WELCOME

WELCOME. NAME:- AKHTER HUSSAIN SOFI Course:-BE.

An electrical grid is an interconnected network for electricity delivery from producers to consumers. Electrical grids vary in size and can cover whole countries or continents. It consists of power stations: often located near energy and away from heavily populated areas electrical substations to step voltage up or down electric power transmission to carry power long distances electric power distribution to individual customers, where voltage is stepped down again to the required service voltage(s). Although electrical grids are widespread, as of 2016, 1.4 billion people worldwide were not connected to an electricity grid. As electrification increases, the number of people with access to grid electricity is growing. About 840 million people (mostly in Africa) had no access to grid electricity in 2017, down from 1.2 billion in 2010..

RYB simply stands for Red, yellow and Blue respectively in a three phase electrical system . In a three phase electrical system, the three phases are separated by an angle of 120 degrees and each phase is given a specific colour, i.e. R,Y and B for the phases to be identified..

Power Formulas in DC, AC 1 Phase & 3 Phase Circuits Power Formulas in DC Circuits Power Formulas in Single Phase AC Circuits Power Formulas in Three Phase AC Circuits P=Vxl p 12 x R P = V Cos @ P = 12 xRvCos @ IR (Cos P = V3 x VLX IL x Cos @ VPhX X Cos @ P = 3xex R x Cos @ 'P (V2 / R) x cos www.electricoltechnotogy.or.

In electrical engineering , three-phase electric power systems have at least three conductors carrying alternating voltages that are offset in time by one-third of the period. A three-phase system may be arranged in delta (∆) or star (Y) (also denoted as wye in some areas). A wye system allows the use of two different voltages from all three phases , such as a 230/400 V system which provides 230 V between the neutral (centre hub) and any one of the phases, and 400 V across any two phases. A delta system arrangement only provides one voltage, but it has a greater redundancy as it may continue to operate normally with one of the three supply windings offline, albeit at 57.7% of total capacity. Harmonic current in the neutral may become very large if nonlinear loads are connected..

A dead-end tower (also anchor tower , anchor pylon ) is a fully self-supporting structure used in construction of overhead power lines . A dead-end transmission tower uses horizontal strain insulators at the end of conductors. Dead-end towers may be used at a substation as a transition to a "slack span" entering the equipment, when the circuit changes to a buried cable , when a transmission line changes direction by more than a few degrees, or at intervals along a straight run to limit the extent of a catastrophic collapse..

A lightning arrester (alternative spelling lightning arrestor) (also called lightning Isolator) is a device used on electric power transmission and telecommunication systems to protect the insulation and conductors of the system from the damaging effects of lightning ..

Grading Ring or Guard Ring equalizes the potential distribution across each disc in Suspension Insulator . Grading Ring nullifies the effect of shunt capacitance of string insulator (suspension type insulator is also called string insulator)..

The current transformer and potential transformer (also called voltage transformer) are both measuring devices. A CT lowers the current signals for measurement purposes, while a PT lowers high voltage values into lower ones. The transformers are designed to measure whether power systems are both accurate and safe. In addition, the CT and PT transformer reduces the current and voltage from high to low value. The current transformer and voltage transformer have similar construction since they feature a magnetic circuit in their primary and secondary winding..

An isolator is a device used for isolating a circuit or equipment from a source of power . An isolator is a mechanical switching device that, in the open position, allows for isolation of the input and output of a device..

According to the power system location, the isolator can be classified into three types namely bus side, line side, and transfer bus side isolator ..

The word insulator comes from the Latin root insulātus , which means "like an island." If your house is built out of good insulators, you might enjoy an island of warmth inside it even during cold winter nights. The opposite of insulator is conductor : a material that easily transmits heat or electricity..

One is main bus and the other is transfer bus . A main advantage is that whole of the load is transferred to the transfer busbar when maintenance or repair are being done on the main busbar . Reserve bus is a bus whose function is continuously in grid station & when the main bus will not functions in it & then a reserve bus will be used in this time & it will generate our system in this time & the function will be properly..

Bay Area Circuits provides bare board electrical testing to ensure that PCBs have been manufactured according to the design (Gerber, ODB++) files by testing for any shorts or opens. Testing is performed by flying probe machines, providing the fastest, most accurate test method for quick-turn prototypes and small to medium production..

A potential transformer is also a kind of instrument transformer, known as a voltage transformer (VT). There is still a primary winding and a transformer high voltage primary and secondary winding. ... The primary terminals can be connected either in line-to-line or in line-to-neutral configuration of voltages ratio..

A PT is an instrument transformer. It is used to convert the bus voltage to a safer lower value for metering and indication . It provides both isolation and scaling. All transformers are essentially linear scaling devices, which could perform this function..

An electrical circuit breaker is a switching device which can be operated manually and automatically for controlling and protecting an electrical power system . As the modern power system deals with huge currents, special attention should be given during designing of a circuit breaker to ensure it is able to safely interrupt the arc produced during the closing of a circuit breaker..

