19-08-2016, 09:57 PM
superconducting magnetic energy storage systems ppt
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Superconducting Magnetic Energy Storage (SMES) systems store energy in the magnetic field created by the flow of direct current in a superconducting coil which has been cryogenically cooled to a temperature below its superconducting critical temperature.
A typical SMES system includes three parts: superconducting coil, power conditioning system and cryogenically cooled refrigerator. Once the superconducting coil is charged, the current will not decay and the magnetic energy can be stored indefinitely.
The stored energy can be released back to the network by discharging the coil. The power conditioning system uses an inverter/rectifier to transform alternating current (AC) power to direct current or convert DC back to AC power. The inverter/rectifier accounts for about 2–3% energy loss in each direction. SMES loses the least amount of electricity in the energy storage process compared to other methods of storing energy. SMES systems are highly efficient; the round-trip efficiency is greater than 95%.
Due to the energy requirements of refrigeration and the high cost of superconducting wire, SMES is currently used for short duration energy storage. Therefore, SMES is most commonly devoted to improving power quality.
Superconducting Magnetic Energy Storage (SMES) is a method of energy storage based on the fact that a current will continue to flow in a superconductor even after the voltage across it has been removed. When the superconductor coil is cooled below its superconducting critical temperature it has negligible resistance, hence current will continue to flow (even after a voltage source is disconnected). The energy is stored in the form of a magnetic field generated by the current in the superconducting coil. It can be released by discharging the coil. The coils are usually made of niobiumtitane (NbTi) filaments which has a critical temperature of around 9K. As SMES stores electrical current the only conversion involved with the process is the conversion from AC to DC. Hence the efficiencies of SMES systems are very high. SMES can switch from full discharge to full charge very quickly and visa versa. It has negligible deterioration due to cycling. However, SMES has a high self-discharge rate due to the energy expenditure of cooling via cryogenic liquid and mechanical stability problems.
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Superconducting Magnetic Energy Storage (SMES) systems store energy in the magnetic field created by the flow of direct current in a superconducting coil which has been cryogenically cooled to a temperature below its superconducting critical temperature.
A typical SMES system includes three parts: superconducting coil, power conditioning system and cryogenically cooled refrigerator. Once the superconducting coil is charged, the current will not decay and the magnetic energy can be stored indefinitely.
The stored energy can be released back to the network by discharging the coil. The power conditioning system uses an inverter/rectifier to transform alternating current (AC) power to direct current or convert DC back to AC power. The inverter/rectifier accounts for about 2–3% energy loss in each direction. SMES loses the least amount of electricity in the energy storage process compared to other methods of storing energy. SMES systems are highly efficient; the round-trip efficiency is greater than 95%.[2]
Due to the energy requirements of refrigeration and the high cost of superconducting wire, SMES is currently used for short duration energy storage. Therefore, SMES is most commonly devoted to improving power quality.