A bus protection method for CTs connected at two sides of a bus-tie switch

A bus protection method for CTs connected at two sides of a bus-tie switch comprises a protection device for more than two sections of buses. The protection device acquires all bus voltages, all branch current and knife switch positions on a bus and CT current and switch positions at the two sides of the bus-tie switch; the protection device automatically calculates bus protection three-phase voltage, large-difference current and small-difference current of each section of bus, calculates bus tie interval differential current of the bus-tie switch itself and current of the CTs at two sides ofthe bus tie, judges whether the bus tie CTs have a line-breaking fault or not and selects a faulty bus or a bus to trip when fault occurs; and meanwhile, a bus tie interval differential protection logic is newly added, the difference current of CTs at the two sides of the bus-tie switch and the current magnitude of the CTs at the two sides of the bus-tie switch are calculated, and the bus-tie switch or the bus is selected