Download Electrical Power System SMJE 2103

Electrical Power System
SMJE 2103
Electrical Power
Delivery System
Power Flow / Load Flow
• A numerical analysis for future planning of
operational power system in order to optimize
generated power.
• The objective is to produce following inform:
i- voltage magnitude and phase angle at each
bus
ii- real and reactive power flowing in each
element
iii- reactive power loading on each generator
Power Delivery
“Overhead Lines - Components”
Power Delivery
“Transmission Line – Single Line”
Power Delivery
“Towers - types”
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“Towers - size”
Height of tower is determine by-
H  h1  h2  h3  h4
h1=Minimum permissible ground clearance
h2=Maximum sag
h3=Vertical spacing between conductors
h4=Vertical clearance between earthwire and
top conductor
Power Delivery
“Conductor - types”

ACSR Conductor(Aluminium Conductor Steel Reinforced)

AAC(All Aluminium Conductor)

AAAC(All Alloy Aluminium Conductor)
Power Delivery
“Line – equivalent circuit”
L’ = Inductance
R’ = Resistance
C’ = Capacitance
G’ = Leakage Resistance
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“Conductor - resistance”
- Short line (up to 80 km)
- Medium-length lines (up to 240 km)
- Long line (above 240 km)
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“Transmission Line”
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“Power Cable”
Power Delivery
“Power Cable”
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“Power Cable - losses”
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“Power Cable - losses”
Dielectric used for cable insulation must have following
properties:
•
•
•
•
•
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High insulation resistance
High dielectric strength
Good mechanical strength
Immune to attack by acids and alkali in the range 0-100o C
Should not be too costly
Should no be hygroscopic (tending to absorb water), or if
hygroscopic should be enclosed in a water tight covering
Power Delivery
“Cable - resistance”
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“Cable - inductance”
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“3- Core Cable - inductance”
Power Delivery
“3- Core Cable – inductance (M & C)”
Power Delivery
“3- Core Cable – inductance”
(Measured)
Power Delivery
“3- Core Cable - inductance”
(Measured)
Example/Tutorial
• A 3 core, 3 phase metal sheathed cable on testing for
the capacitance gave the following results:
i) Capacitance between all conductors bunched and
sheath, Cm1=0.6uF
ii) Capacitance between two conductor bunched with
sheath and third conductor, Cm2=0.36 uF
With the sheath insulated find,
a) Capacitance between any two conductors
b) Capacitance to neutral
c) Charging current if cable is connected to 11kV, 3
phase, 50 Hz system
Power Delivery
“3- Core Cable – Gas-pressure”
Power Delivery
“3- Core Cable – Gas-pressure”
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“3- Core Cable – Gas-pressure”
Power Delivery
“Insulator”
Power Delivery
“Insulator - Types”
There are several types of insulators
but the most commonly used are :
1)Pin Insulator
2)Suspension Insulator
3)Strain Insulator and
4)Shackle insulator.
Power Delivery
“Pin Insulator”
- Nonconducting material such as porcelain, glass,
plastic, polymer, or wood.
- Upto 33 kV
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“Pin Insulator”
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“Suspension Insulator”
- For high voltages (>33 kV)
- Each unit or disc is designed for low voltage, say 11 kV
- The number of discs in series would obviously depend upon
the working voltage
Power Delivery
“Suspension Insulator”
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“Strain Insulator”
- Dead end of the line or corner or sharp curve.
- For low voltage lines (< 11 kV).
- Two or more strings are used in parallel.
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“Strain Insulator”
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“Shackle Insulator”
- Used for low voltage distribution lines.
- Horizontal or vertical position.
Power Delivery
“Shackle Insulator”
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“Insulator”
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“Circuit Breaker”
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“Circuit Breaker”
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“Circuit Breaker”
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“Circuit Breaker”
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“Circuit Breaker”
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“Switchgear (GIS)”
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“Switchgear (GIS)”
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“Switchgear (GIS)”
Power Delivery
“Switchgear (GIS)”