Pv. Brennan, RESIDUAL CURRENT DEVICE WITH HIGH IMMUNITY TO NUISANCE TRIPPING, IEE proceedings. Part G. Circuits, devices and systems, 140(2), 1993, pp. 140-144
Residual current devices, though offering a high degree of protection
from fire and electric shock hazards, are notoriously prone to nuisanc
e tripping. Efforts have been made to counter the problem primarily by
the use of simple time delays, with a moderate degree of success. Thi
s paper presents two techniques that greatly reduce the vulnerability
to nuisance tripping: phase detection to eliminate sensitivity to capa
citive leakage and a more elaborate two-stage time delay to reduce vul
nerability to transients. Results obtained with a prototype design are
presented to confirm the improvement in performance.