A Synchrophasor-and-Active-Load-Based Oscillation Damping ... · A...

A Synchrophasor-and-Active-Load-Based Oscillation Damping Controller Hardware Prototype for the Icelandic Power System

Guðrún Margrét Jónsdóttir, [email protected]

Muhammad Shoaib Almas (supervisor), [email protected]

Luigi Vanfretti (professor), [email protected]

22-24th March 2015NASPI Work Group Meeting

mailto:[email protected]



https://www.wikipedia.org/

Iceland

2www.telegraph.co.uk

www.icelandluxury.com

www.boredpanda.com

icelandintro.is

www.bluelagoon.com

https://www.wikipedia.org/

http://www.telegraph.co.uk/news/picturegalleries/worldnews/10258908/Splendid-Iceland.html

http://www.icelandluxury.com/

http://www.boredpanda.com/stunning-landscape-photography-iceland/

http://icelandintro.is/

http://www.bluelagoon.com/gallery/

Motivation

3

-> Heavily loaded and aging infrastructure

-> Poorly damped inter-area oscillatory modes.

Load disconnection

0.4 Hz oscillation

Line Trip

0.3 Hz oscillation

Icelandic Power System

Idea:Control the load of aluminium smelters.

3

Assumptions and limitations The study was limited to only one inter-area oscillatory mode at a time.

The Icelandic system, and most other power systems, have several modes that need to be considered.

The tests were carried out using the two-area four-machine Klein-Rogers-Kundur power system model.

Resembles the Icelandic network.

The aluminum smelter load were not modelled in detail.

Aluminum smelters are represented using three phase dynamic loads.

The load could be increased and decreased instantaneously.

Aluminum smelters load demand can be increased instantaneously, however, their power output needs to be modulated within equipment constraints.

4

• Determine the maximum and minimum.

• Determine whether to increase or decrease.

The Load Control Algorithm

d/dt

max

minLoad control algorithm

Load ModulationPhasor

POD

Local/Remote Measurements

Oscillatory Content Load Change

SignalSwitch>0

Sinus waveDerivative

Phasor POD

• Separates the oscillatory content from the average value of the input signal.

• Requires to specify the frequency of oscillation.

• Offers phase compensation.

Find the derivative Load Modulation

5

Requirements

System DesignOffline Simulation

Software DevelopmentSoftware-in-the-Loop

System

System TestHardware-in-the-Loop

Component Test

Hardware-in-the-Loop

Validation

Verification

Design and Softw

are Developm

ent Har

dwar

e-in

-the

-Loo

p Te

stin

g

MATLAB & Simulink LabVIEW

The algorithm testing approach

6

7

Hardware-in-the-LoopSoftware-in-the-Loop

1. Real-time execution of power system model.2. Send Voltage and Current signals to PMU.3. The PMU forwards the data to the PDC.4. S3DK unwraps the PDC stream to access raw measurements.5. Load control algorithm deployed on the NI-cRIO. 6. Send Load modulation signal back to the RTS.

Real-TimeSimulator

SEL-487 E PMU

Communication Network

(Managed Ethernet Switch)

PMU Stream

Phasor Data Concentrator (PDC)

Legend

HardwiredHardwired

PMU streamPMU stream

PDC streamPDC stream

Feedback SignalFeedback Signal

Bypass Amplifiers Connect to Low-level

Input on the PMU

Load Modulation

Two Area Kundur Test System simulated on the

Real-Time Simulator

1.

2.

3.

4.

5.

6.

G1

G2

Area 1

Local Loads

220 Km Parallel Transmission Lines

Power TransferArea 1 to Area 2

G3

G4

Local Loads

Area 2

Control Load in Area 2

d/dt <0

max

min Load control algorithm

Load Modulation

Phasor POD

Local/Remote Measurements

Oscillatory Content Load Change

SignalSwitch

To External controller

MATLAB/SimulinkSimPowerSystems

Model Design

OPAL-RT‘s eMEGASIM Real-Time Simulator

d/dt <0

max

min

Phasor POD

Switch

G1

G2

Area 1

G3

G4

Area 2

Control Load in Area 2

64 Analog Out

16 Analog In

Simulator Analog and Digital I/Os

OP 5251 (64 DO)

OP 5251 (64 DI)

1.

2. 3.

4.

5.

