Study with the several resources on Docsity
Earn points by helping other students or get them with a premium plan
Prepare for your exams
Study with the several resources on Docsity
Earn points to download
Earn points by helping other students or get them with a premium plan
An overview of basic equipments in electrical installations, focusing on power handling equipment such as transformers, ats, ups, and distribution boards, as well as cable installation and classification. Various connections, protection codes, wiring and raceways, and cable construction details.
Typology: Lecture notes
1 / 52
This page cannot be seen from the preview
Don't miss anything!
Power Distribution system is composed from four groups of equipments :-
1- power Handling Equipments
a- medium voltage distribution board b- transformer c- emergency generators and ATS d- Distribution Boards
Faculty of Engineering Electrical Engineering Department
Power Distribution system is composed from four groups of equipments :- 2- Wiring and Raceways 3- Protective Devices a- CBs b- Fuses 4- Control and Utilization Equipments Lights , pumbs , elevators , sockets
Faculty of Engineering Electrical Engineering Department
Power Handling equipments
Transformer
transformer (11 ,20 KV /400 V)
Usually described by :
Power rating of the transformer (MVA) (< 5MVA)
Earthing of the neutral point :- Solidly earthed or connected by 10 ohm resistor to the earth.
Percentage Impedance (x% ,Z%)
Ways of primary and secondary windings connection
Faculty of Engineering Electrical Engineering Department
Power Handling equipments
Transformer
Ways of primary and secondary windings connection (star/delta, deta/delta… )
Each of theses connections has advantages and disadvantages relating to :-
1- preventing third harmonics or zero sequence current
2- economical manufacturing (no of turns and isolations)
3- need of neutral or not
4- the balance of the neutral point.
Faculty of Engineering Electrical Engineering Department
Power Handling equipments Transformer cooling (oil, fan, air,…) As the cooling efficiency is increased as the transformer efficiency is increased. Usually 4 letters are used to describe the cooling way:- the first two letters refers to the fluids used to cool the coils of the transformer and the ways of pushing the fluid. The last two letters refers to the fluid used to cool the body of the transformer and the way to push the fluid. ONAN (oil transformer , oil is naturally pushed , the body is cooled using Air and is pushed naturally)
Faculty of Engineering Electrical Engineering Department
Power Handling equipments
Transformer
Faculty of Engineering Electrical Engineering Department
Power Handling equipments
Transformer
oil used
isolation between the coils and between the coils and the body of the transformer
Cooling of the body of the transformer
sound level (should be less than 65 dB).
Faculty of Engineering Electrical Engineering Department
Power Handling equipments
Transformer
no 925554 is found on the body of the transformer.
First two letters means the year of manufacturing (95)
The third letter refers to the rating of the transformer
The first ,second and third nmber from right refers to serial no of the transformer.
Faculty of Engineering Electrical Engineering Department
Power Handling equipments
Standby generators
the switching of the power source can be done either manually ( Manual Transfer switching ) or automatically ATS (automatic transfer switch).
usually the emergency loads are 10-20% in the buildings ( lighting corridors , fire exits, alarm systems , telephones ,elevators ,… )
In hospitals , the emergency load can be up to 50% of the loads
Faculty of Engineering Electrical Engineering Department
Power Handling equipments
ATS (Automatic Transfer Switch)
ATS is a device that can transfer the supply of any emergency DB automatically in the case of the current cut from the main source (usually the electrical
distribution company )
to the second source
such as generator as
shown below.
Faculty of Engineering Electrical Engineering Department
Power Handling equipments
Distribution boards
It consists of
Busbars
Circuit breakers and fuses
Measurment devices
Pulbs (indicators)
Faculty of Engineering Electrical Engineering Department
Power Handling equipments
Distribution boards
The distribution boards can be classified into
Open frame construction (closed areas)
Construction panels (closed areas)
Cubicle Construction (open areas)
Withdraw able units
Box type construction
Faculty of Engineering Electrical Engineering Department
Power Handling equipments
Distribution boards
Code-IP
Faculty of Engineering Electrical Engineering Department
Power Handling equipments
Wiring and raceways
Cable and wires installations in projects
1- using pipes
Using cable trays
Directly buried underground
Faculty of Engineering Electrical Engineering Department
