Composite Insulator Corona Rings For HV Test Laboratory , Steel And Copper Grading Ring
DIN,ISO, Non-Standard or according to customers’requirement
Power Hardware, Cable Hardware,High Voltage Test etc
International standard package such as carton wooden or according to your requirements
According to the quantity of products but will as soon as possible
L/C, T/T, Western Union
30% TT before the produce, 70% before the shipment
Place of Origin
Corona&Shielding Ring for Insulator is used to very high voltage power transmission insulators and switchgear, and on scientific research apparatus that generates high voltages, for lower its maximum values below the corona threshold, preventing corona discharge.
What is Grading Ring?
Compared to electric porcelain insulator, composite insulator is featured with high intensity, light weight, high wet-flashover and flashover voltage, easy operation maintenance, strong ability of impulse withstand, widely applied to transmission line suspension string, and has spread application in tension string in recent years. Surface field distribution and potential distribution for composite insulator without corona ring is greatly uneven, due to composite insulator structure characteristics and high resistivity feature of silicon rubber, surface field density is highest at mandrel and steel cap joint, distribution voltage is highest at first umbrella dress near high voltage end. Exorbitant surface field density not only generate corona discharge, affect transmission line electromagnetic environment, produce audible sound pollution, but also cause strong electric erosion, causing further insulator aging. Corona ring installation is the normal solution to the problem of uneven potential field density distribution at insulator high voltage end. Installation of corona ring helps to transfer maximum field density from insulator surface to corona ring surface, thus effectively improves electric field distribution on insulator surface.
How Corona Ring Works?
Corona discharge is an electrode-outer air current flow that happens (among other) in high-voltage power lines. One way to reduce corona discharge is using corona rings - a ring made of thick metal rod positioned orthogonal to the wire, earthed and mounted to the power line post.
Corona discharge damages insulators and may produce breakdown products which can cause catastrophic insulation failure. If electric field at a certain point in air is strong enough, electrons will be stripped from the atoms and make the air a conductive plasma instead of an insulator. An object with high voltage and a small curvature (wire, sharp points) enables a field of enough high strength, forming a conductive layer of air, which is then surrounded by normal insulating air. In this case the conductive layer can increase in size (usually in one direction) until it forms a complete conductive path to another object, and then a huge arc-shaped current flow. Even a non-arc-shaped field can form a corona discharge. For that a conductive layer of plasma stops expanding and stays around the wire, ions in the plasma layer are repelled into neutral air and drift slowly in the air until discharged on another object, which is still a current flow yet much smaller.
Corona Ring Material
Aluminum, steel and copper are main material for Corona Ring and shielding components.
The corona ring packing can be done by wooden case and cartons.
1). Wooden Packing:
Wooden packing suitable for heavy weight corona rings. For export, Fumigation Certificate will be necessary when case is made of solid wood.
1.No bark allowed on wooden package.
2.Ship fumigated wooden package as soon as possible, ensure separate storage and segregation with non-fumigated wooden materials.
3.Validity of the certificate of fumigation is 21 days.
Inquire local ship agency whether fumigation is necessary every time after learning the lot package material, booking with a certain answer. Method of wood case fumigation include chemical preparation method and heat treatment.
2). Carton Packing:
Carton Packing always light weight and convenient for moving by hands. Its suitable for light weight rings.