Solid state solutions to some protection grading problems

The author sets out to show how the problems faced by protection grading engineers, which have become more intense in recent years, may be reduced by the use of solid-state protective relays in preference to electro-mechanical relays. The author has no particular manufacturer in mind (most of the major relay manufacturers produce suitable solid-state relays) but for the sake of simplicity concentrates on the GEC MCGG relay