Nxtphase T&d Corporation

Nxtphase Technology Srl

Perseus 2000, LLC

Zhiying Zhang

Glenn William Swift

Robert George Coish

Mark Anthony Weekes

Gang Li

David J Fedirchuk

Dean S Ouellette

A protection relay for a power line system that employs current transformers for detecting current on a bus is provided with a fault trip scheme that includes transformer current saturation detection so as to avoid false tripping due to temporary transformer current saturation.

Electrical bus protection method & apparatus

An apparatus for monitoring and controlling the operation of an electrical power transformer includes a processor with input transducers for providing to the processor inputs indicative of electrical current in a winding of the transformer and ambient temperature outside the transformer. The processor is arranged using an algorithm based upon heat transfer to repeatedly calculate a first prediction, based upon the present values of electrical current and ambient temperature, of a time period before the hot spot temperature exceeds a pre-set allowable maximum and a second prediction, based upon the current value of power, of a time period before the accumulated loss of life exceeds a pre-set allowable maximum. If the shorter time period of the two calculations is less than a pre-set value, for example one half hour, the processor generates an alarm signal and a display counting down the time remaining in the period, together with a second alarm signal at a shorter second time of for example one quarter hour.

Apparatus and method for predicting an overload trip for an electrical power transformer

Apparatus for preventing thermal damage to an electrical power transformer

Growing community of inventors

Winnipeg, Canada

Zhiying Zhang