The existing power grid is load driven and centralized. Thismeans that the generation is varied to match the load at every instance oftime. The traditional power grid consists of generating stations located awayfrom the load.
The power generated is stepped up to higher voltage andtransmitted via transmission system. The transmission system usually consistsof overhead line or underground cable which carry high voltage at low currentto reduce transmission losses. The power is then fed to a substation where thevoltage is stepped down to distribution voltage and dispatched to industriesand residential load. As we can see from this traditional model, the power flowis unidirectional. The load is a passive system which does not contribute powerto the grid.
The traditional power grid has some disadvantages. Firstly, theinfrastructure used is quite old and needs to be updated. Therefore, the gridis unable to meet increasing demand of electricity. Secondly, the utility isnot transparent to the customer about the price of electricity at a particulartime and the demand for electricity. Thirdly, using fossil fuels to generateelectricity leads to release of CO2 into to the atmosphere and willcontribute to climate change and global warming.
Hence, there is a need toupdate the existing grid to a so called “Smart Grid”. Insteadof overhauling the existing grid completely, Smart grid involves integration ofICT such as Smart meters, sensors, digital relays, fault recorders etc., intothe current grid that makes grid monitoring, control and automation feasible.Smart grid also introduces the concept of “Prosumers”. This means thatelectricity can be fed into the grid by users who consume and produceelectricity.
Integrating renewable energy resources and storage systems hasresulted in the formation of microgrids. These microgrids have distributedenergy resources (DER) in contrast to the traditional centralized power plants.These DERs can be installed by individual consumers so that electricity can begenerated close to the load. This improves the efficiency as the electricity willtravel lesser distance compared to the traditional method. To facilitate the above-mentionedconcept, ICT becomes mandatory.
By placing smart devices, a large amount ofinformation can be obtained about the grid status, price of electricity, demandat an instant of time, circuit break position and so on. Instead of wastingthese valuable information, a smart grid tries to make use of this data tooptimize demand and supply of electricity, grid monitoring and control. Thisalso helps the customers to know the price of electricity so that they can aninformed decision as to when to use electricity. In this paper, we look at anoverview of different sections of smart grid and the standards and protocolsused in them and comparison of the different standards and scope of integration.Smart grid consists of different aspectsnamely, Wide area monitoring, substation automation, distributed generation,demand response, electric vehicles.
Standards and protocols have beenestablished for each one of them. In the following sections, a summary of theimportant standard(s) used in each domain is specified.