That JPS island wide blackout

THE EDITOR, Madam:

Wow! "Old time something come back again" best describes last Friday's island wide power blackout, reminiscent of the 1970 and 80’s!

That widespread blackout, suggests a series of failures in the protection systems, inclusive of generation or failure of equipment. Power systems design has features to protect itself such that a fault on a section of the system should not cause a catastrophic failure of the entire system - much like in a household where there are circuit breakers that would operate and isolate a faulty toaster in the kitchen, while the remainder of the house is unaffected.

All power systems, including JPS system employs that basic design concept but with much sophistication due to the components employed from generation to transmission and distribution to the customers.

The island's power system has a number of generators to feed the grid system. Together they maintain the capacity to supply the public normal demands – power at prescribed voltage and frequency. All is well!

However, unexpected sustained demand may occur in the form of overload due to loss of generation, equipment failure or failure of the actual device(s) that are used to detect and trigger protective devices action as aforementioned. A sustained unexpected demand is measured as overload lasting seconds up to about a minute.

A sudden increase in demand, without sufficient spinning reserve in generation capacity to meet that situation, may precipitate a cascading system collapse – if the protection system fails to detect and remove that demand.  The system frequency will drop; under frequency relay(s) must detect and initiate cascading load shedding as required to maintain system stability and avert total system collapse.  The above scenario is likely what precipitated last night’s island wide blackout; JPS investigations will undoubtedly determine the exact cause.

Still, the system was restored quickly considering the various preliminary checks and procedures that are required when such collapse happens.  

NORMAN LEE

Brampton, ON