CG 220KV La - Surge Arresters

Product Details

Components in any power system face in service, overvoltages that arise either due to natural lightning or inevitable switching operations. Surge arresters are used to protect power system installations and equipment against Lightning Overvoltages, Switching Surges etc. Generally arresters are connected across the equipment to be protected, typically between phase and earth for three phase installations. CG metal oxide Surge Arresters consist of active part, which is a series of highly nonlinear ceramic resistors made essentially of Zinc Oxide. Fine Zinc Oxide crystals are surrounded by other metal oxides (additives). Special Features  Unique doughnut construction of ZnO elements offer high energy capability, provide uniform density and temperature distribution.  Shatter proof performance.  Simple, robust construction of Arresters.  Extremely high non-linearity of ZnO elements.  Positive locking of Zinc Oxide elements.  Low power loss resulting in enhanced performance at elevated temperatures.  Controlled environment assembly line.  Ultra stable elements resulting in enhanced overvoltage protection capacity.  Available in Brown & ANSI-Grey Porcelains & composite. All CG Arresters in this Catalogue are designed in line with the requirements of ANSI-IEEE Standard C62.11 & IEC 60099-4. Note : CG Ltd. reserves the right to change Design and specifications in this catalogue without notice, due to continuous product improvements.xplanation of Terms • Voltage Rating : The voltage rating of an arrester is that voltage which can be applied for a limited time after the arrester has absorbed a large amount of energy as established in the operating duty tests. The rated voltage is used as a reference parameter for the specification of operating characteristics. • Maximum Continuous Operating Voltage (MCOV) : The MCOV is the maximum permissible rms value of power frequency voltage that may be applied continuously between the terminals of the arrester. • Temporary Overvoltage Capability : An arrester must be selected with a high enough voltage rating to withstand temporary overvoltages which might be caused by various occurrences on the system. The most common event causing a temporary overvoltage is a single line to ground fault. For an effectively grounded system such faults will normally be cleared in less than one second. Therefore an overvoltage capability based on a duration of one second is usually recommended. Also, the below table shows Temporary Overvoltage Capability for a time range of 0.1 to 1,000 seconds. Arrester Voltage Ratings The chart below indicates the minimum MCOV customers need to specify for an arrester as a function of system voltage. The minimum recommended ratings for solidly grounded systems allow for a temporary voltage rise of at least 40% over a period of one second. Higher temporary overvoltages may require higher MCOV.