This document describes an automatic grid synchronization system using a microcontroller. The system monitors voltage and frequency from external power sources connected to the grid. It detects any abnormalities outside acceptable limits that could cause failures. When deviations are sensed, the erring power source is automatically disconnected from the grid to prevent large blackouts. This warns the grid in advance so alternatives can prepare. The system uses a microcontroller to monitor under/over voltage from comparators and a variable frequency generator to change frequency for testing. It drives a lamp load when parameters exceed thresholds, simulating a blackout. The design could further isolate problematic sources using power electronics for more precise cycle-by-cycle deviation detection.

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Automatic Grid Synchronization using Microcontroller
ABSTRACT
The project is designed to develop a system that detects synchronization failure of any
external supply source to power grid on sensing the abnormalities in the frequency or voltage.
There are several power generating units connected to the grid, such as hydel, thermal, solar, etc.,
to supply power to the load. For any deviation of the voltage or frequency from the acceptable
limits of the grid, it becomes mandatory that the same feeder should automatically get disconnected
from the grid, which by effect is termed as islanding. This prevents large scale brown out or black
out of grid system. It is preferable to have a system that can warn the grid in advance so that
alternate arrangements are kept on standby to avoid complete grid failure.
This system is based on a microcontroller of the 8051 family. The microcontroller monitors
under/over voltage being derived from a set of comparators. As regards the frequency ,since the
mains supply it cannot be changed, the project uses a variable frequency generator (555-timer) for
changing frequency, while a standard variac is used to vary the input voltage to test proper
functioning of both these parameters of the project. A lamp load (indicating a predictable blackout,
brownout) is driven by the microcontroller in case of voltage/frequency going out of acceptable
range.
Furthermore, this project can be enhanced by using a power-electronic device to isolate the grid
from the erring supply source by sensing cycle-by-cycle deviation for more sophisticated means
of detection.
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BLOCK DIAGRAM
HARDWARE REQUIREMENTS:
8051 series Microcontroller, LCD , Op-Amps,
555 timer, Crystal, Resistors, Capacitors, Diodes,
Transformer, Voltage Regulator, Relay,
Transistors, Slide Switch, Lamp.
SOFTWARE REQUIREMENTS:
Keil compiler
Language: Embedded C or Assembly.
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