HIGH VOLTAGE TRANSMISSION AND DISTRIBUTION

PPT PRESENTATION

1. EE504.61 to 62 1
DEPARTMENT OF TECHNICAL
EDUCATION(A.P)
Name :S.Srinivasa Babu.
Designation :HOS
Branch :Electrical and Electronics Engg.
Institute :Sir C.R.R.Polytechnic,Eluru.
Year/Semester : V- Semester.
Subject :Power System-II( Transmission & Distribution)
Subject Code :EE-504
Topic :Substations
Duration :50 minutes
Subtopic :Substation Auxiliary supply& Auxiliary equipment
Teaching Aids :PPT

2. EE504.61 to 62 2
RECAP
We have discussed already in the last class about
• Different types of equipment used in substations.

3. EE504.61 to 62 3
OBJECTIVES
•Upon the completion of this topic the you would be able to
know
•Auxiliary Supply &Auxiliary Equipment of Substation.

4. EE504.61 to 62 4
KNOWN TO UNKNOWN
• Up to this topic we know
• 1)What is a Substation.
• 2)Need for Substation.
• 3)Functions of a substation.
• 4)Types of Substation.
• 5)Equipment used in Substation
• But we don’t know how to get supply for
• 1)The substation itself (L.T.Supply).
• 2) Other auxiliary equipment.

5. EE504.61 to 62 5
Substation auxiliary supply
• In substations two transformers connected to the 11KV In substations two transformers connected to the 11KV
main Busbars for main Busbars for
• 1)the supply of auxiliaries at a voltage of 440V/230V.1)the supply of auxiliaries at a voltage of 440V/230V.
• 2)Electric supply is required for auxiliaries like2)Electric supply is required for auxiliaries like
Lighting CircuitsLighting Circuits
Air blast fans of transformerAir blast fans of transformer
Battery charging setsBattery charging sets
Compressor unitsCompressor units
Water supplyWater supply
Heating system equipment etc.Heating system equipment etc.

6. EE504.61 to 62 6
SUBSTATION AUXILIARY SUPPLY (IN DETAIL)
•The following auxiliary supplies, equipment and services have generally to be
provided at a grid substation.
1)D.C.Supply
•In large H.V Switchgear installations independent sources of supply are necessary
for
Signaling
Remote position control
Remote indication etc.

7. EE504.61 to 62 7
•They are particularly important for switch tripping circuits.
•For this purpose fixed storage batteries are generally used.
•The storage batteries are of lead acid type (or) alkaline type.
•Lead acid type is more commonly used at power stations and
substations.

8. EE504.61 to 62 8
•Because they have comparatively high cell voltage & lower costs.
•Complete D.C equipment for a substation may be divided in to
three parts.
1)Storage Battery & Accessories
2)Charging Equipment.
3)Distribution Board

9. EE504.61 to 62 9
STORAGE BATTERY & ACCESSORIES
•1)Choice of battery is the selection of voltage. Standard
voltages of auxiliary circuits are
24 Volts,30 Volts,50 Volts,110 Volts&240 Volts.
•For circuit breaker operation a voltage below 110 Volts should
not be used.

10. EE504.61 to 62 10
•2)Battery Voltage depends upon number cells connected in
series (or) parallel (or) series parallel.
•3)Important characteristics to be fixed for the battery is the
Amp-Hour capacity.

11. EE504.61 to 62 11
ACCESSORIES OF STORAGE BATTERY
•1)Bridging clamp for cutting out individual cell in the event of
defect.
•2)Hydrometer.
•3)Cell testing voltmeter.

12. EE504.61 to 62 12
CHARGING EQUIPMENT
•Charging equipment is required for
• 1)Initial charging
• 2)Quick Charging after the battery has discharged under
heavy loads.
• 3)Trickle charging.

13. EE504.61 to 62 13
D.C.DISTRIBUTION PANEL
•1)one incoming circuit from the D.C battery.
•2)Number of out going circuits separate for
• a) closing & tripping.
• b) Alarm and indication for each control and relay
board.

14. EE504.61 to 62 14
LOW TENSION A.C.SUPPLY
•Low tension circuits from the transformer are carried to the L.T. Distribution
board.
•Some of the circuits generally required are mentioned below.
• 1)colony feeders
• 2)For indoor lighting and indicating lamps.
• 3)For outdoor lighting.
• 4)For battery charging equipment.

15. EE504.61 to 62 15
• 5)For emergency lighting.
• 6)For oil filtration plant.
• 7)For compressed air plant.
• 8)For tube well pump motor.
• 9)For power plugs.
• 10)For work shop (if provided) etc.

16. EE504.61 to 62 16
OIL FILTRATION PLANT
•Insulating oils must have some specifications in dielectric
break down strength for safe and satisfactory operation of the
oil filled apparatus.
•Formation of the acids increases the corrosion and makes the
insulating material brittle.

17. EE504.61 to 62 17
•Similarly the sludge deposits make the heat transmission
difficult there by causing over heating which further increases
the formation of water acids etc.
•The oil in the circuit breaker is carbonized due to arcing.

18. EE504.61 to 62 18
•Treatment of oil is necessary to
•1)remove suspended impurities such as sludge fibers and other
contaminants.
•2)remove free water.
•3)neutralise acidity of oil.

19. EE504.61 to 62 19
•Oil filtration plants work on the following principles
•1) Blotter press filtration
•2)Centrifuge filtration
•3)vacuum filtration
•4)Edge filtration
•5)chemical(cold) filtration etc.

20. EE504.61 to 62 20
•The oil filtration plant may be of fixed type erected in a room
(or) made portable depending on the extent of the switchyard
and the oil content of the transformers and circuit-breakers.

21. EE504.61 to 62 21
COMPRESSED AIR SUPPLY
•Compressed air supply is required at a substation for one (or)
more of the following purposes
• 1)As arc extinguishing medium in air circuit-breakers.
• 2)For closing and opening of circuit-breakers and isolating
switches.
• 3)For air conditioning i.e. to keep insulators dry in certain
types of air blast circuit-breakers.

22. EE504.61 to 62 22
SUMMARY
•We have discussed about
• 1)uses of low tension A.C.supply
• 2)Discussed about oil filtration plants &Compressed air
supply.

23. EE504.61 to 62 23
1)How to get A.C. Supply (440/230V) for the sub station

lighting
a) From another sub station
b) By means of generation
c) By means of transmission
d) None of the above
QUIZ

24. EE504.61 to 62 24
Frequently asked Questions
•1)Explain about oil filteration plant & compressed air plant?
•2)Explain applications of low tension A.C.supply?