摘要 |
FIELD: protection of electric plants. ^ SUBSTANCE: method includes phase-wise forming of differential current, proportional to difference of secondary currents at input and output of protected electric plant, and breaking current, consisting of two components, first of which is proportional to square root of vector result of multiplication of said secondary currents, and values of second are calculated by integration of additionally current, equal to difference between sum of modules of said secondary currents and module of differential current, fall of second component of breaking current is delayed, differential current is compared to bas and breaking current and on basis of results signal for activation of protection is given. ^ EFFECT: it is possible without decrease of protection sensitivity to provide selectiveness of its action during external short-circuits, followed by intensive transfer processes. ^ 3 cl, 3 dwg |