real-time software-in-the-loop performance analysis of synchrophasor-and-active load-based power...

RT-SIL Performance Analysis of Synchrophasor-and-Active Load-BasedPower System Damping Controllers

G.M. Jónsdóttir*, M.S. Almas*, M. Baudette*, M.P. Palsson¶, L.Vanfretti*†

*Electric Power Systems Division, KTH Royal Institute of Technology, Stockholm, Sweden†R&D Department, Statnett SF, Oslo, Norway, ¶System Planning Department, Landsnet, Reykjavik, Iceland

Introduction

Test System Modelling

Load Controls

Conclusions and Future Work

Discussion and Simulation Results

· Algorithm 1 provides quicker oscillation damping.

· Algorithm 2 best suits to the TSOs where load shedding is undesirable to perform oscillation damping.· Future work:

Deploy load control algorithm on an external controller and test the algorithm in RT-HIL. Analyze flexibility of the algorithm using both local and remote signals from a real PMUs.

· Transmission constraints in the Icelandic power system often lead to inter-area oscillations.

· Conventional stabilization methods have been applied, not enough.

Idea: Control industrial load.

· Introduce two damping controllers with synchrophasor signals and local measurements as inputs.

· Damping is achieved by load modulation generated by a phasor-based oscillation signal.

· RT-SIL testing is performed using Opal-RT’s eMEGAsim Real-Time Simulator.

· First step towards testing in RT-HIL.

G1

G2

Area 1Area 1

Local Loads

900 MVA900 MVA

900 MVA900 MVA

900 MVA20 kV / 230 kV

900 MVA20 kV / 230 kV

25 Km25 Km 10 Km10 Km

900 MVA20 kV / 230 kV

900 MVA20 kV / 230 kV

967 MW100 MVAR (Inductive)

-387 MVAR (Capacitive)



220 Km Parallel Transmission Lines

220 Km Parallel Transmission Lines

Power TransferArea 1 to Area 2

Power TransferArea 1 to Area 2

10 Km10 Km 25 Km25 KmG3

900 MVA900 MVA

900 MVA20 kV / 230 kV

900 MVA20 kV / 230 kV

G4

900 MVA20 kV / 230 kV

900 MVA20 kV / 230 kV

900 MVA900 MVA

Local

Loads





Area 2Area 2

Bus1Bus1 Bus2Bus2

Phasor POD

Load Control

Algorithm

Local/RemoteMeasurement

Local/RemoteMeasurement

Oscillatory Content

Oscillatory Content

Load Modulation

Load Modulation

Phasor-POD: is the approach used to generate the command signal for the load control. It separates the oscillatory part from the measured value of the input signal.

Algorithm 1: Increase load at peak of oscillation, shed load at minimum of oscillation.

Algorithm 2: Same as Algorithm 1 except block when load should be shed.

Software-in-the-Loop Validation

MATLAB/SimulinkSimPowerSystems

Model

Model Splitting into Sub-systems for

RT-Simulation

Real-Time Model Simulation in RT

Targets

RT-Lab Software Interface Compiles and Loads the Model into

RT-Targets64 Analog Out

16 Analog In

Simulator Analog and Digital I/Os

OP 5251 (64 DO) Digital Output and Digital Input are looped back

Control Signal from Simulink Load control model is configured to one of the Digital Output of the Simulator

OP 5251 (64 DI)

Control Signal is received at one of the Digital input of the Simulator which is configured in the Simulink Model to change the load.

Workstation with RT-LAB software Interface. Provides console for monitoring real time simulation

Scenario 1: A small disturbance in the form of 5% positive magnitude step in the reference voltage of Generator 1 applied for 4 cycles at t = 60 sec.

Scenario 2: A large disturbance in the form of three phase to ground fault (4 cycles, i.e. 80 ms) at t = 60 sec in the middle of one of the two 220km transmission lines connecting together the two areas.

55 60 65 701.5

2

2.5

3

3.5

4

4.5

5

5.5

6x 10

8

Time [s]

Po

we

r tr

an

sfe

red

fro

m

A

rea

1 t

o A

rea

2 (

Wa

tts

)

Scenario 2: Large Disturbance (Three Phase to Ground Fault for 4 cycles) Power Transfer between Area 1 and Area 2

No Active Load Control

Load Control Algorithm 1


62 64 66 68 70 72 74

1.6

1.62

1.64

1.66

1.68

1.7

1.72

x 109

Time [s]

Ac

tiv

e P

ow

er

Co

ns

um

pti

on

by

Dy

na

mic

Lo

ad

in

A2

(W

att

s)

Scenario 2: Large Disturbance (Three Phase to Ground Fault for 4 cycles) Load Control in Area 2




55 60 65 70

3

3.5

4

4.5

5

x 108

Time [s]

Po

we

r tr

an

sfe

red

fro

mA

rea

1 t

o A

rea

2 [

Wa

tts

]

Scenario 1: Small distrubance (5 % Change in Vref

of Generator 1)

Power Transfer Between Area 1 and Area 2




55 60 65 70 75

1.63

1.64

1.65

1.66

1.67

1.68

x 109

Time [s]

Scenario 1: Small distrubance (5 % Change in Vref

of Generator 1)

Load Control in Area 2




Act

ive

Po

we

r C

on

sum

tio

nB

y D

ynam

ic L

oad

in A

2 (

MW

)

RLS or Low Pass Filtering based

Phasor Extraction Phase

Shift

Δω

Poscillatory

Phase angle computation

Input signal

Unit delay

PIController

Free Running Oscillator

∑

ω

ωt

∑

Paverage

d/dt <0

max

Switch

min

Only for Case 1

Load control algorithm

Damping signal

real-time software-in-the-loop performance analysis of synchrophasor-and-active load-based power...

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