Introduction

The electrical station may be a junction purpose wherever 2 or additional transmission lines terminate. surely, most EHV and HV substations may be the purpose wherever quite [*fr1] a dozen lines terminate. In several giant transmission substations, the whole numbers of lines terminating exceeds one or twenty-four. A station bus theme is an appointment of the overhead bus bar and associated change instrumentation (circuit breakers and isolators) in an exceeding station. The operational flexibility and responsibleness of the station greatly rely upon the bus theme.

The first demand of any station style is to avoid a complete ending of the station for the aim of maintenance, or thanks to a fault somewhere out on the road. a complete ending of the station means that the entire ending of all the lines connected to the station.

Clearly, Associate in Nursing EHV or UHV transmission station wherever an outsized variety of important lines terminate is extraordinarily necessary

1. Single Bus

As the name implies, this station configuration consists of all circuits connected to one bus. A fault on the bus or between the bus AND circuit breaker can lead to Associate in Nursing outage of the complete bus or station. Failure of one fuse will lead to Associate in Nursing outage of the complete bus.

Maintenance of any fuse needs conclusion of the corresponding circuit/line and maintenance of the bus needs a whole conclusion of the bus. A bypass switch across the breaker ought to be used for maintenance of the corresponding breaker. Circuit protection is disabled during this case.

The single bus station configuration is that the simplest and least expensive of all configurations. This configuration needs less installation space and it is simply swollen. Single bus configurations don’t seem to be thought of reliable systems and that they ought to solely be enforced in substations wherever high responsibleness isn’t needed, like giant transmission yards. responsibleness and accessibility of this method is improved by increasing and sectionalizing the bus.

2. Main Bus and Transfer Bus

In this arrangement, one or additional busses is additional to the one bus station theme. One or additional circuit breakers is also utilized in this arrangement to create connections between the most and transfer bus. once no Tie CB is gift, for maintenance of an electrical fuse, the transfer bus is energized by closing the isolator switches to the transfer bus. Then the electrical fuse to be maintained is opened and isolated on each side. Circuit protection is disabled during this maintenance arrangement.

When a tie electrical fuse is gift, electrical fuse maintenance is achieved by closing the tiebreaker. The transfer bus is energized and also the isolator nearest the transfer bus of the breaker to be maintained is closed. The electrical fuse to be maintained is currently opened, isolated and removed for maintenance. The circuit beneath maintenance is transferred to the transfer bus.

In the main and transfer bus configuration, the protecting relay theme is sort of advanced because of the need of the tiebreaker to handle every scenario for maintenance of the other electrical fuse. This bus theme is additional expensive than the one bus configuration, however, is additional reliable and might be simply dilated.

The change procedure is sophisticated for the maintenance of an electrical fuse. Failure of a breaker or fault on the bus ends up in Associate in Nursing outage of the complete station.

3. Double Bus Double Breaker

This configuration utilizes 2 buses and 2 breakers per circuit. each buses square measure unremarkably energized ANd any circuit is removed for maintenance while not an outage on the corresponding circuit. Failure of 1 of the 2 buses won’t interrupt a circuit as a result of all of the circuits is fed from the remaining bus and analytic the unsuccessful bus.Substations with the double bus double breaker arrangement need doubly the instrumentation because the single bus theme however square measure extremely reliable. Load equalisation between buses is achieved by shifting circuits from one bus to the opposite. This theme is often found in EHV transmission substations or generating stations.

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4. Double Bus Single Breaker

Substations utilizing this configuration are provided with 2 busses. every circuit is supplied with one breaker and is connected to each buses exploitation isolators. A tiebreaker connects each main buses and is often closed, granting additional flexibility operative. A fault on one bus needs isolation of the bus whereas the circuits are fed from the alternative bus.

The double bus single breaker theme is dearer and needs additional installation house than the one bus configuration. it’s common to search out this theme with a further transfer bus in EHV transmission substations.

5. Ring Bus

In the ring bus configuration, because the name implies, the circuit breakers are connected to make a hoop, with isolators on each side of every breaker. Circuits terminate between the breakers and every circuit is fed from each side. Any of the circuit breakers will be opened and isolated for maintenance while not interruption of service.

This theme has sensible operational flexibility and high dependability. If a fault happens during this configuration, it’s isolated by tripping a breaker on each side of the circuit. By tripping 2 breakers, solely the faulted circuit is isolated whereas all the opposite circuits stay in commission.

The main disadvantage of the ring bus system is that if a fault was to occur, the ring is split that might result in 2 isolated sections. each of those 2 sections might not have the correct combination of supply and cargo circuits. this will be somewhat avoided by connecting the supply and cargo circuits aspect by aspect.

Ring bus schemes will be dilated to accommodate extra circuits, however, its typically not fitted to quite six. Careful designing ought to be used with this theme to avoid difficulties with future growth.

6. Breaker and Half

Any fuse will be isolated and removed for maintenance functions while not interrupting provide to any of the opposite circuits. in addition, one amongst the 2 main busses will be removed for maintenance while not interruption of service to any of the opposite circuits.

If a middle fuse fails, the adjacent breakers are tripped to interrupt each circuit. If a breaker adjacent to the bus fails, tripping of the center breaker won’t interrupt service to the circuit related to the remaining breaker within the chain. solely the circuit related to the unsuccessful breaker is aloof from service.

The breaker and [*fr1] configuration is incredibly versatile, extremely reliable, and additional economical as compared to the Double Bus Double Breaker theme. protecting relay schemes during this configuration area unit extremely difficult because the middle breaker is related to 2 circuits. It conjointly needs extra space as compared to alternative schemes so as to accommodate the big range of parts.

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