WEIGHT OF POLES IN USE

TYPE OF POLES ---------------WEIGHT                    

6M/50Kg ----------------------- 345Kg

8.3m/100Kg --------------------- 610Kg

8.3m/500Kg --------------------- 1100Kg

10m/300Kg ---------------------- 1010Kg

11m/350Kg ---------------------- 950Kg

11m/500Kg ---------------------- 1100Kg

11m/850Kg ---------------------- 1400Kg

11m/1200Kg --------------------- 1600Kg

13m/500Kg ---------------------- 1450Kg

13m/850Kg ---------------------- 1900Kg

13m/1200Kg --------------------- 2305Kg

METHOD OF REDUCING CORONA EFFECT

1. BY INCREASING CONDUCTOR SIZE.

2.BY INCREASING CONDUCTOR SPACING.

PRACTICALS

Protection Of Transformers.

Transformers are static devices, totally enclosed and generally oil immersed.therefore chances of faults occurring on them are very rare.


Small distribution transformers are usaually connected to the supply system through series fuses insted of circuits breakers. Consequently , no automatic protective relay equipment is requried.

What is CORONA ?

when an alternating potential is applied across two conductors whose spacing is large as compared to their dimaters, there is no appparent charger i n the condition of atmosphereic air surroundingthe wire if the applied voltage is low.

However , when the appiled voltage exceeds a certain value,called "critical disruptive voltage", the conductors are surrounded by a faint violet glow called "Corona".

Past Paper

Past Papers

Useful Equations

V=IR
P=VI
P=I*IR
P=V*V/R

what are the conductor(ABC) sizes ?

Phase Conductor -- 70 mm2(cross section area).

NeutralConductor -- 54.6 mm2(cross section area).

Street Lampconductor -- 16 mm2(cross section area).

what are the constitute of ABC ?

Insulation Meterial
XLPE -Cross Link Poly Ethylene.

Phase Conductors - Hard Drawn Aluminium.
Neutral Conductors - Aluminium Alloy.
Street Lamp Conductor - Hard Drawn Aluminium.

what is Span and Sag of a Transmission Line ?

the Span and Sag as below image,





LT (Low Voltage) span = 40 ~ 45 m.
HT (High Voltage) Span = 70~75 m.

What are the types of ABC ?

1. 3 Phases and 1 Neutral.
2. 3 Phases, 1 Neutral & 1 Street Lamp Line.
3. 3 Phases , 1Neutral & 2 Street Lamp Lines.

What are the types of ABC ?

What are the Advantages of ABC ?

Possiable of live tapping.
Higher Revenue and least Cost to Authority.
Pole Shareing.
Ease of Augmentation.
ABC -install any where.
Leser no of Fiwer Impedance.
Corrosion Resistance.

What are the advantages of ABC ?

Super safe.
Super Reliabilty.
Eco- friendly.
Low cost of maintenance.

what is stand for ABC ?

ABC is stand for Aerial Bundled Conductor.

What is the difference between AAC and ACSR?

AAC is stand for All Aloye Conductor.

All stands of this conductor is Aloye (Fly and Wasp only)

ACSR is stand for Aluminium Conductor Steel Reinforce.

six stands are aluminium and other one stand is steel reinforced.(Racoon,weasal and Lynx)

What are the conductors used in electricity?

conductors are as follows;

Weasal - 7/0.102"(7/2.59mm) 95 A (Maximum current) 33mm2(cross section area).(AAC)

Fly - 7/0.134"(7/3.40mm) 155 A (Maximum current) 63mm2(cross section area).(AAC)

Racoon - 7/0.161"(7/4.09mm) 200 A(Maximum current) 78mm2(cross section area).(ACSR)

wasp - 7/0.173"(7/4.39mm) 200 A (Maximum current) 100mm2(cross section area).(AAC)

Lynx 37/1.10"(37/2.79mm) 325 A(Maximum current) 175mm2(cross section area).(ACSR)

GNT - 7/2.21mm Maximum current 85A. (AAC).

Lady Bird - 7/2.79mm,Maximum current 120A,(AAC).

Ant - 7/3.10mm,Maximum current 137A,(AAC).

Earwing - 7/3.78mm,Maximum current 180A,(AAC).

Mink - 7/3.66mm,Maximum current 155A,(ACSR).

Dog - 7//1.57mm or 6/4.72mm ,Maximum current 205A,(ACSR).

Tiger - 37/2.36mm,Maximum current 265A,(ACSR).

Goat - 37/3.71mm,Maximum current 495A,(ACSR).

Zeebra - 61/3.18mm,Maximum current 575A,(ACSR).

Power losses in electricity network

as followes;

Generation = 7 %
Transmisson = 5 %
Distribution = 13 %

What are the high voltages used in sri lanka ?

33Kv
66Kv
132Kv
220Kv

why is the high Voltage Transmit ?

When the current is transmitting through the cables,power may be loss due to heat.
that is you can understand by using below equation;

power(P)= I*I*R


I= current through cable(Amp).
R= Cable Resistance(ohm).
P= Power (Watt)
When the current is increased, Power may be increased according to the above equation.therefore power loss is increase.

in order to reduced the power loss, you have to reduced the current through the cable.
According to the Ohms law, to reduced the current you must increase the voltage . as below,
V=I*R

therefor High voltage used to transmit the current.

SOURCES OF ENERGY

1.The Sun.
2.The wind.
3.water
4.fule.
5.Nuclear Energy.

What are the importance of Electrical energy?

Electrical energy is superior to all other forms of energy due to the following reasons;

1. Convenient Forms.

2. Easy Control.

3. Greater Flexibility.

4. Cheapness.

5. cleanliness.

6. High Transmission Efficiency.

INTRODUCTION

Energy is the basic necessity for the economic development of a country. Many function necessary

To present day living grind to half when the supply of energy stops.
It is parctically impossiable to estimate the actual magnitude of the part that energy has played in the building up to present-day civilisation. The availability of huge amount of energy in the morden times has resulted in a shorter working day higher agricultural and industrial production , a healthier and more balanced dite and better transportation facilities.