D.M.C.R. Protection Relay for Oil Transformer

Introduction to D.M.C.R.

The DMCR is a protection relay designed for the hermetically sealed oil immersed transformers without gas cushion. This device enables complete control of the tank’s internal parameters, i.e. pressure, temperature, oil level and gas detection.

Fitted directly to the transformer cover, this relay ensures protection against internal faults, prolonged over voltages and fire risks associated with the use of inflammable dielectric fluids.

The accessory continuously monitors:

1. Dielectric fluid level,
2. Tank internal pressure,
3. Dielectric fluid temperature at two different thresholds.

To operate properly, the protection relay must be fully filled with fluid (level higher than the float visible in the transparent section of the unit). If this is not the case, check the instructions which appear inside each casing.

To ensure optimum protection, the following action and adjustments are recommended:

Finding	Recommended adjustment	Fault detected	Action to be taken
Gas emitted or drop in level	Large float at the top	Serious fault	De-energize unit
Pressure switch	0.20 bar	Serious fault	De-energize unit
Thermostat threshold 1	90°C	Over voltages	Activate alarm
Thermostat threshold 2	100°C	Over voltages	De-energize unit

 The DMCR is a protection relay designed for the hermetically sealed oil immersed transformers without gas cushion. This device enables complete control of the tank’s internal parameters, i.e. pressure, temperature, oil level and gas detection.

This protection relay has been designed according to the European standard EN 50216-3, specification which came into action on the 5th of June 2002.

This standard applies to protection relays for hermetically sealed oil immersed transformers, (in accordance with the EN 60076 standard) and induction coils (in accordance with the EN 60289 standard) without gas cushion for an indoor or outdoor use.

The DMCR relay is an IDEF Systemes design, made in France. It has two French and one European patents.