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IT The challenge of bushing
High-voltage bushings are an important component of the power transmission and distribution. The requirements for the bushings are increasing, particularly in light of longer transmission routes and higher voltages. The voltage range for transformer bushings is now up to 1100 kV.
CondenserBushings and HighCurrentBushings are the products of a highly developed design and manufacturing process. There are various designs of high-voltage bushings in which aluminum foil and insulation paper or crepe fiber must be wound precisely.
The production of bushing
Using practiced and high-precision winding technology, we are able to offer high-voltage bushings up to a width of 14000 mm. Our unwinders have precise guidance and tension-controlled drive systems as well as integrated edge cutting and edge strip winders. RIF dry type condenser bushings use high insulation performance glass fiber impregnated with epoxy resin. And the winding process is automatically controlled by microcomputer to produce the insulation by crossing stacking according to geodesic. Based on the special mechanical paving design, HeweiPower have excellent mechanical strength, can handle with complex operating environment and have excellent shock and earthquake resistance, far exceeding the requirement of a magnitude 9 earthquake intensity of 0.4 g.
High-voltage and high-current bushings
How capacitor-controlled high-voltage and high-current bushings work?
All materials that carry an electrical charge generate an electrical field. If a current-carrying conductor is near a material at earth potential, it can build up very high field strengths, especially where the field lines are forced to bend sharply around the earthed material. The bushing controls the shape and strength of the field and reduces the electrical voltages in the insulating material.
Capacitor bushings may seem simple, but they are the product of a sophisticated design and manufacturing process. Unlike solid bushings, a capacitor bushing uses coaxial conductive layers inserted into the insulation at predetermined radial intervals; this design separates the center conductor from the outer insulator (casing) of the bushing.
The multiple conductive inserts form concentrically arranged and series-connected capacitive elements called “capacitors.” Their purpose is to control the electric field around the center conductor (axially and radially graded) so that the voltage is more evenly distributed throughout the bushing’s surrounding insulation system. The electric field is controlled to optimize the size, mass, and electrical performance characteristics of a bushing based on voltage class and other operating requirements.
Different types of capacitor-controlled high-voltage and high-current feedthroughs
• RBP (Resin Bonded Paper) is a term for a feedthrough made of a resin-coated kraft paper
• OIP (Oil Impregnated Paper) is a term used for feedthroughs that use plain kraft paper and the capacitor core is impregnated with transformer-grade mineral oil.
• Printed OIP (Oil Impregnated Paper) is areas on kraft paper printed with conductive graphite ink that absorb voltage like a capacitor and the capacitor core is impregnated with transformer-grade mineral oil.
• RIP (Resin Impregnated Paper) is a technology that uses a crepe-like paper in the capacitor core that is wrapped with aluminum foils to provide voltage grading. After the paper core is wound to form the capacitor, it is inserted into a metal cylinder that is completely filled with epoxy resin under vacuum.
• RIN (Resin Impregnated Nonwoven) is very similar to RIP and RIS except for the insulating material used to accommodate the aluminum foil voltage gradients. The RIN capacitor core uses a nonwoven fabric instead of the crepe paper or synthetic mesh to allow resin penetration at the lowest possible material moisture and to form a fully encapsulated, void-free capacitor body with almost no partial discharge.
• RIF (Resin Impregnated fiber) is very similar to RIP except for the insulating material used to accommodate the aluminum foil voltage gradients. The RIF capacitor core uses a fiber instead of the crepe paper to allow resin penetration and to form a fully encapsulated, void-free capacitor body with almost no partial discharge. Hewei Power produces RIF bushing with wide experience. Welcome to check www.heweipower.com
