Virtual Tours
Pin It Share

500kV Current Transformer

Instrument Transformer

One of the many challenges faced when operating a high voltage AC transmission network is how to monitor critical measurements in the system. Watts are important in calculating load flow and direction, accurate current readings (amps) are needed to ensure components are not overloaded, and voltages must be strictly maintained within the tolerances of the switchgear and transmission lines. 
This function is achieved by the use of "instrument transformers". These are highly engineered and accurate current transformers (CTs) and voltage (also called "potential") transformers (VTs/PTs).
Effectively, these devices transform extremely high currents & voltages into values that can be tolerated by low voltage sensitive measuring and protection equipment. Using the derived current and voltage measurements, power flow direction and magnitude(watts), frequency (Hz), phase angle, harmonics, and others can be calculated.
They are typically connected in sets of three, one transformer on each phase, and strategically located to gain the most benefit from the least number of devices.
The current transformer displayed outside our museum was designed to transform up to 3000 amps at 500,000 volts to 5 amps which can then be easily handled by the low voltage measuring instruments and protective relays within the substation.

Initially purchased as a spare unit, this current transformer was donated to the Edmonton Power Historical Foundation in 2016 by EPCOR Utilities when it was made obsolete by an upgrade to the Genesee Switchyard.

Author: ephf

Edmonton Power Historical Foundation is a non-profit society dedicated to preserving the history of electric power in the City of Edmonton and the Province of Alberta, for the education and entertainment of current and future generations.

Edmonton Power Historical Foundation

Hours of operation 2023

We are located on the grounds of the Leduc West Antique Museum. Travel 5 miles west of Leduc on Highway 39. Go north on Range Road 260 (Cohne Dale Road) for about a mile and the museum will be on your right. The museum is closed for the winter, however we are looking forward to opening our doors on May 27 for the Leduc West Antique Society Spring Swap Meet, Tractor Pull & Music Series. Featured will be all manner of vendor tables, displays, tours, and the first Tractor Pull of the season. In the evening the first concert of the Music Series will feature "Prairie Sky" on stage.
July 22 & 23 is theLWAS Annual Exposition, the biggest event of the year which will include public tours, exhibits, a parade of antique vehicles, and a Tractor Pull; on Saturday evening the Music Series will feature "The Jivin' Belles" performing songs heavily influenced by close harmony groups of the 40's like the Andrews Sisters.
September 9 & 10, the final event of the summer season is the Fall Harvest event… with public tours, exhibits and the Tractor Pull Provincial Finals event. The final music performance of the season will feature “Celtera” and as their name implies is steeped in the music from the Emerald Isle and Scotland.


Leave us a message