Ever wonder how electricity gets to your home?
The electricity generation, transmission, distribution and control networks make up the electrical grid. Electric power transmission is bulk transfer of electrical energy from generating power plants to substations. Electricity is transported over long distances at high voltages, minimizing the loss of electricity. Electric power distribution includes the local wiring between high-voltage substations and customers. Combined, these form a network known as the “power grid”.
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The basic process
- Electricity is generated at power plant by huge generators. Power plants use coal, gas, water or wind
- The generated voltage is stepped-up and transmitted over high-voltage transmission lines that stretch across the country
- It reaches a substation, where the voltage is lowered for distribution
- It travels through distribution lines to the neighborhood, where smaller pole-top transformers reduce the voltage again to take the power safely to use in homes
- It passes through a meter that measures how much energy a home uses to the wall outlets
Components along the power (electrical) grid are summarized below
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System Component |
Function |
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Voltage classification |
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Inputs for power generation |
Electricity generator uses fossil fuel power, nuclear power and renewable resources such as hydroelectric dams, solar photovoltaic systems, wind turbines, and biomass. |
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Generation (AC power supply ) |
Generators transform the energy of heat, wind, solar and water to electrical energy. Power is generated by large and smaller generation facilities. At generating stations, electricity is typically produced at less than 25 kV. Before entering the transmission lines, the electricity is “stepped-up” to high voltages by Step-up transformers. |
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Electrical substations |
Power is generated comparatively in lower voltage levels. It is economical to transmit power at higher voltage levels. Distribution of electrical power is done at lower voltage levels. For maintaining these voltage levels and for providing greater stability, a number of transformation and switching stations have to be created in between generating stations and consumer ends. These transformation and switching stations are generally known as electrical substations. Based on their functions, Substations can be classified into
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Transmission |
Moves electricity at high voltage from generators to local Sub-transmission and distribution system. Transmission lines could be:
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Transmission substation |
A transmission substation connects two or more transmission lines and contains high-voltage switches that allow lines to be connected or isolated (also referred to as a switching station). The substation may have transformers to convert between two transmission voltage levels or equipment such as phase angle regulators to control power flow between two adjacent power systems. |
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Sub-transmission |
Moves electrical energy at medium voltage from transmission system to distribution system. Sub-transmission lines carry electricity at voltages less than 200 kV, typically 66 kV or 115 kV. They can also be placed underground. |
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Distribution |
From the distribution substation, electricity is transferred to industrial, commercial and residential customers through Distribution Lines. While some high volume electricity users have specialized substations on their premises, retail consumer relies on local power distribution systems. |
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Distribution substation |
A Distribution substation reduces voltage from the high-voltage transmission system to a lower voltage suitable for the local distribution system of an area. It is uneconomical to directly connect electricity consumers to the high-voltage transmission network, unless they use large amounts of energy. Distribution substations are generally located closer to the consumers. |
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Equipment for protection & control , communications, power quality , testing and maintenance
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The following category of equipment are utilized along of the grid:
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Operators : Utilities |
The following Utilities/Operators manage the grid
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Consumers, revenue metering |
Electricity consumers are divided into classes of service (residential, commercial, industrial, and other) based on the type of service they receive. The type of meter installed and the rates are also dependent upon class of the service sector. |
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Power losses : Technical , commercial
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Losses in the grid are mostly composed of resistance losses occurring in the transmission lines and of so-called corona losses created on the surface of conductors in certain weather conditions. The technical losses are due to energy dissipated in the conductors and equipment used for transmission, transformation, sub- transmission and distribution of power. These technical losses are inherent in a system and can be reduced to an optimum level. The commercial losses are caused by pilferage, defective meters, errors in meter reading and unmetered supply of energy. |
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Smart grid |
The gradual increase of electricity cost, inadequate infrastructure, electricity losses, carbon footprint and climate changes are some of the major player for shift towards a smarter grid. The smart grid is the next generation grid network that promises advantages such as decentralized control, digitalization, flexibility, intelligence, resilience and sustainability. |
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TI’s role |
Product & solutions :
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