Electrical Substations
bullet Electrical Network comprises the   following regions:
1 - Generating Stations.   
2 - Transmission Systems.
3 - Distribution Systems.    
4 - Load Points.
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Functions of a Substation
 1 - Supply of required electrical power.
2 - Maximum possible coverage of the supply network.
3 - Maximum security of supply.
4 - Shortest possible fault-duration.
5 - Optimum efficiency of plants and the network.
6 - Supply of electrical power within targeted frequency limits, (49.5 Hz and 50.5 Hz).
7 - Supply of electrical power within specified voltage limits.
8 - Supply of electrical energy to the consumers at the lowest cost.
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Substation Layouts
1. Switching requirements for normal operation.
2. Switching requirements during abnormal operations,
     such as short circuits and overloads.
3. Degree of flexibility in operations, simplicity.
4. Freedom from total shutdown and permissible period of shutdown.
5. Maintenance requirements, space for approaching various
6. Safety of personnel.
7. Protective zones, main protection, back-up protection
8. Bypass facilities.
9. Technical requirements such as ratings, clearances,
    Earthing lightning protection, Noise, radio  interference, etc.
10. Provision for extensions, space requirement.
11. Economic considerations, availability, foreign 
      exchange involvement, cost of the equipment.
12. Requirements of network monitoring, power line
     communication, data collection, Data transmission etc.
13. Compatibility with ambient conditions.
14. Environmental aspects, audible noise, RI, TI etc.
15. Long service life, Quality, Reliability, and Aesthetics.
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bullet Essential Features for substation
1 - Outdoor Switchyard having any one of the above.
2 - Bus-Bar schemes.
3 - High voltage Switchgear. Medium voltage Switchgear, Low voltage
    Switchgear and control room. 
4 - Office building.
5 - Roads and rail track for transporting equipment.
 6 - Incoming line towers and outgoing line towers/cables.
7 - Store.
8 - Maintenance workshop (if required).
9 - Auxiliary power supply Low voltage AC.
10 - Battery room and low voltage DC. Supply system.
11 - Fire fighting system.
12 - Cooling water system; drinking water system, etc.
13 - Station Earthing system.
14 - Lighting protection system, overhead shielding.
15 - Drainage system.
16 - Substation lighting system etc.
17 - Fence and gates, Security system etc.
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