Method for Sectioning With a Section Switch a Medium-Voltage Electric Power Distribution Line Exhibiting a Disturbance, Section Switch for Medium-Voltage Electric Power Distribution Line Applicable Thereon and Electronic Circuit for Detecting a Fault Current and Comprised by Said Section Switch

摘要

The present invention discloses a method for sectioning a medium-voltage distribution electric line evidencing a disturbance, wherein said method comprises the stages of: (a) evaluating a current in a medium-voltage line with a detection coil; (b) converting the intensity generated by said current by the detection coil in a potential difference, further transferring the information to a microprocessor; (c) analyzing the profile of the wave generated by the current by an algorithm to analyze harmonic levels by Fourier Series, and (d) determining the behavior or the section switch from the result obtained in (c). Step d) comprises making no count to trigger the disconnection mechanism (i) when the current value does not exceed a predetermined value for which said current is detected as a fault current; (ii) when el the wave profile corresponds to a transformer input current or in-rush current; or (iii) making a count to trigger the disconnection mechanism when the wave profile corresponds to a short-circuit exceeding the predetermined current value as fault current. Given the case of d) (ii) the method further comprises step e) comprising: (i) not triggering the disconnection mechanism when a transient fault is involved; or either, (ii) triggering the disconnection mechanism when the predetermined count number is reached. The method can simultaneously with e) ii) further comprise f) sending a RF signal to other or others parallel connected section switches at a point of the distribution line in order to be jointly disconnected. The invention also refers to section switches for electric power distribution lines for auxiliary branches where the main fine is protected by an automatic reset circuit breaker, which comprises an electronic circuit with a microcontroller capable of distinguishing a permanent fault current from a transient fault current, thereby immunizing the section switch against “in-rush” currents; and to said electronic circuit.