Technical Data Of The Measuring Devices - ABB REX 521 Technical Reference Manual, General

REX 521
4.1.6.2.
20
Protection Relay
Technical Reference Manual, General
The scaling factor is calculated channel by channel as follows:
Scaling factor = I / I
nmd
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 analog 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...

Technical data of the measuring devices

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.
Values to be set for a current transformer:
• 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°)
Values to be set for a voltage transformer:
• 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
np,
1MRS 751108-MUM
I = 500 A
nmd
I = 250 A
np
500 A / 250 A = 2.00