Modeling & Simulation of Distribution Networks · response over 1 second is computed in exactly 1 second. –For a ggpyiven time step of say 50 microseconds, all calculations required

Modeling & Simulation of Distribution NetworksDistribution Networks- Multi-agent based LFC for islanding operation

Seung Tae ChaCentre for Electric Technology (CET)Centre for Electric Technology (CET)Technical University of Denmark (DTU)

Sept 22, 2011

Technical University of Denmark (DTU)

Founded:1829 by Hans Christian Ørsted

Staff:Staff: 550 Faculty members

1550 Researcher / Senior researchers1950 Support staff

Research:1883 Research papers in ISI-journals 175 PhD dissertations

Students: 7000 Students850 PhD-students (3 years)600 Exchange students (3-6 months)g ( )

Ranking:122th (ref: Times World University Ranking)

Workshop Vind i Øresund, LTH, Lund 20112 DTU Electrical Engineering, Technical University of Denmark

Outline

• IntroductionReal time simulation platform• Real time simulation platform

• Multi-agent based controllerD i ti f t t t• Description of test system

• Case study resultsC l i• Conclusion

• Future work – PSO, SIL & PHIL


Introduction

• DG source is gaining popularity and is ever increasing in importance

• DGs installed in the grid are gaining in complexity

• Islanded Distribution System• Islanded Distribution System

• New forms of operation & develop sophisticated control strategiescontrol strategies

• EMT simulation is now a common tool for power system engineerssystem engineers

• Real time simulators are more accessible than ever


Frequency control of generators

SynchronousPM0

PM1N

S

Rated frequencyAGCSynchronous

Generator

S

PM1

N

S

S

N

Sω0ω1

PM0

PM2

PM2

PL

N

S

PM3

L

N

Sω0ω2

PPM3

ωω

PM0 1. Increase in consumption Decrease in Freq of each Gen

2. Increase in PM based on droop characteristics of each Gen

3 AGC from grid control center Frequency recovery


ω0ω3 3. AGC from grid control center Frequency recovery

Source : WeGAT research center, Korea 2011

Goal & Idea

•Develop a multi-agent based controller to stabilize the frequency and voltages of an active distribution network in the event of islanding operation


Real Time Simulation Platform

RTDS i t i l t th t l •RTDS is a power system simulator that solves electromagnetic transients in real time

What is Real Time Simulation:–By using the RTDS Simulator, a system’s

response over 1 second is computed in exactly1 second.

–For a given time step of say 50 microseconds, all g p ycalculations required to determine the power system’s state are solved in precisely that


amount of time.

Real Time Simulation Platform (continue)

Middleware SW

Each agent creates its connection and has an individual channel of control commands which ensures


decentralized nature and robustness of the control

Multi Agent based Controller

•Central Control Agent is responsible for controlling & •Central Control Agent is responsible for controlling & managing the grid.

•Device Agent interact directly with the physical power system components and performs control functionsfunctions.

– Generator agent (P, Q set point)Breaker agent (open & close)

•Physical power system components are DGs, loads, lines etc These agents have fixed data such as

– Breaker agent (open & close)

lines, etc. These agents have fixed data such as – Unit names, min & max power, fuel cost coefficient

Power production value & current status of the unitWorkshop Vind i Øresund, LTH, Lund 20119 DTU Electrical Engineering, Technical University of Denmark

– Power production value & current status of the unit

Multi Agent based Controller

DG agent calculates its cost function based upon its current state, and sends a bid...cumulates...which DG agent shall provide regulation and how much power


agent shall provide regulation and how much power should be delivered !!

Modified IEEE 9-bus Test System

•The modified IEEE 9 bus system comprises a 60kV •The modified IEEE 9-bus system comprises a 60kV, 50Hz grid which feeds an 11kV network through a 60/11kV transformer.60/11kV transformer.

