What are the voltages for transmission?
Commonly used transmission voltages are 69 kV and 138 kV. There are also 44 kV, 115 kV, 161 kV, 169 kV, and 230 kV systems. On large utility systems, there are bulk transmission and inter-connection circuits at 345 kV, 500 kV and more recently 765 kV.
How is electricity transmitted over long distances?
At a power plant, a transformer increases the voltage of generated power by thousands of volts so it can be sent of long distances through high-voltage transmission power lines. Transmission lines are bundles of wires, known as conductors, that ship electric power from power plants to distant substations.
Why are high voltages used for long distance transmission of electrical energy?
The primary reason that power is transmitted at high voltages is to increase efficiency. The lower current that accompanies high voltage transmission reduces resistance in the conductors as electricity flows along the cables. This means that thin, light-weight wires can be used in long-distance transmission.
What are the standard transmission and distribution voltages?
Electrical Transmission and Distribution Systems That network consists of electrical distribution substations which step-down the transmission line voltage levels between 69 kV and 765 kV to distribution voltage levels, usually 35 kV or less. Typical distribution voltages range from 34,500Y/19,920 V to 4,160Y/2400 V.
Which is used to carry higher voltage for long distance transmission?
Most transmission lines are high-voltage three-phase alternating current (AC), although single phase AC is sometimes used in railway electrification systems. High-voltage direct-current (HVDC) technology is used for greater efficiency over very long distances (typically hundreds of miles).
What are the standard distribution voltages?
As indicated previously, the standard primary distribution voltage levels include 4.16kV, 7.2kV, 12.47kV, 13.2kV, 14.4kV, 23.9kV, and 34.5kV. However, equipment is specified in terms of voltage class. Equipment of one voltage class may be utilized in at any operating voltage assigned to that class.
What is the difference between electricity distribution and transmission?
Transmission power lines are for long-distance, high-voltage electricity transportation. Distribution power lines are for shorter distances and transport lower voltage electricity on a local scale. These power lines are installed, and visible, along the sides of streets.
What kind of voltage is needed for long distance transmission?
Long-distance transmission is typically done with overhead lines at voltages of 115 to 1,200 kV. At extremely high voltages, where more than 2,000 kV exists between conductor and ground, corona discharge losses are so large that they can offset the lower resistive losses in the line conductors.
How are voltages maintained in power transmission lines?
Voltage in Power Electric Lines. This level of voltage is increased at different suitable levels, it may be at 400 kV or 765 kV or 1000 kV. This high voltage or extra high voltage level is maintained to transmit the power to a long distant substation. It is call primary transmission of power.
How are transformers used in long distance power transmission?
Transformers and Long-Distance Power Transmission. Transformers are devices which use mutual induction to change the voltage and current of an AC circuit.
Which is the highest voltage used for power transmission?
Voltages used for electric power transmission increased throughout the 20th century. By 1914, fifty-five transmission systems each operating at more than 70 kV were in service. The highest voltage then used was 150 kV.