More Knowledge About Distribution Substations


A substation is a high-voltage electric system office. It is utilized to switch generators, hardware, and circuits or lines all through a system. It likewise is utilized to change AC voltages starting with one level then onto the next, and/or change alternating current to direct present or direct current to alternating current. A few substations are small with minimal more than a transformer and related switches. Others are expansive with a few transformers and many switches and other hardware. There are three aspects to substations:

Substation Types: Although, there are for the most part four sorts of substations are a combination of two or more sorts.

  • Step up Transmission Substation
  • Step down Transmission Substation
  • Distribution Substation
  • Underground Distribution Substation
  • Substation Functions
  • Substation Equipment

Distribution substations are situated close to the end-users. Distribution substation transformers change the transmission or sub-transmission voltage to lower levels for utilization by end-users. Typical distribution voltages vary from 34,500Y/19,920 volts to 4,160Y/2400 volts.

34,500Y/19,920 volts are interpreted as a three-stage circuit with a grounded neutral source. This would have three high-voltage conductors or wires and one grounded neutral conductor, a sum of four wires. The voltage between the three stage conductors or wires would be 34,500 volts and the voltage between one phase conductor and the neutral ground would be 19,920 volts.

From here the power is distributed to modern, business, and private clients.

Substations are intended to achieve the accompanying functions, although not all substations have every one of these functions:

  • Change voltage starting with one level then onto the next
  • Direct voltage to make up for system voltage changes
  • Switch transmission and distribution circuits into and out of the grid system
  • Measure electric power qualities flowing in the circuits
  • Connect communication signals to the circuits
  • Eliminate lightning and other electrical surges from the system
  • Connect electric generation plants to the system

Make interconnections between the electric systems of more than one utility

Significance Of Switchboards


An electric switchboard is a gadget that directs power from one or more sources of supply to a few smaller areas of utilization. It is a get together of one or more boards, each of which contains switches that permit power to be redirected.

The U.S. National Electrical Code (NEC) characterizes a switchboards as “a large single board, edge, or assemblies of boards on which are mounted, on the face, back, or both, switches, over-present and other defensive gadgets, buses, and generally instruments”. The part of a switchboard is to permit the division of the current supplied to the switchboard into littler currents for further distribution and to give switching, current security and metering for those currents. Switchboards may circulate energy to transformers, panelboards, control equipment, and, at last, to individual system loads.


Inside a switchboard there will be one or more busbars. These are flat pieces of copper or aluminum, to which the switchgear is associated. Busbars bring large currents through the switchboard, and are supported by insulators. Bare busbars are general, yet numerous sorts are manufactured with an insulating covers on the bars, leaving just connection points uncovered.

The operator is shielded from electric shock by safety switches and fuses. There may likewise be controls for the supply of power to the switchboard, originating from a generator or bank of electrical generators, particularly recurrence control of AC power and load sharing controls, in addition to gauges demonstrating frequency and maybe a synchroscope. The power going into a switchboard should constantly equivalent to the power going out to the loads.


Present day modern switchboards are metal encased and of “dead front” construction; no empowered parts are available when the covers and panels are shut. A switchboard may have incoming bus bars or bus conduit for the source connection, furthermore for large circuits fed from the board. A switchboard may incorporate a metering or control compartment separated from the power distribution conductors.

Present day modern switchboards are metal encased and of “dead front” construction; no empowered parts are available when the covers and panels are shut. A switchboard may have incoming bus bars or bus conduit for the source connection, furthermore for large circuits fed from the board. A switchboard may incorporate a metering or control compartment separated from the power distribution conductors.

Segregated Phase Bus Duct- Managing the Low and Medium Voltage Requirements

segregated phase bus

Generation and distribution of electricity is of vital importance for everything nowadays. Every enterprise and every household requires electricity. There are various devices and components which are involved in the production and management of electricity as it is a very complex process. Segregated Phase Bus Duct is one such device which is designed for the low and medium voltage requirements.

