METHOD AND DEVICE FOR ELECTRICAL SHORT-CIRCUIT TESTING AND LOCATING FOR LINES,PREFERABLY FOR CONTACT LINES OF ELECTRIC RAILWAYS

摘要

A variable-frequency (f) electric supply signal (U, I) is generated and is applied to the catenary (13-18) via an electrical oscillation circuit (9, 10). The frequency of the supply signal is altered until the electric signal exhibits an extreme and the phase angle ($g(f)) becomes zero, providing a criterion for the presence of a short circuit. A conclusion can be reached concerning the location (lk?) of the short circuit from the degree of detuning between the supply signal frequency (fk?) at the extreme and phase angle zero and the natural frequency (fo?) of the oscillation circuit.