METHOD AND DEVICE FOR AUTOMATICALLY CONTROLLING THE INTEGRITY OF THE RESISTOR FOR TREATING THE ARTIFICIAL NEUTRAL PHASE OF THE AVERAGE VOLTAGE ELECTRIC NETWORKS

摘要

The invention relates to a method and device for automatically controlling the integrity of the resistor for treating the artificial neutral phase of the average voltage electric networks of (20 kv) for the distribution of the electrical energy, in the two states it can be in the installations: in function and in stand-by. according to the invention the method consists in using the voltage occurring at the terminals of the resistor for treating the artificial neutral, due to unbalance exisiting in the average voltage energetic installations for sensing the increase of impedance, breaking the resistor in function prior to producing a mono-phase short-circuit or to grounding in the network and in using the injection of energy to sense the breaking of the resistor in reserve. According to the invention, the device comprises a maximal impedance relay for signalling the failure of the resistor in function and in reserve, respectively, prior to producing a mono-phase short-circuit or a grounding in the average voltage network, and it also comprises a maximal current relay (1) for signalling the failure of the resistor in function, in case a mono-phase short-circuit occurs near the transformation station, the maximal impedance relay being made with a voltage module (T3, C1, D15 and D16), a current module (T1, T2, D5...D14) and an electrical balance (D1, D2, D3 and D4). The current module of the maximal impedance relay consists of two identical transformers (T1 and T2) each having two primary windings in series with the maximal current relay (I) and connected in phase opposition so that the energy injection in the adapter transformer (Ta) towards the reserve resistor is carried out exclusively through a second measuring transformer (TT-2) without the galvanic interruption of the secondary circuits of a first measuring transformer (TC-1).