early 1871 Belgian inventor Zénobe Gramme invented a generator powerful enough to produce power on a commercial scale for industry.[1]
In 1878, a hydroelectric power station was designed and built by William, Lord Armstrong at Cragside, England. It used water from lakes on his estate to power Siemens dynamos. The electricity supplied power to lights, heating, produced hot water, ran an elevator as well as labor-saving devices and farm buildings.[2]
In January 1882 the world's first public coal-fired power station, the Edison Electric Light Station, was built in London, a project of Thomas Edison organized by Edward Johnson. A Babcock & Wilcox boiler powered a 93 kW (125 horsepower) steam engine that drove a 27-tonne (27-long-ton) generator. This supplied electricity to premises in the area that could be reached through the culverts of the viaduct without digging up the road, which was the monopoly of the gas companies. The customers included the City Temple and the Old Bailey. Another important customer was the Telegraph Office of the General Post Office, but this could not be reached through the culverts. Johnson arranged for the supply cable to be run overhead, via Holborn Tavern and Newgate.[3]
In September 1882 in New York, the Pearl Street Station was established by Edison to provide electric lighting in the lower Manhattan Island area. The station ran until destroyed by fire in 1890. The station used reciprocating steam engines to turn direct-current generators. Because of the DC distribution, the service area was small, limited by voltage drop in the feeders. In 1886 George Westinghouse began building an alternating current system that used a transformer to step up voltage for long-distance transmission and then stepped it back down for indoor lighting, a more efficient and less expensive system which is similar to modern systems. The war of the currents eventually resolved in favor of AC distribution and utilization, although some DC systems persisted to the end of the 20th century. DC systems with a service radius of a mile (kilometer) or so were necessarily smaller, less efficient of fuel consumption, and more labor-intensive to operate than much larger central AC generating stations.early 1871 Belgian inventor Zénobe Gramme invented a generator powerful enough to produce power on a commercial scale for industry.[1]
In 1878, a hydroelectric power station was designed and built by William, Lord Armstrong at Cragside, England. It used water from lakes on his estate to power Siemens dynamos. The electricity supplied power to lights, heating, produced hot water, ran an elevator as well as labor-saving devices and farm buildings.[2]
In January 1882 the world's first public coal-fired power station, the Edison Electric Light Station, was built in London, a project of Thomas Edison organized by Edward Johnson. A Babcock & Wilcox boiler powered a 93 kW (125 horsepower) steam engine that drove a 27-tonne (27-long-ton) generator. This supplk
2. INTRODUCTION
The relays used in power system protection are of different
types. Among them differential relay is very commonly used
relay for protecting transformer and generators from localised
faults.
Differential relays are very sensitive to the faults occurred
within the zone of protection but they are least sensitive to the
faults that occur outside the protected zone. Most of the relays
operate when any quantity exceeds beyond a predetermined
value for example over current relay operates when current
through it exceeds predetermined value. But the principle of
differential relay is somewhat different. It operates depending
upon the difference between two or more similar electrical
quantities. Using microcontroller technology we are detecting
the input and output current using differential current sense
using CT module and trip the circuit using contactor
technology.
4. AURDINO CONTROLLER
ARDUINO CONTROLLER :
Arduino/Genuino Uno is a microcontroller board based
on the Atmega 328 It has 14 digital input/output pins (of
which 6 can be used as PWM outputs), 6 analog inputs, a 16
MHz quartz crystal, a USB connection,
Current Transformer
A current transformer is an “instrument transformer” that is
designed to provide current in its secondary, which is
accurately proportional to the current flowing in its primary.
6. A DC POWER SUPPLY SYSTEM, WHICH MAINTAINS
CONSTANT VOLTAGE IRRESPECTIVE OF FLUCTUATIONS IN
THE MAIN SUPPLY OR VARIATION IN THE LOAD, IS KNOWN
AS REGULATED POWER SUPPLY .THE 7805 IC REFERRED TO
FIXED POSITIVE VOLTAGE REGULATOR, WHICH PROVIDES
FIXED VOLTAGE 5 VOLTS. THE 7805 REGULATOR IS KNOWN
AS FIXED VOLTAGE REGULATOR. FIXED –VOLTAGE
REGULATOR DESIGN HAS BEEN GREATLY SIMPLIFIED BY THE
INTRODUCTION OF 3-TERMINAL REGULATOR ICS SUCH AS
THE 78XX SERIES OF POSITIVE REGULATORS AND THE
79XXX SERIES OF NEGATIVE REGULATORS, WHICH
INCORPORATE FEATURES SUCH AS BUILT-IN FOLD BACK
CURRENT LIMITING AND THERMAL PROTECTION, ETC.
