Introduce Substation :
A station that incorporates a transformer will increase the voltage whereas decreasing the present, whereas a transformer decreases the voltage whereas increasing the present for domestic and business distribution. The word station comes from the times before the distribution system became a grid.
Electricity traveling long distance is stepped up to the next voltage to attenuate energy losses on the manner. once it’s time to “exit the highway” therefore to talk, it enters a station wherever the voltage is stepped all the way down to be distributed to the top user – the buyer. Likewise, it’d be stepped up if it’s traveling within the other way.
Electrical substations area unit the interface between components of the distribution grid and transmission systems. These enclosed off areas step down the voltage within the transmission lines to at least one that’s appropriate for the distribution grid. they’re conjointly equipped with circuit breakers to shield the distribution system and might be accustomed to managing the flow of current in numerous directions.
Substation Design :
Elements of a substation
Substations usually have the switch, protection, and management instrumentality, and transformers. in an exceedingly massive station, circuit breakers are accustomed to interrupting any short circuits or overload currents that will occur on the network. Smaller distribution stations could use recloser circuit breakers or fuses for a cover of distribution circuits. Substations themselves don’t sometimes have generators, though an influence plant could have a station close.
The first step in designing a station layout is that the preparation of a one-line diagram, that shows in simplified kind the switch and protection arrangement needed, yet because the incoming offer lines and outgoing feeders or transmission lines. in an exceedingly common style, incoming lines have a disconnect switch and a fuse. In some cases, the lines won’t have each, with either a switch or a fuse being all that’s desired. A disconnect switch is employed to produce isolation since it cannot interrupt load current.
Selection of the situation of a station should take into account several factors. enough acreage is needed for installation of kit with necessary clearances for electrical safety, and for access to keep up massive equipment like transformers. wherever land is dear, like in urban areas, gas insulated switchgear could economize overall. Substations placed in coastal areas tormented by flooding ANd tropical storms could usually need an elevated structure to stay instrumentality sensitive to surges hardened against these parts.
Equipment Use in substation :
Substations usually have the shift, protection and management instrumentation and one or additional transformers. during a giant station, circuit breakers are accustomed to interrupting any short-circuits or overload currents which will occur on the network. Smaller distribution stations might use recloser circuit breakers or fuses for a defense of distribution circuits. Substations don’t sometimes have generators, though an influence plant might have a station near.
Where a station encompasses a bronze fence, it should be properly grounded to shield folks from high voltages which will occur throughout a fault within the network. Earth faults at a station will cause a ground potential rise. Currents flowing within the Earth’s surface throughout a fault will cause metal objects to own a considerably completely different voltage than the bottom below a person’s feet; this bit potential presents a hazard of electrocution.
High-rise buildings might have many indoor substations. Indoor substations are sometimes found in urban areas to cut back the noise from the transformers, for reasons to look, or to shield switchgear from extreme climate or pollution conditions.
Types of Substation :
Substations could also be delineated by their voltage category, their applications inside the facility system, the strategy accustomed insulate most connections, and by the design and materials of the structures used. These classes don’t seem to be disjointed; for instance, to resolve a specific drawback, a transmission station might embrace vital distribution functions.
- Indoor Station
- Outdoor Station
- Step-up substation
- Step-down substation
- Primary Step-down Substation
- Secondary Step-down Substation
- Mobile substation
A transmission station connects 2 or a lot of transmission lines. the only case is wherever all transmission lines have an equivalent voltage. In such cases, station contains high-voltage switches that permit lines to be connected or isolated for fault clearance or maintenance. A transmission station could have transformers to convert between 2 transmission voltages, voltage control/power issues correction devices like capacitors, reactors or static volt-ampere compensators and instrumentation like section shifting transformers to regulate power flow between 2 adjacent power systems.
A distribution station transfers power from the transmission to the distribution system of a section. it’s uneconomical to directly connect electricity customers to the most transmission network unless they use massive amounts of power, therefore the distribution station reduces the voltage to grade appropriate for native distribution. The input for a distribution station is often a minimum of 2 transmission or sub-transmission lines. The input voltage could also be, for instance, 115 kV, or no matter is common within the space. The output could be a range of feeders. Distribution voltages square measure usually a medium voltage, between 2.4 kV and thirty-three kV, looking on the scale of the world served and therefore the practices of the native utility.
The station is made underneath the roof is termed indoor kind substation. Generally, eleven kV and generally thirty-three kV station ar of this sort.
The outdoor kind station is made within the outdoors. Nearly all 132KV, 220KV, 400KV station are out of doors kind station. though today special GIS (Gas insulated substation) is made for an additional high voltage system that is mostly set underneath the roof.
In distributed generation comes like a power plant, a collector station could also be needed. It resembles a distribution station though power flow is within the wrong way, from several wind turbines up into the transmission grid. Usually, for an associate economy of construction, the collector system operates around thirty-five kV, and therefore the collector station steps up voltage to a transmission voltage for the grid. The collector station can even give power issue correction if it’s required, metering, and management of the power plant. In some special cases, a collector station can even contain associate HVDC device station.
Step-up substation :
These substations raise the voltage from generators (usually at power plants) so electricity is often transmitted with efficiency. For a lot of data on why higher voltages square measure a lot of economical for the transmission of power, see electrical transmission.
Step-down substation :
These facilities lower the voltage from transmission lines to what’s referred to as a sub-transmission voltage, that is usually used for industrial functions. Otherwise, the output is then directed to a distribution station.
Primary Step Down station
The primary step down substations square measure created nearer to load center on the first transmission lines. Here primary transmission voltages square measure stepped all the way down to totally different appropriate voltages for secondary transmission purpose.
Secondary Step Down Substation
Along the secondary transmission lines, at load center, the secondary transmission voltages square measure any stepped down for primary distribution purpose. The stepping down of secondary transmission voltages to primary distribution levels square measure done at secondary step-down the station.
Mobile substation :
A mobile station may be a station on wheels, containing an electrical device, breakers, and make-work mounted on a self-contained semi-trailer, meant to be the force by a truck. area unit|they’re designed to be compact for travel on public roads and are used for temporary backup in times of natural disaster or war. Mobile substations area unit typically rated a lot of below permanent installations and will be in-built many units to fulfill road travel limitations.