Power grid synchronization failure detection and recovery

IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 05 Issue: 03 | Mar-2016, Available @ http://www.ijret.org 156
POWER GRID SYNCHRONIZATION FAILURE DETECTION AND
RECOVERY
Pankaj Singh1
, Anuj Sharma2
, Shubham Saha3
, Anshul Chauhan4
, Amit Verma5
1,2,3,4,5
Department of Electronics and Communication Engineering, S.R.M University, NCR Campus, Ghaziabad, U.P
Abstract
As the power grid failure problems continue to persist in the country, need arises to make it more efficient and effective. This is a
demonstration devised to provide such kind of a system that could detect the failure in synchronous working of the power grid in
case any external supply source that is supplying to the grid is encountering any kind of abnormalities may be in current levels,
voltage levels, temperature and oil level. There are various generation units that usually supply power to the grids such as
thermal plants, solar plants, hydro-electric plants etc. All the generation units that connect to the grid have to obey the rules or
standards laid down for the operation of a grid. These rules involve maintaining of voltage variation, current variation, oil-level
variation and temperature variation within these specified limits. If there are any kind of abnormalities or deviations from the
acceptable limits laid down by the grid, it then gets crucial that the particular feeding source should get automatically
disconnected from the entire grid temporarily, this process is widely termed islanding. This would prevent large scale occurrences
of events of black outs. Hence it would be beneficial and wise if we could have a system that would be so efficient that it could
issue intimations about the potential variations in the arrangements and in addition provide the exact distance of the fault
location on a feeder line from the base grid and keep the particular source temporarily on a standby basis while this process takes
place. Variation of the system voltage should be around +-5% as per central electricity authority of India Regulations, 2010. This
paper is an approach on devising out a system that helps the grid resolve problems related to black out situations hence making it
a smart grid.
Keywords: - current variation, voltage variation, temperature variation, oil level detection, islanding, smart grid,
active method, passive method.
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1. INTRODUCTION
An approach towards a smarter tomorrow is always an
achievement and this paper discusses how this approach
helps make our power grid’s functioning more enhanced and
reliable. The problem of islanding is a common problem
when we talk about the distribution system and hence
methods that have been devised for the prevention of
possible islanding situation are grouped into following
categories:
 Passive methods.
 Active methods.
These methods and their performance is characterized by
certain requirements that have been laid down by the
Institute of Electrical and Electronics Engineering (IEEE),
International Electro Technical Commission (IEC) and
many other Standards Organizations. As far as active
methods are concerned, minor disturbances are introduced
into the power system and thereafter the response that the
system provides is observed and monitored. These methods
result in alteration of the balance of power existing amid
generators and the load, hence reducing the quality of the
power that we obtain from the system. There are several
examples of the active method a few of them being
impedance measuring method, AFD-Active frequency drift,
AFDPF-Active frequency drift with positive feedback, APS-
Automatic phase shift and ALPS-Adaptive logic phase shift.
Whereas on the other hand passive methods continuously
monitors various parameters of the power grid like in this
case over voltage, over current, temperature variation and
oil level indication.
2. OPERATIONAL PRINCIPLE
In passive method the parameters may vary differently
affecting the working of the grid. Hence any source that
violates the rules of grid would be immediately terminated.
But the process will not stop there because just elimination
is not enough, we need to know the reason of the fault i.e
which parameter is showing variation is it current, voltage
or any other and also we need to determine what the location
of the fault site is from the base of grid. Since our
demonstration here depicts 3 different sources as shown in
Fig.1, meanwhile if one source misbehaves the load will be
shared by the other two sources that are connected to the
grid hence the transmission will be uninterrupted. Hence the
concept of load sharing is quite a crucial part of this
demonstration. At the same time the entire faulty line is
being examined for detection of the cause of the error as
well as the distance of that particular fault location.

