WAMS Analytical Approach

WAMS Analytical Approach

By : Chandan Kumar Engineer ,WRLDC

What is WAMS

WAMS In WR Grid

WAMS Application

Under Development

at WRLDC

Few Real Time

Application

Whats More on the Way

15-Feb-13 WRLDC ,POSOCO

• It is based on Phasor measurement units (PMUs) which can deliver precisely time synchronized values of voltage and current phasors and other power system related quantities like frequency, ROCOF, breaker positions.

• It’s a collective technology to monitor power system dynamics in real time, identify system stability related weakness and helps to design and implement countermeasures . (IEEE)

What is WAMS ?


•Visualization and analysis tools •Wide area situational awareness system. •Wide area protection and control

•Phasor Measurement Unit (PMU) •Phasor Data Concentrator(PDC) •Global Positioning System (GPS for Time Synchronization of the phasors) • Communication channel( Preference to optical fiber cable )

Components of WAMS


Advantage of PMU

1 • More number of Samples(25-100 Phasors/sec)

2 • GPS Time Synchronized data to Control Centre from All Locations

3 • Finer View of the Electrical System

4 • Adaptive protection system can be developed

5 • Post Disturbance analysis with more accuracy which helps in planning.

6 • Many more …..


Lets Have a closer view of SCADA and PMUs

Attribute SCADA PMUs

Measurement Analogue Digital

Resolution 2-4 samples per second Up to 100 samples per second

Observability Steady State Dynamic/Transient

Monitoring Local Wide- Area

Phasor Angle Measurement No Yes


SCADA and PMU

Data from Present SCADA (Second Information , No time synchronization)

Millisecond Information with time synchronization


X-Ray vs. MRI of the GRID

PMU+Visulization+Analysis+ GIS + Data

(Source : California ISO and OSIsoft LLC)


Technology can Change what we See : Lets See How

Situational Awareness : Be preplanned rather than to wait

(Source : Space Time Insight)


On our Path to Make the grid Smart and safely operate we have :

• PMU data

• RTU data

• GIS data

• Meteorological dept data

• Outage data

• Market data

So now We have BIG DATA

Need to Analyse Process VisualizeOperate


Lets visit the world of PMU Advancement

Real-time Applications •Wide-area situational awareness •Frequency stability monitoring and trending •Power oscillation monitoring •Voltage monitoring and trending •Alarming and setting system operating limits, event detection and avoidance •Resource integration •Real time Dynamic State estimation •Dynamic line ratings and congestion management •Outage restoration •Operations planning

More Visual Aids rather than Watching Number for Operators : A change that is required with increase in the system Complexity and Big Data


Contd..

Offline Application • Base lining power system performance

• Event analysis

• Dynamic system model calibration and validation

• Power plant model validation

• Load characterization

• Special protection schemes and islanding

• Primary frequency (governing) response


WAMS in Western Region

• 5 PMUs(1 Nos. Bhadrawati, 2 Nos. Jabalpur, 2Nos Raipur)

• Different Vendors : GE,SEL,NI (More on way like Hitachi, Qualitrol)

• PDC : OpenPDC, GE PDC (planning for iPDC and OSIpi)


Application under development @ WRLDC

Data Analysis Information Planning Decision Implementation


•Oscillation Monitoring Systems •Model validation. •Dynamic Line Loadability. •Voltage stability analysis. •Dynamic & hierarchical State estimation •Wide area situational awareness. •Online stability assessment – Early warning.


Application 1 : Oscillation in Grid

Spring Mass System It oscillates with frequency

f = 1/2π (√(k/m)) Only one mode of frequency

•In Similar manner electrical grid has electrical inertia connected by AC lines. So have modes of oscillation due to non-linearity of the system.

Mass-Rod system No oscillation

•In similar manner system connected with DC lines do not oscillate with each other


What oscillation are observed in Electrical Grid ?

Small Signal Stability

Local

(Intra Area)

Local plant mode

(0.7 - 2.0 Hz)

Inter-Unit

(1.5-3.0 Hz)

Global

(Inter Area)

very low frequency

(0.1 to 0.3 Hz)

Higher frequency

(0.4 to 0.7 Hz)


What Methods are used by WRLDC ?

Methods Techniques Event

PMU Data

Modal

Prony

Matrix Pencil

FDD (Frequency Domain

Decomposition)

FFT


Why such oscillations poses threat to the system

• In normal power system state such LFO (Low frequency Oscillations ) are well damped.

• However they get excited during any small disturbance in the system and lead to oscillation in power system parameters like rotor velocity, voltages, currents and power flows.

• Due to oscillations in parameters, protection of equipments may operate leading to cascade tripping in power system.

• That’s why the observation of such modes is very essential in respect to system reliability and security.

• Among these parameters the rotor velocities of the generators and the power flows in the network are the most important.

• The rotor velocity variation causes strain to mechanical parts in the power plant and should be limited.

• The power flow oscillations may amount to the entire rating of a power line as if they are superimposed on the stationary line flow it will limit the transfer capacity by requiring increased safety margins.


• HVDC Damping Controller

• TCSC POD Tuning

• PSS Tuning of generators

• Proper Planning of transmission lines to Strengthen the transmission network.

• Need to adapt Global PSS Tuning

Actions Required to Damp such Oscillations


Application 2 : GRID INERTIA CALCULATION


•Incident :Talcher-Kolar Pole 2 Blocked on 19-05-12 16:14Hrs. •System Frequency before operation of SPS(fo) : 50.21121 Hz •Generation Loss(PL-PG) : 716.875 MW (SPS Operation) •Generation of NEW grid after Tripping (PG): 81092.99 •df/dt observed from PMU =-0.02455 Hz/sec

H= 9.04 Seconds (Nearly matched with the calculated Value)

Help in defining the response required from generation and load during such disturbance

Application 3 : Phase Angle Measurements and its importance


Load

Generation

What Causes Power to Flow in the Grid

DC power system - Power flows from a point of high voltage to a point of low voltage.

AC power system - Power flows from a point of high voltage angle to a point of low voltage angle. The higher the angle the greater the power flow.

What more we are working on


Collective effort from Operators-Academia-Industry to develop good PMU tools for analysis Cloud computing for analysis Performance of PMUs from different vendors Latency rate of PMUs depending on communication channel used Establishment of WAMS Lab Voltage collapse analysis using PMUs Looking for collaboration from all.

Please Find more detail on application in “Synchrophasors Initiative in India”

By POSOCO.

: [email protected] Mob No : 09869251460

Thank You