The purpose of such designs is to meet specific, continuous and short circuit current ratings and generating stations, substations and industrial distribution systems which can be installed indoors and outdoors. In a segregated bus duct, each phase conductor is separated by a grounded barrier from adjacent phases unlike in non-segregated phase ducts where all phase conductors are in the same enclosure. For conducting large currents between devices, a cable bus is used. For very large currents in generating stations or substations, where it is difficult to provide circuit protection, an isolated-phase bus is used. Each phase of the circuit is run in a separate grounded metal enclosure. The only fault possible is a phase-to-ground fault, since the enclosures are separated. This type of bus can be rated up to 50,000 amperes and up to hundreds of kilovolts (during normal service, not just for faults), but is not used for building wiring in the conventional sense.

One of the greatest advantages of bus ducts is that they are capable of adding or removing a branch circuit without removing voltage from the whole duct. It carries large amounts of amperage across a distance. This is useful in plant design so that you can pull individual leads down from it to machinery. The problem with this is control. If it is installed and the plant does not properly keep up on load documentation, it is easy to overload it. Installing bus duct requires the installer to work with and handle high voltages and currents which can cause instant death. Therefore, it should be done with utmost care and all the necessary precautions should be taken.

Distribution Substation: Final Stage in the Process of Electrical Distribution

In today’s modern day and age, no one can even conceive of fulfilling any task without electricity being available. Electricity is required for everything, from keeping the water cold and the food fresh in the refrigerators to the air conditioning that is required in the summer months when the temperature gets extremely high and unbearable. Also, in the months of winter electricity is required for heating purposes.

In such a scenario, the job of those who are producing and distributing electricity becomes very vital. It is the job of the Distribution Substation to send the electricity in the right amount and the right voltage to the final consumers.

distribution-substationRole of the Distribution Substation

After electricity has been produced in the generating station, from there the produced electricity travels to the distribution substation where the voltage is transformed from low to high or vice-versa. Between the electricity being produced in the generating station and reaching the final consumers or the users, the electric current may flow through a number of distribution substations at different voltage levels.

A distribution substation contains transformers in order to transform voltage. Generally, a distribution substation has two kinds of transformers- a step- up transformer and the other one is the step- down transformer. As the name suggests, the step-up transformer function is to increase voltage and reduce the electric current. On the other hand, the job of the step- down transformer is to decrease the voltage and increase the electric current.

The role that the Distribution Substation plays is extremely important. They transfer the electric current from a transmission system into a distribution system. In a Distribution Substation generally there are two transmission lines that provide the input and it also contains a set of feeders that act as output. The voltage runs through the substation, and out of the feeders. It then travels to a distribution transformer and generates electricity.

Switchboard: Main Circuit Board of the House

It should be highly taken care of while installing commercial, industrial or residential purpose. It is regarded as the most complicated and intricate constituent of the residential or industrial purpose. If installation is not proper, whole electric functionality of the place gets hampered. Whether it’s a residential, commercial or industrial place, it needs to be installed in a proper and apt way so that the mechanism of the component is not destroyed. They play integral role among all the electric components.

Switchboard is consisted of several constituents and not only single but every single component associated to switch boards are quite necessary. Switch board are sustenance of the circuit. It is through these current is passed to the electrical wires and thus current lets the appliance gets on or off. Installation of switch board is quite necessary for the house. Furthermore it should be made sure, that switch boards are installed by only the experts, not by the amateurs.

Any ambiguity while installing the switch boards, laying the electrical wires, keeping in mind the live and earthing wire; would help in properly placing and installing the wires in every electrical appliance. Every wire must be properly placed and installed so that there is no short circuit in the switch board and in turn the wires of the appliance.

switch-boards-250x250Short circuit in the wires also becomes a cause of short circuiting the appliance. Therefore, it must always be made sure that the switch boards, wired are installed only by the professionals and experts. If this complicated task is not given in the hands of the professionals and experts, but to amateur, then it may perhaps tend to cause mayhem in the house. Even a single inappropriately installed wire might become a cause of short circuit in the house.

