Hi krisys,thanks for the response. Actually,it is 34.5kV and the voltage divider insulator also supplies an indicating lamp to indicate presence of voltage in the power cable.
Recently we have a failure of a support insulator in the secondary bank cubicle of an outdoor type metalclad switchgear. The insulator which is an epoxy resin type provides support to the busbar where the power cable terminates. An electrical discharge chipped of the side portion of the...
Thanks prc and waross. Our requirement is to buy a 3-phase unit rated 300mva, 230-115kv-13.8kv auto-transformer. To be a qualified supplier, new bidders should provide a short circuit withstand test for a 3-phase transformer unit on ratings similar to or greater than the specs of our...
Thank you very much prc. What i have read on iec 60076-5 or ansi c57.12.90 is that 1-phase test can be done on a 3-phase unit in case the test facilities is limited. I also conform to your caution that a 1-phase test can also be accepted if the pxf unit is very large and cannot be constructed as...
One of the major requirement of our utility company is to require prospective power transformer suppliers to submit a type test report performed by an independent testing company like KEMA or CESI. The particular test that we are interested is the full short circuit test done either at KEMA or...
We have the same problem qman5. In our utility, our existing nominal rating is 220kV which is OK with the 242 kV max design voltage of IEEE. Even if our transmission grid operator is supplying us with a nominal voltage of 230kV, the 10kV difference between our 220kV primary transformer rating is...
Thank you very much for the responses. Our utility is in a tropical country thus our transformer WTI and OTI gauges are scaled from 0 to 150 deg. Our initial action was to revise our fan control scheme so that the OTI can also start run the cooling fans instead of the WTI only. We have also...
Recently we have a failure on the 34.5kV cap and pin bus support on our substation. The substation is already old (more than 25 years old) and we read thru posts in the internet that the porcelain cap and pin type insulators are already being being replaced by other utilities due to their design...
Thank you very much for the reply. May I know if this zero temp tripping is standard among WTI's? We have Thyoda made in Japan and AKM Qualitrol as our other brands of WTI. What standards do I have to use to refer this issue?
Transformer winding temperature indicator (WTI) zero temperature trip. Recently, our transformer WTI made by MSRT Terman tripped swhen the capillary tube leaked and temperature reading dropped to zero. We did not know this feature of the WTI thus we opened it and found that the design would...
