Substation Definition & Types of Electrical substation or Power substation
An electrical substation or power substation are important for electricity. There are many types of power substation or electrical substation such as transformer substation, distribution substation, indoor substation, outdoor substation, Step up and step down substation, Electrical device substation, Transmission substation, switching substation, frequency changer substation, converting substation, industrial substation, power factor switching substation, Underground substation, converting substation, pole mounted substation, distribution substation, Primary & secondary grid substation.
Substation
The assembly of equipment to
vary some characteristics of electrical power provide is named station. The
current power system may be a.c. i.e. power is generated, transmitted, and
distributed within the variety of the AC. the electrical power is made at a
power station that area unit settled at favorable places usually quite far from
the shoppers.
Classification of Substation
There are many types of substation
According to service requirement types of substation is classified as:
·
Transformer Substation
·
Electrical device substation
·
Transmission substation
·
Switching Substation
·
Frequency changer Substations
·
Converting Substation
·
Industrial Substation
·
Power factor correction Substations
According to constructional feature the types of substation is
classified as:
§ Indoor Substation
§ Outdoor Substation
§ Step up substation
§ Step down substation
§ Underground Substation
§ Primary grid substation
§ Secondary grid substation
§ Distribution substation
§ Pole mounted Substation
Transformer Substation
Figure Transformer substation
It's delivered to the shoppers
through an oversized network of transmission and distribution. Transformer Substations are also
in hand associate degree operated by an electrical utility or are also in hand
by an oversized industrial or industrial client.
Electrical device station or Power transformer
electrical device They are called
electrical device substations or power transformer as a result of the
electrical device is the main element used to vary the voltage level, relying
upon the purposed served electrical device substations.
A transmission station
What does a substation do? A transmission substation which convert the voltage level of
electrical rations are named transformer this substation. These substations
receive power at a voltage and deliver it at another voltage.
Connects 2 or a lot of transmissions lines. The only case is wherever all
transmission lines have identical voltage. In such cases, the station contains high-voltage switches
that enable line to be connected or isolated for fault clearance or
maintenance.
A transmission station might
have transformers to convert between 2 transmission voltages, voltage
control/power issue correction devices like capacitors, reactors
Switching Substation
Substation
transformers also decrease the voltage higher to lower voltage, where it
transforms 33 kV voltages to 11 kV voltages. After this transformation the 11kV
is transmitted to the distribution part where within the transmission
lines the distribution transformers occur to lower down the voltage
(11 kV to 230 V). Those substations don't turn the energy level incoming and
outgoing channels have equal the energy.
Though
they simply complete the switching methods of energy lines power factor
correction substation.
Power
Transformer is a device that converts inbound electricity to a
better or lower value of voltage for specific purposes. it's a
serious component in grid to produce voltage in many
nations. the 2 main functions of the transformers are:
·
To supply current from
source to destination
·
To regulate the voltage
of the present
It
consists of a coil system within the device that manages the
present flow within a particular range. Transformer
generally employed in transmission network is
generally referred to as power transformer. Basically, power
transformer is employed in grid and substation.
Frequency Changer Substation
Those
substations which change the frequency are referred to as changer
substation, such a frequency change could also be rewired for
industrial utilization.
An
electrical grid is an interconnected network to produce electricity
to consumers on a grid from the producer. Here 132 kV / 33 kV Step down power
transformer is employed and transmitted to the substation parts. In
Bangladesh most of this power transformers are of oil immerge type
transformers. The capacity of grid transformer is sometimes 50/75
MVA.
Converting Substation
An
electric substation for the conversion of electrical current—primarily with
relation to frequency or the number of phases. It will be wont to convert a
three-phase current of an advert frequency generated by an electrical station
into an instantaneous current to feed, for instance, high-power electrolytic
equipment, variable-speed electric drives for machine tools and rolling mills,
galvanic baths, and phone systems of electrified transport. Conversion to an
electrical energy of a frequency that's higher or below the commercial
frequency is employed for supplying power to such devices as variable-speed AC
electric drives, warming equipment, and induction furnaces. Conversion to a
single-phase electrical energy is finished to produce power to, for instance,
high-capacity arc furnaces and single-phase contact systems. In DC power
transmission lines, converter substations are accustomed convert a three-phase
current to an immediate current (rectification) at the sending end of the road
and to attain a reverse conversion (inversion) at the receiving end of the
road. additionally, inversion is employed when a DC source, like a magneto
hydrodynamic generator or a voltaic battery, must be connected to an AC
distribution system.
Industrial Substation
How does a substation work? The
Industrial Substation possibly a watertight design intended for close, dirty,
and outside circumstances. The station consists of a sturdy watertight and
dustproof casing (IP -65) of glowing aluminum metal. The first board is
connected to the rear casing to authorize quick passage during foundation and
improvement. The station has spiral extremities with numbers and also the three
organs give the watertight and dustproof conjunction of lighting cable and
amplifier wires. Those substations which provide energy to the different
industrial company are called industrial substations.
Indoor substation
A station within which the
equipment is provided within the station building is named indoor station.
Such form of station is
especially used for the voltage up to 11000 v, however once the encircling air
is contaminated by impurities like metal chemical action gases and
fumes, semi conductive dirt,
etc., their voltage will be raised up to 33000 V to 66000 V.
