Smart Grid- For Today and Tomorrow

The world we see today is growing more and more power hungry. The Global demand for Energy is expanding at a rate of over 3 percent per year and India is leading the way with a demand growth of over 7-8 percent per year . The conventional grid systems are falling short of catering to the new changes and growing demand. Thus, the electrical systems are now migrating to ‘Smart Grid’ networks.

The complete architecture of a ‘Smart Grid’ is an extensive subject and shall be discussed in the coming articles. Here I would only like to present some trends which shall mark the need and advantages of ‘Smart Grid’. IEC 61850 will be the primary protocol for ‘Smart Substation’ Automation. More info about it can be found in the earlier article. The following points will discuss the basic premise and thought behind smart grid :

1)      Smart Consumption: - In conventional grid systems, the generation pattern followed the load pattern. E.g. During daytime, plants used peak time turbines which then sat idle throughout the day and at night, very few turbines ran and that too at low loads. A ‘Smart Grid’ system uses ‘Smart Metering’ to make the load follow generation pattern. i.e . In daytime, it will regulate the load pattern to match the generation by controlling peak demand and will transfer non-critical activities to night to ensure smooth load patterns. This ensures efficient use of available resources enhancing system stability.  E.g. A smart demand controller will provide alarms if demand overshoots the capabilities and will shed non-essential loads as per set priorities.

2)      Smart Substations: - Substation Automation will be integrated using a protocol like IEC 61850 . Conventional SCADA model shall be replaced by Nodal Substation model wherein the substation shall act as a nodal point collecting the data from Intelligent Field Devices for various parameters in Metering, Protection and Control. The data will be processed at Substation level and shall be integrated with the smart grid. The data exchange between substations shall be on a high-bandwidth open protocol like IEC 61850 which shall improve the information exchange and power flow management.

3)      Distributed Generation :- The emphasis of Smart Grid is on maximizing use of renewable energy sources like Hydro, Wind, Solar, Geothermal and Biomass . The Power Generation by these resources normally happens in an isolated way. Smart Grid proposes to integrate them into the existing grid system and utilise them as virtual power plants. By providing a robust distributed generation scheme, we can provide reliable power at times of need e.g Solar Power at peak times in the day and Wind power for non-essential loads at night. Effective management of these resources can provide a major boost to strained fossil fuel based systems.

4)      FACTS and HVDC – Using Flexible AC Transmission Systems (FACTS) can provide a multitude of benefits ranging from increased transmission capacity ,increased system stability and reduced transmission losses. By utilizing HVDC systems, power can be transmitted at voltages as high as 500kV DC to the magnitude of Gigawatts . Such a system can be ideal to connect Smart grid to isolated power plants e.g Offshore wind generation. Such systems can act to enhance system stability and boost grid efficiency.

Above is a simple schematic explaining benefits of Smart Grid Networks.