Power supply system comprising an a.c. voltage supply source, a load and a connecting cable between the source and the load

摘要

A power supply system comprising an a.c. voltage source (ACS), a load (LL) and a detachable (DCC) cable connection (CC). In order to prevent a dangerously high a.c. voltage from occurring between cable conductors (CC1, CC2) when the cable (CC) is loose, a safety circuit (CITSR) providing an on/off switching circuit (S1, SR1, S2, SR2) is provided. In accordance with the invention, there is present in the safety circuit (CITSR) a parallel arrangement (CI) of at least one capacitor (C) and a direct current source (I), which parallel arrangement (CI) is present in a direct current circuit (CC2, DC2, CC1, S1, DC1, CC2) which is closed via the cable conductors (CC1, CC2), the a.c. voltage source (ACS) and the load (LL). The parallel arrangement (CI) is coupled to the on/off switching circuit (S1, SR1, S2, SR2) via a threshold circuit (TC). When a controllable a.c. voltage source (ACS) is used to produce a low voltage (30V) and a high supply voltage (700V) before the high voltage (700V) is supplied, it is detected at the low voltage (30V) whether there is a high-ohmic load or a short-circuit between the cable conductors (CC1, CC2).