Topic objective to know
1. What is protective relaying
2. What is its purpose
3. How does protective relaying works.
4.To know the basic parts of a relay and its function
5.To know what are the types of relays.
6.What is and instrument trasformer.
7. To know the different types of Instrument transformer.
- is a collective term which defines all equipment necessary for:
- the removal of a fault or abnormal condition from the power system.
- is a system employed in a power circuit basically used for:
Protect from what?
b.Short Circuit of Fault
What is a RELAY?
- A device designed With precise measuring instruments
To interpret input conditions in a prescribed manner and specified conditions
To operates when the quantities flowing through them exceed or go below some predetermined value
- Equipped with auxiliary contacts and are made to respond by closing the contacts.
THREE FUNDAMENTAL TYPES OF RELAYS
2.Solid-state / static relay
3.Digital / Numeric relay
What is a POWER CIRCUIT BREAKER?
-A device used to close or open a power circuit which is live and loaded.
-Also used to interrupt a power circuit under fault condition.
-it serves as the muscle in the protection system which does the work of isolating the faulty component, while the relay is the brain, which gives order to the breaker.
Circuit breakers are strategically placed in a power system so that each generator, transformer, bus and transmission line etc., can be completely disconnected from the rest of the system
- Are usually step down transformers used to keep values of voltage or current to levels within the capabilities of relays.
- They provide insulation against the high voltage of the power circuit, and supply the relays with accurate quantities proportional to that of the power circuit, but sufficiently reduced in magnitude so that the relays can be made relatively small and inexpensive.
- Allow relays and meters to measure high values of current and voltage accurately.
- In protective relaying, they give the relay the necessary input, may it be current or voltage, for the relay to evaluate and then decide to what action to be taken.
TYPES OF INSTRUMENT TRANSFORMERS
POTENTIAL OR VOLTAGE TRANSFORMERS
-Standard voltage transformers are single-phase units designed and constructed so that the secondary voltage maintains a fixed relationship with primary voltage.
-The primary are made to suit high voltage, while the secondary are usually 120 volts
-A device used to transform line current into values suitable for standard instruments and protective relays.
-This device serves two purposes:
1.Insulates the relay from primary voltage.
2.Allows a 0-5 amp output to be used for relays.
How do protective relaying operate?
- Basically protective relaying has three major components namely:
Is the sensor of the system
It usually detects either current, voltage or frequency
It feed the information to the relay, which is the brain of the system
is the brain of the system
it receives input signal from the instrument transformer
it then evaluate the input condition and then decide what to do.
it gives advice to the breaker to trip, if the relay decides to do so.
is the muscle of the system
is always ready to implement whatever the relay want him to do.
Wednesday, October 1, 2008
Topic objective to know
- SemiConductors Lessions and Tutorials
- AMPLIFIERS AND ACTIVE DEVICES Chapters
- SOLID-STATE DEVICE THEORY Chapters
- DIODES AND RECTIFIERS Chapters
- BIPOLAR JUNCTION TRANSISTORS Chapters
- JUNCTION FIELD-EFFECT TRANSISTORS Chapters
- INSULATED-GATE FIELD-EFFECT TRANSISTORS Chapters
- THYRISTORS Chapters
- OPERATIONAL AMPLIFIERS Lessions
- PRACTICAL ANALOG SEMICONDUCTOR CIRCUITS
- ELECTRON TUBES Lessions
- TRANSMISSION LINES Lessions
- Digital Circuits All Chapters index
- BOOLEAN ALGEBRA Tutorials and Guide
- KARNAUGH MAPPING Tutorials and Guide
- COMBINATIONAL LOGIC FUNCTIONS Tutorials and Guide
- MULTIVIBRATORS tutorials and guide
- COUNTERS Tutorials and Guide
- SHIFT REGISTERS Tutorials and Guide
- DIGITAL-ANALOG CONVERSION Tutorials and guide
- ADC DIGITAL-ANALOG CONVERSION Tutorials and Guide
- DIGITAL COMMUNICATION Tutorials and Lessions
- DIGITAL STORAGE (MEMORY) Tutorials and Guide
- PRINCIPLES OF DIGITAL COMPUTING Tutorials and Guid...
- DC Circuits Chapters
- Details of wire ampacity table
- Three unit 100 kva design and estimate
- BASIC CONCEPTS OF ELECTRICITY Guide
- OHM's LAW Guide
- ELECTRICAL SAFETY Guide
- SCIENTIFIC NOTATION AND METRIC PREFIXES Guide
- SERIES AND PARALLEL CIRCUITS Guide
- DIVIDER CIRCUITS AND KIRCHHOFF'S LAWS Guide
- SERIES-PARALLEL COMBINATION CIRCUITS Guide
- DC METERING CIRCUITS Guide
- ELECTRICAL INSTRUMENTATION SIGNALS Guide
- DC NETWORK ANALYSIS Guide
- BATTERIES AND POWER SYSTEMS Guide
- PHYSICS OF CONDUCTORS AND INSULATORS Guide
- CAPACITORS Guide
- MAGNETISM AND ELECTROMAGNETISM Guide
- INDUCTORS Guide
- RC AND L/R TIME CONSTANTS Guide
- Electronics Experiments Very Important including p...
- PERIODIC TABLE OF THE ELEMENTS INTRODUCTION in Ele...
- BASIC CONCEPTS AND TEST EQUIPMENT in Electronics
- DC CIRCUITS Tutorials Guides and Example Images
- AC CIRCUITS Guide Images and Tutorials
- DISCRETE SEMICONDUCTOR CIRCUITS Tutorials and Guid...
- ANALOG INTEGRATED CIRCUITS Tutorials and Guide
- DIGITAL INTEGRATED CIRCUITS Tutorials
- free download Worms 3D Themes
- free download Winter Themes
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- free download Windows Vista Themes
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- free download Vista Blue Themes
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- free download sony ericsson The Body Themes
- free download sony ericsson Terminator Themes
- free download sony ericsson String Theory Themes
- using load buster
- pad mounted transformer
- Substation convert from 138 kv to 69 kv
- stray voltage
- the one line diagram on power distribtion line
- Transformer banking Design
- how kilo watt hour meter works
- How SCADA works
- all in one convertion table
- Transformer Classification
- Power Cable
- CIRCUIT BREAKER SIZING ON FAULT CALCULATIONS
- Feeder and Subfeeder Design
- INSTRUMENT TRANSFORMERS
- LOW VOLTAGE SYSTEMS AND APPLICATION
- HOW SURGE ARRESTERS WORKS
- Protective Relaying Fundamental
- ▼ October (79)