Bus protection method connected to ct on both sides of bus tie switch

Abstract

A bus protection method connected to CTs on both sides of a bus tie switch, including: protection devices for more than two sections of bus bars, the protection devices collect all bus voltages, currents of all branches on the bus and switch positions, and CT currents on both sides of the bus tie switch and switch position; the protection device automatically calculates the three-phase voltage, large difference current and small difference current of each bus section for bus protection; calculates the bus-tie interval differential current of the bus-tie switch itself and the current of the CTs on both sides of the bus-tie; judges whether the bus-tie CT In the event of a disconnection, select the faulty bus or bus trip when a fault occurs; at the same time, add a bus-coupler interval differential protection logic to calculate the differential current of the CTs on both sides of the bus-tie switch and the current magnitude of the CTs on both sides of the bus-tie switch. Bus tie breaker differential current and current magnitude on both sides select bus tie breaker or busbar tripping. The invention is simple and reliable, and improves the rapidity and accuracy of protection cut-off when the dead zone of the busbar fails.

Description

technical field [0001] The invention relates to a busbar protection method connected to CTs on both sides of a busbar switch, especially for the situation that all busbars need to be cut off quickly or the busbar is disconnected first and then the faulty busbar is selected for tripping when the busbar dead zone fault is required. Background technique [0002] The principle of bus differential protection is mainly to judge the fault inside and outside the bus area according to the large difference current, and select the faulty bus to trip according to the small difference current. For the bus tie interval, usually the bus protection only connects to the CT current on one side of the bus tie switch. When a fault occurs between the switch and the CT, there is a fault that cannot be removed quickly. The bus protection first jumps to the normal bus, and then through the dead zone protection or bus tie failure. The protection then removes the fault condition. This solution has t...

AI Technical Summary

Problems solved by technology

For the bus tie interval, usually the bus protection only connects to the CT current on one side of the bus tie switch. When a fault occurs between the switch and the CT, there is a fault that cannot be removed quickly. The bus protection first jumps to the normal bus, and then through the dead zone protection or bus tie failure. Protection and then fault clearing

This solution has the characteristics of expanded fault removal range and slow fault removal time, which has a great impact on the safe and stable operation of the system

In most projects, CTs are installed on both sides of the bus coupler. At the same time, when a fault occurs between the CTs on both sides of the bus coupler, the two sections of the busbar should be cut off at the same time, but there is a lack of selectivity and flexibility.

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