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As we know, the choice of fuse coordination is a repetitive process, overlaying Time Current Curves(TCCs) lends
itself nicely to tabular representation. Thus, the fuse-fuse coordination problem can be solved by using either
the TCC coordination method or a coordination table. The table that is used in the module is shown in table 1.
The label protecting and protected device are defined in the Power System Protection link.
Table 1. Type T fuse links coordination table
In the KBS module that has been developed, fuse-fuse coordination
is solved using the coordination table, which is derived from TCC coordination.
Now to choose the fuse size for this problem, we need to start from the protecting fuse. Similar with the previous
example, the fuse size is found by how large a continuous current it can carry. 20T and 30T fuses have been choosen to protect
line 2 and line 3 respectively. To find the protected link we can find 20T in the "protecting fuse link rating" at the left column,
and then follow horizontally to the right to the "maximum fault current" that is greater than 1190 amperes.
Thus, the 50T fuse is used to protect the source-side. Once the simulation is run, the result is shown below.
We can see that all devices are coordinated properly. This result is confirmed by checking it with table 1.
First, find the 20T in the "protecting fuse link rating" at the left column, and then follow horizontally to find 50T fuse link.
From there we can see that the 20T can coordinate up to 3200 amperes with the 50T, which is greater than 1190 amperes at loacation A.
Similarly for line 3. the 30T fuse can coordinate up to 1500 amperes with the 50T fuse.
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