When a number generators or feeders have same voltage then there is necessity to connect all unit electrically, bus-bars are used as the common electrical component. In this article, we will discuss about different bus-bar arrangements.
What is Bus-Bar?
Bus-Bar are thick copper rods which is operate at constant voltage and carrying an electric current to which many co9nnections may be made.
The Bus-bar is arranged in different manner. The different bus-bar arrangements are given below.
- Single Bus-Bar Arrangement
It is a simplest form of arrangement of bus-bar. It is used in power stations and small outdoor substations having small number of incoming and outgoing feeders. Each generator and feeder is controlled by a circuit breaker.
It has low initial cost.
It required less maintenance.
If fault occurs on bus-bar, whole supply is affected.
For repair and maintenance of the bus-bar, whole of the system has need to be de-energized.
Single Bus-Bar Arrangement with Sectionalization
In large power generating stations, where several numbers of generators and feeders are required to be connected to the bus-bar. In that cases, Single bus-bar arrangement with sectionalization is employed. Normally the number of sections of a bus-bar is 2 to 3 in generating station and substation.
- In case, when fault occurs on any section faulty section can be disconnected without affecting other section.
- This arrangement is more reliable that single bus-bar arrangement.
- The repair and maintenance of any section of the bus-bar can be carried out be disconnecting that section only.
- Future extension is possible in this arrangement.
In this arrangement additional circuit breakers and isolators are required for sectionalisation. Hence, cost is increased.
Ring Bus-Bar Arrangement
In this arrangement, each feeder is supplied from two paths. This is an extension of the sectionalized arrangement.
This arrangement provides greater flexibility. In case, fault occurs , it does not affects the other section.
The number of circuit breaker required in this arrangement almost same as in a single phase bus-bar system. It reduces the initial cost.
Extension is not possible in this arrangements. Separately protection system is required for each circuit.
Main and Transfer Bus-Bar Arrangements
Such a arrangement consists of two bus-bars a “main bus-bar” and “an auxiliary bus-bar. This arrangement is adopted where continuity of supply. Each generator and feeder may be connected to either bus-bar with the help of bus coupler which consists of a circuit breaker and isolating switches.
If fault occurs on the bus-bar, supply can be maintained by transferring it to the healthy.
The other feeders can be connected to the bus-bars without disturbing the existing system.