Smarter GridOps with Synchrophasors - Chalmers · Freq change means: Sudden Gen-Load MW imbalance somewhere in the grid X-ray Phasor data (PMU) Refresh rate 30-60 samples/sec Time

Copyright ALSTOM Grid

Smarter Power Grid Operations with

Synchrophasors

Jay Giri [email protected]

March 29th, 2012

2012

The Next Generation Energy Management System (EMS)

mailto:[email protected]

Copyright ALSTOM Grid Copyright ALSTOM Grid

The Interconnected Power Grid… Thoughts to ponder..

“The interconnected electric power grid is one of the most complex real-time, 7x24, engineering machines in existence today!” Millions of equipment components need to work in concert, to get power from the source to the customer, around the clock!

“Operating the power grid is not rocket science…

It is much more than that!!“

Terry Boston, CEO PJM


Greatest Engineering Achievements: Of the 20th Century

20. High-performance materials

19. Nuclear technologies

18. Laser and fiber optics

17. Petroleum and petrochemical technologies

16. Health technologies

15. Household appliances

14. Imaging

13. Internet

12. Spacecraft

11. Highways

10. Air conditioning and refrigeration

9. Telephone

8. Computers

7. Agricultural mechanization

6. Radio and television

5. Electronics

4. Water supply and distribution

3. Airplane

2. Automobile

As voted by the US National Academy of Engineers in 2001

#1. Electrification

“Electricity is a key Prime-mover which Drives Society ”



L. Fink, K. Carlsen, IEEE Spectrum, March 1978

Secure

A-Secure

System not intact System intact

Reduction in reserve margins and/or increased probability of disturbance

Restorative Resynchronization

E I

Emergency Heroic Action

E I

System splitting and/or load loss

In extremis Cut losses, Protect Equipment

E I

Normal Objective: Load tracking, cost minimization, system coordination

E I

Insecure Alert Preventive Control

Violation of inequality constraints

E I

E = Demand is met

I = Constraints are met

Power System Grid Operating States


Sources of Grid Vulnerability

• Natural calamities

• Component failures, communication link failures

• Protection and control failures

• Faults

• Human errors

• Inadequate security margin

• Gaming in the market

• Missing or uncertain information

• Sabotage or cyber-intrusion by external agents • http://www.digitalbond.com/2012/01/30/documenting-the-lost-decade-ics-vuln-analysis/#more-10966 • http://www.us-cert.gov/control_systems/pdf/ICS-ALERT-12-046-01.pdf

http://www.digitalbond.com/2012/01/30/documenting-the-lost-decade-ics-vuln-analysis/
















The Reality We Face….

“Blackouts will occur again in the future”….

− Our power grids are too complex to make it fail-safe!

Our challenge is:

− To Prevent the Cascading, Uncontrolled Spread of an initiating blackout!

− And more importantly: To Restore power to affected customers ASAP!


The Grid Operation Challenge!

1. Electricity as a Commodity Cannot be Stored!

2. Electricity Demand changes from instant to instant

3. Supply needs to change instantaneously to meet Demand… − Otherwise, Frequency goes off-normal (not 60Hz)…

resulting in:

• Protective relay trips of generating units, loads, etc.

• Potential trigger for a cascading blackout..


Economics Reliability

9

Electric Utilities Goal – Balancing Reliability and Economics



Automation Products ‘Meter to Market’

EMS Components


EMS Views of the Grid

Asynchronous, Uncorrelated,

Telemetry view SCADA

System-wide, correlated

Existing system-wide view

Generation, Ties

Energy Balance (Freq) view

What is coming up next

Future system-wide view

AGC

SE & CA

DTS


Control Center Operator



The emerging, new power grid paradigm

Growth of Synchrophasor Measurements

From Phasor Measurement Unit (PMU) devices


What is SynchroPhasor Technology?

− Next generation measurement

technology. (voltages, currents, frequency,

frequency rate-of-change, etc)

− Higher resolution scans (e.g. 30 samples/second). ─ Improved visibility into dynamic grid conditions. ─ Early warning detection alerts

− Precise GPS time stamping. ─ Wide-area Situational Awareness. ─ Faster Post-Event Analysis.

