Development of new protection for interconnected overhead 33 kV circuits

A new protection scheme has been developed for use on interconnected 33 kV circuits. This development was necessary principally because of the insecurity of existing metallic rented pilots. The project was undertaken in conjunction with a University which has a long established collaborative relationship with the utility concerned. A proprietary hardware relay product was used as the basis of the scheme and the software utilises substantial modules of established program which have been used in a variety of applications. The confidence level in the scheme as a whole is high because of the investment in both simulation testing and test bench testing. The equipment is connected to a live circuit and is permitted to operate circuit breakers in a trial installation.<>