Various Bus-Bar Arrangements.

Several types of Bus-bar schemes that are used in power grids are explained.

1. RAGHU ENGINEERING COLLEGE (AUTONOMOUS) DEPARTMENT OF EEE Academic year: 2018-2019 II year II-semester Power Systems-I Generation and Utilization CASE STUDY ON VARIOUS BUSBAR ARRANGEMENTS . BATCH-2 A.Snehitha-18985A0206 A.S.S.R.Murthy-18985A0207 A.Sai Sampath-18985A0208 B.Naga Venkatesh-18985A0209 B.Chaitanya-18985A0210 FACULTY: V.Pramadha Rani. Assosiate Professor. 2/28/2019 Power Systems-I 1

2. What is a busbar? An electrical bus bar can be defined as a conductor or groups of conductors which collects electrical power from the incoming feeder and distributes them to outgoing feeder. Busbars distribute electricity with greater ease and flexibility than some other more permanent forms of installation and distribution. They are often metallic strips of copper, brass, or aluminum that both ground and conduct electricity. 2/28/2019 Power Systems-I 2

3. Busbar Arrangements. The choice of particular arrangement depends upon viz., system voltage, position of substation, system flexibility and cost. In addition, the following technical considerations must be borne in the mind while deciding an arrangement: Simplicity is the keynote of a dependable system. Maintenance should be possible without interruption of supply. Alternative arrangements should be available in case of outage of any apparatus. The installation should be as economical as possible. 2/28/2019 Power Systems-I 3

4. Single Busbar Arrangement. The arrangement is the cheapest possible and simple in construction. But, it suffers from two major defects, Maintenance without interruption of supply is not possible. Extension of substation without shutdown is not possible. 2/28/2019 Power Systems-I 4 Fig A : Single Busbar Scheme.

5. Single Bus-bar Arrangement with Sectionalizer . It is used as an alternative for the single bus-bar arrangement because any breaker can be taken for maintenance. Though it requires an extra breaker, and the switching is more complex. A fault in the bus may shut down the whole system. Generally, used for 110kv substations. Fig B: Single busbar scheme with sectionaliser . 2/28/2019 Power Systems-I 5

6. Comparison. Single Bus-bar Scheme. It is simplest scheme with artless protection system. Any fault on bus results in disconnection of power. Any maintenance on any breaker will lead to disconnection of relevant breaker, relevant line or whole system in some cases. Single Bus-bar with sectionalizer . Single breaker single busbar scheme is slightly improved by dividing the bus into two sections. This scheme is only effective if there are two incoming lines and outgoing lines are distributed evenly in each section. 2/28/2019 Power Systems-I 6

7. Main and Transfer Bus Scheme. It is more flexible because half number of feeders are connected on each bus. But, it needs an extra breaker coupler circuit. Line breaker fault may result in taking of all the circuits connected to out of service and also failure in the bus-bar results in shutdown of complete system. Mostly used for substations of 66kv, 132kv and up to 220kv. Fig C: Main and transfer bus-bar scheme. 2/28/2019 Power Systems-I 7

8. Double Bus-bar Arrangement. It is more flexible as we can connect feeders on either of buses. This scheme is highly reliable as any breaker can be taken for maintenance whenever required. It is far more expensive when compared to normal double bus-bar scheme. Generally, used for high voltage or EHV substations. Fig D: Double bus arrangement. 2/28/2019 Power Systems-I 8

9. Comparison. Double Bus-bar Arrangement. In double bus system load can be connected on either of the bus. The infeed and the load circuit can be separated in two if needed from operational considerations. Either bus can be taken out of maintenance. Main and Transfer Bus-bar System. This is alternative for double bus scheme. It provides facility for breaker maintenance but not bud maintenance. Whenever maintenance is required the circuit can be shifted to another bus and controlled using bus coupler. 2/28/2019 Power Systems-I 9

10. One and Half Breaker Scheme. More flexible in operation as all the switching is done by breakers. Selective tripping is possible. But any breaker can’t be removed without interruption of supply. Generally, used for substations for 220kv to 440kv ratings. Fig E: One and half breaker scheme. 2/28/2019 Power Systems-I 10

11. Ring/Mesh Arrangement. Bus-bars gives more operational flexibility. Any fault in the unit separates the ring into two halves thereby increasing the complexity of reclosing and protection. Breaker failure during fault on one circuit causes loss of additional circuit because of breaker failure. Mostly used for very high power rating generating stations. Fig F: Ring Bus-bar Arrangement. 2/28/2019 Power Systems-I 11

12. Single Bus-bar Scheme using Simulink . 2/28/2019 Power Systems-I 12

13. Double Bus-bar Scheme using Simulink . 2/28/2019 Power Systems-I 13

14. Thank You. 2/28/2019 Power Systems-I 14