Siemens SIPROTEC 7SD80 - Page 92

Functions
2.4 Backup Overcurrent
SIPROTEC, 7SD80, Manual
E50417-G1140-C474-A1, Release date 09.2011
92
Characteristic Curves for the 50N Element
During configuration of the scope of functions at address 126, the available characteristics were determined.
Depending on the selection made there, only the parameters associated with this characteristic curve are ac-
cessible.
The inverse time elements enable the user to select different characteristic curves. Address 126 allows you to
specify whether you work with IEC characteristics (50(N) 51(N) IEC) or ANSI characteristics(50(N)
51(N)ANSI).
If you work with IEC characteristics, you can select the following setting options at address 2642:
• Normal Inverse
• Very Inverse
• Extremely Inv.
• LongTimeInverse
If you work with ANSI characteristics, you can select the following setting options at address 2643:
• Inverse
• Short Inverse
• Long Inverse
• Moderately Inv.
• Very Inverse
• Extremely Inv.
• Definite Inv.
The characteristics and equations they are based on are listed in the „Technical Data“. They apply for direc-
tional and non-directional elements alike.