In an alternating current electric power system, synchronization is the process of matching the speed and frequency of a generator or other source to a running network. An AC generator cannot deliver power to an electrical grid unless it is running at the same frequency as the network. There are several power generation units connected to the grid such as hydra, thermal, solar etc., to supply power to the load. These generating units need to supply power according to the rules of the grid. These rules involve maintaining a voltage variation within limits and also the frequency. If any deviation from the acceptable limit of the grid, it is mandatory that the same feeder should automatically get disconnected from the grid which by effect is termed as islanding. This prevents in large scale brown out or black out of the grid power. So, it is preferable to have a system which can warn the grid in advance so that alternate arrangements are kept on standby to avoid complete grid failure. In this paper hardware controller based system to identify the abnormalities and to disconnect the faulted part from the grid is proposed

1. Detection of power grid synchronization failure on sensing
frequency and voltage beyond acceptable range
BATCH NO : 1
Under the esteemed guidence of
Mr.Y.Rajesh Babu M.Tech(Ph.D)
Assistant professor
M.V.SUSMITHA (14JR1A0213)
N.BHARATH (14JR1A0230)
S.KEERTHI CHANDANA ( 14JR1A0215)
S.SUBBAREDDY (14JR1A0235)
PRESENTED BY
DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING
KKR & KSR INSTITUTE OF TECHNOLOGY &SCIENCES 1

2. ABSTRACT
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This project is designed to develop a system to detect synchronization failure of
any external supply source to the power grid on sensing abnormalities in
frequency and voltage.
The microcontroller monitors the under/over voltage and under/over frequency
from utility grid and the processed value of voltage and frequency for turning
ON/OFF the relay.
The project would alternatively use a variable frequency generator using
555timer for changing the frequency while a standard variac shall be used to
vary the input voltage for achieving the test conditions as stated above.

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INTRODUCTION
The use of fossil fuels for electric power generation has many problems
with the environment. This, along with the day by day increasing demands
of power lead to a demand of power generation using renewable energy
sources, which mainly include solar power, wind power, small hydro
power as a distributed generation system.
These Distributed Generation (DG) systems need to be controlled
properly in order to ensure sinusoidal current injection into the grid. The
major issue associated with the distributed generation system is their
synchronization with utility voltage vector.

4. Synchronization:
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Synchronization means the minimization of difference in voltage, frequency
and phase angle between the corresponding phases of the generator output
and grid supply. An alternating current generator must be synchronized with
the grid prior to connection. It can’t deliver the power unless it is running at
same frequency as the network.
Synchronization must occur before connecting the generator to a grid.
Synchronization can be achieved manually or automatically. The purpose of
synchronization is to monitor, access, enable, and automatically take the
control action to prevent the abnormalities of voltage and frequency.

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Synchronization circuit may fail for responding to a received input pulse.
It happens when the received input pulse is shorted than the sampling period
of the synchronizer.
Then no synchronized representation will take place.
Synchronization circuit may fail, when the pulse rate of the input signal is higher than
the synchronization rate of the synchronizer
Reason for synchronization failure:
The fault level contribution from the grid to sub-station may be lost.
It can be dangerous to utility workers.
The voltage levels may go outside of normal operating limits, and the quality
of supply may be reduced.
Effects of synchronization failure:

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Grid synchronization Techniques:
1.PHASE LOCKED LOOPS
A PLL is a nonlinear circuit which synchronizes its output signal (v0) with a reference or input
signal (vi) frequency as well as phase
The fundamental frequency and phase-angle of vi are ω1 and θ1; they are
related by θ1 = ω1t + ϕ1 where ϕ1 is an offset dc constant.

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Interconnection of power systems:

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Simulation results: three phase V-I waveforms (balanced condition)

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Simulation results : single phase current wave forms (balanced condition)

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Simulation results: single phase voltage waveforms (balanced condition)

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Simulation results: Three phase V-I waveforms (unbalanced condition)

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Simulation results: voltage waveforms (unbalanced condition)

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Simulation results: current waveforms (unbalanced condition)

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Block diagram for detection of abnormal conditions and removing faulty grid from system:

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Controller Block:

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Simulation results: three phase V-I waveforms

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Simulation results: voltage waveforms

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Simulation results: current waveforms

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Block Diagram

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• Arduino UNO
• LCD
• Op-Amps
• 555 timer
• Crystal
• Resistors
• Capacitors
• Diodes
• Transformer
• Voltage Regulator
• Relay
• Transistors
• Slide Switch
• Lamp
Hardware requirements

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Arduino UNO:
A micro controller board , contains on-board power
supply,USB port to communicate with PC , and an atmel
micro controller chip.
It simplify the process of creating any control system by
providing the standard board that can be programmed and
connected to the system without the need to any
sophisticated PCB design and implementation

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555 timer :
The 555 timer IC is an integrated circuit used in a
variety of timer, pulse generations, and oscillator
applications
The 555 timer is used to provide time delays, as an
oscillator , and as an flip –flop element

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Liquid Crystal Display :
A Liquid Crystal Display commonly abbreviated as LCD is basically a display unit built using Liquid Crystal
technology.
When we build real life/world electronics based projects, we need a medium/device to display output values and
messages.
The most basic form of electronic display available is 7 Segment display– which has its own limitations.
The next best available option is Liquid Crystal Displays which comes in different size specifications.
Out of all available LCD modules in market, the most commonly use done is 16×2 LCD Module which can
display 32ASCII characters in 2 lines (16 characters in 1 line).

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25. Conclusion:
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The project is designed to develop a system to detect the synchronization failure
of any external supply source to the power grid on sensing the abnormalities in
frequency, voltage &phase sequence. This type of indicators are much needed in
most crowed EHV substations where number of voltage levels, number of
sources ,number of power transformers and number of load lines are existing. if
any deviation in acceptable limits of grid the indicator will gives advance warn
in LCD indicator .so that alternator arrangements kept on stand to avoid
complete failure of grid.

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References:
[1].Zongjie Liu, Lifeng Zhu, Li Deng, Lijun Qin, Feng Jiao, “The Research of
Islanding Detection about the Photovoltaic Grid-Connected Generation
System”- International Journal of Computer and Electrical Engineering, Vol. 5,
No. 3, June 2013
[2]. Karan Gupta, Shreyas Gupta, KummadVerma, Anil Singh, Abhimanou
Sharma, “Detecting Power Grid Synchronization Failure on Sensing Bad
Voltage or Frequency Documentation”-International Journal of Engineering
Research and General Science, Volume 4, Issue 2, March- April, 2016
[3]. Laukik S. Raut, Shahrukh B. Pathan, Gaurav N. Pawar, Mandar V. Pathak,
“Detecting Power Grid Synchronization Failure on Sensing Frequency or
Voltage beyond Acceptable Range”- International Journal of Research in
Advent Technology, Vol.4, No.4, April 2016
[4]. Rohan Solanki, Divyesh Patel, Yuvraj Gharia, Daivik Sailor, Bhumit Patel,
Ashish Chaudhari, “Detection And Protection of power grid synchronisation
failure”- International Research Journal of Engineering and Technology,
Volume 03, Issue: 05, May-2016.

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