Novel patented equipment, designed by CPRI, Bangalore, for DGA

Based on ASTM D-3612 –A and IS: 9434:1992

Oil sample is drawn from transformer, in gas tight sampling tubes and
introduced to high vacuum extraction at ambient temperature.

Fault gases are extracted in three stages, from the same sample oil
and an efficiency of more than 98% is achieved.

Gas tight sampling tube made of SS 304 or SS 316 grade in sizes 500 ml, 1000 ml, 1500 ml and 2000 ml.

SS Needle valves are provided at both the ends of SS tube.

Also SS nozzles are attached to SS valves

Gas Tight Borosilicate glass tube is in capacity 150 ml, 250 ml or 400 ml.

A side port with PTFE lined septum facilitates syringing out of sample oil
for tests in Moisture Content, BDV, Head Space Analysis etc

At both ends of sampling tube, screw type adapters with nozzles are
provided for inserting in to connecting tubes and can be used directly with
Dakshin multi-stage gas extractor.

This tube is supplied in thermo foam container for storage and transportation, without exposure to sunlight.

This equipment is for the standard test method for Stability of Insulating mineral oil as per ASTM D 6180 -98.

In this method sample oil is introduced into a discharge cell under vacuum at room temperature. An AC potential of 10 kV is applied between a high voltage electrode and a grounded salt water electrode for 300 minutes.

The gradual increase of pressure inside the discharge cell is measured using digital vacuum gauge as a function of time.

This equipment is to assess the quality of new transformer oil or re-processed oil as described in IEC 60628:1985 Method A

This method determines the gassing tendency of an insulating liquid under a
hydrogen atmosphere and expresses the results in terms of gassing rate over a
relatively short test period.

After being dried and saturated with hydrogen gas, the insulating liquid and the
hydrogen pocket above the liquid are subjected in a gassing cell with
electrode, to a radial electrical stress under following experimental conditions.

Voltage : 10 kV
Frequency : 50 Hz or 60 Hz
Temperature : 80 °C
Test duration : 120 min at 50 Hz or 100 min aat 60 Hz

The equipment consists of constant temperature oil bath with glass window and
protective dome, gassing cell, gas burette, Rota meter, rapid cooler, high voltage
transformer etc.