Siemens Siprotec 7UM611 Manual page 55

Figure 2-12
The changeover to the lower current pickup value on decreasing voltage (loop enable)
is performed on a phase by phase basis in accordance with Table 2-3.
7UM61 Manual
C53000-G1176-C127-3
2.8 Inverse-Time Overcurrent Protection (ANSI 51V)
Logic Diagram of the Voltage Controlled Inverse Overcurrent Time Protection
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