– 3 DG units (1.5 MW, Bus 1,3,4)8 T/L– 8 T/L

– 1 TR– 4 Loads (6 MW, Bus 5 -8)


Modified IEEE 9-bus Test System (continue)T2

T-LINE NAME:

T-LINE / CABLECALCULATION BLOCK

T3T-LINE NAME:


T4T-LINE NAME:


T6T-LINE NAME:


T7T-LINE NAME:


T8T-LINE NAME:


T5T-LINE NAME:


T1T-LINE NAME:


0.0W3

0.0W2

0.0W1

GEN1

EF IF VMPUA

B

VGB1

BUS1

C1B1A11.00040 /_-30.08172

BUS #1

GEN2

EF IF VMPUA

B

EF2 VGB2

BUS3

C3B3A31.00039 /_-30.07523

BUS #3

GEN3

EF IF VMPUA

B

EF3 VGB3

BUS4

C4B4A41.00039 /_-30.06276

BUS #4

1 <-- SS --> 1

LINE CONSTANTS:T2

CONTROL ANDMONITOR IN

THIS SUBSYSTEM

1 <-- SS --> 1

LINE CONSTANTS:T3


THIS SUBSYSTEM

1 <-- SS --> 1

LINE CONSTANTS:T4


THIS SUBSYSTEM

1 <-- SS --> 1

LINE CONSTANTS:T6


THIS SUBSYSTEM

1 <-- SS --> 1

LINE CONSTANTS:T7


THIS SUBSYSTEM

1 <-- SS --> 1

LINE CONSTANTS:T8


THIS SUBSYSTEM

<-- SS -->S1 -- S1

T-LINE NAME:T1

1

BRKG170

BRKG1

<-- SS -->S1 -- S1

T-LINE NAME:T5

1

BRKG270

BRKG2

<-- SS -->S1 -- S1

T-LINE NAME:T7

1

BRKG3BRKG370

GEN1

IEEE Type ST1ExcitationSystem

Ef If Vpu

Vs

EF1

GEN2


Ef If Vpu

Vs

GEN3


Ef If Vpu

Vs

LINE CONSTANTS:T5


THIS SUBSYSTEM

1 <-- SS --> 1

LINE CONSTANTS:T1


THIS SUBSYSTEM

1 <-- SS --> 1

IEE2STPSS

GEN3

Pe w

Vs

1 <-- SS --> 1

IEE2STPSS

GEN2

Pe w

Vs

IEE2STPSS

GEN1

Pe w

Vs

GPC

TMW

B

C

W1

T-LINE NAME:T2

SENDING ENDTERMINAL NAME:

T2SE

1

2

3

GPC

TMW

B

C

W2 TM22

T-LINE NAME:T6


T6SE

1

2

3

GPC

TMW

B

C

W3 TM33

T-LINE NAME:T8


T8SE

1

2

3

<-- SS -->S1 -- S1

<-- BUS -->BUS6 -- BUS1

<-- SS -->S1 -- S1

<-- BUS -->BUS8 -- BUS3

<-- SS -->S1 -- S1

<-- BUS -->BUS7 -- BUS4

<-- BUS -->BUS5 -- BUS1


T1SE

2

3

<-- BUS -->BUS5 -- BUS3


T5SE

2

3

<-- BUS -->BUS4 -- BUS6

RECEIVING ENDTERMINAL NAME:

