SUPERCONDUCTING MAGNETIC ENERGY STORAGE SYSTEM PRESENTED BY: AMRUTHA P S

Contents Introduction History What is SMES Components of SMES Operating principle Application Advantages and disadvantages Conclusion

Introduction RENEWABLE energy sources will have a key role in supplying energy in the future. There are several issues regarding large scale integration of new renewable into the power system. One of the problems is the security of supply. These energy sources will provide energy, or not provide, independent of the demand. The output power can also have relatively large variations within a short time span. A solution to this problem is the concept of energy storage, and there are several different concepts. There are devices which can store large amounts of energy, but do not react so fast. In the other end there are fast acting devices which store smaller amounts of energy. Superconducting Magnetic Energy Storage (SMES) is placed in this group.

Historical Review Of SMES 1969:first concept was proposed by Ferrierin in France. 1971: research performed in university of Wisconsin in the US This research led to construction of the first SMES device High temperature super conductors (HTS) Appeared commercially in late 90 s 1997: first signifying size HTS – SMES was developed by American super conductors.

SMES SYSTEM Superconducting Magnetic Energy Storage (SMES) is an energy storage system that stores energy in the form of dc electricity by passing current through the superconductor and stores the energy in the form of a dc magnetic field. The conductor for carrying the current operates at cryogenic temperature where it becomes superconductor and thus has virtually no resistive losses as it produces the magnetic field. The magnetic field is created by flow of direct current through the coil .SMES systems are highly efficient; the efficiency is greater than 98%.

Components of SMES system Superconducting coil with the magnet The power conditioning system (PCS) The cryogenic system The control unit

Superconducting Coil Main part of a SMES system Most superconducting coils are wound using conductors which are comprised of many fine filaments of a niobium-titanium (NbTi) alloy embedded in a copper matrix. The Size of the coil depends upon the energy storage require- ment .

Power Conditioning System The power conditioning system uses an  inverter/ rectifier to transform alternating current (AC) power to direct current or convert DC back to AC power. An ac/dc PCS is used for two purposes: One is to convert electric energy from dc to ac. The other is to charge and discharge the coil.

Cryogenic Unit The SMES coil must be maintained at a temperature sufficiently low to maintain a superconducting state. Commercial SMES temperature is about 4.5 K. It uses helium as the coolant or liquid nitrogen. The refrigerator consist of one or more compressor -cold box It affect the overall efficiency and cost of SMES system.

Control system Establishes a link between power demands from the grid and power flow to and from the SMES coil. Maintains system safety and sends system status information to the operator. Modern systems are tied to the internet to provide remote observation and control.

SMES System

Operation Of SMES Stand-by mode Discharging mode Charging mode There are three different modes of operations of the SMES coil :- Charging mode Stand-by mode Discharging mode

Applications Of SMES Paper industry Motor vehicle assembly Petrochemical Refineries Chemical & pharmaceutical Companies

Advantages of SMES SMES systems have the ability of fast response. They can switch from charge to discharge state (vice versa) within seconds. The absence of moving parts and high efficiency are some additional advantages. It can be deployed in places where other technologies such as battery system or compressed air are not feasible.

Common Challenges Main drawback of the SMES technology is the need of large amount power to keep the coil at low temperature, combined with the high overall cost for the employment of such unit. To achieve commercially useful levels of storage, around 1 GW.h a SMES installation would need a loop of around 100 miles (160 km). Another problem is the infrastructure required for an installation.

Market Analysis It is estimated that, over 100 MW of SMES units are now operating in worldwide. . At the larger scale, the projected development of a 100 MWh load leveling system could be implemented during 2020-30.

Conclusion With the advancement in the science of superconductor technology , cost of installation of the SMES system is eventually going to be comparable to that of the existing storage technologies. Hence, it will promote this system which is capable of discharging larger amount of energy for short period of time thus helping with dynamic performance.

References Z. Wang, Z. Zou, Yang Zheng, “Design and control of a photovoltaic energy and SMES hybrid with current source grid inverter,” IEEE Trans. Appl. supercond. Vol.2, no.3, pp.254-253, Jun.2013. 2. R.M. Vamsee, D.S. Bankar, “Control of system under normal grid condition,” IEEE Trans. Power. electron. Vol.22, no.2, pp.587-594, mar.2011. Wikipedia 4. slideshare

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