RVII Testing on Tenaga Power System - naspi.org · Quanta Technology(QT) and Tenaga Nasional Berhad (TNB) worked together on integrating RVII functionality with their OpalRT simulator,

Confidential & Proprietary | Copyright © 2015

Quanta Technology, LLC4020 Westchase Blvd.Raleigh, NC 27607, USAwww.quanta-technology.com


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

0 50 100 1500.86

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0.8System impedance, vs load impedance

System XLoad X

(a) (b)


RVII Algorithm Types

■ Bus RVII■ Area RVII■ Corridor RVII

• Leverages Bus RVII and analytical computation of the corridor to improve quality of Equivalent parameters


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


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


Problem Background ■ Three main power utilities in Malaysia: TNB, SESB & SEB


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


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.


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


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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Example 2: Interface @ Maximum Power Transfer

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• 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


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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System XLoad X

Very insignificant change in Thevenin Impedance


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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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


Concluding Remarks

■ Model-free algorithm, like RVII, requires extensive validation via simulation ahead of deployment

■ A Real-Time testbed, 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


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RVII Testing on Tenaga Power System - naspi.org · Quanta Technology(QT) and Tenaga Nasional Berhad (TNB) worked together on integrating RVII functionality with their OpalRT simulator,