Synchronization of Grid Voltage for Solar and Wind Distributive Systems Under Grid Faults by using Advanced Phase Locked Loop Techniques

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 04 Issue: 10 | Oct -2017 www.irjet.net p-ISSN: 2395-0072
© 2017, IRJET | Impact Factor value: 5.181 | ISO 9001:2008 Certified Journal | Page 404
SYNCHRONIZATION OF GRID VOLTAGE FOR SOLAR AND WIND
DISTRIBUTIVE SYSTEMS UNDER GRID FAULTS BY USING ADVANCED
PHASE LOCKED LOOP TECHNIQUES
Mr.CH. DINESH1, Mr. V. ANJANEYULU2
1PG Scholar, M.Tech, Power Systems, PRIYADARSHINI COLLEGE OF ENGINEERING AND TECHNOLOGY, NELLORE-
524004, SPSR Nellore (Dist.), AP, India,
2Assistant.Prof, M.Tech, PRIYADARSHINI COLLEGE OF ENGINEERING AND TECHNOLOGY, NELLORE-524004,
SPSR Nellore(Dist.),AP,India,
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Abstract: With an increase in power demand usage of
renewable sources plays a life-sustaining role in generating
electrical power. Among renewable resources wind and
solar energy are very demanding. The transmission system
operators are more interested about low-voltage-ride
through necessity. Solutions depends on installation of
STATCOM and Dynamic Voltage Restorer(DVR) as well as
advanced control functionalities for the existent power
converters of distributed generation plants ,have given to
improve response at distorted and faulty conditions to
satisfy these requirements. To get fast and accurate grid
voltage synchronization algorithmic rules under unbalanced
and distorted conditions. In proposed model synchronous
reference frame Phase Locked Loop (PLL), dual second order
generalized integrator PLL; Three-phase enhanced PLL
methods are used. Though early systems have used
frequency-locked loops, PLL’S have chosen their interlink
with dqo controllers. In this different algorithm rules are
executed and their performance can be tested with
experimental setup controlled and simulation can be done
suing MATLAB or in the form of SIMULINK. The results show
the effectiveness of proposed model at different algorithm
rules
Index Terms: Frequency estimation, Harmonic analysis,
Electric variable measurements, Monitoring, Frequency
Locked Loops, phase locked loop.
INTRODUCTION
Increase in penetration of technologies in
electrical network strengthen the existing methods among
transmission system operators their shape in grid stability.
The grid considerations are becoming un-permissiveness
for distributive generation systems. The grid code
requirements and constraints are gained importance for
these systems. These determine the fault boundaries for
which the grid system remain connected to connect. These
will give rise to specific voltage profiles and clearance time
of voltage sag that must withstand. Such requirements are
known as Low Voltage Ride Through and they are
represented by voltage versus time.
In this proposed model three phase advanced grid
considerations are choosen,The decoupled double
synchronous reference frame PLL(DDSRF PLL),the dual
second order generalized integrator PLL(DSOGI PLL),three
phase enhance PLL(3ph EPLL).Their performance
,reliability of amplitude and phase detection of positive
sequence voltage under distorted and unbalanced
conditions. The TSO’s provide active/reactive power
pattern to be injected into network during voltage sag. In
power systems synchronous reference frame PLL (SRF
PLL) is the most extended technique for synchronizing
three phase systems.
II. GRID SYNCHRONIZATION SPECIFICATIONS
BASED ON GCR
The fault detection can be done using algorithmic
rules the importance of advanced grid synchronization
systems lies in the necessity of having accurate
information about the magnitude and phase of the grid
voltage during the fault, in order to inject the reactive
power required by the TSO. According to German
standard, it is stated that voltage control must take place
within 20 ms after the fault recognition, by providing a
reactive current on the low voltage side of the generator
transformer to at least 2% of the rated current for each
percent of the voltage dip, as shown in Fig. 1. 100%
reactive power delivery must be possible, if necessary.
Fig. 1. E-on voltage support requirement in the
event of grid fault.

