Voltages of Distribution The voltages on primary lines range from 2,300 to 39,000 volts. Depending on the distribution voltages a utility employs, common primary line voltages include 2,300, 4,160, 12,470, 13,800, 25,000, and 34,500 volts. Secondary line voltages that are often used are 120, 208, 240, 277, and 480 volts. Some large utilities have secondary voltages as high as 630 volts or more.
The voltage on each conductor within the cable is called its "line-to-line voltage." This voltage is either directly measured at points where cables enter junction boxes or calculated from information listed in the cable's specifications sheet. If a utility uses two different voltages on its primary lines, then it will usually specify which cable goes to what house. For example, if a property is served by a service call bus and a ring main, the service call bus might be 26,000 volts while the ring main is 32,000 volts. In this case, the owner of the house would be given call buses to prevent him or her from being shocked by both lines. If a single conductor carried both signals, it would be impossible for a property owner to know which line was hot. A transformer at the substation changes the line voltage before it enters the city limits.
Electric power transmission lines have traditionally been made from aluminum because of their lightweight and resistance to corrosion when exposed to weather conditions.
The voltages on transmission lines range from 44,000 to over 765,000 volts. The greater the voltage, the more electricity can be carried by the line. Transmission lines usually have steel or aluminum conductors insulated with plastic or other materials. The actual distance that a transmission line will carry current depends on how much it is loaded down. If a long section of line isn't loaded, it will still carry current just like a low-voltage line. This type of line is called an "ungrounded" line.
When a transmission line is grounded at one end, such as at a substation, this means that the line is being used to carry current from one place to another rather than being used to transmit high voltage from a power station to a market center. At the other end of the line, if it's not loaded, it will still carry current but there's no need for a ground wire since it won't transmit any voltage.
Loads and conditions can change the distance that an ungrounded line will carry current, so engineers must know the load on each section of line before they design it. For example, if a line carries current up to a certain point and then stops working, it's called a "shorted" line.
Electric utility companies frequently transmit primary distribution voltage in the range of 3 Kv to 35 Kv, which is a range between 3,000 V and 35,000 V since, in order to be consumed by the public, they utilize transformers to reduce the voltage to less than 1 Kv. This may be utilized in the home, so choose one of the alternatives...
The choice of distribution voltage depends on many factors such as cost, load requirements, technical specifications, etc., but it usually falls in the range from 100 V to 600 V for residential applications. The higher number is generally chosen to minimize the number of conductors needed to distribute power, while the lower number is chosen for technical reasons related to equipment design.
In conclusion, the most probable distribution voltage for a residential electricity provider is in the range of 100 V to 600 V.
Over the years, a vast network of transmission lines has been built to evacuate power generated by various electrical producing plants and distribute it to customers. The most popular nominal Extra High Voltage lines are +-800 kV HVDC & 765 kV, 400 kV, 230/220 kV, 110 kV, and 66 kV AC lines. Other lines such as 431 kV, 347 kV, 285 kV, and 182 kV have also been installed but they are less common.
The voltage produced by different generators varies with their type. For example, small diesel generators produce about 1200 V, large hydropower stations usually produce over 4000 V, and nuclear power reactors can produce up to 55000 V. All these voltages are much higher than what is needed at point of consumption which typically ranges from 110 V to 140 V. To reach this level of reduction, large quantities of electricity are required which can only be obtained by distributing the power produced by multiple low-voltage units.
In India, transmission system operators (TSOs) own and operate all major transmission facilities, including sub-stations, transformer houses, switchyards, and overhead conductors. They also supply energy to their consumers through distribution systems owned by separate companies called Transmission Service Providers (TSPs). A TSO or an independent engineering company selects the location for a new transmission line project. After the site selection process, the TSO requests a quotation from potential contractors for the project.