METREL EurotestXE, Instruction Manual

Page: 70 / 114

MI 3102(H) BT Eurotest XE Measurements
70
Figure 5.59: Examples of IMD test results
Displayed results:
R1 ............ threshold indicative insulation resistance for L1
R2 ............ threshold indicative insulation resistance for L2
I1 .............. calculated first fault leakage current for R1
I2 .............. calculated first fault leakage current for R2
Calculated first fault leakage current at threshold insulation resistance is given as:
) 2 ( 1
2 1
) 2 ( 1
R
U
I
L L
 
U
L1-L2
is line-line voltage. The calculated first fault current is the maximum current that would
flow when insulation resistance decreases to the same value as the applied test resistance, and
a first fault is assumed between opposite line and PE.