A circuit breaker is an automatically operated electrical switch designed to protect an electrical circuit from damage caused by excess current from an overload or short circuit. Its basic function is to interrupt current flow after a fault is detected ..

A transformer is a passive component that transfers electrical energy from one electrical circuit to another circuit, or multiple circuits. A transformer is a device used in the power transmission of electric energy. The transmission current is AC..

Core Winding Insulation Tank Terminal and bushings Transformer oil Oil Conservators Breather Radiators and fans Tap changers Buchholz relay.

CORE:- The core provides a low reluctance path for electromagnetic flux and supports the primary and secondary windings. It is made by stacking thin sheets of high-grade grain-oriented steel which are separated by thin insulating material. In order to minimize the hysteresis and eddy currents, the carbon content of the core steel is maintained below 0.1%. When it is alloyed with silicon, eddy currents can be reduced . WINDING:- Transformer carries two sets of winding per phase – Primary winding and secondary winding. These winding consists of several turns of copper or aluminium conductors, insulated from each other and the transformer core. The type and arrangement of winding used for transformers depend upon the current rating, short circuit strength, temperature rise, impedance and surge voltages . INSULATION:- Insulation is the most important part of transformers. Insulation failures can cause the most severe damage to transformers. Insulation is required between the windings and the core, between windings, between each turn of the winding and between all current-carrying parts and the tank. The insulators should have high dielectric strength, good mechanical properties and high-temperature withstand ability. Synthetic materials, paper, cotton etc are used as insulation in transformers..

TANK:- Tank bodies are made by fabricating rolled steel plates to containers. They are provided with lifting hooks and cooling tubes. In order to reduce weight and stray losses, aluminium sheets are also used instead of steel plates. However, aluminium tanks are costlier than steel ones . Terminal and bushings:- For connecting incoming and outgoing cables, terminals are present in transformers. They are mounted upon the bushings and is connected to the ends of the windings. Bushings are insulators that forms a barrier between the terminals and the tank. They are mounted over the transformer tanks. They serve as a safe passage for the conductors connecting terminals to the windings. They are made from porcelain or epoxy resins . Transformer oil:- In all oil-immersed transformers, transformer oil provides added insulation between the conducting parts, better heat dissipation, and fault detection features. Hydro-carbon mineral oil is used as transformer oil. It is composed of aromatics, paraffin, naphthenes , and olefins. Transformer oil has a flashpoint of 310 degrees Celsius, relative permeability of 2.7, and a density of 0.96 kg/cm3..

Oil Conservators:- The oil conservator is moved on the top of the transformers and is located well above the tank and bushings. Normally a rubber bladder is present in some oil conservators. The transformer oil expands and contracts with an increase and decrease in temperature. The oil conservator provides adequate space for oil expansion. It is connected to the main tank through a pipe. A level indicator is fitted to the conservator to indicate the oil level inside . Breather:- Breather is present in all oil-immersed transformers that have a conservator tank. It is necessary to keep the oil-free from moisture. As the temperature variations cause the transformer oil to expand and contact, air flows in and out of the conservator tank. This air should be free from moisture. Breather serves this purpose . Radiators and fans:- The power lost in the transformer is dissipated in the form of heat. Dry transformers are mostly natural air-cooled. But when it comes to oil-immersed transformers, a variety of cooling methods are followed. Depending on the kVA rating, power losses, and level of cooling requirements, radiators and cooling fans are mounted on the transformer tank..

Explosion vent An explosion vent acts as an emergency exit for oil and air gases inside a transformer. It is a metallic pipe with a diaphragm at one end, held slightly above the conservator tank. Faults occurring under oil elevates the pressure inside the tank to dangerous levels. Under such circumstances, the diaphragm ruptures at a relatively low pressure to release the forces from within the transformer to the atmosphere. Tap changers:- Tap changers are used to adjust the secondary voltage of transformers. They are designed to change the turns ratio of the transformer as required. There are two types of tap changers: On-load tap changers and Off-load tap changers . Buchholz relay Buchholz relay is one of the most important parts of oil-immersed transformers rated over 500kVA. It is an oil and gas actuated relay that is used to sense faults occurring in the parts immersed in the oil. Short circuits occurring under the transformer oil generate enough heat to decompose the oil into hydrogen, carbon monoxide, methane etc. These gases gradually move towards the conservator tank through the connecting pipe. Buchholz relay, which is mounted on the pipe connecting the conservator tank and the main tank, senses these gases and activates the trip and alarm circuits. The trip circuit opens the circuit breaker supplying current to the primary winding and interrupts the current flow..

It's a valve that relieves excess pressure in the water heater tank . By doing so, it can prevent excess pressure buildup that has the potential to cause a tank burst and flood your home..

DIAGRAM OF TRANSFORMER.

DIAGRAMM OF GRID STATION.