1. The power system model and the load controller are simulated on two separate cores on the RTS.

2. Load modulation signal from Load controller model in Simulink is configured to one of the DOs of the RTS.

3. Digital Output and Input are looped back.

4. Load modulation signal is received by one of the DIs of the RTS and configured to change the load.

5. Workstation with RT-Lab software for monitoring the RT simulation.

The power system model in MATLAB/SimulinkArea 2 in the power system model in MATLAB/Simulink

The load controlled in Area 2

The load control algorithm implemented in MATLAB/SimulinkThe load control algorithm implemented in LabVIEW FPGA

Analog OutAnalog In

OP5142EX1 Ctrl

Board index: 0

Mode:Master

Error

IDs

OpCtrl OP5142EX1

Slot 1 Module B Subsection 1

Volts

Status

OP5142EX1 AnalogIn1'OP5142EX1 Ctrl'

Slot 2 Module A Subsection 2Volts

OP5142EX1 AnalogOut3'OP5142EX1 Ctrl'

Measurements Area 1

Measurements Area 2

I/O blocks added to real-time model of the power system

7

RTS

PDC interface

SEL PMUs

NI-cRIO

The Lab Setup

8

The prototype controller design

Network communication

Raw synchrophasors

LabVIEW Networkpublished Shared Variables

Input Signal Selection

PhasorPOD

Load ControlAlgorithm

NI-cRIOPC

RT processor FPGA

20ms 100µs20ms

LoadModulation

AnalogOutput

C37.118

Three level design:1. Remotely run VI

• Runs on a PC.• S3DK used to unwrap PDC stream

2. Real-Time Software VI• Runs on the real-time processor of

the cRIO.• Manages the signal selection.

3. Core FPGA Software VI• Runs on the FPGA • The load control algorithm

implemented.

1.2.

3.

9

Controller performance for different inputs (Local & Wide-Area)

10

G1

G2

Area 1

Local Loads

900 MVA

900 MVA 900 MVA20 kV / 230 kV

25 Km 10 Km

900 MVA20 kV / 230 kV

967 MW100 MVAR (Inductive)

-387 MVAR (Capacitive)



10 Km 25 Km

900 MVA900 MVA20 kV / 230 kV

G4900 MVA

20 kV / 230 kV 900 MVA

Area 2

Bus1 Bus2

Local Loads



Phasor POD

Load Control

Algorithm

Local/RemoteMeasurement

Oscillatory Content

Load Modulation

PMUM1

PMUM2

G3PMUM3

PMUM4

PMUMiddle

PMUA1

PMUA2

Input signal 1: 𝑃12

Input signal 2: 𝑉𝐴𝑟𝑒𝑎1+


Input signal 4: 𝐼𝐴𝑟𝑒𝑎1+


Input signal 6: 𝑉𝜑𝐴𝑟𝑒𝑎1 − 𝑉𝜑𝐴𝑟𝑒𝑎2

Input signal 7: 𝑉𝑀1+𝑉𝑀2

2−

𝑉𝑀3+𝑉𝑀4

2

Input signal 8: 𝑉𝜑𝑀1+𝑉𝜑𝑀2

2−

𝑉𝜑𝑀3+𝑉𝜑𝑀4

2

ΔVref G1

Input Signal

Decay Ratio

Overshoot[MW]

Undershoot [MW]

Settling Time [s]

1. 0,906 32,3 -42,8 6,13

2. 0,906 63,0 -45,8 6,63

3. 0,907 42,8 -44,3 6,50

4. 0,904 34,6 -44,4 6,10

5. 0,904 34,5 -43,6 6,06

6. 0,905 35,0 -45,0 6,15

7. 1,009 66,5 -64,0 32,81

8. 0,904 32,6 -47,2 5,31

Decay Ratio: The ratio between the peak of the first and nextoscillation.Overshoot: Highest deviation of active power transfer.Undershoot: Lowest deviation of active power transfer.Settling Time: The time at which the oscillations have decreased to avalue that is within 1% change from the original active power transfer.

Software-in-the-Loop58 60 62 64 66 68 70 72

300

350

400

450

500 No ControlInput Signal 1Input Signal 2Input Signal 3Input Signal 4Input Signal 5Input Signal 6Input Signal 7Input Signal 8

Act

ive

Po

we

r T

ran

sfe

rre

d f

rom

Are

a 1

to

Are

a 2

[W

att

s]

Time [s]








2−

𝑉𝑀3+𝑉𝑀4

2


2−


2

10

Controller performance for different inputs (Local & Wide-Area)

11

G1

G2

Area 1

Local Loads

900 MVA

900 MVA 900 MVA20 kV / 230 kV

25 Km 10 Km

900 MVA20 kV / 230 kV





10 Km 25 Km

900 MVA900 MVA20 kV / 230 kV

G4900 MVA

20 kV / 230 kV 900 MVA

Area 2

Bus1 Bus2

Local Loads



Phasor POD

Load Control

Algorithm

Local/RemoteMeasurement

Oscillatory Content

Load Modulation

PMUM1

PMUM2

G3PMUM3

PMUM4

PMUMiddle

PMUA1

PMUA2








2−

𝑉𝑀3+𝑉𝑀4

2


2−


2

ΔVref G1


Act

ive

Po

we

r T

ran

sfe

rre

d f

rom

Are

a 1

to

Are

a 2

[M

W]

