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”

Power Delivery “Towers - size” Height of tower is determine by- h 1 =Minimum permissible ground clearance h 2 =Maximum sag h 3 =Vertical spacing between conductors h 4 =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

Power Delivery “Conductor - resistance” -Short line (up to 80 km) -Medium-length lines (up to 240 km) -Long line (above 240 km)

Power Delivery “Transmission Line”

Power Delivery “Power Cable”

Power Delivery “Power Cable - losses”

Dielectric used for cable insulation must have following properties: 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 “Power Cable - losses”

Power Delivery “Cable - resistance”

Power Delivery “Cable - inductance”

Power Delivery “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, C m1 =0.6uF ii)Capacitance between two conductor bunched with sheath and third conductor, C m2 =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 “Insulator”

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 “Insulator - Types”

- Nonconducting material such as porcelain, glass, plastic, polymer, or wood. - Upto 33 kV Power Delivery “Pin Insulator”

Power Delivery “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”

Power Delivery “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.

Power Delivery “Strain Insulator”

Power Delivery “Shackle Insulator” - Used for low voltage distribution lines. - Horizontal or vertical position.

Power Delivery “Shackle Insulator”

Power Delivery “Insulator”

Power Delivery “Circuit Breaker”

Power Delivery “Switchgear (GIS)”