Post on 02-Dec-2014
description
Dr. Sarasij Das
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This Presentation is based on the paper
Sarasij Das, and Tarlochan Sidhu, "Detecting Synchrophasors
Computed Over Fault/Switching Transients", IET Generation,
Transmission & Distribution,
http://digital-library.theiet.org/content/journals/10.1049/iet-gtd.2013.0493
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Brief overview of Wide Area Measurement
Systems (WAMS)
Proposed algorithm
Conclusions
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Voltage/current waveforms sinusoid in nature
Phasor = representation of sinusoid in complex
plane
Phasors estimated by measuring
- magnitudes
- phase angles
Traditional SCADA monitoring slow
One complete SCADA polling may take 2-10 s
Measurements are not time synchronized
Phase angle measurement no possible
Not suitable for system dynamics monitoring
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WAMS = PMU based monitoring systems
Synchrophasor = phasor + GPS time tagging
Synchrophasor = magnitude & phase angles
Synchrophasors used in system dynamics
monitoring
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Control Center
Voltage, Current Synchrophasors
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IEEE standard C37.118.1-2011[2] specifies
accuracy requirements for synchrophasors
IEEE standard C37.118.2-2011[3] specifies
message formats for communication data packets
IEEE standard C37.244-2013 [4] describes functional requirements for PDCs
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Context Synchrophasor validations mostly happen in
PDCs
Validation often offline and time consuming
Lack of samples makes validation difficult in PDCs
Lack of algorithms to compute synchrophasor quality at PMU
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Motivation
Fault/switching transient synchrophasors
computed over pre and post fault/switching
samples
Unusable in applications
Not easy to detect from values
1( ) 89.998
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1.0045( 1) 90.1340
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X k
X k
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Motivation
No existing Algorithm
However, Algorithms [1][5] can be used
Existing Algorithms [1][5] make wrong detections in
presence of harmonics, decaying dc
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Proposed low complexity algorithm to detect
fault/switching transient synchrophasor
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Suggested to apply on current signals
Success Rate
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X=Xm [1+ksx u(t-ts)]cos(ωot +ksa u(t-ts))
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Performance
during
Oscillations
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Performance
in presence of
missing samples
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Proposed algorithm performs satisfactorily
- during nominal and off-nominal frequencies
- in presence of harmonics, decaying DC
- in presence of oscillations, ramping
- in presence of a number of missing samples
- for estimation windows 2.5 cycles or
greaterPlease see the paper for additional results
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Algorithm has been proposed to tag fault/switching
transient synchrophasors
Proposed algorithm performs satisfactorily in various
scenarios
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1. “Synchronized phasor measurements and their applications”, by Arun G. Phadke, John Samuel Thorp
2. “IEEE Standard for Synchrophasor Measurements for Power Systems”, IEEE C37.118.1-2011, (Revision of IEEE Std. C37.118-2005)
3. “IEEE Standard for Synchrophasor Data Transfer for Power Systems”, IEEE C37.118.2-2011
4. “IEEE Guide for Phasor Data Concentrator Requirements for Power System Protection, Control, and Monitoring”, IEEE Std C37.244-2013
5. Sodhi, Ranjana, S. C. Srivastava, and S. N. Singh. "A transient monitor to reflect the quality of synchrophasors." Power and Energy Society General Meeting, 2010 IEEE. IEEE, 2010.
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