In frequency signaling, the generating units match the frequency of the power transmission system. In, if the frequency decreases, the power is increased. (The drop in line frequency is an indication that the increased load is causing the generators to slow down.) , and other distributed storage and generation systems can be connected to the power grid, and interact with it to improve system operation. protection []Failure Under excess load conditions, the system can be designed to fail gracefully rather than all at once. occur when the supply power drops below the demand. occur when the supply fails completely. Rolling blackouts, or load shedding, are intentionally engineered electrical power outages, used to distribute insufficient power when the demand for electricity exceeds the supply. []Communications Operators of long transmission lines require reliable communications for of the power grid and, often, associated generation and distribution facilities. Fault-sensing at each end of the line must communicate to monitor the flow of power into and out of the protected line section so that faulted conductors or equipment can be quickly de-energized and the balance of the system restored. Protection of the transmission line from and other faults is usually so critical that telecommunications are insufficiently reliable, and in remote areas a common carrier may not be available. Communication systems associated with a transmission project may use: Rarely, and for short distances, a utility will use pilot-wires strung along the transmission line path. Leased circuits from common carriers are not preferred since availability is not under control of the electric power transmission organization. Transmission lines can also be used to carry data: this is called power-line carrier, or . PLC signals can be easily received with a radio for the long wave range. Optical fibers can be included in the stranded conductors of a transmission line, in the overhead shield wires. These cables are known as optical ground wire (). Sometimes a standalone cable is used, all-dielectric self-supporting (ADSS) cable, attached to the transmission line cross arms.
In frequency signaling, the generating units match the frequency of the power transmission system. In, if the frequency decreases, the power is increased. (The drop in line frequency is an indication that the increased load is causing the generators to slow down.) , and other distributed storage and generation systems can be connected to the power grid, and interact with it to improve system operation. []Failure protection Under excess load conditions, the system can be designed to fail gracefully rather than all at once. occur when the supply power drops below the demand. occur when the supply fails completely. Rolling blackouts, or load shedding, are intentionally engineered electrical power outages, used to distribute insufficient power when the demand for electricity exceeds the supply. []Communications Operators of long transmission lines require reliable communications for of the power grid and, often, associated generation and distribution facilities. Fault-sensing at each end of the line must communicate to monitor the flow of power into and out of the protected line section so that faulted conductors or equipment can be quickly de-energized and the balance of the system restored. Protection of the transmission line from and other faults is usually so critical that telecommunications are insufficiently reliable, and in remote areas a common carrier may not be available. Communication systems associated with a transmission project may use: Rarely, and for short distances, a utility will use pilot-wires strung along the transmission line path. Leased circuits from common carriers are not preferred since availability is not under control of the electric power transmission organization. Transmission lines can also be used to carry data: this is called power-line carrier, or . PLC signals can be easily received with a radio for the long wave range. Optical fibers can be included in the stranded conductors of a transmission line, in the overhead shield wires. These cables are known as optical ground wire (). Sometimes a standalone cable is used, all-dielectric self-supporting (ADSS) cable, attached to the transmission line cross arms.
48337626-Electric-power-transmission.docx