GE Multilin B30 Bus Differential System 9-39 APPLICATION OF SETTINGS 9.2 ZONING AND DYNAMIC BUS REPLICA99.2ZONING AND DYNAMIC BUS REPLICA 9.2.1 DESCRIPTIONThe figures in this section show the adopted protection zoning for the two bus sections.To provide the bus differential zoning as shown in the figures, eight currents need to be measured. Consequently, the pro-tection cannot be accomplished by one B30. However, as each bus has not more than six connections, two B30s can beused.9.2.2 NORTH BUS ZONEWith reference to the following diagram, the North bus differential zone is bounded by the following CTs: CT-1, CT-2 (if S-1closed), CT-3 (if S-3 closed), CT-4 (if S-5 closed), CT-5 and CT-8. The North bus protection should operate the followingbreakers: B-1, B-2 (if S-1 closed), B-3 (if S-3 closed), B-4 (if S-5 closed), B-5 and B-7.Consequently, the B30 for the North bus should be wired and configured as follows:• CT-1 currents should be configured as SRC 1 and used as the source 1A of the bus differential zone 1 together withthe FlexLogic “On” constant for the status.• CT-2 currents should be configured as SRC 2 and used as the source 1B of the bus differential zone 1 together withthe status of the S-1 switch.• CT-3 currents should be configured as SRC 3 and used as the source 1C of the bus differential zone 1 together withthe status of the S-3 switch.• CT-4 currents should be configured as SRC 4 and used as the source 1D of the bus differential zone 1 together withthe status of the S-5 switch.• CT-5 currents should be configured as SRC 5 and used as the source 1E of the bus differential zone 1 together withthe FlexLogic “On” constant for the status.• CT-8 currents should be configured as SRC 6 and used as the source 1F of the bus differential zone 1 together withthe FlexLogic “On” constant for the status.• The trip signal should be routed directly to the B-1, B-5 and B-7 breakers while it should be supervised by the status ofS-1, S-3 and S-5 for the B-2, B-3 and B-4 breakers, respectively.Depending on utility practice, extra security may be required with respect to the status signals. This may include bringing inboth the normally opened and normally closed contacts of a switch as well as status of a peer switch (S-1 and S-2, forexample). If this is the case, the required security filtering should be accomplished using FlexLogic and a single (final) sta-tus operand should be indicated for the status signal when setting the bus differential zone.Figure 9–3: NORTH BUS ZONE836733A1.CDRNORTH BUSSOUTH BUSCT-7CT-8B-7B-5B-6CT-5CT-6S-5S-6B-4CT-4S-3S-4B-3CT-3S-1S-2B-2CT-2CT-1B-1C-1 C-2 C-4C-3 C-5
