Technical Guide P12y/EN FT/D22
User Guide
MiCOM P125/P126/P127 Page 9/108
3. GENERAL CHARACTERISITCS
3.1 Analogue Inputs
The analogue inputs for each relay are shown in the following table:
Type of Analogue Inputs
MiCOM
P125
MiCOM
P126
MiCOM
P127
Phase current inputs 3 3
Earth current inputs (high, medium,
low sensitivity by Cortec code)
1 1 1
Residual voltage input 1 1 1/0
Phase to neutral or phase to phase
voltage inputs
2/3
Total analogue inputs 2 5 7
Following is a description of the voltage inputs connection for the P127 relay.
Case A
2 phase to neutral voltage inputs
1 residual voltage input
VC is then calculated as VC= VA+ VB + Ve
To obtain a correct reading of the input voltage the exact voltage transformer ratio
for Ve has to be set.
Case B
2 phase to phase voltage inputs
VCA is then calculated as VCA= VAB + VBC
Case C
3 phase to phase voltage inputs
No residual voltage input
Ve can be calculated as Ve = (VA+ VB+ VC )/3
· On the MiCOM P125 relays rear terminals there is one current input rated 1A
and one current input rated 5A available and one voltage input. On the MiCOM
P126 relay rear terminals there are four current inputs rated 1A and four current
inputs rated 5A available and one voltage input. On the MiCOM P127 relay rear
terminals there are four current inputs rated 1A and four current inputs rated 5A
available and three voltages input.
· By using the Cortec code (see the appropriate section) the user can choose the
voltage range for voltage inputs for the MiCOM P125 & P126 (one input) and
P127 (three inputs).
All logic outputs can be programmed to respond to any of the available control or
protection functions. Logic inputs can be assigned to various control functions.
All logic digital inputs can be programmed to respond to any of the available control
or protection functions. Their supply level is the same as the power supply selected of
the relay by Cortec. They can be supplied in A.C or D.C current by Cortec choice.
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