DOC. MIE91093 Rev. 1.34
Page 125 of 145
generation on the auxiliary output: the currents add, and
produce a second harmonic distorted current. This current is
applied to one of the relay inputs.
Test procedure:
Connect the two currents to the relay input;
Increase I1 only until the relay trips;
Then increase Aux to increase the current from D1000
or TD1000, until the relay trip drops out.
Take note of the two currents and calculate the 2
nd
Harm %
H
%
:
the harmonic percentage is, with D1000:
100
*
_
_
2
2
%
I
Ext
Iac
I
Ext
H
Or, with TD1000:
100
*
2
1
2
2
2
%
I
I
I
H
1.16
P
RIMARY END TO END TEST
The purpose of the test is the check the complete protective
scheme of a line differential relay, including the CTs. This kind
of test is particularly complex and requires a big effort in the
coordination of two teams of technicians at both ends of a line.
A a
B b
C c
N n
I
1
I
2
I1 + I2
100 Hz
50 Hz
