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Confidential & Proprietary | Copyright © 2015
Quanta Technology, LLC4020 Westchase Blvd.Raleigh, NC 27607, USAwww.quanta-technology.com
Confidential & Proprietary | Copyright © 2016
RVII Testing on Tenaga Power System
Dino Lelic, Rahul Anilkumar, Boza Avramovic, Tony Jiang,Damir Novosel
Quanta Technology LLC
Nik Sofizan B Nik Yusuf , Sheikh Kamar Sheikh Abdullah,Muhammad Tarmizi Azmi , Mohd Khairun, Nizam Mohd
SarminTenaga Nasional Berhad
NASPI International Synchrophasor SymposiumAtlanta, GeorgiaMarch 22-24, 2016
Confidential & Proprietary | Copyright © 2016Slide 2
RVII Foundation
■ Just like a relay, real time computation that uses only local information (no network model needed)
■ Unlike a relay , able to avoid point #1 (figure a & b), and includes point #2
Fundamentally, local voltage instability detector
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System XLoad X
(a) (b)
Confidential & Proprietary | Copyright © 2016Slide 3
RVII Algorithm Types
■ Bus RVII■ Area RVII■ Corridor RVII
• Leverages Bus RVII and analytical computation of the corridor to improve quality of Equivalent parameters
Confidential & Proprietary | Copyright © 2016Slide 4
Uses of RVII’s System View■ Three stage approach to meet
objectives
■ Real Time voltage instability DETECTION
■ WHAT IF analysis:• Extrapolation
− Margin to Instability− Margin to Operating boundary
• Predictions− Margin to Instability− Margin to Operating boundary
Confidential & Proprietary | Copyright © 2016Slide 5
RVII Margins
■ Extrapolation• Constant power factor load increase
until boundaries reached• System equivalent params kept fixed
■ Prediction• Additional information used (hybrid of
RT model-less, and much slower model-based) − To define more accurately load change
path− To update equivalent parameters as a
function of load increase− Plot reactive power margin
■ RVII implements Extrapolation
Extrapolation vs. Prediction
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Operating PointOperation LimitCollapse Limit
Confidential & Proprietary | Copyright © 2016Slide 6
Problem Background ■ Three main power utilities in Malaysia: TNB, SESB & SEB
Confidential & Proprietary | Copyright © 2016Slide 7
Kulim
Lumut
Kuala Berang
TemerlohBentong
Gua Musang
Kuala Lipis
Jerantut
Muadzam Shah
Mentakab
Kuala Pilah
Segamat
Mersing
Kluang
Kuah
Sg. Petani
Dungun
Taiping
Teluk Intan
Kuala Selangor
Kuala Kubu Baru
Banting
Gemas
Muar
Batu Pahat
Pontian Kechil
Seri Iskandar
Kampar
Melaka
Seremban
Georgetown
Kota Bharu
Kuala Terengganu
Ipoh
Kuantan
Shah Alam
Kangar
JOHOR
PAHANG
MELAKA
NEGERI SEMBILAN
SELANGOR
PERAK
KEDAH
PULAU PINANG
KELANTAN
TERENGGANU
PERLIS
WILAYAHPERSEKUTUAN
LANGKAWI
PAHLAWAN
Pasir Gudang
BERSIAKENERING
TEMENGOR
KENYIR
SG PIAH UPPERSG PIAH LOWER
JOR
WOHODAK
CHENDEROH
PERGAU
Johor Bahru
PRAI
SEGARI
CONNAUGHT BRIDGE SERDANG
KAPAR
POWERTEK
PD POWER
GENTING SANYEN
TJPS
YTL
PASIR GUDANG
PAKA
YTL
Ayer Tawar
Batu GajahPapan
Kuala Kangsar
Bukit TambunJunjung
GurunBedong
Kota Setar
Chuping
Bukit Tarek
KL (N) KL (E)
Hicom G
KL (S)
Salak Tinggi
Melaka
Kg Awah
Skudai
Telok Kalong
Tanah Merah
Yong Peng (N)
ButterworthBukit Tengah
GELUGOR
JANAMANJUNG
TTPC
MELAKA
Gelang Patah
Alor Setar
High Load
Demand
Problem Background
Confidential & Proprietary | Copyright © 2016Slide 8
TNB Testing Background
■ Quanta Technology(QT) and Tenaga Nasional Berhad (TNB) worked together on integrating RVII functionality with their OpalRT simulator, which uses a complete transient stability model of TNB bulk power system.
