Power Transformer Maintnance Testing

[rockman7892]

We have a site (customer owned substation) where we are looking to perform maintenance testing of an 30/33.5 MVA 230kV-4.16kV substation transformer.

In reviewing IEEE Std C57.152-2013 the recommended testing for In Service transformers is insulating liquid/DGA analysis, and Infrared testing on the main tank and Infrared and PF/Tan-Delta testing on the bushings.

There are several other tests listed as "As Needed" based on the results of the above recommended tests (insulation resistance, winding resistance, Turns Ratio, etc...) I'm curious to hear from others which of these tests are typically provided as routine maintnance testing for transformers of this size/voltage.

Transformer has been in service since Mid-70's and I'm not sure how often routine testing/maintenance has been performed for this transformer.

I appreciate any feedback.

 

[prc]

Since it is a > 40 year old transformer, the following are recommended:
- DGA of main tank oil (half yearly) Tap changer chamber oil (annually)
- Oil Quality (annually) -BDV, Water, Tan delta ,IFT, Resistivity, Furan
- capacitance & PF of HV bushings (half yearly) and windings(annually)
-Insulation resistance of windings and core(annually)
- Infrared checking of bushing terminal connections, ground connections and tap changer compartment (annually)
-Visual inspection for oil leak (weekly)- to be attended immediately
- Check of cooler control, direction of fans (annually)