Monday, May 24, 2010

Extra High Voltage Systems - 400kV Lines

Nominal Voltage                      400kV
Cicuits per phase                     1
Sub-conductors per phase        2
Span                                      400m
Conductor Name and Size       Moose,54/3.53mm Alluminium  7/3.53mm Steel
Sub-conductor Diameter          3.177cm
Bundle Configuration                Horizontal
Bundle Spacing                       450mm
Interphase Spacing                   11m
Condutor Configuration            Horizontal
Resistance per phase per km at 20degrees 0.0274Ohm
Inductive Reactance per phase per km              0.3321Ohm
Shunt Admittance per phase per km                  3.2983*10-6
Surge Impedance                    282Ohm
Surge Impedance Loading        505MW
Current Carying capacity at 40degrees ambient temperature 900A
Ground Wire                           2Number,7/3.66mm Galvanised Steel
Ground wire height at tower                30.4m
Tower height                           30.4m
Conductor Height at tower           20.75m
Conductor sag at 0degrees           8.39m
Ground wire sag at 0degrees               6.654m
Shielding angle                           10degrees
Suspension string                   23dics,225*145mm
Impulse Flashover voltage                   1550kV

Examples:Sultanpur-Lucknow Line, Obra-kanput Line, Kanpur-Maradnagar Line.

Friday, May 14, 2010

D.C. Generators #1

An electrical generator is a machine that converts mechanical energy into electrical energy.
This conversion is based on the production of dynamically induced emf whenever a conductor cuts magnetic flux –Faraday’s Law of Electromagnetic Induction.
Essential Parts of an Electrical Generator
----Magnetic Field
----Conductor/Conductors which move so as to cut the flux

Wednesday, May 12, 2010

50kVA PMTx Substation Transformer

Name : 50kVA Pole Mounted Substation Transformer
Rating: 50kVA
Cooling: Oil Cooled
Application: Commercial,Heavy Residential,Farmhold

This  type of transformer is mainly used for Step-Down purposes of voltages in the range of 11kV~415/240V.

Thursday, May 6, 2010

Masinga Dam Scare - Dam Failure Possibilities

In the Tana Delta and Garissa, Masinga dam is currently at 1053.6m against a Full Supply Level (FSL) of 1056.5m, according to KRCS. This means that Masinga is only 2.9m to reaching the FSL. The EOC, KenGen and the UoN School of Mathematics will determine the overspill point or neighborhood. Once this is determined and if the rains persist as projected by the KMD, risk reduction measures ahead of the imminent floods are required.