Substations of the Integrity
designed kind In such form of station, the device is provided on website. In
such station, the cell structure is built of concrete or bricks.
Substations of the composite
kind In such form of stations manufacturing plant or workshop area unit
designed however area unit assembled on website among a substation switch gear
space.
The compartments of such
substations take the shape of metal cupboards or enclosures, every of that
contains the instrumentality of 1 main association cell.
In such cupboards, associate
degree oil breaker, a load device switch, and one or a lot of voltage
transformers is also mounted.
Unit kind manufacturing plant
made-up Substations and Metal Clad Switchboards These area unit in-built electrical
workshops and area unit carried to the positioning of installations totally
pre-assembled.
once installations of
substations and switchboards solely association to the incoming and outgoing
power circuits area unit needed to be created.
Advantage
- Less area is needed
- Operation is less complicated than out of doors
station Disadvantage
- Future extension is tough
- Capital price is high
More risk of step-up Outdoor station for
voltage on the far side 33kV, instrumentality is invariably put in in out of
doors.
A station that is employed
for all voltage levels between fifty-five kilovolt to 765 kilovolts is named
out of doors station.
Such form of station needs
less time for construction however uses extra space.
The out of doors substations
area unit chiefly classified into 2 varieties, specifically pole-mounted
station and foundation-mounted substations.
Underground Substation
In thickly inhabited areas,
the house offered for instrumentation and building is restricted and value of
land is high.
underneath such condition the
station is formed underground.
In this station all the
instrumentation space assembled and also the substations ar embedded by the
fence for safety purpose.
The instrumentation needed
for such kind of substations ar serious, and hence the positioning selected for
such kind of station must have a decent path for heavy transport Pole
Mounted station Such
substations ar used for supporting distribution transformers having the
capability up to 250 kVA.
Such styles of transformers
ar the most affordable, simplest, and smallest of distributions.
All the instrumentation is
that the out of doors kind and mounted on the supporting structures of
high-tension distribution line.
Triple pole automatically
operated switch used for shift on and off the high-tension cable.
The electrical devices having
a capability up to a hundred twenty-five kVA are mounted on the double pole
structure and for the transformer having a capability between a
hundred twenty-five to 250
kVA 4-pole structure with the acceptable platform is employed.
Advantages
Ø Easy
to future extension
Ø Low
capital cost
Ø Easy
to fault location
Disadvantage
Ø More
space is required
Ø Operation
is difficult
Step-Up station
The generation voltage is
stepped up to high voltage to have an effect on the economy in the transmission
of electrical power. This area unit usually settled within the power homes and
area unit of an outside kind.
Such varieties of substations
generate low voltage like three.3, 6.6, 11, or 33kV. This voltage is stepped up
by the assistance of a transformer for transmittal the ability over giant
distances. It's settled close to the generating station.
Step-Down station
This station is placed close
to the load Center wherever the first distribution is stepped down for
sub-transmission. The secondary distribution electrical device feeds the patron
through the line.
Primary Grid station
This station lowered the
worth of primary stepped-up voltages. The output of the first grid station acts
because of the input of the secondary substations. The secondary station is
employed for stepping down the input voltage to a lot of lowered for more
transmission.
Secondary Grid station
At a secondary station, the
voltage is more steeped right down to 11KV. The 11KV lines run on the necessary
road of the town. The secondary substations also are of an outside kind.
Distribution station
A distribution station
transfers power from the gear mechanism to the distribution system of a region.
The input for a distribution station is usually a minimum of 2 transmission or
sub-transmission lines. Distribution
voltages area unit usually medium voltage, between 2.4 and thirty-three
potential unit counting on the dimensions of the world served and also the
practices of the native utility.
Besides dynamic the voltage,
the work of the distribution station is to isolate faults in either the
transmission or distribution systems. Distribution substations may be the
points of voltage regulation, though on long distribution circuits (several
km/miles).
Pole mount substation
Pole mount substation is a
substation that is situated form a pole.it is a small substation that is not
required more space, it’s need only a pole. In this substation is step down
substation
Distribution Substation of 33/11 kV
The Bangladesh Rural Electrification Board (BREB) has 33/11
kV distribution Sub Stations. Under this 33/11 kV distribution
Substation Gazipur Palli Bidyut Samity-1 (GPBS-1) has 22 Substations. I am
very lucky to say that I got an opportunity to od my internship into one of
them. Which is situated as Gazipur Palli Bidyut Samity-1. 33/11 kV Substation
Zajor Gazipur.
Substation of GPBS-1
The Zajor Palli Bidyut (Gazipur PBS-1) 33/11 kV distribution
substation is situated beside the Head Quarter of the Gazipur PBS-1 in Zajor,
Board bazar, Dhaka. The type of substation is the 33/11 kV outdoor substation.
This substation has a total Two (2) power transformer of 10/12.5 MVA. The
capacity of this substation is a total of 20 MVA. The substation has to take 33
kV source power as input from Power Grid Company Bangladesh Ltd. (PGCB). The
total load of this substation is 18 MW.
Single Line Diagram of GPBS-1 Substation
Fig Single line diagram of 33/11 kV Substation GPBS-ii
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