Solar – grid domestic, Off – grid

Solar power generation is one of the major
renewable sources of energy today, and it has several benefits over other forms
of renewable energy generation, it is noiseless. The solar photovoltaic (PV) systems are a great solution for urban
residential areas since the system is noiseless. The main problem with solar
energy is its intermittency. The growth of solar photovoltaic
products in consumer market shows awareness of renewable energy but to have
reliable power. The applications of
Solar PV power systems can be split into four main categories:

Off – grid domestic,

Off – grid non-domestic

Grid – connected

Grid – connected

The main components of a
PV power plant are PV modules, mounting (or tracking) systems, inverters and
transformers. Solar PV modules are made up of PV cells, which are most commonly
manufactured from silicon but other materials are also available. Cells can be
based on either wafers (manufactured by cutting wafers from a solid ingot block
of material) or “thin film” deposition of material over low cost substrates. In
general, silicon-based crystalline wafers provide high efficiency solar cells
but are relatively costly to manufacture, whereas thin film cells provide a
cheaper alternative but are less efficient. In general, good quality PV modules
are expected to have a useful life of 25 to 30 years, although their
performance will steadily degrade over this period. Selecting the correct
module is of fundamental importance to a PV system, keeping in mind the
numerous internationally accepted standards. When assessing the quality of a
module for any specific project, it is important to assess its specifications,
certifications and performance record besides the track record of the
manufacturer. PV modules must be mounted on a structure. This helps to keep
them oriented in the correct direction and provides them with structural
support and protection mounting structures may be either fixed or tracking.
Since fixed tilt mounting systems are simpler, cheaper and have lower
maintenance requirements than tracking systems, they are the preferred option
for countries with a nascent solar market and with limited indigenous
manufacturers of tracking technology. PV modules are generally connected
together in series to produce strings of modules of a higher voltage. These
strings may then be connected together in parallel to produce a higher current
DC input to the inverters. Inverters are solid state electronic devices that
convert DC electricity generated by the PV modules into AC electricity,
suitable for supply to the grid. In addition, inverters can also perform a
range of functions to maximize the output of a PV plant. In general, there are
two main classes of inverters: central inverters and string inverters. Central
inverters are connected to a number of parallel strings of modules. String
inverters are connected to one or more series strings. While numerous string
inverters are required for a large plant, individual inverters are smaller and
more easily maintained than a central inverter. While central inverters remain
the configuration of choice for most utility-scale PV projects, both
configurations have their pros and cons. Central inverters offer high
reliability and ease of installation. String inverters, on the other hand, are
cheaper to manufacture, simpler to maintain and can give enhanced power plant performance
on some sites.

Storage batteries are used in off-grid thereby
increasing the overall cost of the system but in case of grid connected solar PV system the demand can be
satisfied by using solar energy and the energy gotten from grid without using
batteries. In this system, if the solar PV panel produces excess power, then
that has to be sent to the grid and the exported excess power must be accounted
for. My project is focused on the energy meter that has to account for imported
power from the grid to consumer system and the exported power from the consumer
system to grid making energy affordable and accessible.


Since the inception of
electricity deregulation and market-driven pricing throughout the
world, utilities have been looking for a means to match consumption with
generation. Traditional electrical and gas meters only measure total
consumption, and so provide no information of when the energy was consumed at
each metered site. Smart meters provide a way of measuring this
site-specific information, allowing utility companies to introduce different
prices for consumption based on the time of day and the season.

Utility companies propose that from a consumer
perspective, smart metering offers potential benefits to householders. These
include, a) an end to estimated bills, which are a major source of complaints
for many customers b) a tool to help consumers better manage their energy
purchases – stating that smart meters with a display outside their homes could
provide up-to-date information on gas and electricity consumption and in doing
so help people to manage their energy use and reduce their energy bills.
Electricity pricing usually peaks at certain predictable times of the day and
the season. In particular, if generation is constrained, prices can rise if
power from other jurisdictions or more costly generation is brought online.
Proponents assert that billing customers at a higher rate for peak times will
encourage consumers to adjust their consumption habits to be more responsive to
market prices and assert further, that regulatory and market design agencies
hope these “price signals” could delay the construction of additional
generation or at least the purchase of energy from higher priced sources, thereby
controlling the steady and rapid increase of electricity prices. There are
some concerns, however, that low income and vulnerable consumers may not
benefit from intraday time-of-use tariffs.

An academic study based on existing trials showed
that homeowners’ electricity consumption on average is reduced by approximately

The ability to connect/disconnect service and read
meter consumption remotely are major labor savings for the utility and can
result in large layoffs of meter readers.


1.4 AIM


The aim of this project is to design and build a
bi-directional energy net meter that measures two quantities, energy delivered
by the electric distribution company to the consumer (imported energy) and
energy delivered by the consumer to the electric distribution company (exported


My objectives during the course of this project

To design an Internet of things (IoT) based
To write the program that controls the whole
operation of the system using MATLAB programming language and the Arduino
IDE (Integrated development environment).
To read the exported energy and imported
energy and calculate the net.
To make energy easily accessible and


Electrical Circuits

1) Voltage
Measurement Circuit: The AC supply
is given to the 12-0-12 transformer with the current rating of 1 amp. In
voltage measuring circuit, a step-down transformer converts 230V AC to 12V AC.
The input of 12V AC is given to the potential divider circuit to reduce the
voltage to 5V AC. The 5V AC is given to the level shifter to get the positive
voltage because the Arduino reads only positive voltages. The output from the
level shifter is given to the port1of the Arduino. Fig.2 shows the voltage
measurement circuit.