Illumination in Stadiums - Introduction

A stadium comes to life when its fully packed to capacity and all its luminaries are working properly. Illumination in stadiums is a very important topic when it comes to the design phase of construction. The manner in which the luminaries are going to be installed impacts the overall performance of the stadium and not to forget the game being played. A well lit stadium/Arena ensures maximum illumination and minimal glare to the fans both on the pitch as well as on the seats. The lamps should be of correct rating to avoid unwanted glare and loss of heat through radiation. To achieve this, powerful luminaries are placed on top or even mounted on special masts at a height distance to reduce heat radiating to the fans and also making sure that maximum light falls on the pitch in the stadium. Less powerful  luminaries are then installed near the pitch to provide light for live television and quality photography.
All these lamps together with those inside the stadium present a power thirsty load to the power supply source. Today’s stadiums are supplied by up to 5 transformers and dedicated substations just to reduce power outages.

Which one is more dangerous, AC or DC?

This question has been asked by many people who have experienced an 

electric shock before.I recently received an electric shock from the 

domestic household current of 10A.The feeling was ecstatic. Many will come 

across large AC currents, but have you ever thought of DC Electrification? 

This would sound weird because DC current available in domestic premises 

is in the order of mA (milliamperes). In industrial environments  DC current 

is available in large quantities and is very lethal when handled improperly. 

The severity of a shock largely depends on:

---Amount of current 
---Amount of time on the exposure 
---Resistance of the body.

AC:Alternating Current
AC in theory would allow your muscles time to be able to move so that you could pull your hand / limb 

away from whatever it was that was giving you the shock. This is so because AC alternates from zero 

to maximum (amplitude) in a specified time frame (frequency).It is during this timeframe that muscle 

signals may retract you hand/limb...

The time frame we are talking about here is only a few milliseconds-which means that for larger 

currents, there is no time for reflex action. However as I said above,

 this largely depends on the amount of current flowing. 

Starting current of motors (128A) would never give you a chance of even thinking!
AC current will allow you to move your hand for the muscles which are not in the path of the electric

 current.In AC (Alternate Current) the muscles will contract and extend and through the spasms you 

might eventually free yourself (that is why people say that the current threw them while, in fact, 

it was their own muscles).

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.

D.C. Generators #1

Defn:
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

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.

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.

AC & DC Machines:::Introduction

A machine is any device that uses energy to perform some work.A simple machine is a device that transforms the direction or magnitude of a force without consuming any energy.Electrical machines are normally grouped into either AC or DC.
Depending on the area of application both types produce the necessary power required each having its own advantages and disadvantages.
Read more>>>

Corona

Have you ever wondered why high voltage power lines buzz (zszszs sound)? Its because they are producing corona which is interacting with the surrounding air.
 Corona is the process by which current, perhaps sustained, develops from an electrode with a high potential in a neutral fluid, usually air, by ionizing that fluid so as to create plasma around the electrode. The ions generated eventually pass charge to nearby areas of lower potential, or recombine to form neutral gas molecules. Plasma is a fourth state of matter (after solid, liquid, and gas). It is like a gas or liquid, but molecules are separated into atoms, and the outer electrons are stripped off and are freed into the plasma. In comparison, the sun is essentially a big ball of very hot plasma.

Power System Network

A detailed explanation of the conversion and distribution of electric energy from the power station to consumer units.This post describes how electric energy moves from the power generating station through conductors of various sizes to consumers premises.To minimize losses and for economical reasons, electrical energy has to be converted into different magnitudes during transmission and distribution until the consumer load.

Electric Pole in the middle of a Road!!

Is this the 8th Wonder of the world?
In Igemebe North Constituency, Eastern Province-Kenya lies a mysterious and mixed up piece of what many might call an engineering mess.Right in the middle of Wiyara Road stands an electric pole.The completion of the road was to follow the installation of power to the area but the two projects ran in to each other resulting to the installation of an electric pole in the middle of the road.