■ Testing was extensive, using a combination of • Time domain transient simulations (PSS/E) in a preliminary tuning and testing
stage• Software in the loop simulations (OpalRT)
■ Tests clearly indicate the capability of RVII to correctly distinguish voltage stable from unstable cases• Referring to Slide #2, it correctly characterizes points #1 and points #2• For example, RVII was able to detect proximity to voltage instability when
relatively high voltages would have masked the actual proximity to voltage collapse if viewed only through SCADA data (or under-voltage relays).
■ Currently implementations of RVII algorithm in TNB’s embedder controllers are being carried out for Hardware in the loop testing.
Confidential & Proprietary | Copyright © 2016Slide 9
Offline Testing Environment■ Prior to RT Deployment, RVII
deployed in test environment• Comprehensive TNB transient
stability model used− PSSE – based
• Establish RVII locations, suitable inputs, and verify accuracy
■ At TNB • OpalRT-based “deployment”
− Entire TNB network− Physical and Virtual PMUs
• Next Step – in progress: − Implementation in TNBs
embedded controller− Hardware in the loop setup
List Branches (for flows and volts)For an RVII location
List of scenarios
(TNB approved)
PSS/E Dyn. Results
PSS/E case
(.raw, .dyr,.idev
fies)
PSS/E
Python Scripts/Response files
MATLAB/LINUX MONO ENVIRONMENT
RVII DLL/.P
Identify Volt-weak buses
MATLAB COM INTERFACE
ACCC tools, CON files
Input: PSSE case; output plots of Thevenin and “Load” Impedance
Confidential & Proprietary | Copyright © 2016Slide 10
Example 1: Interface @ base Power Transfer• Impact of outage at Zero Transfer Level on
critical TNB interface• This references post - outage condition• Low voltages in the vicinity of the study zone, but• Clear separation between Thevenin and Load
Impedances• The conclusion: system voltage stable• Fig. below shows system operating further
away (wider margin) from operational or collapse limits.
Note: in this case voltage was relatively low
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Operating PointOperation LimitCollapse Limit
Confidential & Proprietary | Copyright © 2016Slide 11
Example 2: Interface @ Maximum Power Transfer
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Operating PointOperation LimitCollapse Limit
• Impact of outage at Interface Transfer limit.• Path TTC limited by transient stability
problem.• RVII successfully detects instability• System is operating with close to zero
margins, at the boundary of instability limits.
RVII detects instability System operating at limits
Note: in this case voltage was relatively high
Confidential & Proprietary | Copyright © 2016Slide 12
Under-voltage Relay Example Double Contingency to Load Pocket■ Drastic action may be taken on voltages of 0.95 p.u to prevent instability. ■ RVII would show, however, that system is far from collapse (verified by PSS/E
time domain simulations).
UVLS Triggers
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Very insignificant change in Thevenin Impedance
Confidential & Proprietary | Copyright © 2016Slide 13
Stability Detection at Brink of UVLS Trigger
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System XLoad X
■ RVII successfully identifies separation between system and load impedances, indicating a stable system condition.
■ Absent RVII, drastic under-voltage action might be taken at voltages of 0.95 puto prevent instability.
UVLS Triggers Insignificant change in Thevenin Impedance
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Confidential & Proprietary | Copyright © 2016Slide 14
Loss of Source to Radial Load Pocket■ RVII successfully identifies separation between system and load
impedances, indicating a stable system condition even in scenarios with loss of source supply to radial load pocket.
■ Also verified through simulation (PSS/E), is the impact of additional dynamic compensation triggered within the load pocket that moves the system away from instability.
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System XLoad X
Confidential & Proprietary | Copyright © 2016Slide 15
Concluding Remarks
■ Model-free algorithm, like RVII, requires extensive validation via simulation ahead of deployment
■ A Real-Time test- bed, like the one available at TNB, or a batch simulation testbed as used in house is crucial to validate results
■ RVII in a pure model-free implementation is suitable for instability Detection and Extrapolation (both important when close to instability); Prediction (which is important when far from instability) requires a hybrid approach
■ Work being pursued in direction of contingency- based RVII --showing promising results.
■ Several applications leveraging benefits of RVII results, such as RVII-triggered load shedding, are currently being validated.
Quanta Technology, LLC4020 Westchase Blvd
Raleigh NC, 27607www.quanta-technology.com
Confidential & Proprietary | Copyright © 2016
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