در ستینگ رله اضافه جریان حفاظت ترانسفورماتور مراعات هماهنگی بین رله های اولیه وثانویه حائز اهمیت است. در زیر بدین موضوع پرداخته شده است. When the amperemetric protection is installed at the starting point of each section., its threshold is set at a value lower than the minimum short-circuit current caused by a fault occurring on the monitored section, and higher than the maximum value of the current caused by a fault located downstream (beyond the monitored area). Once set, each protection is only activated for faults located immediately downstream of its position (inside the monitored zone), and is insensitive to faults occurring beyond this point. Nevertheless, in practice, it is difficult to define the settings of two cascading protection devices (while continuing to ensure proper selectivity), when the current does not notably decrease between two neighboring zones. However, for line sections separated by a transformer, this system can be used advantageously as it is simple, economical and quick (tripping with no time delay). The most interesting application example is the case where two line sections are separated by a transformer: see Figure below. 
