First, the contestants analyzed the dual-ended Comtrade fault records, captured by two SMART Blocks®, source-end waveform shown below:
Drag to Zoom
The contestants could see the fault was a Single Line-to-GND (SLG) fault (phase B) and they were provided the line-length, PT/CT ratios, and Phase-B based Sequence Components, as below:
Line length (miles):
PT ratio:
Whole number
CT ratio:
Whole number
B-PHASE BASE For fault types: B-GND, A-C, and A-C-GND
Source end
Zero Sequence Components
Positive Sequence Components
Negative Sequence Components
v0_b_rms:
0.00
v0_b_ang:
0.00
v0_b_re:
0.00
v0_b_im:
0.00
i0_b_rms:
0.00
i0_b_ang:
0.00
i0_b_re:
0.00
i0_b_im:
0.00
v1_b_rms:
0.00
v1_b_ang:
0.00
v1_b_re:
0.00
v1_b_im:
0.00
i1_b_rms:
0.00
i1_b_ang:
0.00
i1_b_re:
0.00
i1_b_im:
0.00
v2_b_rms:
0.00
v2_b_ang:
0.00
v2_b_re:
0.00
v2_b_im:
0.00
i2_b_rms:
0.00
i2_b_ang:
0.00
i2_b_re:
0.00
i2_b_im:
0.00
Remote end
Zero Sequence Components
Positive Sequence Components
Negative Sequence Components
v0_b_rms:
0.00
v0_b_ang:
0.00
v0_b_re:
0.00
v0_b_im:
0.00
i0_b_rms:
0.00
i0_b_ang:
0.00
i0_b_re:
0.00
i0_b_im:
0.00
v1_b_rms:
0.00
v1_b_ang:
0.00
v1_b_re:
0.00
v1_b_im:
0.00
i1_b_rms:
0.00
i1_b_ang:
0.00
i1_b_re:
0.00
i1_b_im:
0.00
v2_b_rms:
0.00
v2_b_ang:
0.00
v2_b_re:
0.00
v2_b_im:
0.00
i2_b_rms:
0.00
i2_b_ang:
0.00
i2_b_re:
0.00
i2_b_im:
0.00
For Single Line-to-GND (SLG) faults, the sequence networks connect in series at the fault point, as below:
Our winners knew that each sequence network is comprised of two parallel paths (between fault nodes), therefore the sum of the voltage drops along each parallel path must be equal.
Using the negative sequence loop is preferred as this network is unaffected by load or zero-sequence mutual coupling.
Therefore, summing the voltage drops along each of the parallel paths within the negative sequence network provides:
Knowing the line impedance (Z2L) and Sequence Components provided by ASAPiQ™ above:
Line impedance (real):
Ohms primary
Line impedance (j):
Ohms Primary
Then m is calculated as:
M_MAG:
nan
% of line-length from source
M_ANG:
nan
And:
Distance-to-Fault:
nan
miles from source
However, our contestants didn't know the line impedance. Instead, they knew the distance-to-fault (a function of m).
Therefore, rearranging the above formula to solve for Z2L, gives:
ASaP iQ™ Advanced Sensing and Prediction platform uses the above techniques to automatically calculate the line-impedance (once the distance-to-fault is entered) or to automatically calculate distance-to-fault (once the line impedance is entered). Both are valuable tools in helping protection engineers quickly and reliably pinpoint the location of faults to help shorten restoration times and keep production lines up and running.