7. APPLICATIONS:
POWER SYSTEM PROTECTION DETECTION OF ENERGY
TAPPING WITH I/P AND O/P METER DIFFERENTIAL CURRENT
TECHNIQUE AND POWER THEFT PROTECTION
PROTECTION OF TRANSMISSION LINE FAULTS
PROTECTION OF T C
ADVANTAGES:
NO MANPOWER REQUIRED
MORE ACCURACY
EFFECTIVE POWER THEFT CONTROL
8. DISADVANTAGES
*EXISTING METERS REQUIRED TO SET FOR THE NEW
TECHNOLOGY IS LITTLE DIFFICULT TASK.
*LIMITED OUTPUTS LINIER REGULATED POWER SUPPLIES
ONLY PROVIDE ONE OUTPUT VOLTAGE
*POOR EFFICIENCY THE AVERAGE LINEAR REGULATED
DEVICE ACHIVES AN EFFICIENCY BETWEEN 30% -60% DUE
TO HEAD DISSIPATION
9. FULL WAVE RECTIFIER:
a full-wave rectifier is a device that has two or more diodes arranged
so that load current flows in the same direction during each half
cycle of the ac supply.
Full-wave rectifier, center-tapped design.
Working of Full Wave Rectifier
The input AC supplied to the full wave rectifier is very high. The
step-down transformer in the rectifier circuit converts the high voltage
AC into low voltage AC. The anode of the centre tapped diodes is
connected to the transformer’s secondary winding and connected to
the load resistor. During the positive half cycle of the alternating
current, the top half of the secondary winding becomes positive while
the second half of the secondary winding becomes negative.
10. CONTACTOR
Operating principle of Contactors
Symbol of contactor the operating principle of a
contactor is very simple. Whenever the electromagnetic coil is
energized, an electromagnetic field is produced. This
electromagnetic field attracts the metallic rod (armature)
towards the gap in the hollow cylindrical magnet. In
contactors with split electromagnets, the movable half of the
electromagnet is attracted towards the fixed electromagnet.
This action closes the contacts. The contacts remains closed as
long as the electromagnet remains excited. When the coil is de
energized, moving contact is pushed back to its normal
position by the spring. Contactors are designed to open and
close contacts rapidly. Moving contacts may bounce as it
rapidly makes contacts with the fixed contacts.
12. FEATURES OF CONTACTORS
A contactor is a relay that is used for switching power.
They usually handle very heavy loads like an electric
motor, lighting and heating equipments and so on.
Though their output is used for switching very high
loads, they are controlled by a circuit with very less
power.
According to the loads they handle, they vary in sizes
from a small device to as huge as a yard.
14. COMPONENTS REQUIRED:
ARDUINO BOARD
LCD
RESISTOR 1K
WORKING OF AUDINO WITH LCD:
LCD CAN BE USED IN TWO MODES- 4 BIT MODE OR 8 BIT MODE. IN 8 BIT MODE
WE REQUIRE 8 DATA PINS AND 3 CONTROL PINS WHEREAS IN 4 BIT MODE, DATA
IS SENT USING 4 DATA PINS AND 3 CONTROL PINS.
R/W PIN IS ALWAYS GROUNDED SO WE REQUIRE ONLY 6 PINS IN 4 BIT MODE,
THUS SAVING NO OF PINS.
FIRST INITIALIZE THE LIBRARY AND THEN DEFINE PINS USING THE COMMAND
LIQUIDCRYSTALLCD(RS, E, D4, D5, D6, D7), PINS ARE ASSIGNED IN THIS
ORDER.
15. THEN IN SETUP FUNCTION WRITE THE MESSAGE TO
DISPLAY AS LCD.PRINT(“MESSAGE”).
WE CAN PRINT MESSAGE ANYWHERE IN THE LCD BY
SELECTING COLUMN AND ROW, IT’S DONE BY WRITING
LCD.SETCURSOR(COLUMN, ROW). HOWEVER THERE IS ONE
THING TO CONSIDER, THAT’S THE NUMBER OF COLUMNS
AND ROWS START FROM ZERO. FOR EXAMPLE, TO PRINT A
MESSAGE ON 2ND ROW 1ST COLUMN, WRITE
“LCD.SETCURSOR(0,1);” BEFORE THE PRINT COMMAND.
SIMILARLY FOR 5TH COLUMN AND 3RD ROW, WE WRITE
LCD.SETCURSOR(4,2).
YOU CAN USE “LCD.WRITE()” TO SEND CHARACTERS. TO
PRINT ZERO ON 2ND COLUM 2ND ROW, TYPE
LCD.SETCURSOR(1,1); LCD.WRITE(48); WHERE 48 IS THE
DECIMAL EQUIVALENT FOR ACII ‘0’.
