Protection of Bus Bars

INTRODUCTION

 The protection scheme for a power system should cover the whole system against all probable types of fault. Unrestricted forms of line protection, such as overcurrent and distance systems, meet this requirement, although faults in the busbar zone are cleared only after some time delay. But if unit protection is applied to feeders and plant, the busbars are not inherently protected. Busbars have often been left without specific protection, for one or more of the following reasons:

a. the busbars and switchgear have a high degree of reliability, to the point of being regarded as intrinsically safe

 b. it was feared that accidental operation of busbar protection might cause widespread dislocation of the power system, which, if not quickly cleared, would cause more loss than would the very infrequent actual bus faults

c. it was hoped that system protection or back-up protection Would provide sufficient bus protection if needed