“MRI quality (3-D color) visibility of power

system, compared to X-ray (2-D b/w) quality

visibility of SCADA” – Terry Boston (PJM)

PMU Resolution

SCADA Resolution

Phasor Measurement Units (PMUs)


Leverage Enabling Technologies… PMUs measure voltages & currents - magnitudes & angles

SCADA data

Refresh rate 2-5 seconds

Latency and skew

‘Older’ legacy communication

Responds to quasi-static behavior

Freq change means:

Sudden Gen-Load MW imbalance

somewhere in the grid

X-ray

Phasor data (PMU)

Refresh rate 30-60 samples/sec

Time tagged data, minimal latency

Compatible with modern communication

technology

Responds to system dynamic behavior

Angle-pair change means:

Sudden MW change in a

specific location of the grid

MRI

Courtesy EIPP, NASPI

Earlier Information for Better Decisions


The changing US landscape

Synchrophasor measurement devices are being deployed aggressively in the US and globally − By 2012, will be a five-fold increase in PMUs across US –

over 1000 PMUs deployed − Each PMU provides 10-12 separate sub-second

measurements − Measurements include voltages, currents and frequencies − Augments traditional 2-4 second SCADA


As PMUs grow relative to existing SCADA..

The utility industry will benefit with a:

• A time-synchronized snapshot of grid conditions at a sub-second rate

• Improved wide-area monitoring systems (WAMS) and future wide area control (WAC) – a self-healing grid!

The next SCADA frontier – “fast, sub-second measurements and fast, automated controls”


Impact of Synchrophasors

on Grid Operations

An Unprecedented Transformational Change:

• to help operate the grid more efficiently & reliably

• to facilitate integration of Green energy resources with variable generation outputs


Where in the grid should we deploy PMUs?

19

Key T

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Key P

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Sep

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Majo

r

Gen

erati

on

or L

oad

Co

ng

esti

on

Man

ag

em

en

t

Win

d

Inte

grati

on

Oscilla

tio

ns

FA

CT

S

Co

ntr

ols

ENTER Business

Priority Weight for

Column Category

2 2 1 1 2 1 2 2 2 3 1

Data Rates

(samples/second)1 1 1 1 10 - 30 10 - 30 10 - 30 10 - 30 60 - 120

123 500.0 ABC ABC 2 1 1 3 7

455 500.0 XYZ ZYZ 2 1 1 2 3 9

Total 2 PMUs

PMU Siting Spreadsheet

Sta

te E

sti

mati

on

Situational Awareness PriorityBus KV level Station Name

Sta

tio

n A

lread

y

Netw

orked

SCORE

(Priority)

Sta

tio

n A

lread

y

CIP

Co

mp

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t



Why PMU-based analysis?

Improve Security

EARLY WARNING OF

INSTABILITY

SITUATIONAL

AWARENESS

ISLANDING RECOVERY

BLACKSTART

SELF-HEALING GRID

Increase Transfer

RELIEVE DAMPING

CONSTRAINTS

STATE ESTIMATION &

CONTINGENCY ANALYSIS

IDENTIFY LINE

PARAMETERS

System Analysis

PSS TUNING

PLANT COMMISSIONING

POST-EVENT ANALYSIS

IMPACT OF RENEWABLES

IDENTIFY DYNAMICS

ISSUES

PSS

ENABLED

PSS

DISABLED



Holistic Generalized Grid Security Analysis

Control Center -PDC

PMU

MEASUREMENT-BASED Analysis

(PhasorPoint)

Traditional

MODEL-BASED Analysis

(EMS)

SCADA

& Alarms WAMS

State

Estimator

State

Measurement

Other EMS

Applications

New

Applications

Small Signal

Stability

Oscillation

Monitoring

Transient

& Voltage

Stability

Stability

Monitoring

& Control


e-terrastability

Dynamic Security Assessment

Transient Stability Analysis

Small Signal Stability Analysis

Voltage Stability Analysis

EMS Integrated with SynchroPhasor Solutions

G G

SynchroPhasor Applications

Framework (PhasorPoint) – Oscillatory Stability Monitoring

– Disturbance Detection

– Composite Events

– Islanding/Restoration/Blackstart

– Post-Event Analysis, Baselining

PMU Data

(30-60 per second)

PMUs

PMUs

PMUs

PMU Data

(1 per second)

Wid

e-Area A

dvan

ced V

isualizatio

n

e-te

rravis

ion

Energy Management System (EMS) – Improved State Estimation

–Grid Security Assessment

–SynchroPhasor State Estimator

e-terratransmission

SE snapshot (1 per min)

PMU based Information/Alerts (few seconds)

FACTS

Damping

control

IEC 61850

Real-Time

Controls

Phasor Data

Concentrator

PDC


Integrated “measurement-based” &

“model-based” Stability Analysis….

