KOTEF Brochure0 pages
INSTRUMENT TRANSFORMERS
nnnnKOTEF
nnnnCombined Metering Unit
nnnn72.5 to 420 kV
nnnnThe KOTEF is designed to provide both current and voltage measurements from a single
nnnndevice. It utilizes the same components as the individual CTs and VTs. Both transformers are
nnnncombined in a single metering insulator and are available in porcelain or composite. This is
nnnnan excellent solution for adding metering capability to either a new substation installation
nnnnor a site being upgraded where space is at a premium.
nnnn□ Metering - Protection
nnnn□ Characteristics:
nnnn- High quality paper-oil insulation
nnnn- Oil expansion by stainless steel
nnnndiaphragm bellows
nnnn- Oil level indicator
nnnn- Secondary cores in aluminum box
nnnn- Changing of primary ratio by primary
nnnnseries-parallel connection (double or triple
nnnnratio) or by secondary taps
nnnn□ Earthquake-proof design: The standard
nnnnKOTEF resists medium intensity seismic
nnnnevents. For highly active seismic regions,
nnnnthe design is adapted accordingly.
nnnn| Alstom Grid Instrument Transformers are installed in the four corners of the world
nnnn□ Compliance with IEC, ANSI/IEEE
nnnnor equivalent standards
nnnnDesign and avantages
nnnnAs with separate transformers, the current
nnnntransformer part is located in the head housing
nnnnand the voltage transformer part in the base
nnnntank. The grading layers between high-voltage
nnnnpotential and ground potential are arranged
nnnnin opposite directions inside the insulator. The
nnnnbase dimensions remain the same as a current
nnnnor voltage transformer of the same nominal
nnnnvoltage.
nnnnThe CT and VT functions are fulfilled within a
nnnnsingle unit. Consequently, considerable cost
nnnnsavings are realized in the initial purchase price,
nnnntransportation, real estate and installation labor
nnnnand materials compared to the equivalent costs
nnnnof two separate transformers.
nnnnLong service life
nnnnand near zero maintenance
nnnnInsulation integrity is assured by the fact that
nnnnthe oil is hermetically sealed from the atmo-
nnnnsphere by a metallic diaphragm assembly. All
nnnnexternal parts are of corrosion-resistant mate-
nnnnrial. Therefore, regular painting of the metallic
nnnnparts is not required.
nnnnKOTEF have been designed for a 30 year
nnnnlifetime and, thanks to the soundness of our
nnnntechnical concepts, many well out-live this
nnnnservice life.
nnnnCustomer Benefits
nnnn• Price advantage
nnnn• Space saving:
nnnnonly one base
nnnn• Cost savings on transporta-
nnnntion and assembly
nnnn• Near zero maintenance
nnnn• Protection against bursting
nnnnGRID
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