Transformer Protection Relay MCHD

The hermetic transformer protection device MCHD for hermetically sealed, liquid immersed distribution transformers without gaseous cushion in accordance with EN 50216-3. It´s main purpose is to detect oil temperature, oil level, overpressure and gas accumulation.

The transformer protection device MCHD for hermetically sealed distribution transformers is equipped with 2 x SPDT adjustable contacts, for min. and max. temperature, a Reed switch for oil level and gas accumulation and a adjustable pressure switch. The housing is made of aluminum with our well-established SOLIDLINE powder coating for harshest C5-M conditions.

The switch elements have been designed separated from the oil circuit. This combination prevents leakage caused by UV influence or cable bushings. Each protection device MCHD is individually tested for tightness and proper functioning and guarantees durability and reliability for hermetically sealed distribution transformers.

Transformer protection device MCHD functions:

  • Oil level (leakage): With sinking oil level, the float moves downwards and switches a reed switch. In addition, the oil level is visualized in the sight glass.
  • Temperature: The oil temperature is transferred by means of a bimetallic thermometer to a temperature scale with a display range of 0 ° C - 140 °C. In addition, the hermetic protective relay MCHD has adjustable limit switches (adjustment range 20°C - 120°C) as well as a resettable trailing pointer.
  • Gas accumulation: When gas collects inside the hermetic relay (170 cm3 max.), it displaces the float and switch a reed switch. In addition, the gas collection can be observed visually in the sightglass.
  • Pressure: A pressure wave occurs in case of an internal defect, the Viton membran detects the rising gas and switches off the transformer. Setting value from 10 - 50 kPa in steps of 5 kPa.

Your benefits at a glance:

  • Reed switch for gas formation and oil level detection
  • Adjustable pressure switch
  • Bimetal thermometer for temperature detection
  • 1/8“ ball valve for oil sampling and air venting
  • UV-resistant C5-M coating SOLIDLINE
  • Switch elements separated from oil circuit

Our transformer protection relay MCHD for hermetically sealed distribution transformers has been designed as an all-in-one device that detects the most important failures. The hermetic protective relay MCHD guarantees absolute hermetic protection for your transformers.

For further Information kindly find below our detailed brochure of transformer protection relay MCHD.

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