The color of silica gel in transformers changes depending on its moisture absorption level. When new or in good condition, the silica gel is blue.
Understanding Silica Gel in Transformers
Silica gel plays a crucial role in the breathing process of power transformers. Transformers contain oil, and as the transformer heats and cools, the oil expands and contracts, causing air to be drawn in and expelled. This air can contain moisture, which is detrimental to the transformer's insulation and overall lifespan.
A breather unit attached to the transformer uses silica gel to absorb moisture from the air entering the tank.
Color as a Moisture Indicator
The silica gel contains a moisture-sensitive indicator that changes color, providing a visual signal about the amount of moisture it has absorbed. This allows maintenance personnel to easily assess the condition of the silica gel and determine when it needs to be replaced or regenerated.
According to the provided reference, "Colour of new silica gel used in transformer is blue. After absorbing moisture they lose the blue colour and finally turn to pink. Colour of silica gel is blue at good condition and it becomes violet then pink as it absorbs moisture."
Here's a simple breakdown of the color changes:
- Blue: Indicates the silica gel is dry and in good condition, effectively absorbing moisture.
- Violet: Shows that the silica gel has started absorbing moisture and is nearing saturation.
- Pink: Signifies that the silica gel is saturated with moisture and is no longer effective at drying the incoming air. It needs to be replaced or regenerated.
| Silica Gel Color | Condition | Moisture Absorption Level |
|---|---|---|
| Blue | Good | Low / Dry |
| Violet | Absorbing | Medium |
| Pink | Saturated | High / Wet |
Monitoring the color of the silica gel in the breather is a standard maintenance practice to ensure the transformer is protected from moisture ingress.
