ABB Industrial IT enabled REX 521 Technical Reference Manual, General page 16

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Technical Reference Manual, General
The scaling factor is calculated channel by channel as follows:
Scaling factor = I / I
nmd np,
I Rated primary current [A] of the measuring device
nmd
I Rated primary current [A] of the protected unit connected to the
np
channel
Example:
Rated primary current of current trafo = 500 A:
Rated current of the protected unit = 250 A:
Scaling factor for current channels:
The scaling factors for the analogue channels can be set via the HMI of the
protection relay or with the Relay Setting Tool. The HMI path for the scaling factors
is: Configuration\Protected unit\IL1: scaling, IL2:
scaling...
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The technical data of the measuring devices is set using the Relay Setting Tool or
via HMI. The set values (Configuration\Meas.devices\) will affect the
measurements carried out by REX 521.
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• rated primary current (1...6000 A) of the current transformer
• rated secondary current (5 A, 2 A, 1 A, 0.2 A) of the current transformer
• rated current (5 A, 1 A, 0.2 A) of the current measuring input (= rated current of
the matching transformer of the protection relay)
• amplitude correction factor (0.9000...1.1000) of the current transformer at rated
current
• correction parameter for the phase displacement error of the current transformer
at rated current (-5.00°...0.00°)
• amplitude correction factor of the current transformer at a signal level of 1% of
the rated current (0.9000...1.1000)
• correction parameter for the phase displacement error of the current transformer
at a signal level of 1% of the rated current (-10.00°...0.00°)
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• rated voltage of primary voltage transformer (0.100...440.000 kV)
• rated voltage of voltage input (same as the secondary rated voltage of the primary
voltage transformer connected to the voltage input, 100 V, 110 V, 115 V, 120 V)
• amplitude correction factor of the primary voltage transformer voltage at rated
voltage (0.9000...1.1000)
• correction parameter for the primary transformer phase displacement error at
rated voltage (-2.00°...2.00°)
where
1MRS 751108-MUM
I = 500 A
nmd
I = 250 A
np
500 A / 250 A = 2.00