differential zones, one for each busbar section. If there is an internal fault on one of the twosections, bus-section circuit breaker and all feeder circuit breakers associated with thissection have to be tripped, leaving the other busbar section in normal operation.xx06000088_ansi.vsdZA ZB152 152 152152152152152ANSI06000088 V1 ENFigure 55: Example of two single busbar sections with bus-section circuit breakerand eight feeder bays per each busbar sectionThis type of busbar arrangement can be quite easily protected. The most common setupsfor this type of station are described in the following table.Table 15:Typical solutions for single busbar arrangements with bus-section breakerVersion of REB670 IED Total number of feedersin both busbar sectionsNumber of REB670 IEDsrequired for the scheme3PH; 2-zones, 4-bays BBP (A20) 3*)/6 1/23PH; 2-zones, 8-bays BBP (A31) 7*)/14 1/21Ph; 2-zones, 12-bays BBP (B20) 11*)/22 3/61Ph; 2-zones, 12-bays BBP (B21) 11*)/22 3/61Ph; 2-zones, 24-bays BBP (B31) 23*)/46 3/6*) with just one CT input from bus-section bayPlease note that table 15 is given for the preconfigured versions of REB670 which do notcontain any VT inputs.For station with just one CT in the bus-section bay, it might be required, depending on theclient requirements, to provide the special scheme for disconnection of bus-section CTwhen the bus-section CB is open. For more information, refer to figure 45.6.1.4.5 H-type busbar arrangementsThe H-type stations are often used in transmission and sub-transmission networks as load-centre substations, as shown in figure 56. These arrangements are very similar to the singleSection 6 1MRK 505 337-UUS -Differential protection132Application manual
