Results at Bottom
And the winners are . . .
Stephen Marx, BPA Kun Ren, ETAP
How they did it . . .
First, the contestants analyzed the dual-ended Comtrade fault records, captured by two SMART Blocks®, source-end waveform shown below:
Drag to Zoom
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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
Roger's handy tip #117:
During normal (pre-fault conditions), each of the three voltage and current phase signal sets are "balanced" (ie, of similar magnitudes and equally separted in phase). During a fault, these phasor sets become unbalanced, both in terms of magnitude and phase separation.

These sets of unbalanced phasors can be fully resolved by the creation of three sub (component) sets of balanced phasors such that when vectorially added together, sum to equal the set of unbalanced phasors.

Balanced sequence component sets:
  • Zero (in phase)
  • Positive sequence (normal phase rotation)
  • Negative sequence (reverse phase rotation)
Being balanced, enables traditional 3-phase voltage calculations (such as Kirchoffs laws) to be applied to any of these sequence component sets "during" fault conditions. This then, enables the calculation of "distance-to-fault" which is vitally important in helping to reduce restoration times.

        v0_b_rms: 2.43
        v0_b_ang: 72.21
        v0_b_re: 0.74
        v0_b_im: 2.31
        i0_b_rms: 2.69
        i0_b_ang: 164.88
        i0_b_re: -2.60
        i0_b_im: 0.70
        v1_b_rms: 36.75
        v1_b_ang: -86.95
        v1_b_re: 1.96
        v1_b_im: -36.70
        i1_b_rms: 3.19
        i1_b_ang: -175.05
        i1_b_re: -3.18
        i1_b_im: -0.27
        v2_b_rms: 2.71
        v2_b_ang: 67.21
        v2_b_re: 1.05
        v2_b_im: 2.50
        i2_b_rms: 2.20
        i2_b_ang: 160.84
        i2_b_re: -2.08
        i2_b_im: 0.72
        v0_b_rms: 1.56
        v0_b_ang: 72.21
        v0_b_re: 0.48
        v0_b_im: 1.48
        i0_b_rms: 1.72
        i0_b_ang: 164.88
        i0_b_re: -1.66
        i0_b_im: 0.45
        v1_b_rms: 23.52
        v1_b_ang: -86.95
        v1_b_re: 1.25
        v1_b_im: -23.49
        i1_b_rms: 2.04
        i1_b_ang: -175.05
        i1_b_re: -2.03
        i1_b_im: -0.18
        v2_b_rms: 1.74
        v2_b_ang: 67.21
        v2_b_re: 0.67
        v2_b_im: 1.60
        i2_b_rms: 1.41
        i2_b_ang: 160.84
        i2_b_re: -1.33
        i2_b_im: 0.46
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:     0.384       % of line-length from source
        M_ANG:     -0.15
        Distance-to-Fault:     0.828       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.

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