transformre oil level indicators

Hermetically seals transformer does not have any oil level indicator. The hermetically seal transformer has a side window that indicate the oil level inside the transformer. You cannot install the oil level with remote indication trip contact to the hermetically seal transformer.

hi Simon,

Thanks for reply. are there any other option for remote oil level indication in hermetically sealed transformer.

Thanks,

Vinod

In the hermetically seal transformer, it does not have any extra space to install the oil level indicator to it. If you look at the construction of the hermetically seal transformer, you will notice that the transformer winding itself (including the center core) is fully occupied the space inside the transformer tank.

It is also dangerous to install the oil level indicator inside the transformer tank, even if, you can look for some spaces to install it. As there is HV and LV circulating in the transformer oil.

Others problem is that, you also need to bore a hole on the top of the transformer steel cover. For making a hole on the top of the transformer steel cover, you need to open up all the HV and LV Bushing. This job is not easy to do, as once you open the transformer cover, your transformer oil will be contaminated with outside air, dust and moisture and you need to do oil filtration works for the transformer.

There is some capacitance sensor in the market that can be use, to sense the level of your transformer oil by the oil level windows. You need to try it out and see if it can works. I have use some of these sensor to sense the oil level of my oil tank thru the glass tube level.

You need to buy the capacitance sensor that have the sensor head smaller than your oil level windows and the sensitivities can be adjusted.

hi simon,

thanks for the reply,

i was thinking of using vertical float level indicators with reed switchs for the same have you come across such level indicators in tranformers

thanks

Vinod

Vertical Float level indicator with reed switches is normally use inside the hydraulic oil tank to indicate the oil level of the hydraulic system. Normally, it has a diameter of 25mm to 35mm diameter. Some have 2 level and some have 3 level.

You have to be careful with the installation. It may not work as you has expected. The reel switch operated by magnetism located at the floating actuator. When you install the reel float switch inside your hermitically seal transformer and when your transformer is energized, the magnetic flux that generated by your transformer may cause faults signal to your reel switch and thus, it will cause tripping to your transformer.

You still need to drill a hole at the top of your transformer steel cover, as I have explain early, it is also dangerous as there is HV and LV voltage circulating in the transformer oil.

Before you proceed to install the reed switch, you need to have a deep study about the advantage and disadvantage of this reed switch modification.

Thanks for the feedback.

but i have seen reed switchs being used in hermetically sealed TR (transformer rectifier) units used in ESP (electrostatic precipitators).

here TR is single phase transformer with rectifier to its secondary side

any way use of reed switch in 3 phase transformer needs study for effect of magnetic flux as you said.

thanks

Vinod