A similar condition is given in the Spanish grid
code, where the wind power plants are required to stop
drawing inductive reactive power within 100 ms of a
voltage drop and be able to inject full reactive power after
150 ms, as shown in Fig. 2. Considering these demands,
this paper will consider that the estimation of the voltage
conditions will be carried out within 20–25 ms, as this
target permits it to fulfil the most restrictive requirements,
in terms of dynamical response, available in the grid codes.
Fig. 2. REE voltage support requirement in the
event of grid fault
III.DESCRIPTION OF THREE SNCHRONIZATION
SYSTEMS
The positive sequence detection algorithm based
on synchronous reference frame PLL (SRF PLL).Even
though system is god under balanced condition the
response is insufficient under faulty conditions, their
operation capability is high in frequency stability which is
uncongenial with the idea of full-bodied synchronization
system. There are different models to overcome the
problems of classical PLL using frequency and amplitude
adaptive structures that deal with faulty and unbalanced
conditions.
A.DDSRF PLL:
It was developed from conventional SRFPLL; three
synchronization frames are rotating one in clockwise and
other in anti-clockwise direction to detect positive and
negative sequence voltages under unbalanced conditions.
When three phase grid voltage is unbalanced, the
positive sequence voltage appears as dc voltage on dq+1
axes of positive sequence SRF and negative sequence
voltage appears on dq-1 axes on negative sequence
SRF.Since amplitude oscillation of positive sequence
should match with negative sequence dc voltage and vice
versa. A decoupling network is applied to signal on dq
positive/negative axes in order to reduce ac oscillations.
The components collect information about amplitude and
phase angle of both positive and negative sequence
components.,
Finally, the PI controller of the DDSRF PLL works
on the decouple q-axis of the positive sequence of vq+1
and performs the same function in SRF PLL, Assign
positive-sequence voltage with d- axis. This component is
free of ac components due to decoupling network, the
bandwidth of lop controller can be increased.
Fig. 3. DDSRF-PLL block diagram
B.DSOGI PLL
The principle of DSOGI PLL to estimate positive and
negative sequence components of grid vectors is based on
using instantaneous symmetrical component method on
the stationary reference frame. To apply ISC method, it is
necessary to have signals like Va-Vb representing the input
voltage vector. In this DSOGI PPL the signals are supplied
to ISC method can be obtained by DSOGI
Fig. 4. DSOGI-PLL block diagram.
C.3PH ENHANCED PPL
It is a synchronization system that has good results over
multiple single phase synchronization system. It is
essentially a band pass filter that can be able to control
cut-off frequency as a function of input signal. It can be
adopted in three phase signal positive sequence obtaining
3PHEPPL is shown in fig.
In this each voltage is independently processed and filters
input signal and generate two sinusoidal outputs of same
amplitude and frequency V’n and jv’n the second one being

90degreeswith respect to V’n.The output result establish
the input for computational input. The positive sequence
voltage component V+abc can be determined.
Fig. 5.3phEPLL block diagram.
IV.TESTING AND EXPERIMENTAL SETUP
The different algorithms are implemented in a control
board using floating-point Texas instruments
TMS320F28335 DSP at 150MHZ.The fat and accurate
synchronization can be tested under faulty conditions
where three phase waveforms experience transients due
to voltage sag, frequency variations and harmonic
pollution. Unbalanced and distorted input voltages were
generated by means of ac programmable source and
auxiliary transformer. Six represented faulty and distorted
conditions are selected to evaluate three synchronization
systems under test.
1) Type “A” Sag Test: In this voltage sag appears as a
consequence of three-phase faults that give rise to high
short circuit currents and to a balanced voltage drop in the
network. The DDSRF PLL and the DSOGI PLL produce a
good response, as both systems achieve a very fast
detection (20 ms) of the positive-sequence components
(less than two cycles). The response of the 3phEPLL,
depicted also shows a good response, but with a larger
transient in the positive-sequence estimation.
2) Type “B” Sag Test: This kind of fault permits analyzing
the behaviour of the PLLs under test in the presence of
zero sequence components at the input. The Clarke
transformation used in DSOGI PLL and DDSRF PLL to
extract the αβ components enhances the response of this
synchronization system when the faulty grid voltage
presents zero-sequence components. Their responses are
fast and accurate. On the other hand, the 3phEPLL does not
cancel out the zero-sequence component from the input
voltage, something which may affect the dynamics of the
positive-sequence estimation loop. However, this effect is
further attenuated by the computational unit; the steady-
state response is also reached with no great delay,
3) Type “C” and “D” Sag Tests: These kinds of sags appear
due to phase-to-ground and phase-to-phase short circuits
at the primary winding of the transformer, respectively, as.
In a distribution network, these distortions are more
common than the previous ones, as they are the typical
grid faults caused by lightning storms. All three PLLs
permit detecting the positive sequence between 20 and 30
ms; however, the 3phEPLL has a slower stabilization. This
effect is a bit more noticeable with the “C” sag, where the
combination of the phase jump and the magnitude change
of two phases occurs.
B. Frequency Changes (50–60 Hz)
In this experiment, similar results are obtained
with the DDSRF and the DSOGI PLL. The low over shooting
in the amplitude estimation in both cases assists the good
phase and frequency detection, Likewise, the response of
the 3phEPLL shows a similar settling time; however, the
initial oscillation in the amplitude estimation of the voltage
contributes to slightly delay.The stabilization of the
frequency magnitude, as displayed.
C. Polluted Grids (THD = 8%)
The 3phEPLL behaves as a band pass filter for the
input Signal, Something that permits filtering the input
without adding extra filters. The 3phEPLL offers the best
filtering capability among the PLLs under test, with a clear
and undistorted estimation of the magnitude and phase of
the input. The response of the DDSRF PLL, which has a
first-order filter at the output, is even better than the one
provided by the DSOGI PLL, due to the latter’s low pass
filtering behavior. Although the DSOGI PLL also behaves as
well as a band pass filter, the tuning of its parameters,
which permits a faster stabilization of the estimated signal
in the previous tests, plays against its immunity in front of
harmonics giving rise to small oscillations in the positive-
sequence estimation.
SIMULATION DIAGRAM
FIG.6.SIMULATION DIAGRAM OF PROPOSED SYSTEM