Medium Voltage Switchgear: Short Circuit Current Interruption

From 3KV to 36KV switchgear system; it is categorized like medium voltage switchgear or MV switchgear. These switchgears are of various kinds. They might possibly be of outdoor type with no metal enclosure, metal enclosed indoor type, metal enclosed outdoor type, and so on. The interruption medium of this switchgear may be SF6, vacuum and oil. The main obligation and necessity of MV power network is to interrupt the current in faulty condition irrespective of what type of CB is used in the MV switchgear system. It might possibly be capable of functioning in also other conditions. Medium Voltage Switchgear ought to be highly capable of:

  1. Short circuit current disruption.
  2. Usual ON/OFF switching operation.
  3. Switching of capacitive and inductive currents.
  4. Various special applications.

All the above mentioned function ought to be carried with high degree of consistency and security.

medium voltageShort Circuit Current Interruption

The main focus of circuit breaker design is that every circuit breaker ought to be capable of interrupting short circuit current with high degree of consistency and protection. The number of faulty tripping occurred in total life period of circuit breaker usually depends on the location of the system, value of environment state and system. If the tripping number is high, the outstanding alternative is vacuum circuit breaker as it may not require any maintenance till 100 faulty tripping with short circuit current till 25KA. Whilst other circuit requires maintenance after 15 to 20 faulty tripping with same short circuit CB current.

The joint substations in rural areas are more often than not of outdoor type, and the best part of them is unattended sort. Hence for this type of applications maintenance free outdoor form, medium voltage switchgear is most suitable. Porcelain clad vacuum circuit breaker meets this obligation against the customary indoor kiosks.

High Voltage Switchgear: Knowing the Configuration and Operation

switchgearThe power system deals with voltage above 36KV, is regarded as high voltage. Since the voltage level is high, the arcing formed during switching operation is also quite high. Therefore, special care is to be taken during the designing of high voltage switchgear. High voltage circuit breaker is the major component of HV switchgear, thus high voltage circuit breaker ought to have special features for reliable and safe operation. Switching operation and faulty tripping of high voltage circuit are very rear. At time these circuit breakers remain, at ON state, and might be operated after a long period of time. Thus CBs must be dependable enough to make sure of safe operation, as when necessary. High voltage circuit breaker technology has changed drastically in the last 15 years.

SF6 circuit breaker, air blast circuit breaker and minimum oil circuit breaker are mostly used for high voltage switchgear. Vacuum circuit breaker is hardly used for this purpose since till date vacuum technology is not sufficient for interrupting very high voltage short circuit current. There are two kinds of SF6 circuit breaker, that is, single pressure SF6 breaker and two pressures circuit breaker. Single pressure system is the latest and updated high voltage switchgear system, these days. Nowadays SF6 gas as arc quenching medium has become most accepted for high and extra high voltage electrical power system. Though, SF6 gas has strong influence on the greenhouse effect. It has 23 times stronger influence on the greenhouse effect, than that of CO2. Therefore, leakage of SF6 gas in the service life of circuit breaker should be prevented. For minimizing the emission of CF4 – SF6, N2 – SF6 and SF6 gas mixture, might be used in circuit breaker in future, as an alternate of pure SF6. It should always be taken into consideration that, no SF6 gas comes out in atmosphere throughout the maintenance of CB.

Points Switchboard Manufacturers Must Know While it’s Make

switch boards

Switch boards, comprising the Main LV switch board, also known by the acronym MLVS are vital to the dependability of electrical installation. It must act in accordance with the set guidelines that govern the construction and design of LV switch gear congregations.

A switchboard is the point at which an incoming power supply segregates into separate circuits, each of that is controlled and protected by the switchgear or fuses of the switchboard. Switchboard is partitioned into a couple of functional units, comprising all the mechanical and electrical elements that contribute to the fulfillment of a given purpose. It symbolizes a key link in the constancy chain.

