related Products
KB heat-shrinkable busbar protection sleeve is made of high-quality polymer and environmentally friendly flame retardant. It is formed by radiation cross-linking after molding. It is widely used in the protection of busbars and outdoor busbars in switchgear. It can prevent short-circuit faults caused by small animals such as mice and snakes; prevent acid, alkali, salt and other chemical substances from corroding the busbars; prevent accidental injury caused by accidental personnel entering the electrified area; adapt to the development trend of miniaturization of switchgear and solve Interphase insulation problem of the busway.
Characteristics
Shrinkage ratio: 2.5:1.
Applicable temperature range: -55 ° C ~ 125 ° C.
Initial shrinkage temperature: 70 ° C, full shrinkage temperature: 120 ° C.
Easy to use, the casing can be shrunk with an oven and a spray gun.
Flame retardant, soft, heat resistant, easy to use, reliable electrical performance and so on.
Application range
1. Eliminate short-circuit faults caused by small animals such as mice and snakes.
2, to prevent acid, alkali, salt and other chemical substances on the busbar corrosion
3, to prevent maintenance personnel from accidentally entering the charging gap to cause accidental injury
4. Adapt to the development trend of miniaturization of switchgear
5, solve the problem of phase insulation between the busbar slot
