In other words, it is necessary to make the 2f detection reset
time faster in order to meet the requirement that the transformer
protection operating time is less than 30ms. In order to solve this
problem, an arithmetic algorithm, based upon the characteristics
of a 765kV transformer, contained within the 2f element is utilized so that resetting of the 2f detection function is faster. As a
result, a typical operating time of less than 26ms has been
achieved.