What is Electrical Power System?
A network of electrical devices used to generate, transmit, & consume electric power is known as an electric power system. A power plant serves as the source of supply, a transmission line serves as the mode of transfer, and a distribution system serves as the represents consumption. Residential uses include running lights and air conditioners in houses, while industrial uses include driving big motors.
Power system structure
- Generation system,
- Transmission system, and
- Distribution system
make up the network that is the power system.
It transforms the energy source (such as coal and diesel) into electrical energy. The power system consists of all of the system’s connected components, such as the cable, motor, transformer, and synchronous generator.
The following are the six fundamental components of the power system:
- Power plant,
- Transformer,
- Transmission line,
- Substations,
- Distribution line, and
- Distribution transformer.
The transformer is used by the power plant to transmit the step-up or step-down electricity that is generated.
The power is sent to the various substations via the transmission line.
The power is transmitted from the substation to the distribution transformer, which steps it down to a suitable level for the users.
The power system’s subsystems are described in depth below.
Generation System
The fuel, such as coal, water, nuclear energy, etc., is transformed into electrical energy at generating stations. The electrical energy is produced step-up for long-distance transmission in the 11kV to 25kV range. The power capacity of the generating substation is mainly divided into three categories:
- Thermal power plants,
- Hydropower plants, and
- Nuclear power plants.
The major parts of the generating station are
- The generator &
- The transformer.
The generator converts mechanical energy into electrical energy.Coal, gas, nuclear fuel, gas turbines, and occasionally internal combustion engines are used to generate mechanical energy.
Power is efficiently transferred from one level to the another by the transformer. With the exception of losses in the transformer, the power transfer from the secondary is nearly identical to the primary. The step-up transformer will lessen line losses that prevent power transmission over long distances.
Transmission System
The overhead lines that transfer generated electrical energy from the generation substation to the distributing substations are carried by the transmission substation. Only big power substations or extremely large users are served by it.
The two functions are mostly carried out by the transmission lines.
- It moves the energy between bulk receiving stations and generating stations.
- It links the two (or) more generating (generation) stations together. The transmission cables allow for the connection of the surrounding substations to one another.
The transmission voltage is greater than 33 KV, and it is line-to-line standardised at 33KV, 110kV, 230kV, 400KV, and 765kV. Extra High Voltage (EHV) is the typical term used to describe transmission lines above 230 kilovolts.
Substations known as high voltage (HV) substations, receiving substations, or primary substations serve as the high voltage line’s termination. The voltage is reduced in a high voltage substation to a reasonable level for the subsequent portion of flow towards the load. It is possible to supply the industrial consumers directly through the transmission system.
Sub-Transmission System
The sub-transmission system is the section of the transmission network that links the high voltage substations to the distribution sub-stations by way of a step-down transformer.
The sub-transmission system voltage level varies between 33KV and 110KV. The sub-transmission system directly serves certain large industries.The capacitor & reactor are situated in substations to maintain the transmission line voltage stable.
The sub-transmission system works similarly to the distribution system. It differs in the following ways from a distribution system.
- The voltage level of a sub-transmission system is higher than that of a distribution system.
- It merely provides larger loads.
- When compared to the distribution system, which provides some loads, it only supplies a few substations.
Distribution System
A distribution system is a component of an electrical power system that connects all of the consumers in an area to the major power sources.Transmission lines connect the main power stations to the generating substations. They provide power to some substations, which are frequently located near load centres.
Domestic, commercial, and relatively small users are served via substations. Significant amounts of power are required by consumers, which are often delivered at the sub-transmission (or) transmission system level.
Primary Distribution System
This is the section of the power system circuit that connects substations to the distribution substation or distribution transformer near the consumer’s premises. Since, the secondary transmission line has terminated at substations where the voltage has been reduced from 33 KV to 11 KV. The 11 KV wires run along the road edges. It should be noted that large users are supplied with power at 11 KV for use with their own substations.
Secondary Distribution System
The secondary distribution system provides electrical power at a voltage adequate for direct use by electrical appliances. The major distribution lines stop at distribution substations near the consumers’ houses, when the voltage is reduced to 415 V, 3-phase 4-wire for the secondary distribution. The voltage between the any two lines in a secondary distribution system is 415 V, and the voltage between any one line & neutral is 230 V.
- Feeders,
- Distributors, and
- Service mains
comprises of secondary distribution.
Electrical Loads
Electrical loads are any devices that need electrical energy to carry out functions.
There are two types of electrical loads.
Single Phase Loads
Fans, coolers, AC, 1-phase motors, electric lamps, and other 1-phase loads are supplied by the any one phase & neutral.
Three Phase Loads
Three-phase loads include three-phase induction motors. There are 2 types of three phase loads:
- Star connected loads &
- Delta connected loads.
Why is an electrical power system required?
Generally, construction of generating stations where resources are cheap and easy to access from an economic perspective. Although consumers use electricity, they may continue to live in places where there are no resources for providing it.
Furthermore, there are occasionally a number of other restrictions that prevent from constructing a generating station closer to the intense consumer areas or load centres.
Instead, utilise a generator that is externally placed, and then employ a long transmission line & distribution system to send the power it generates to the load centres.
The term “electric power system” to refer to the entire system for providing electricity reliably and efficiently, from power stations to consumer ends.