Fig.7.System Voltage under Three Phase Fault (LLLG) for
DSOGI-PLL, DDSRF-PLL and 3phEPLL
Fig.8.Voltage magnitude and Theta of the system by using
DSOGI-PLL under three phase fault
3ph EPLL under three phase fault
DDSRF-PLL under three phase fault
Fig.11.System voltage under Line to Ground Fault for
DSOGI-PLL, DDSRF-PLL and 3phEPLL (case1)
3phEPLL under Line to ground fault
Fig.13.System voltage under Line to Line fault for DSOGI-
PLL, DDSRF-PLL and 3phEPLL
DSOGI-PLL under Line to Line fault

DDSRF-PLL under Line to Line fault
3phEPLL under Line to Line fault
Fig.17.System Voltage under Phase to Ground Fault for
DSOGI-PLL, DDSRF-PLL and 3phEPLL (case2)
DSOGI-PLL under Line to ground fault
DDSRF-PLL under Line to ground fault
3phEPLL under Line to ground fault
Polluted Grids (THD)
Fig.21.System voltage under polluted grid condition for
DSOGI-PLL, DDSRF-PLL and 3phEPLL
DSOGI-PLL under Polluted Grid

DDSRF-PLL under Polluted Grid
3phEPLL under Polluted Grid
Fig.25.Total Harmonic Distraction (THD) of polluted grid
in DSOGI-PLL
in DDSRF-PLL
in 3phEPLL
Frequency Changes (50–60 Hz)
Fig.28.Amplitude, phase (rad), and frequency detection for
the DSOGI PLL
the DDSRF PLL
the 3phEPLL

COMPARISON OF DDSRF, DSOGI AND 3PH EPLL
CONCLUSION
Finally simulation done at different algorithms
with advanced PLL techniques i.e,DDSRF,DSOGI,3PH
EPLL.The immunity of polluted network is better when
using the 3phEPLL and the DDSRF, due to their greater
band pass and low-pass filtering capabilities. As DSOGI is
affected by harmonics because of inherent band pass
filtering structure. Because of low cost DDSRF PLL and the
DSOGI PLL together with their easy estimation of the
voltage parameters, offers a better tradeoff between the
presented systems, making them particularly suitable for
wind power applications. The simple structure of DDSRF
and DSOGI are easier to tune control parameters and
accurate in control of transient response.
REFERENCES
[1]A. Zervos and C. Kjaer, Pure Power: Wind Energy
Scenarios for2030. Brussels, Belgium: European Wind
Energy Association (EWEA), Apr. 2008. [Online]. Available:
http://www.ewea.org/index.php?id=11
[2] “Grid code—High and extra high voltage,” Bayreuth,
Germany.Apr. 2006. [Online]. Available:
http://www.pvupscale.org/IMG/pdf/D4_2_DE_annex_A3_
EON_HV_grid__connection_requirements_ENENARHS2006
de.pdf
[3]PO-12.3 Requisitos de Respuesta Frente a Huecos de
Tension de lasInstalaciones Eolicas, Comisión Nacional de
Energía, Madrid, Spain,Oct. 2006.
[4]M. Tsili and S. Papathanassiou, “A review of grid code
technical requirements for wind farms,” IET Renew. Power
Gen., vol. 3, no. 3, pp. 308–332,Sep. 2009.
[5]F.Iov, A. Hansen, P. Sorensen, and N.Cutululis, “Mapping
of Grid Faults and Grid Codes,” Risø Nat. Lab., Roskilde,
Denmark, Tech. Rep. Risoe-R-1617, 2007.
BIOGRAPHIES
CH.Dinesh,received B.Tech from
Priyadarshini Institute of Technology,
AP, India.Currently pursuing M.Tech at
Priyadarshini College of Engineering
Technology, Nellore, AP, India. The
research interest includes Electrical
power Control and Energy Efficiency.
Mr.V.Anjaneyulu, received M.Tech
from JNTU Kakinada. His area of interest
includes Power System Stability and
Power Systems deregulation.He is
working as Asst. Professor at
Priyadarshini College of Engineering &
Technology, Nellore, AP,India.

Synchronization of Grid Voltage for Solar and Wind Distributive Systems Under Grid Faults by using Advanced Phase Locked Loop Techniques

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Synchronization of Grid Voltage for Solar and Wind Distributive Systems Under Grid Faults by using Advanced Phase Locked Loop Techniques