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GRID
January 2012
Current Transformer
From Definition to Manufacturing
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Agenda
1 Critical data for Current Transformer Design and Calculation
2 Standard Lead time
Current transformer From Definition to Manufacturing 2012-01-06
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Agenda
1 Critical data for Current Transformer Design and Calculation
2 Standard Lead time
RMC Export Plan 2011-12-08
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Critical data for Current Transformer Design and Calculation
Electrical Parameters and Site conditions
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Critical data for Current Transformer Design and Calculation
CT Type OSKF 170Head Size 1 Size 2 Size 3
Core Box 1 2 3
Insulator A B C D E F H I J
Electrical Parameters and Site conditionsCores definition is now needed to definte the right Core Box, Head and Insulator Size
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Critical data for Current Transformer Design and Calculation
Size of cores depend among
others on
Accuracy class & burden
Transformation ratios
Short circuit current
Size (and price) of CT depends on Size of core box holding the cores
Type of ratio changes
Misestimated requirements may
lead to unnecessary costs
Secondary Cores Definition
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Critical data for Current Transformer Design and Calculation
10 VA 5P20 20 VA 5P20 50 VA 5P20
Core cross section
Secondary core + winding
Secondary Cores Definition has direct impact on Cores Box, Head andInsulator size
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Critical data for Current Transformer Design and Calculation
2000/1 A
Vkp>240 Volts with Rct=5 ohms
Core cross section
Secondary core + winding
Impact due to Class X defintion and choice of Rct value
2000/1 A
Vkp>240 Volts with Rct=10 ohms
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Critical data for Current Transformer Design and Calculation
1600/1 A
Vkp>1600 Volts with Rct=4 ohms
Core cross section
Secondary core + winding
Impact due to Class X defintion and choice of Vkp value
1600/1 A
Vkp>800 Volts with Rct=4 ohms
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Critical data for Current Transformer Design and Calculation
Secondary Cores Definition
Core definition is not possible without Class X parameters Input
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Critical data for Current Transformer Design and Calculation
Secondary Cores Definition
For each Core withClass X :Vk, Io and Rct have tobe defined
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Agenda
1 Critical data for Current Transformer Design and Calculation
2 Standard Lead time and Manufacturing Process
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Standard Lead time and Manufacturing Process
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Standard Lead time and Manufacturing Process
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Standard Lead time and Manufacturing Process
Cores are placed in such a way
to make best possible use of the available space.
(Simulation)
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Standard Lead time and Manufacturing Process
Magnetic sheet secondary cores
design & manufacturing
Winding of secondaries
Mounting of secondary cores inan aluminum shell
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Standard Lead time and Manufacturing Process
Magnetic sheet secondary cores
design & manufacturing
Winding of secondaries
Mounting of secondary cores inan aluminum shell
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Standard Lead time and Manufacturing Process
Magnetic sheet secondary cores
design & manufacturing
Winding of secondaries
Mounting of secondary cores inan aluminum shell
High voltage insulation : paper
taping
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Standard Lead time and Manufacturing Process
Magnetic sheet secondary cores
design & manufacturing
Winding of secondaries
Mounting of secondary cores inan aluminum shell
High voltage insulation : paper
taping
Intermediate semi-conductive
screens
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Standard Lead time and Manufacturing Process
Magnetic sheet secondary cores
design & manufacturing
Winding of secondaries
Mounting of secondary cores inan aluminum shell
High voltage insulation : paper
taping
Intermediate semi-conductive
screens
More paper taping
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Standard Lead time and Manufacturing Process
Magnetic sheet secondary cores
design & manufacturing
Winding of secondaries
Mounting of secondary cores inan aluminum shell
High voltage insulation : paper
taping
Intermediate semi-conductive
screens
More paper taping
Final conductive screen
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Standard Lead time and Manufacturing Process
Assembling:
Porcelain mounting
Secondary terminal box
cablingPrimary winding assembly
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Standard Lead time and Manufacturing Process
Assembling:
Porcelain mounting
Secondary terminal box
cablingPrimary winding assembly
Treatment:
Heat (105 C)
Vacuum (0.1 mBar)
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Standard Lead time and Manufacturing Process
Assembling:
Porcelain mounting
Secondary terminal box
cablingPrimary winding assembly
Treatment:
Heat (105 C)
Vacuum (0.1 mBar)
Oil treatment:
Oil filling under vacuum
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Standard Lead time and Manufacturing Process
Top cover mounting
Final inspection
Routine tests:
Dielectric
Partial discharges
Accuracy
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GRID
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