M.T. grounding resistor with continuity monitoring

RAM-UMT-02 is a set of grounding resistors in M.T. with the differential of having an earth-neutral circuit integrity monitoring, allowing the detection of ruptures and avoiding serious accidents.


Why monitor the continuity of ground resistors?

During its useful life, it is natural that components age, being subject to corrosion, humidity and thermal stress. All this contributes to the possibility of circuit breakage, which prevents its disconnection in the event of a fault to the ground and results in transitory overvoltages. If it is not easy to prevent the circuit from breaking, monitoring allows to anticipate the problem and provide maintenance, ensuring that it is always able to perform its functions.

Technical and Operational Features

Applicable to grounding resistors in the range of 2.4kV to 13.8kV, the monitoring in question is made from a set composed of a microprocessor electronic unit and a resistive sensor, a set that operates based on the injection of an online controlled current in the form of a loop circulating in the stretch of circuit to be monitored. If the loss of electrical continuity occurs (rupture of the resistive elements), the current loop will be interrupted and the electronic unit will actuate signaling this occurrence through a contact for remote actuation.

  • Aux. feeding voltages available: 85-265 Vac and 100-230 Vcc;
  • Auxiliary contacts:
    01 NAF (remote indication of fault);
    01 NAF (remote indication of the presence of the auxiliary supply voltage).

The monitoring through the UMT-02 unit can be performed in existing ground resistor installations in the form of "upgrade" or in new installations.

Constructive Features

  • UMT-02 unit mounted in plastic case75x55mm;
  • In the new installations the UMT-02 unit and the resistive sensor are installed inside the grounding resistor housing itself.

Simplified Electrical Diagrams

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