T7RE

2

3

P3P3

P1P1

IEEE Type 1Governor/Turbine

GEN1

Tm(HP)wTM11

P2P2


GEN2

Tm(HP)w


GEN3

Tm(HP)w

A5FREQHzA5 A8 Hz

A8FREQ

T-LINE NAME:T3

1

BUS2

C2B2A21.00020 /_-30.06147

BUS #2

T-LINE NAME:T1

180.66666667

80 66666667

BUS5

C5B5A51.00003 /_-30.11053

BUS #5

T-LINE NAME:T2

180.66666667

80 66666667

BUS6

C6B6A61.00015 /_-30.09676

BUS #6

T-LINE NAME:T3

180.66666667

80 66666667

BUS7

C7B7A70.99992 /_-30.09417

BUS #7

BUS8

C8B8A80.99992 /_-30.10040

BUS #8

<-- SS -->S1 S1

<-- SS -->S1 S1

<-- SS -->S1 S1

A8

B8

C8rms

pu

VLOAD8

A7

B7

C7rms

pu

VLOAD7

A6

B6

C6rms

pu

VLOAD6

A5

B5

C5rms

pu

VLOAD5

BRK4BRKG470

<-- SS -->S1 S1

T-LINE NAME:T4

1

<-- BUS -->BUS2 -- BUS7

<-- SS -->S1 -- S1

BRK9A

BRK9B6

N4

60

.99

99

2

80.66666667

80 66666667

frequencyA6

frequency

Hz

A6FREQA7

frequency

Hz

A7FREQ frequency


T3RE

2

3

T-LINE NAME:T4


T4RE

1

2

3


T1RE

2

3

T-LINE NAME:T5


T5RE

1

2

3

80.66666667

80.66666667

1.50 MW


T2RE

2

3

T-LINE NAME:T7


T7SE

1

2

3

80.66666667

80.66666667

1.50 MW


T3SE

2

3

T-LINE NAME:T8


T8RE

1

2

3

80.66666667

80.66666667

1.50 MW

S1 -- S1<-- BUS -->

BUS2 -- BUS7

<-- SS -->S1 -- S1

<-- BUS -->BUS2 -- BUS8

S1 -- S1<-- BUS -->

BUS5 -- BUS1

<-- SS -->S1 -- S1

<-- BUS -->BUS5 -- BUS3

S1 -- S1<-- BUS -->

BUS6 -- BUS1

<-- SS -->S1 -- S1

<-- BUS -->BUS4 -- BUS6

<-- SS -->S1 -- S1

<-- BUS -->BUS7 -- BUS4

1.50 MW

<-- BUS -->BUS2 -- BUS8

S1 -- S1

<-- SS -->S1 -- S1

<-- BUS -->BUS8 -- BUS3

T-LINE NAME:T6


T6RE

1

2

3


T4SE

2

3BRK9C

BRK9B

BU

S1

6

N4

8N

47

0/_

-30

.10

04

0

80.66666667

80.66666667

Place control processor wherethe GTNET-DNP card is physically connected.

A

B

C

A

B

C

Tmva = 210

6011

Trf = 2Winding

#1#2 I

Lags

Station9

C9B9A91.00000 /_ 0.00000

BUS #9

SRC1

GPC1

1

1

A

B

C

AC Type

SCR = 1.0 /_0 degZth = Ohms

BRK10A

BRK10C

BRK10B

EX

TE

RN

N3

eN

2e

N1e

1.0

00

00

/_0.0

00

00 SL1

PB21

0

PB11

0 B C

A

CB9S-R

FLIPFLOP

S

R

Q

Q

0.2

0.2

BRKOPEN1

0

time

CB2S-R

FLIPFLOP

S

R

Q

Q


LagsRISC

1Ell=60.025037kV

P4P4

0.2

Modified IEEE 9-bus Test System (continue)


Modified IEEE 9-bus Test System (continue)

•Intelligent controller : Reacts to respond quickly to •Intelligent controller : Reacts to respond quickly to the frequency deviation in the event of islanding situationsituation

LFC shceme used to control the speed of the DGs. Measures the system frequency and changes load setting of DGs via the AGC signal based on participation factors calculated using cost-functions associated with each DG.


Case Study Results Case I

Change the set point of Gen#2

C 1 E t l di t d


Case 1 – External source disconnected

Case Study Results

Case ICase I

Step1. Loss of 1.5 MW power from the grid due to an outage or intentional islandingintentional islanding

Step2. Created an imbalance in the islanded part of the network

Step3. Load agents observe voltage & frequency drop

Step4. Load agents contact DF agent for any available regulation service

Step5. DF agents informs the current service availability and provides Step5. DF agents informs the current service availability and provides its reference (i.e P_Gen2=0.6415)

Step6. Load agents request DG #2 agent for provision of service

St 7 DG #2 t t th t d id th i b Step7. DG #2 agent accepts the request and provides the service by increasing its active power set point

Step 8. Voltage & frequency recover at the nodes of all loads


Case Study Results

Case ICase I


50.02A5FREQ

50.02A6FREQ

50 50

49.96

49.98

49.96

49.98

65s10s

0 15 30 45 60 75 9049.94

0 15 30 45 60 75 9049.94

65s10s

The controller was capable of bring back the frequency

50

50.02A7FREQ

50

50.02A8FREQThe controller was capable of bring back the frequency

to 50Hz and restored at about 65 s.

49.98 49.98

49.96 49.96


0 15 30 45 60 75 9049.94

0 15 30 45 60 75 9049.94

1.05VLOAD5

1.05VLOAD6

0.95

1

0.95

1

0.9 0.9

0 15 30 45 60 75 900.85

0 15 30 45 60 75 900.85

1.05VLOAD6

1 05VLOAD8

The controller was also capable of reducing the voltage deviations and keeping them within the permissible limits.

11

1.05limits.

