Electrical Adda

Transformer Marshaling  Box  Transformer  M arshalling  box consists of Transformer Winding   Temperature   &   Oil  Temperatures. DESCRIPTION              TRIP SETTINGS        ALARM                           TRIP WINDING TEMPERATURE   (WTI) 80 °C   90 °C   OIL  TEMPERATURE   (OTI) 85 °C 90 °C WTI OTI Practically under loaded condition oil temperature & Winding temperatures changes based upon load & outside Atmosphere.        TIME    WINDING TEMP   OIL TEMP MORNING 36 °C 34 °C AFTERNOON 60 °C 58 °C NIGHT 48°C 46 °C Generally temperature ranges from (36-60 °C)

conservator tank oil level (Mog) The MOG  (Magnetic Oil Gauge)  is a device by which we can supervise the level of oil inside the tank or conservator of power transformer and also gives us an alert low oil level indication .  A decrease in level of Transformer oil in Conservator is an indication of leak and therefore MOG level is an important parameter to be monitored. Practically under running condition oil level remains at 3/4 th level.

  Silica gel breather cup of a Transformer   The silica gel breather cup of a Transformer is partially filled with oil to avoid entering of moisture into the Transformer. As the oil expands due to rise in temperature, the pressure builds up , consequently, the vapour and dry air accumulated in the conservator are breathed out.   During the fall of temperature, oil in the Transformer contracts and creates partial vacuum in the tank which makes the Transformer to breathe in air from the outside. In the process of breathing in outside air, moisture and dust particles in the outside air are also sucked in. But, the oil in the breather cup obstructs dust particles and settles them at its bottom. The moisture entered is absorbed by the silica gel in the breather. The oil in the breather cup is only partially filled up to the mark given on the cup. If oil in the cup is over filled, while breathing in, the oil gets into contact and absorbed by the silica gel resulting in bot