Basler Electric BE1-11m - Manual (Page 569)

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Equation 73. 2 nd Slope (Starting) Pickup Setting
Figure 392 shows an example of 2 nd Slope Restrained Operation.
Figure 392. 2 nd Slope Restrained Operation Example
Based upon good engineering practices during starting mode to overcome dc offset and CT mismatches,
set Restraint Slope 2 % at 1.7 times the running mode slope and add a 25 percent margin. Restraint
Slope 2 % is calculated using Equation 74.
𝑅𝑒𝑠𝑡𝑟𝑎𝑖𝑛𝑡 𝑆𝑙𝑜𝑝𝑒 2 % = 𝐷𝐶 𝑂𝑓𝑓𝑠𝑒𝑡 ∙ 25% 𝑀𝑎𝑟𝑔𝑖𝑛 ∙ 𝑅𝑒𝑠𝑡𝑟𝑎𝑖𝑛𝑡 𝑀𝑜𝑑𝑒 1 % = 1.7 ∙ 1.25 ∙ 0.15% = 32%
Equation 74. Restraint Slope 2 %
Set the 2 nd Slope Pickup (starting) at 3.42 and the Restraint Slope 2% at 32.
Alarm
The BE1-11m provides a Slope % alarm for cases where high loads or through faults cause unbalance in
the differential. The Slope % Alarm is calculated in Equation 75.
𝑆𝑙𝑜𝑝𝑒 % 𝐴𝑙𝑎𝑟𝑚 = 1.5 ∙ 𝑅𝑒𝑠𝑡𝑟𝑎𝑖𝑛𝑡 𝑆𝑙𝑜𝑝𝑒 2 % = 1.5 ∙ 32% = 48%
Equation 75. Slope % Alarm
The setting range for Slope % Alarm is 50 to 100 in increments of 1, so a Slope % Alarm of 50% is used
for this example.
The Current Differential (87) screen is shown in Figure 393.
BE1-11m Settings Calculation Examples