According to the specifications of the BP-2C Busbar Protection Device, after the protection issues a trip command to the bus tie (sectional) switch, if the total differential current element does not reset within the set time delay and current still exists in the current transformer of the bus tie (sectional) switch, the bus tie (sectional) failure protection shall trip all branches of the relevant busbars after being blocked by the busbar differential composite voltage. The bus tie (sectional) failure protection is only initiated when the bus tie (sectional) switch acts as an interconnection switch. The bus tie failure protection is enabled by default, with the following operation logic diagram:

△ Bus Tie Failure Operation Logic Diagram

For the double-busbar single-section wiring configuration, the dotted polarity terminals of each bus tie CT are defined as shown in the figure below, and the dotted polarity terminals of each branch CT are on the busbar side.

△ Primary System Schematic Diagram

1 Protection Settings and Test Wiring

Enable the failure protection function and set the failure current setting value to 0.5A.

For test wiring, the voltage lines may be disconnected to ensure the voltage release of the two busbar sections. Connect the current lines of the Relaystar-S60 Handheld Relay Protection Tester to the Bus Tie 1 branch.

The bus tie failure initiation has multiple conditions; the "Bus Tie Three-phase Trip Initiate Failure Input" mode can be selected. Use the output signal of the Relaystar-S60 and connect its Output 1 in parallel to the bus tie three-phase trip initiate failure input terminal.

2 Commissioning of Bus Tie Failure Protection

The State Sequence Test Module is generally used for commissioning: set State 1 as the normal protection state, and apply the failure current while sending the protection failure input signal in State 2.

△ Failure Protection State Settings

Click Start in the toolbar to run the test.

Observe the panel information of the protection device; after the Alarm indicator on the panel turns off, click the Start button in the toolbar to switch to the fault state, and the protection device shall operate at this time.

BP-2C Busbar Protection Device – Integrated Operation Report

Protected Equipment: Protection DeviceProtection Board Version: V1.00Management Board Version: V1.00Print Time: 2021-07-10

△ Bus Tie Failure Operation Commissioning Report

Note: The bus tie failure protection is essentially an overcurrent protection, and the preconditions for failure operation must be noted. This test is based on the failure initiation signal as the precondition. In actual commissioning, the busbar differential protection may also serve as the initiation condition, and the commissioning method is similar to this one.