Switch gear and protection
- switchgear components
- Types
- Testing
- Maintenance
- protection
Prepared by . Eng. Mahmoud mostafa
Introduction
Power system components
-Generation
-Step up transformers
- transmission ( T.L , U.G cables )
-Step down transformers
- distribution
Introduction
STANDERDS
IEC ( International Electrotechnical Commission)
is an international standards organization that prepares and publishes
international standards for all electrical, electronic and related technologies
IEEE ( Institute of Electrical and Electronics Engineers)
is a professional association that develops, defines, and reviews electronics
and computer science standards
ANSI (American National Standards Institute)
is a private non profit organization that oversees the development
of standards for products, services, processes, systems, and personnel in the
United States
NFPA (National Fire Prevention Association)
is a global, non-profit organization that promotes safety standards,
education, training, and advocacy on fire and electrical-related hazards
EGYPTION CODE
Introduction
VOLTAGES DIVISIONS ( AC R.M.S VOLTAGE VALUES)
- LOW VOLTAGE FROM 50 V TO 1000 V
- MEDIUM VOLTAGE FROM 1000 V TO 66 KV
- HIGH VOLTAGE FROM 66 KV TO 220 KV
- EXTRA HIGH VOLTAGE FROM 220 KV TO 750 KV
- ULTRA HIGH VOLTAGE ABOVE 750 KV
Introduction
GENERATION
-The Ordinary generating voltage may be 6.6 KV ,11 kV , 12 kV or 13.8 Kv
-means of electricity generation
1- hydro turbines ( depends on water)
2-thermal generation stations ( depends on fossil fuel)
3-photovoltaic systems
4- nuclear power plants
5- wind turbines
Most power plants in oil and gas are thermal generation stations
Introduction
STEP-UP STATIONS
- BY STEP-UP TRANSFORMERS CONVERT GENERATION VOLTAGE TO
TRANSMISSION EXTRA HIGH VOLTAGE LEVELS THIS IS FOR THE FOLLOWING :
POWER = VOLTAGE X CURRENT X POWER FACTOR
AS VOLTAGE INCREASED AND TO MAINTAIN POWER CONSTANT SO THE CURRENT
WILL BE DECREASED THIS HAS A GREAT EFFECT ON
- CONDUCTORS CROSS SECTION AREAS (ECONOMICAL )
- POWER LOSS OR ENERGY LOSS THAT WILL BE CONVERTED TO HEATING
- VOLTAGE DROP WILL BE DECREASED
Introduction
TRANSMISSION
MEANS OF ELECTRICAL ENERGY TRANSMISSION ARE :
THROUGH O.H.T.L ( OVERHEAD TRANSMISSION LINES)
OR U.G ( UNDER GROUND CABLES )CABLES
Introduction
STEP DOWN AND DISTRIBUTION
- IN THIS STAGE THE TRANSMITTED POWER WILL BE DISTRIBUTED TO
CONSUMERS THROUGH SUITABLE VOLTAGE SIZES
- VOLTAGE WILL BE DCREASED THROUGH STEP-DOWN TRANSFORMERS TO
MEDIUM VOLTAGE SUITABLE FOR DISTRIBUTION TO CONSUMERS
- THIS POWER WILL BE HANDLED THROUGH DISTRIBUTION SUBSTATIONS
Introduction
SWITCHGEAR
DEFINITION:
IS A GENERAL TERM COVERING A WIDE RANGE OF EQUIPMENT CONCERNED
WITH SWITCHING AND PROTECTION
- WHERE IS THE SWITCHGEAR IN POWER SYSTEM:
ANY PART IN POWER SYSTEM YOU WILL FIND SWITCHGEAR THAT WILL HANDLE
SWITCHING PROCESSES AND PROTECTION OF THE NETWORK AGAINST ANY
ABNORMAL OPERATIONS (FAULTS AND TRANSIENT CONDITIONS)
Introduction
FAULTS AND ABNORMAL CONDITIONS
FAULT IS DEFINED AS A DEFECT IN THE ELECTRICAL CIRCUIT DUE TO RAPID
INCREASE IN CURRENT VALUE
THIS MAY OCCUR DUE TO BREAKING OF CONDUCTORS , FAILURE OF INSULATION
OR MECHANICAL FAILURE
FAULTS CAN BE CLASSIFIED AS :
1- SINGLE LINE TO GROUND FAULT 2- DOUBLE LINE TO GROUND
3- LINE TO LINE FAULT 4- SYMMETRICAL SHORT CIRCUIT
5- OPEN CIRCUIT
ABNORMAL CPNDITIONS :
1- VOLTAGE AND CURRENT UN BALANCE 2- UNDER / OVER VOLTAGE
3-REVERSE POWER 4- UNDER / OVER FREQUENCY
5- POWER SWINGS 5- TEMPERATURE RISE
ELECTRICAL DRAWINGS
is a drawing that shows the components of a particular circuit, their electrical
relationship to each other, and the way they are connected together, it is
usually detailed so that you can follow the various branches of the circuit and
analyze how the circuit functions
Types of electrical diagrams
- BLOCK DIAGRAM
is a lay out of a circuit in which the individual components are indicated by
simple geometric shapes, each containing a short definition of its function
ELECTRICAL DRAWINGS
Types of electrical diagrams
- SINGLE LINE DIAGRAM
- A single line diagram is similar to a block diagram except that the various
control components are shown by symbols instead of geometric shapes.
-The symbols indicate the general nature of the components
ELECTRICAL DRAWINGS
Types of electrical diagrams
- SINGLE LINE DIAGRAM
one way to read a S.L.D. is to follow the main power path from the circuit
power source through the components and control circuits that use the power
ELECTRICAL DRAWINGS
Types of electrical diagrams
- SCHEMATIC DIAGRAM
- A schematic diagram explains how the system works .
- a schematic diagram identifies all of the components in an electrical system, the
components represented on the diagram are not necessarily shown in their correct physical
locations , but they are shown in their proper positions in the electrical flow path
ELECTRICAL DRAWINGS
Types of electrical diagrams
- CONNECTION DIAGRAM OR WIRING DIAGRAM
- a layout of a control circuit in which the primary emphasis is on physical
relationship
- Connection diagrams are used to identify components and wires during
installation, wire tracing, or trouble-shooting activities
ELECTRICAL DRAWINGS
SINGLE LINE DIAGRAM MAIN SYMBOLS
ELECTRICAL DRAWINGS
SINGLE LINE DIAGRAM EXAMPLES
ELECTRICAL DRAWINGS
SINGLE LINE DIAGRAM EXAMPLES
Safety tips
Hazard , risk , incident , nearmiss , accident
- Hazard :is something that can cause harm, e.g. electricity, chemicals,
working up a ladder, noise, a bully at work, stress, etc
- Risk : the chance, high or low, that any hazard will actually cause somebody
harm
Safety tips
Hazard , risk , incident , nearmiss , accident
- incident :
An incident in the workplace is an unplanned event that doesn’t result in
injury, but does cause damage to property, or has enough significant risk to
merit recording
- You can categorise an incident under two sub-categories:
Near miss
(Is an incident in which no property was damaged and no personal injury was
sustained, but where, given a slight shift in time or position, damage or injury
easily could have occurred).
Dangerous occurrence
which is reportable under RIDDOR and should be reported within 10 days.
Safety tips
Hazard , risk , incident , nearmiss , accident
- Accident : is defined as an unplanned event that results in personal injury or
property damage
- An accident is a specific event that results in the injury, death, or ill health of
an employee or a member of the public.
Questions