0.95 0.95

0.9 0.9


0 15 30 45 60 75 900.85

0 15 30 45 60 75 900.85

Case Study Results

Case IICase II


50.2A5FREQ

50.2A6FREQ

49.8

50

49.8

50

49.6 49.6

80s10s

0 15 30 45 60 75 9049.4

0 15 30 45 60 75 9049.4

A7FREQ 50 2A8FREQ

80s10s

50

50.2A7FREQ

50

50.2

49.8 49.8

49.6 49.6


0 15 30 45 60 75 9049.4

0 15 30 45 60 75 9049.4

1.05VLOAD5

1.05VLOAD6

0.95

1

0.95

1

0.9 0.9

0 15 30 45 60 75 900.85

0 15 30 45 60 75 900.85

1

1.05VLOAD7

1

1.05VLOAD8

0.95 0.95

0.9 0.9


0 15 30 45 60 75 900.85

0 15 30 45 60 75 900.85

Case Study Results Case III

Load Shedding at Bus 8Load Shedding at Bus 8

C 3 E t l di t d


Case 3 – External source disconnected

Case Study Results

Case IIICase III


50.15A5FREQ

50.15A6FREQ

50.05

50.1

50.05

50.1

49 95

50

49 95

50

0 15 30 45 60 75 9049.95

0 15 30 45 60 75 9049.95

A7FREQ A8FREQ

90s

50.1

50.15Q

50.1

50.15A8FREQ

The controller was capable of bring back the frequency to 50Hz and restored at about 90 s.

50.05 50.05

0 15 30 45 60 75 9049.95

50

0 15 30 45 60 75 9049.95

50


0 15 30 45 60 75 90

1 00496

1.00644VLOAD5

1.00628VLOAD6

1.00199

1.00347

1.00496

1.00192

1.00337

1.00483

0.99903

1.00051

0 15 30 45 60 75 900.99756

0.99901

1.00047

0 15 30 45 60 75 900.99755 0 15 30 45 60 75 90

The controller was also capable of reducing the voltage deviations and keeping them within the permissible

1.00462

1.00608VLOAD7

0.83317

0.9998VLOAD8limits.

1.00023

1.00169

1.00315

0.33327

0.4999

0.66653

0 15 30 45 60 75 900.99731

0.99877

0 15 30 45 60 75 908.049E-7

0.16663


LFC-ON

LFC-OFF


Conclusions

• A multi-agent based controller for islanding operation of active distribution system has been

d h l bili h f & lproposed to help stabilize the frequency & voltage

• The proposed contoller can respond to the islanding situation fast and efficiently stabilize the frequency under contingency

• However, there are a number of challenges

• Multi-set of DG units & loads, coordination Multi set of DG units & loads, coordination strategies, and scalability


Bornholm Power System

•The Bornholm power system comprises a 60kV •The Bornholm power system comprises a 60kV, 50Hz grid which feeds an 10kV network through a 60/10kV transformer.60/10kV transformer.

– Peak Load : 63 MW18 S b t ti– 18 Substations

– AC submarine cable connection to Sweden– 44 Transformers– Unit 5 : 25 MW– Unit 6 : 37.5 MW CHP– Wind, Biogas, Diesels (67 MW)



Future work

PSO b d L d F C t l f Di t ib ti • PSO based Load Frequency Control for Distribution System

• Coordinated Tuning of PSS and WPS based on SIL Test


Submitted to IEEE Transactions on Smart Grid, 2011

Power Hardware-In-the-Loop (PHIL) Test

• CONTRIBUTOR : Ranjan Sharma, Qiuwei Wu

• Present at 10th International Workshop on Large Present at 10th International Workshop on Large Scale Integration of Wind Power, 25-26 Oct, 2011


B2 B1

PMSG WT

RTDS

PMSG WT

C t l C t l C t lControl Control Control

GTAO

K K

GTAIGTAOInterfacing Cards GTAI

CHOPPERH/W d t t CHOPPER

AMPLIFIER

H/W under test

PWM DSP


BH2 BH1

Amplifier

RTDS

VSC

RTDS DSP Interface

I/O


Cards

Power Hardware-In-the-Loop (PHIL) Test

• An off-shore wind power plant (WPP) interconnected to the on-shore grid via VSC-HVDC

• To verify the H/W interaction & the control co-ordination between the WPP and the VSC of the HVDC

• To provide a FRT response during the grid faultsp p g g

• Technical challenges remain

D t il d WPP t ti ith bl: Detailed WPP representation with cables

: Inclusion of both end VSCs


Modeling & Simulation of Distribution Networks · response over 1 second is computed in exactly 1 second. –For a ggpyiven time step of say 50 microseconds, all calculations required

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