The synchronous grids of Europe The two major and three minor interconnections of North America Major WASGs in Eurasia and northern Africa A wide area synchronous grid also called an "interconnection" in North America is an electrical grid at a regional scale or greater that operates at a synchronized frequency and is electrically tied together during normal system conditions. Synchronous grids with ample capacity facilitate electricity market trading across wide areas. Interconnections can be tied to each other via high-voltage direct current power transmission lines DC tiesor with variable-frequency transformers VFTswhich permit a controlled flow of energy while also functionally isolating the independent AC frequencies of each side. The benefits of synchronous zones include pooling of generation, resulting in lower generation costs; pooling of load, resulting in significant equalizing effects; common provisioning of reserves, resulting in cheaper primary and secondary reserve power costs; opening of the market, resulting in possibility of long term contracts and short term power exchanges; and mutual assistance in the event of disturbances.
Generation subsystem includes generators and transformers. Generators Three-phase ac generator from around An essential component of General structure of electrical power system systems is the three-phase ac generator known as synchronous generator or alternator. Synchronous generators have two synchronously rotating fields: One field is produced by the rotor driven at synchronous speed and excited by dc current.
Electrical power system deals with the technology of generation, transmission and distribution of electrical energy. An electric power system consists of different subsystem are explained as follows. I. Generation subsystem. The conversion from one source to electrical energy through the process of electromagnetic conversion. This system . Capacity factor: The amount of energy that the system produces at a particular site as a percentage of the total amount that it would produce if it operated at rated capacity during the entire year. For example, the capacity factor for a wind farm ranges from 20% to 35%. Thirty-five percent is . 2. BASIC ELECTRICITY. ELECTRICITY AND MAGNETISM BASICS -It all starts with the electrons moving around atoms. Electricity is the movement of electrical charge from one place to another.
The other field is produced in the stator windings by the three-phase armature currents. The dc current for the rotor windings is provided by excitation systems. In the older units, the exciters are dc generators mounted on the same shaft, providing excitation through slip rings. Current systems use ac generators with rotating rectifiers, known as brushless excitation systems.
The excitation system maintains generator voltage and controls the reactive power flow. Because they lack the commutator, ac generators can generate high power at high voltagetypically 30 kV.
The source of the mechanical power, commonly known as the prime mover, may be hydraulic turbines, steam turbines whose energy comes from the burning of coal, gas and nuclear fuel, gas turbines, or occasionally internal combustion engines burning oil. A steam turbine used to provide electric power Steam turbines operate at relatively high speeds of or rpm.
The generators to which they are coupled are cylindrical rotor, two-pole for rpm, or four-pole for rpm operation. Hydraulic turbines, particularly those operating with a low pressure, operate at low speed.
Their generators are usually a salient type rotor with many poles. In a power station, several generators are operated in parallel in the power grid to provide the total power needed. They are connected at a common point called a bus.
With concerns for the environment and conservation of fossil fuels, many alternate sources are considered for employing the untapped energy sources of the sun and the earth for generation of power. Some alternate sources used are solar power, geothermal power, wind power, tidal power, and biomass.
The motivation for bulk generation of power in the future is the nuclear fusion. If nuclear fusion is harnessed economically, it would provide clean energy from an abundant source of fuel, namely water.
The transformer transfers power with very high efficiency from one level of voltage to another level. The power transferred to the secondary is almost the same as the primary, except for losses in the transformer.
Using a step-up transformer will reduce losses in the line, which makes the transmission of power over long distances possible. Insulation requirements and other practical design problems limit the generated voltage to low values, usually 30 kV. Thus, step-up transformers are used for transmission of power.
At the receiving end of the transmission lines step-down transformers are used to reduce the voltage to suitable values for distribution or utilization. The electricity in an electric power system may undergo four or five transformations between generator and consumers.
Top Transmission and Subtransmission Subsystem An overhead transmission network transfers electric power from generating units to the distribution system which ultimately supplies the load.
Transmission lines also interconnect neighboring utilities which allow the economic dispatch of power within regions during normal conditions, and the transfer of power between regions during emergencies.
Transmission voltages above kV are usually referred to as extra-high voltage EHV. High voltage transmission lines are terminated in substations, which are called high-voltage substations, receiving substations, or primary substations.
The function of some substations is switching circuits in and out of service; they are referred to as switching stations. At the primary substations, the voltage is stepped down to a value more suitable for the next part of the trip toward the load.
Very large industrial customers may be served from the transmission system. The portion of the transmission system that connects the high-voltage substations through step-down transformers to the distribution substations is called the subtransmission network.Full Article.
Tips on Electrical System Use and Maintenance Part III: DC Systems by David H. Pascoe, Marine surveyor. DC Systems. The same advice about jury-rigging wiring applies to .
Electrical protection and lightning protection. I have a query on earthing system design. One designer has submitted me an earthing plan which interconnects the earth electrodes meant for equipment earthing and those for lightning protection purposes. Structure Of Power Systems – Generating stations, transmission lines and the distribution systems are the main components of an electric power system.
Generating stations and a distribution system are connected through transmission lines, which also connect one power system (grid, area) to another.
2. BASIC ELECTRICITY. ELECTRICITY AND MAGNETISM BASICS -It all starts with the electrons moving around atoms. Electricity is the movement of electrical charge from one place to another. Cet the voltage generated #line to line% at the alternator be 1/ k$.Basic structure of a power system Transmission system he huge amount of power generated in a power station #hundreds of *3% is to be transported over a long distance #hundreds of kilometers% to load centers to cater power to consumers with the help of transmission .
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