The course aims to provide understanding of the systems, constants, effects and
mechanical consideration of both overhead and underground transmission and distribution lines, effects of low power factor on system performance are also included.
The 2nd half of the course in designed to provide understanding of system protection techniques, switch gear involved and protective relaying schemes. It is also aimed to provide sufficient knowledge of various solid state (Static) relays being used and the schemes of protection of generators, transformers, feeders and transmission lines.

UNIT ONE
(TRANSMISSION AND DISTRIBUTION OF ELECTRIC POWER)
1. BASICS OF ELECTRICAL TRANSMISSION SYSTEMS.                       16 Hrs.
1.1 Components of power system.
1.2 Purpose of transmission
1.3 Classification of transmission lines
1.3.1 With respect to voltage level (low, medium, high, extra high and ultra high
voltage lines).
1.3.2 Representation of power system with single line diagram showing all
components of power system
1.4 Comparison of different transmission systems (AC vs DC, overhead vs
underground)
1.5 Choice of frequency, voltage level, and supply circuits for a particular transmission
line.
1.6. Transmission line circuits and their comparison (radial, ring, mesh etc.)
1.7 Factors effecting line cost
2. ELECTRICAL DESIGN OF TRANSMISSION AND DISTRIBUTION LINES                                                                                                                           16 Hrs.
2.1 Constants of transmission lines (resistance, inductance, capacitance and
conductance) of 1 phase & 3 phase (with equal spacing).
2.2 Formulae (without derivations) & calculation of line constants
2.3 Charging current of transmission lines and its effect, simple calculations.
2.4 Classification of transmission lines based on length (short, medium and long T/Ls).
2.5 Voltage drop in short transmission lines (vector diagram & simple calculations)
2.6 Voltage drops in M.V. transmission lines, simple calculations using!
2.6.1 T-Method, vector diagram.

2.6.2 Pi (π)-Method, vector diagram.
Voltage Regulation of transmission lines.
2.7 Effect of load on voltage. Inductive, capacitive, Surge Impedance and no-load
behavior
2.8. Effects on transmission lines.
2.8.1 Ferranti effect.
2.8.2 Skin effect
2.8.3 Corona effect.
2.8.4 Proximity effect
3. MECHANICAL COMPONENTS OF TRANSMISSION AND DISTRIBUTION
LINES.                                                                                                         8 Hrs
3.1 Line conductors (materials and types) 2 Hrs.
3.2 Line insulators (types and materials) 4 Hrs.
3.3 Line supports (materials and types) 2 Hrs.
3.4 Sag and its calculation . 4 Hrs.
4. UNDER GROUND POWER CABLES                                                     4 Hrs.
4.1 Classification and sub classification of power cables with respect to construction
(solid paper insulated and XLPE insulated cables, screened cables, oil filled cable
and gas filled cables etc).
1.2 Constructions and characteristics of above cables.
1.3 Capacitance of single and three core cables
1.4 Stress on insulation & capacitance.
1.5 Laying of under-ground cables
4.6 Jointing of power cables.
2. POWER FACTOR CONSIDERATIONS OF TRANSMISSION LINES                                                                                                                                              6 Hrs
5.1 Causes of low power factor and its effect on generation, transmission and
distribution.
5.2 Importance of power factor from consumer point of view.
5.3 Power factor correction methods (Static capacitors, Synchronous condensers,
SVCs).
5.4 Power factor improvement calculation.
6 High Voltage DC Transmission (HVDC) 1 Hr.
6.1 Introduction
6.2 Merits and demerits
7 AC DISTRIBUTION LINES AND THEIR VOLTAGE DROPCALCULATIONS. 6 Hrs.
7.1 Calculations of AC Distributors (Voltage drop, voltage regulation, power loss,
vector diagrams)

8. BALANCERS & BOOSTERS (A.C & D.C)                                                   2 Hrs.
8.1 Balancers-Definition.
8.1.1 Types of Boosters.
8.1.2 Types of Balancers.
8.1.3 Uses of each.
9. SUB-STATIONS AND INTERCONNECTED POWER SYSTEMS.               5Hrs.
9.1 Classification of sub stations (with respect to duty and construction)
9.2 Describe relative merits and demerits of Indoor, outdoor and & underground
substations.
9.3 Equipment used in 132/11KV substation.
9.4 Bus Bar arrangement schemes.
9.5 Grounding of star Neutral point.
9.5.1 Necessity of grounding.
9.5.2 Solid grounding.
9.5.3 Resistance grounding.
9.5.4 Reactance grounding.
9.5.5 Different sub-station schemes.
9.6 Importance & advantages of Interconnected power stations.
9.7 National Grid system of Pakistan.
9.8 Necessity of Load management (NPCC, K-Electric/DISCOs).
9.10 Gas insulated substations

UNIT -2
(Power System Protection)