Time [s]58 60 62 64 66 68 70 72 74 76

250

300

350

400

450

500

550

No ControlInput Signal 1Input Signal 3Input Signal 4Input Signal 6

Input Signal 2Input Signal 5Input Signal 7Input Signal 8

No Control

Act

ive

Po

we

r T

ran

sfe

rre

d f

rom

Are

a 1

to

Are

a 2

[M

W]

Time [s]58 60 62 64 66 68 70 72 74 76

250

300

350

400

450

500

550Input Signal

Decay Ratio

Overshoot[MW]

Undershoot [MW]

Settling Time [s]

1. 0,935 44,6 -41,2 12,63

2. 0,951 49,2 -40,8 21,74

3. 0,925 31,5 -45,6 25,88

4. 0,981 46,4 -51,0 14,74

5. 0,959 48,7 -53,9 25,89

6. 0,945 47,1 -54,9 18,15

7. 0,969 52,4 -48,8 49,80

8. 0,964 45,0 -52,2 17,32








2−

𝑉𝑀3+𝑉𝑀4

2


2−


2

Decay Ratio: The ratio between the peak of the first and nextoscillation.Overshoot: Highest deviation of active power transfer.Undershoot: Lowest deviation of active power transfer.Settling Time: The time at which the oscillations have decreased to avalue that is within 1% change from the original active power transfer.

11

RT-SIL and RT-HIL Comparison

55 60 65 70 75200

250

300

350

400

450

500

550

Time [s]Act

ive

Po

wer

Tra

nsf

er f

rom

A1

to A

2 [M

W]

No Control

RT-HIL Load Control

RT-SIL Load Control

60 65 70 751620

1630

1640

1650

1660

1670

1680

Time [s]A

ctiv

e Po

wer

Loa

d Co

nsum

ptio

n A

rea

2 [M

W]

RT-HIL Load Control

RT-SIL Load Control

Input Signal 6: 𝑉𝜑𝐴𝑟𝑒𝑎1 − 𝑉𝜑𝐴𝑟𝑒𝑎2

Input Signal Decay Ratio Overshoot [MW] Undershoot [MW] Settling Time [s]

RT-SIL 0,905 35,0 -45,0 6,15

RT-HIL 0,945 47,1 -54,9 18,15

12

Further Analysis of Simulation ResultsMain factors contributing to difference in RT-HIL and RT-SIL simulation results:

D/A

Co

nversio

n

A/D

Co

nversio

nD

/A C

on

version

A/D Conversion

Real-TimeSimulator SEL-487 E PMU

PDC

PC

cRIORT

FPGA

TCP

TCP

TCP

1. 2. 3.

4.5.

6.

Digital signal

Analog signal

Model simulated in Real-Time

Divide by1.4*103

Divide by1.8*105

Voltage

Current

Inside Real-Time Simulator

Multiply by1000

Multiply by10

Inside PMU

Compute input signal

Inside cRIO

1. 2. 3.

4.

Divide by120

Multiply by3*106

1. Signal has to be within ±5𝑉.

2. Scaled up with pre-configured CT and VT turn ratio.

3. Signal has to be within ±10𝑉.

4. Analog input limit of simulator.

Load

Co

ntr

ol S

ign

al

Time [s] Time [s]60 65 70 75 80

-1

0

1

2x 10

7

61.4 61.6 61.8 62 62.2 62.41.211

1.212

1.213

1.214

1.215x 10

7

(a) (b)

• Latency

• Scaling

• NoiseNoise in the range of ±20 kW.

Note that the peak output is 121 MW.

Fixed delay: • RTS• PMU• NI-cRIO

Non-deterministic delay:• PDC• S3DK• The communication protocols

• Difference in implementation

Requirements

System DesignOffline Simulation

Software DevelopmentSoftware-in-the-Loop

System

System TestHardware-in-the-Loop

Component Test


Validation

Verification

Design and Softw

are Developm

ent Har

dwar

e-in

-the

-Loo

p Te

stin

g

MATLAB & Simulink LabVIEW

The same programming language and development platform can not be used for SIL and HIL.

13

Summary

A load control algorithm was designed for damping of inter-area oscillations.

The algorithm utilizes synchrophasor measurements (local and/or remote) as an input signal.

Tested in RT-SIL and RT-HIL for eight different input signals (synchrophasors).

Voltage angle difference, current and active power performed the best.

HIL performance is affected by scaling, noise, latencies and difference in implementation.

14

Future Work Create an equivalent model of the Icelandic power system in Simulink

SimPowerSystems and prepare for real-time simulation on OPAL RT eMEGASIM real-time simulator.

Verify the model using PMU measurements from the system.

Test the load controllers damping performance in the system.

Enhancement of the load control algorithm.

Design and testing multiple oscillatory modes and ambient load variations.

15

Thank you!

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