Ring bus schemes can be expanded to accommodate additional circuits, but its generally not suited for more than six. Each of these two sections may not have the proper combination of source and load circuits, this can be somewhat avoided by connecting the source and load circuits side by side. The main disadvantage of the ring bus system is that if a fault was to occur, the ring is split which could result into two isolated sections. By tripping two breakers, only the faulted circuit is isolated while all the other circuits remain in service. If a fault occurs in this configuration, it is isolated by tripping a breaker on both sides of the circuit. This scheme has good operational flexibility and high reliability, any of the circuit breakers can be opened and isolated for maintenance without interruption of service. Circuits terminate between the breakers and each circuit is fed from both sides. In the ring bus configuration, as the name implies, the circuit breakers are connected to form a ring, with isolators on both sides of each breaker.
![power world simulator case two bus power system power world simulator case two bus power system](https://s2.studylib.net/store/data/018676146_1-27e0209dde97faaf6863fc5ae82582a1-768x994.png)
Failure of a breaker or fault on the bus results in an outage of the whole substation. The switching procedure is complicated for maintenance of any circuit breaker.
![power world simulator case two bus power system power world simulator case two bus power system](https://al-roomi.org/multimedia/Power_Flow/10BusSystem/Glover10BusSystem.jpg)
This bus scheme is more costly than the single bus configuration but is more reliable and can be easily expanded. In the main and transfer bus configuration, the protective relay scheme is quite complex due to the requirement of the tie breaker to handle each situation for maintenance of any other circuit breaker. The circuit under maintenance is transferred to the transfer bus. The circuit breaker to be maintained is now opened, isolated and removed for maintenance. The transfer bus is energized and the isolator nearest the transfer bus of the breaker to be maintained is closed. When a tie circuit breaker is present, circuit breaker maintenance is achieved by closing the tie breaker. Circuit protection will be disabled in this maintenance arrangement. When no Tie CB is present, for maintenance of a circuit breaker, the transfer bus is energized by closing the isolator switches to the transfer bus, then the circuit breaker to be maintained is opened and isolated on both sides. One or more circuit breakers may be used in this arrangement to make connections between the main and transfer bus. In this arrangement one or more busses is added to the single bus substation scheme. Reliability and availability of this system can be improved by expanding and sectionalizing the bus.
![power world simulator case two bus power system power world simulator case two bus power system](https://i1.rgstatic.net/publication/333922986_Lesson_Learned_from_Power_System_Design_with_PowerWorld_Simulator/links/5eaa687545851592d6abc7a0/largepreview.png)
Single bus configurations are not considered reliable systems and they should only be implemented in substations where high reliability is not required, such as large transmission yards. This configuration requires less installation area and it can be easily expanded. The single bus substation configuration is the simplest and least expensive of all configurations. Circuit protection is disabled in this case. A bypass switch across the breaker should be used for maintenance of the corresponding breaker. Maintenance of any circuit breaker requires shutdown of the corresponding circuit/line and maintenance of the bus requires a complete shutdown of the bus. Failure of a single circuit breaker will also result in an outage of the entire bus. A fault on the bus or between the bus and circuit breaker will result in an outage of the entire bus or substation. There are six common substation bus schemes that every test technician should understand:Īs the name implies, the sigle bus substation configuration consists of all circuits connected to a main bus. A total shutdown of the substation means complete shutdown of all the lines connected to the substation.Ĭlearly, a EHV or UHV transmission substation where a large number of critical lines terminate is extremely important, and the substation should be designed to avoid total failure and interruption of minimum numbers of circuits. The first requirement of any substation design is to avoid a total shutdown of the substation for the purpose of maintenance, or due to fault somewhere out on the line. The operational flexibility and reliability of the substation greatly depends upon the bus scheme. In many large transmission substations, the total numbers of lines terminating exceeds one or two dozen.Ī substation bus scheme is the arrangement of overhead bus bar and associated switching equipment (circuit breakers and isolators) in a substation.
![power world simulator case two bus power system power world simulator case two bus power system](https://i.ytimg.com/vi/kDfRc_QV9uo/maxresdefault.jpg)
In actuality, most EHV and HV substations can be the point where more than half a dozen of lines terminate. The electrical substation is a junction point where two or more transmission lines terminate. A substation bus scheme is the arrangement of overhead bus bar and associated switching equipment.