1. REPRESENTATION OF POWER SYSTEM BY.                          5 Hrs.
11.1 One (single) line diagram,
11.2 Impedance diagram.
11.3 Reactance diagram.
11.3.1 per unit & percentage quantities.
2. FAULTS IN POWER SYSTEM.                                                     5 Hrs.
2.1 Types of faults in power system.
2.2 Selection of Base KVA.
2.3 Calculation of percentage reactance at base KVA.
2.5 Symmetrical fault.
2.6 Short circuit capacity.
3. REACTORS IN POWER SYSTEM.                                              4 Hrs.
3.1 Necessity of reactors.
3.2 Construction of reactors.
3.3 Advantages and disadvantages of reactors.
3.5 Types of reactors.
3.5.1 Unshielded.
3.5.2 Magnetically shielded.
3.6 Methods of Locating Reactors.
3.6.1 Generator reactors.
3.6.2 Feeder reactors
3.6.3 Bus bar reactors. (Ring system, Tie bus bar system)
.
4. CIRCUIT BREAKERS.                                                               16 Hrs.

4.1 Need of circuit breakers in power system.
4.2 Theory of A.C Interruption
4.2.1 Phenomena of arc & its effects.
4.2.2 Magnitude of arc
4.2.3 Maintenance of arc and (Arc quenching) in (oil, air, gas and vacuum circuit
breakers)
4.3 Ratings of circuit breakers (Normal current rating, making capacity, breaking
capacity, short circuit current rating, rated voltage and operating duty)
4.4 Oil circuit breakers (working, construction, types and advantages).
4.5 Air Circuit Breakers.(Working and construction, types and advantages).
4.6 SF6 Gas Circuit Breakers.
4.6.1 Dielectric, Physical& chemical properties of SF 6 Gas.
4.6.2 Working & Construction of SF6 Circuit Breakers.
4.6.3 AdvantagesSF6 Circuit Breakers.
4.7 Vacuum Circuit Breakers.
4.7.1 Working & construction.
4.7.2 Advantages.
5. ISOLATORS.                                                                                 2 Hrs.
5.1 Types of Isolators.
5.2 Working principle.
5.3 Uses.
6. FUSES.                                                                                          4  Hrs.
6.1 Definitions- Fuses, current carrying capacity, fusing current, prospective current & cut off current, Arcing & pre-arcing (Melting) time, total operating time, breaking
capacity.
6.1.1 Fuses Materials.
6.1.2 Factors affecting fusing currents.
6.1.3 Fusing factors.
6.2 Types of High voltage fuses, their construction and applications.
7. PROTECTIVE RELAYS.                                                                 12 Hrs.
7.1 Necessity of relaying.
7.2 Requirements of relaying.
17.2.1 Speed.
17.2.2 Selectivity.
17.2.3 Sensitivity.
17.2.4 Reliability.
17.2.5 Simplicity.
17.2.6 Economy.
7.3 Primary & back-up protections.
7.4 Classification of relays w.r.t
17.4.1 Construction & Principle

17.4.2 Application (Uses).
17.4.3 Time of operation.
7.5 Principle of operation.
7.5.1 Buchholz’s relay including its construction.
7.5.2 Induction over current relay (Non directional).
7.5.3 Induction reverse-power relay.
7.5.4 Induction directional over current relay.
7.5.5 Distance relay.
7.5.6 Impedance relay.
7.5.7 Beam relay.
7.5.8 Frequency relay.
7.5.9 Static relays (Electronic relays).
7.5.10 Amplitude-comparator relays.
7.5.11 Phase comparator relay.
7.5.12 Static over current relay.
7.5.13 Static distance relay.
7.5.14 Differential protection.
a. Current Balance.
b. Voltage Balance.
8. BUS-BAR PROTECTION.                                                                   4 Hrs.
8.1 Bus bar protection.
8.2 Frame leakage protection.
8.3 Circulating current protection.
9. FEEDER & TRANSMISSION LINE PROTECTION.                           4 Hrs.
9.1 Time Graded Protection.
9.2 Differential protection.
9.3 Ring mains protection.
10. ALTERNATOR PROTECTION.                                                           3 Hrs.
10.1 Alternator faults.
10.2 Protection against stator faults (Merz-price).
10.3 Balanced Earth fault protection.
10.4 Stator In-turn protection.
10.5 Un-Balanced loads.
11. TRANSFORMER PROTECTION.                                                        3 Hrs.
11.1 Transformers faults.
11.2 Merz-price system of protection for:
11.2.1 Delta-Star.
11.2.2 Delta-Delta.
11.2.3 Star-Delta.
11.2.4 Star-Star

11.3 Over current & Unrestricted earth fault protection.
12. LIGHTNING ARRESTERS.                                                                    2 Hrs.
12.1 Phenomenon (Mechanism) of lightning.
12.2 Effects of lightning on Electrical power system.
12.3 Lightning strokes.
22.3.1 Direct stroke.
12.3.2 Indirect strokes.
12.4 Protection of H.T Lines & building with ground wire.
12.5 Types of arrestor.
22.5.1 Expulsion.
22.5.2 Valve type.
22.5.3 Horn gap (Rod gap) type