The existing power grid is load driven and centralized. This
means that the generation is varied to match the load at every instance of
time. The traditional power grid consists of generating stations located away
from the load. The power generated is stepped up to higher voltage and
transmitted via transmission system. The transmission system usually consists
of overhead line or underground cable which carry high voltage at low current
to reduce transmission losses. The power is then fed to a substation where the
voltage is stepped down to distribution voltage and dispatched to industries
and residential load. As we can see from this traditional model, the power flow
is unidirectional. The load is a passive system which does not contribute power
to the grid. The traditional power grid has some disadvantages. Firstly, the
infrastructure used is quite old and needs to be updated. Therefore, the grid
is unable to meet increasing demand of electricity. Secondly, the utility is
not transparent to the customer about the price of electricity at a particular
time and the demand for electricity. Thirdly, using fossil fuels to generate
electricity leads to release of CO2 into to the atmosphere and will
contribute to climate change and global warming. Hence, there is a need to
update the existing grid to a so called “Smart Grid”.
of overhauling the existing grid completely, Smart grid involves integration of
ICT such as Smart meters, sensors, digital relays, fault recorders etc., into
the current grid that makes grid monitoring, control and automation feasible.
Smart grid also introduces the concept of “Prosumers”. This means that
electricity can be fed into the grid by users who consume and produce
electricity. Integrating renewable energy resources and storage systems has
resulted in the formation of microgrids. These microgrids have distributed
energy resources (DER) in contrast to the traditional centralized power plants.
These DERs can be installed by individual consumers so that electricity can be
generated close to the load. This improves the efficiency as the electricity will
travel lesser distance compared to the traditional method.
To facilitate the above-mentioned
concept, ICT becomes mandatory. By placing smart devices, a large amount of
information can be obtained about the grid status, price of electricity, demand
at an instant of time, circuit break position and so on. Instead of wasting
these valuable information, a smart grid tries to make use of this data to
optimize demand and supply of electricity, grid monitoring and control. This
also helps the customers to know the price of electricity so that they can an
informed decision as to when to use electricity. In this paper, we look at an
overview of different sections of smart grid and the standards and protocols
used in them and comparison of the different standards and scope of integration.
Smart grid consists of different aspects
namely, Wide area monitoring, substation automation, distributed generation,
demand response, electric vehicles. Standards and protocols have been
established for each one of them. In the following sections, a summary of the
important standard(s) used in each domain is specified.