Computing Coefficients - ABB DPU 1500R Instruction Book

ABB Distribution Protection Unit 1500R

Computing Coefficients

Step 1: If desired, the user may enter a description in the Description field.
Step 2: Under Standard, the user should select either ANSI curves or IEC curves.
Step 3: Under the data entry method, the user should select Compute Coefficients. At this point, the Compute
Coefficients Tab towards the top of the screen should appear. Click this tab.
Step 4: Using the mouse, place the cursor on Row 1, Column 1 (Current M)
Step 5: Type the desired multiple of tap, M, and press the TAB key. Now type the corresponding time. Press the
TAB key again to enter a second point. Continue until at least 5 data points are keyed in (100 points max).
Please note that whether you are using ANSI or IEC type curves, the points you enter are equivalent to a
time dial of 1.
Step 6: After all points are entered, click on solve. The computed coefficients will appear on the screen. In order to
see these points on a graph, hit the Apply button.
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Optional Features