APPLICATION NOTES APPENDIX B
B-2
Once again, if the polarity of one of the phases is out by 180°, the magnitude of the resulting vector on a balanced system will be out by
a factor of 1.73.
On a three wire supply, this configuration will always work and unbalance will be detected properly. In the event of a single phase, there
will always be a large unbalance present at the interposing CTs of the relay. If for example phase 'A' was lost, phase 'A' would read zero
while phases 'B' and 'C' would both read the magnitude of phase 'C'. If on the other hand, phase 'B' was lost, at the supply, 'A' would be
180° out of phase with phase 'C' and the vector addition would equal zero at phase 'B'.
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