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Fig.1 Basic block depicting sources, line and grid base.
The microcontroller section acts as the power grid hub. This
section will continuously monitor the entire system. As
shown in Fig.1 different sensors have been used. The current
sensor measure the variation in current values in case a
shorted or an open line and after that it forwards this
information to the controller, which intern determines with a
predetermined threshold level weather to cut off the source
or not. The voltage sensor also operates in the similar
fashion. Temperature is another parameter which is
responsible for grid failures in case it goes out of desired
ranges, hence here the sensor would monitor the temperature
of the transformer and any variation in current levels will
trigger a change in the temperature which the sensor would
detect and convey the information to controller, which again
will compare it to a predetermined threshold value of
temperature and decide if to terminate the line or not. The
oil level indication also works on the same principle as
above and determines if the oil level has reduced drastically
below the unaccepted range and alerts the grid about the
same.
After the cause of fault has been determined and displayed
at the grid hub one more parameter is there that can be
determined and can add up I easing the complexity of
recovery and maintenance and that is the distance
calculation of a shorted or an open point on the feeder line
coming from three different sources. The fault can be
anywhere in the line hence being able to determine the exact
distance of the point where the fault has occurred is a task
that would add up to the effective management of the grid.
For this purpose switches can be used at, say each kilometer
and the on and off state of a switch could help determine the
fault location. Hence calculated distance can be provided at
the grid base station and physical maintenance can be
initiated within no time.
Fig.2 Circuit diagram of the actual implementation
Fig.2 given above is a generalized circuit diagram for the
implementation of above mentioned concept. Fig.2
comprises of the entire section starting from the transformer
section that shows three different sources supplying power,
and then comes the transmission lines section that consists
of three different lines connecting to the controller
separately, these lines are being continuously monitored by
the sensors namely a current sensor, voltage sensing unit, oil
level detection and temperature sensing unit which have
been depicted in the leftmost section of fig.2. The controller
section however acts as the grid base, taking all the crucial
decisions regarding the safety of the grid.
Whenever the controller section encounters any variation in
the predetermined limits set for each of the parameters it
issues a signal that is directed to the LCD section and that
particular alert message is then displayed and at the same
time the source that has been creating this abnormality is
also detected and temporarily eliminated from the grid
hence safeguarding the failure of entire grid. The relay unit
has been employed for the purpose of elimination of the
disturbing source temporarily. The switches on the other
hand that have been employed on the transmission line
section are the fault detection switches that would let us
calculate the distance to the fault site, the controller section
would be providing this information to the display unit
hence telling us the exact distance of the occurrence of a
shorted line or an open line accordingly hence the
maintenance work can be started thereafter.
3. EFFECTIVE MANAGEMENT &
RECOVERY
Maintaining a power grid online 24hrs and keeping it
efficient and effective at the same time is quite a tough task
seeing the complexity of the grids. Hence our
implementation offers a way in which it would become quite
effective to run the maintenance process and recover the
grid back into normal functioning in cases of occurrences of
faults.

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This implementation would yield following outcomes:
 Current overload detection.
 Voltage overload detection.
 Temperature variation & oil level indication.
 Distance determination from grid to fault site.
With all this precise information at the doorsteps of the grid
base it becomes convenient to run the maintenance and
recovery tasks. Knowing the fault location precisely enables
the physical workforce to manually correct it and at the
same time when the fault in line is corrected the grid would
immediately sense this and the source and the feeder line
that was previously terminated would be again recovered
and connected back to the grid hence restoring the entire
balance.
4. REALISTIC CONSTRAINTS
 When we talk about distribution lines, one major
drawback is they are earthed at the substations, so when
the generation unit and lines get disconnected the line no
longer remains earthed hence causing voltage overloads.
 If the distribution lines are short circuited, then the large
amount of current will flow leading to current overload.
 Due to islanding one major problem grid faces is that of
establishing a reconnection with the source as at that
time both source and grid might be out of
synchronization hence resulting in huge power flows that
could possibly cause damage to grid, to lines, stations
and consumer units.
CONCLUSION
This implementation concludes that it is possible to have a
power grid system that is smarter, more effective as well as
efficient in its operation, thus proving to be more
economical as compared to be the present installations. The
challenge is a continuous and uninterrupted transmission
which can be very well achieved with the implementation
described by this paper and in addition to the continuous
transmission several other parameters i.e. the passive
parameters are being monitored regularly and any
discrepancies occurring in these, are taken into account and
accordingly worked upon thus making the process of
management and recovery convenient and effective.
ACKNOWLEDGEMENT
A sincere gratitude towards our mentor and guide Mr.
Pankaj Singh who has been always a great motivator and a
great help and we would like to acknowledge our project co-
coordinators for their valuable contributions in drafting and
accomplishment of this proposal. Also we would like to
express our utter thanks to them for sharing their wisdom
with us.
REFERENCES
[1]. J.Shortle, Steffen Rebennack, Fred, W.Glover, Syst.
Eng. & Oper. Res., George Mason Univ., Fairfax, VA,
United States. IEEE paper on “Transmission-Capacity
Expansion for Minimizing Blackout Probabilities”, 13
September 2013.
[2]. Sabita Maharaj, Quanyan, Yan Zang, Stien Gjessing,
Tamer Basar, Simula Res. Lab., Formebu, Norway.
IEEE paper on “Response management in smart grids
in largely populated regions” IEEE Transactions on
Smart Grid (vol:7, Issue: 1), 1 June 2015
[3]. Moussa Reda Mansour, Luis Fernando, Costa Alberto,
Rodrigo Andrade Ramos, University of Sao Carlos,
Brazil. IEEE paper on “Preventive control design for
voltage stability considering multiple contingencies”.
IEEE Transcriptions on Power Systems (vol: 31, Issue:
2), 30 April 2015.
[4]. Shuhui Li, Julio Proano, Dong Zang. IEEE paper on
“Micro grid power flow study in grid connected and
islanding modes under converter control strategies”.
IEEE 2012.

Power grid synchronization failure detection and recovery

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