Search results for query: *

sorry Busbar..it was yourself who reminded me if the aux supply. I forgot to add the upstream fuses are planned to be D type DIAZED. However if a suitably low impedance fuse cannot be got then we'll just have to replace them with a bigger rating and forgo the protection aspect!

Thanks for the reply jbartos. The meters aux power will come from the same vt supply, thanks for reminding me!. The internal fuses at the meter were orginally planned to be 2A for protection of the meter (& aux supply) but these cartridge type were found to drop too many volts (2A fuses too high...

Hi folks, This has probably come up before in one way or another but anyway....what do the letters describing fuse types mean? e.g. gL gG gR gH and aM ? I'm looking to specify a fuse on the secondary side of a VT for high accuracy metering purposes. The meter is 0.2% and VT cores are CL0.2s...

Thanks edison123, that jolts the memory now! I just need to find the J&P handbook..! thanks

Hi! We're reviewing specs for new power transformers and I've forgotten the basic theory behind temperature monitoring on transformers. For large power transformers the tank thermometer is temperature compensated by a ring CT on one of the LV bushings. ? What is the exact reason for doing this...

Thanks for the info!, but as the rubber is flexible (manufacturer quotes full recovery after 90 deg. bend) is there a danger under short circuit conditions of the conductors pulling apart and causing havoc? has this occured anywhere and prompted a rethink on the use of polymer insulators ?

Hi! Interested to hear of anybody’s experience with silicone insulators. Traditionally our substations have used porcelain insulators (for historic reasons). Recent breakage’s of porcelain has highlighted the fragile nature of the material and the possibility of a serious failure occurring is...

In Rep. Ireland a similar scheme is used on the 40kV network for earth fault detection. The neutral at the transformers is arc suppressed through Petersen coils and a single VT fed to an ABB SPAU 110C relay set for 30% to avoid residual voltages, this would correspond to 6.5kV on our system. We...