| 摘要 |
FIELD: phase-to-phase fault protection of double-ended or ring-circuit single-ended power transmission lines. ^ SUBSTANCE: proposed method includes continuous measurement of electrical installation current and its comparison with reference current, measurement of time equivalent of angle between current and shaped reference signal, and comparison with first and second values of angle equivalent; if current exceeds reference value, time equivalent of angle is higher than first and lower than second reference values of angle equivalent, then OFF-signal is supplied in a certain time delay to electrical installation; reference signal is shaped by memorizing length of preceding current cycle, and time equivalent of angle is found as increment between shaped reference signal and length of present cycle of current. ^ EFFECT: enlarged functional capabilities and enhanced reliability. ^ 1 cl, 4 dwg |
