The switching apparatus and the method are for varying the impedance of a phase line of a segment of an electrical power line. The phase line includes n conductors electrically insulated from each other and short-circuited together at two ends of the segment. The apparatus comprises a controllable interrupter connected in series for each conductor; a parameter detector; a first controller for controlling the interrupters; and a disabling unit for disabling the interrupters. The disabling unit comprises n controllable switches associated with the interrupters, position detectors for detecting which of the interrupters is closed, and a second controller having a command output to command the controllable switches and ensure that, at all operating times, at least one of the interrupters is closed and disabled.

The switching apparatus and the method are for varying the impedance of a phase line of a segment of an electrical power line. The phase line includes n conductors electrically insulated from each other and short-circuited together at two ends of the segment. The apparatus comprises a controllable interrupter connected in series for each conductor; a parameter detector; a first controller for controlling the interrupters; and a disabling unit for disabling the interrupters. The disabling unit comprises n controllable switches associated with the interrupters, position detectors for detecting which of the interrupters is closed, and a second controller having a command output to command the controllable switches and ensure that, at all operating times, at least one of the interrupters is closed and disabled.

An electro-mechanical disconnector mounted between an HV overhead power line conductor and a voltage transformer, mounted on a support of the support power line of HV overhead power line conductors. The electro-mechanical disconnector comprises an isolating element and a sacrificial element arranged in series with each other. The sacrificial element is made of a material capable of melting upon the passage of a fault current, and the sectioning element is capable of moving to an electrically insulating distance from the conductor following the melting of the element.