A very nice marriage!

PMU Measurement-based analysis

PhasorPoint

PREDICT & MITIGATE

TRUE

LIMIT

GRID

OPERATING POINT

Model-based analysis:

Corrective actions based on ‘what-if’ analysis

EMS

Limit

NEW

Limit


PMU Benefits to Grid Operations

Situational awareness tools

− Advanced visualization − Early warning detection alerts − Quick, reliable assessment of system during emergencies

Integration of PMU’s in State Estimator

− Voltage & current phasors as part of SE solution − State Estimator as a validation tool, as PMUs are deployed − Improved subsequent network analysis and optimization

Fast online stability solutions

− Small signal Oscillation Monitoring • Detection of poorly damped oscillations & control recommendations

− Voltage Stability margins − Transient Stability margins

Disturbance Locator

− Triangulate PMU and SCADA information to precisely locate where a disturbance originated

Identification of coherent groups of generators

− Recommendations for Online Adaptive islanding

Improved forensic analysis

− Post-event recreation − Improved restoration procedures

24


New EMS applications – using only PMU data

Uses PMU data at the sub-second rate

Oscillation Monitoring

Grid-wide Disturbance Locator

Fast Stability Analysis & Control

25


Oscillatory Stability Management

1/F MODE FREQUENCY

MODE AMPLITUDE

A

MODE DECAY TIME

EXP(-t/ )

MODE PHASE

Mode Frequency

Mode Amplitude

Mode decay time

Mode Phase

Exp(-t/)

Measured P / f /

Simultaneous multi-oscillation detection and characterisation direct from measurements

For each oscillation detected, alarm on:

mode damping and/or

mode amplitude for

Operations

Planning & Analysis, Plant Performance

Unlimited oscillation frequency sub-bands

Individual alarm profiles for each sub-band

Post-event analysis

Dynamic model validation

Damping controller performance assessment

Dynamic performance baselining

Early warning of poor damping (two level alarms)

Fast Modal Analysis: Alarms

Trend Modal Analysis: Analysis

Wide area mode alarms Mode locus plot with alarm thresholds

Copyright ALSTOM Grid 27

Disturbance Location

Use PMU and to triangulate & precisely locate

the origin of the disturbance

A sudden disturbance causes a traveling wave that can be detected by PMU data across the grid:

Source: VirginiaTech FNET

Disturbance Location


Visualization of dynamic clusters and frequency

28


Dynamic Dashboard: Current area of interest



PMU angle differences



Contour: area Voltage

Query: station voltages

Flyout: SCADA 1-lines

Power flow animation

Integrated SCADA & GIS Displays



Voltage Stability – Locations & Controls



Where are the VAR sources?



Oscillation Modes & Damping



Weather Radar Overlay



Today:

Protecting the Power System Grid

To “Keep the Lights On! “

Local, Device protection predominantly: − Transformers, lines, bus structures, generating units, etc

System-wide, Grid protection: − AGC: Automatic Generation Control

• A pioneering Smart-Grid application since the ‘70s!

• Automatically maintains system’s frequency and tie-flows

− Remedial action schemes (RAS), special protection schemes (SPS or SIPS), etc.

• Drawbacks are: − Logic is fixed and does not adapt to current conditions

− Are conservative by design; have to work for a wide range of 7/24 operating conditions


Tomorrow:

Wide Area Monitoring & Control, too!

Grid Protection, In the Future: − Develop protective control schemes

that dynamically adapt to current power system conditions, to preserve the integrity of the “grid” as an entity.

− Tightly integrate fast sub-second measurements with fast sub-second controls (FACTS, HVDC, etc)


Intelligent Decentralized Wide-area Grid Control



Grid Control Devices


Best

Adequate

Not

appropriate

J

L

K


Thank you…

Documents

Smarter GridOps with Synchrophasors - Chalmers · Freq change means: Sudden Gen-Load MW imbalance somewhere in the grid X-ray Phasor data (PMU) Refresh rate 30-60 samples/sec Time