Therefore, the type of switchboard should be perfectly modified to its application. Switchboard Manufacturers must note that the construction and design must comply with working practices and applicable standards.

The switchboard enclosure offers dual protection:

  • Security of switchgear, indicating relays, fusegear, instruments, etc. against vibrations, mechanical impacts and various other external influences are prone to interfere with operational integrity (dust, EMI, vermin, moisture, etc.)
  • The defense of human life against the possibility of direct and indirect electric shock.

Modern industrial switchboards are sternly fabricated with metal enclosed design construction; no energized parts are easy to get while the panels and covers are closed. Earlier, open switchboards were made with switches and several other devices were mounted on panels fabricated of ebony, granite or slate asbestos board. Metal enclosure of switchboard is linked to earth ground for personnel protection. Large switchboards might be unattached floor mounted enclosures with stipulation for incoming connections at the top or bottom of the enclosure. Switchboard may perhaps have incoming bus duct or bus bars for the source connection and for large circuits fed from the board. Switchboard might include a control or metering compartment estranged from the power distribution conductors.

Electrical Substations: How Engineers Layout Its Design?

Electrical Substation, a part of an electrical transmission, distribution and generation system’s main concern is encountering is its cost and reliability. An apt design attempts to strike a balance between the two sub stations, to attain reliability without a high cost. The design must also allow growth of the station, whenever obligatory.

Selection of the location of Electrical Substations must consider a lot of factors. Adequate land area is obligatory for installation of equipment with obligatory clearances for electrical protection, and for access to preserve large electrical machines like transformers. Where the land is expensive, like in urban areas; gas insulated switchgear may perhaps save money. The location or the spot must have room for expansion because of the load growth or premeditated transmission additions. Ecological effects of the substation should be considered, like, road traffic, noise and drainage effects. Earthing or grounding system ought to be designed. The total ground probable rise, and the gradients in probable throughout the fault (known as “touch” and “step” potentials), have got to be calculated to defend passers-by throughout the short-circuit in the transmission system. The substation locations have got to be rationally central to the distribution area to be provided. The location should be secure from intrusion by passers-by, together with protecting people from harm by arcs or electric shock, and to defend the electrical system from disoperation because of vandalism.

The primary step in planning a substation layout is the planning out of one line diagram that shows in simplified form the switching and protection requisite display and the incoming supply lines and transmission lines or outgoing feeders. It is a general practice by several electrical utilities to chart out one-line diagrams with principal elements, such as, switches, lines, transformers, circuit breakers set on the page similarly to the way the apparatus would be laid in the definite station.

Switchgear : Their Underlying Benefits


Electrical switchgear is a term that comprises of all the switching devices related with mostly the power system protection. Switchgears in substations are situated on both the low voltage and high voltage side of large power transformers. The switchgear on the lower voltage side of the transformers may perhaps be located in the building, with medium voltage circuit breakers for distribution circuits, all along with protection, control and metering equipment.

Medium Voltage Switchgear Application

Arc Furnace

An arc furnace is necessary to get switch off and on often. The current to be switched might be from 0 to 8 times of the rated current of the furnace. An arc furnace is be switched on and off at its normal rated current up to 2000A, approximately 100 times per day. A normal, oil, air or SF6 circuit breaker is not at all reasonable for this frequent operation. Typical vacuum circuit breaker is most suitable alternative for this frequent high current circuit breaker operation.

Railway Traction

One more application of medium voltage switchgear is single phase railway track system. The major function of the circuit breaker is linked with railway traction system, is to disrupt short circuit, on the overhead catenary system that come about frequently and are transitory in nature. Thus circuit breaker used for this purpose must have, short breaking time for short arcing time, small contact gap, VCB and quick breaking is the best probable solution. In fact arcing energy is much higher in the single phase CB than 3 phases CB. It is much lesser in circuit breaker than that in usual circuit breaker. The number of short circuit takes place in the overhead catenary system much higher than those occurring on electrical transmission system. The medium voltage switchgear possessed with vacuum circuit breaker is most appropriate for traction application.