Insulators
Insulators for power transmission and distribution
Overhead line insulators are subject to electrical and mechanical stresses. Insulators have to isolate the conductors form potential to earth and must provide physical supports. Insulator must be capable of withstanding these stresses under all conditions encountered in a specific line. The electrical stresses result from: the steady-state operating power-frequency voltage (highest operation voltage of the system), temporary overvoltages at power frequency, switching and lightning overvoltages. Insulators are the electrically insulated connection between tower and conductor line. The individual units are connected by fittings of malleable cast iron or forged iron. Insulators made from aluminous porcelain are most frequently adopted. These insulators are puncture-proof. Failures under operation are extremely rare. Insulators show superior behavior, especially in polluted areas. Also insulators should be protected from bending loads by suitable fittings. Composite insulators are the third major type of insulator for overhead power line applications. The composite insulator is made of a glass fiber reinforced epoxy rod. The glass fibers applied are ECR glass fibers that are resistant to brittle fracture (ECR = electrical grade corrosion to be withstood and the pollution to which the insulation is resistant glass fibers).
Insulators portfolio for power transmission and distribution systems
Composite insulators, epoxy resin insulators, glass insulators, porcelain insulators, ceramic insulators are in use, depending on the requirements and the experience with certain insulator types. These insulator types provides superior performance and reliability, particularly because of improvements over the last 20 years and has been in service for more than 30 years. Depending on voltage level and the acting forces of the overhead line, different classes are adopted. Distribution class is applicable for system voltages up to 72,5kV, specified mechanical loads up to 70 kN (from 12 kV to 145 kV), specified mechanical loads up to 100 kN (from 24 kV to 420 kV), high creepage distances, max. flashover distance. Transmission class is applicable for system voltages up to 170kV, specified mechanical loads up to 120kN (from 24 kV to 420 kV), specified mechanical loads up to 160kN (from 72,5 kV to 550 kV) high creepage distances, max. flashover distance. To handle switching and lightening overvoltages, insulators are designed according to IEC 61109, IEC 62217, IEC 60815, IEC 61466, IEC 60071, according to design tests: interface & connection of the end fittings, assembled load-time tests, tracking & erosion tests, dye penetration, water diffusion, flammability, mechanical load-time test as well as according to electrical tests: lightning impulse withstand voltage, switching impulse wet withstand voltage, power-frequency wet withstand voltage, maximum withstand voltage of pollution, corona characteristics.
Cost-efficient and well-proven insulators for AIS substations, GIS substations, overhead lines, substation services
For electrical design of insulators, the following important features and must be considered in advance: low weight, less volume and less damages, shorter string length compared to cap-and-pin – and porcelain insulator strings, high mechanical strength, vandalism resistance, high performance in polluted areas, maintenance free, long service life, compact structure, high quality of silicon and glass, high mechanical tensile strength and high creepage distance, low weight, highest level of electrical insulation, environmental protection, short delivery time, compact design, no moisture ingress due to overmoulding design system, high UV-,Ozone-,Erosion-resistance fubber housing, control of E-field distribution due to high-end design of end fitting modeling an integrated grading ring, one-piece housing with “overmoulding” system, no sealing system, end fittings, Accessories (arcing horns, corona rings), acid resistant, hydrolyse resistant, the silicone housing overlaps a small part of the metal end fittings, best pollution performance, electrical-corrosion-resistant, high temperature vulcanizing silicone rubber, tracking resistant, fire-proof, hydrophobicity transfer mechanism, self-cleaning surface (due to hydrophobicity), forged steel, cast iron, hot dip galvanized, erosion-free, low weight, high insulation level and high creepage distance, best performance in contaminated environments, no brittle fracture, one-piece direct moulded housing, no moisture ingress, control of E-field distribution in the critical point, no sealing system needed, erosion-free housing, e-field control, no sealing needed, minimized power loss, maximized service life, maximized service life, minimized power loss, minimized costs, hydrophobicity, UV-resistant, erosion resistant, high contamination applications, maintenance free, low service costs, reliability, best pollution performance, long creepage distance, high insulation level, service life, electrical corrosion resistant, safety, breakage cracking resistant, unexplosive housing, handling and costs, low weight, maintenance-free, self-cleaning housing surface.
