GE P642, Technical Manual, Page: 187 / 592

to disappear, because the constant current nature of the transducer output simply raises the voltage and
continues to force the correct output signal around the loop.
The device provides power-on diagnostics and continuous self-checking of the current loop hardware. If a failure is
detected, all the current loop output functions are disabled and an alarm signal (CL Card O/P Fail) is raised. A
maintenance record (with an error code) is also produced, which provides additional details about the type of
failure.
6.4 APPLICATION NOTES
6.4.1 CLI SETTING GUIDELINES
For each analog input, you can define the following:
● The current input range: 0 – 1 mA, 0 – 10 mA, 0 – 20 mA, 4 – 20 mA
●
The analog input function (in the form of a 16-character input label)
● Analog input minimum value
●
Analog input maximum value
● Alarm threshold, range within the maximum and minimum set values
●
Alarm function (under or over)
● Alarm delay
●
Trip threshold, range within maximum and minimum set values
● Trip function (under or over)
●
Trip delay
The Maximum and Minimum settings allow you to enter the range of physical or electrical quantities measured by
the transducer. These are without units, however, you can enter the transducer function and the unit of the
measurement using the 16-character user-defined CL Input Label. For example, if using an input to monitor a
power measuring transducer, the text could be “Active Power (MW)”.
You need to set the alarm and trip thresholds within the range of physical or electrical quantities. The device will
convert the current input value into its corresponding transducer measuring value for the protection calculation.
For example if the CL input minimum is -1000 and the CL input maximum is 1000 for a 0 to 10 mA input, an input
current of 10 mA is equivalent to a measurement value of 1000, 5 mA is 0, and 0 mA is -1000.
These values are available for display in the CLIO Input (n) cells in the MEASUREMENTS 3 menu. The top line shows
the CL Input Label and the bottom line shows the measurement value.
6.4.2 CLO SETTING GUIDELINES
The outputs can be assigned to any of the following relay measurements:
● Magnitudes of IA, IB, IC of every CT input
●
Magnitudes of IA, IB, IC at HV, LV and TV sides of the transformer
● Magnitudes of IN Measured and IN Derived of every winding
●
Magnitudes of I1, I2, I0 at HV, LV and TV sides of the transformer
● Magnitudes of VAB, VBC, VCA, VAN, VBN, VCN, VN Measured, VN Derived
●
Magnitude of Vx
● VAN RMS, VBN RMS, VCN RMS
●
Frequency
● CL Inputs 1-4
●
RTD 1-10
P64x Chapter 7 - Transformer Condition Monitoring
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