Insulators for power transmission and distribution
Overhead line insulators are subject to electrical and mechanical stresses. Insulators have to isolate the conductors form potential to earth and must provide physical supports. Insulator must be capable of withstanding these stresses under all conditions encountered in a specific line. The electrical stresses result from: the steady-state operating power-frequency voltage (highest operation voltage of the system), temporary overvoltages at power frequency, switching and lightning overvoltages. Insulators are the electrically insulated connection between tower and conductor line. The individual units are connected by fittings of malleable cast iron or forged iron. Insulators made from aluminous porcelain are most frequently adopted. These insulators are puncture-proof. Failures under operation are extremely rare. Insulators show superior behavior, especially in polluted areas. Also insulators should be protected from bending loads by suitable fittings. Composite insulators are the third major type of insulator for overhead power line applications. The composite insulator is made of a glass fiber reinforced epoxy rod. The glass fibers applied are ECR glass fibers that are resistant to brittle fracture (ECR = electrical grade corrosion to be withstood and the pollution to which the insulation is resistant glass fibers).
Insulators portfolio for power transmission and distribution systems
Composite insulators, epoxy resin insulators, glass insulators, porcelain insulators, ceramic insulators are in use, depending on the requirements and the experience with certain insulator types. These insulator types provides superior performance and reliability, particularly because of improvements over the last 20 years and has been in service for more than 30 years. Depending on voltage level and the acting forces of the overhead line, different classes are adopted. Distribution class is applicable for system voltages up to 72,5kV, specified mechanical loads up to 70 kN (from 12 kV to 145 kV), specified mechanical loads up to 100 kN (from 24 kV to 420 kV), high creepage distances, max. flashover distance. Transmission class is applicable for system voltages up to 170kV, specified mechanical loads up to 120kN (from 24 kV to 420 kV), specified mechanical loads up to 160kN (from 72,5 kV to 550 kV) high creepage distances, max. flashover distance. To handle switching and lightening overvoltages, insulators are designed according to IEC 61109, IEC 62217, IEC 60815, IEC 61466, IEC 60071, according to design tests: interface & connection of the end fittings, assembled load-time tests, tracking & erosion tests, dye penetration, water diffusion, flammability, mechanical load-time test as well as according to electrical tests: lightning impulse withstand voltage, switching impulse wet withstand voltage, power-frequency wet withstand voltage, maximum withstand voltage of pollution, corona characteristics.
Cost-efficient and well-proven insulators for AIS substations, GIS substations, overhead lines, substation services
For electrical design of insulators, the following important features and must be considered in advance: low weight, less volume and less damages, shorter string length compared to cap-and-pin – and porcelain insulator strings, high mechanical strength, vandalism resistance, high performance in polluted areas, maintenance free, long service life, compact structure, high quality of silicon and glass, high mechanical tensile strength and high creepage distance, low weight, highest level of electrical insulation, environmental protection, short delivery time, compact design, no moisture ingress due to overmoulding design system, high UV-,Ozone-,Erosion-resistance fubber housing, control of E-field distribution due to high-end design of end fitting modeling an integrated grading ring, one-piece housing with “overmoulding” system, no sealing system, end fittings, Accessories (arcing horns, corona rings), acid resistant, hydrolyse resistant, the silicone housing overlaps a small part of the metal end fittings, best pollution performance, electrical-corrosion-resistant, high temperature vulcanizing silicone rubber, tracking resistant, fire-proof, hydrophobicity transfer mechanism, self-cleaning surface (due to hydrophobicity), forged steel, cast iron, hot dip galvanized, erosion-free, low weight, high insulation level and high creepage distance, best performance in contaminated environments, no brittle fracture, one-piece direct moulded housing, no moisture ingress, control of E-field distribution in the critical point, no sealing system needed, erosion-free housing, e-field control, no sealing needed, minimized power loss, maximized service life, maximized service life, minimized power loss, minimized costs, hydrophobicity, UV-resistant, erosion resistant, high contamination applications, maintenance free, low service costs, reliability, best pollution performance, long creepage distance, high insulation level, service life, electrical corrosion resistant, safety, breakage cracking resistant, unexplosive housing, handling and costs, low weight, maintenance-free, self-cleaning housing surface.