September 2017

E. Tröster, T. Ackermann, N. Martensen (Energynautics, Germany)

Contact: E.Troester@energynautics.com

In Cooperation with

Simulations and Tests of a Danish Smartgrid – The Cell Controller Pilot Project

DEVELOPMENT IN THE DANISH POWER SYSTEM

2

Source: Energinet.dk

• Increased security of supply

• Sufficient domestic resources must be available to maintain a balance between demand and generation

• Improved operator knowledge of actual system conditions both locally and centrally

• Efficient system control particularly during emergencies

• Active usage of distributed generators

• Black starting capabilities using distributed generators

• Organising distributed generators into controllable Virtual Power Plants

IDENTIFIED TARGETS OF THE REDESIGN PROCESS

3

150 kV 150 kV

∼

∼

∼

∼

60 kV 60 kV 60 kV

10 kV 10 kV 10 kV

60 kV 60 kV

60 kV

10 kV

10 kV 60 kV

10 kV

60 kV

Input

Cell controller

Output

4

THE CELL CONTROLLER

5 5

ÅRR

AGB

GLE

HEJ

VOB

BMØ

GØR HOS

FØV

BRØ

HOD

LIK

REV

VJV

BIS

MØR

BIO

BID

G

G

G

G

15,5 MW

G

8,8 MW

2 MW

3 MW 3,8 MW

Wind Wind

Wind

Wind

3,6 MW

7 MW

3,3 MW

2 MW

Wind

Wind 2 MW

2 MW

Wind

4 MW

Test Area 1

Installed CHP: 37 MW Installed Wind: 39 MW Max Load: 61 MW 150/60 kV Trafo: 100 MVA

PILOT CELL: HOLSTED 60 KV GRID AREA

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CELL CONTROLLER CONCEPT

• Each Cell can be regarded as a Virtual Generator with same or better controllability compared to a traditional power station unit of equal size

• Local distribution companies attain strongly increased possibilities of distribution network on-line monitoring and active control

• Automatic Cell transition to controlled island operation in case of imminent transmission system break-down

• Black-start of transmission system • Robust Cell Controller Concept designed to encompass all new types of DG units and

controller functionalities

Increase in security of supply Any new functionality as pure software development Re-design for the future Danish electric power system

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Monitoring total load and production within the Cell

Active power control of synchronous generators

Active power control of wind farms and large wind turbines

Reactive power control by utilising capacitor banks of wind turbines and grid

Voltage control by activating AVRs on synchronous generators

Frequency control by activating SGSs on synchronous generators

Capability of operating 60 kV breaker on 150/60 kV transformer

Capability of operating breakers of wind turbines and load feeders

Automatic fast islanding of entire 60 kV Cell in case of severe grid fault

Automatic fast generator- or load shedding in case of power imbalance

Voltage, frequency and power control of islanded Cell

Synchronising Cell back to parallel operation with the transmission grid

Black-starting support to transmission grid in case of black-out

LEVEL OF FUNCTIONALITY OF THE CELL CONTROLLER

8

Hejnsvig: 2x 1.3 MVA

Billund: 3x 3.6 MVA

CHPS IN TEST AREA 1

9

4x 1000 kW Windturbine NEG Micon NM60/1000

Monitoring

WINDTURBINES IN TEST AREA 1

10

800 kVA synchronous condenser for voltage control

SYNCHRONOUS CONDENSER AND DUMP LOAD (SLC)

11

1000 kW dump load for frequency control

500.0400.0300.0200.0100.000.000 [s]

1.005

1.002

0.999

0.996

0.993

0.990

Grid Breaker: Electrical Frequency/Terminal iGrid Breaker: Electrical Frequency/Terminal j

500.0400.0300.0200.0100.000.000 [s]

0.20

0.00

-0.20

-0.40

-0.60

-0.80

Grid Breaker: Active Power Import in MWGrid Breaker: Reactive Power Import in Mvar

DIg

SILE

NT

Resynchronisation Islanding

Frequency Dip

Frequency

Active Power

Reactive Power

SIMULATION: ISLANDOPERATION WITH WINDTURBINES

12

500.0400.0300.0200.0100.000.000 [s]

1.00

0.75

0.50

0.25

0.00

-0.25

SLC Loadbank: Total Active Power in p.u.SLC BL Control: SetpointSLC BL Setpoint Calc: CtlSetpoint

500.0400.0300.0200.0100.000.000 [s]

1.04

1.02

1.00

0.98

0.96

0.94

0.92

SLC Loadbank: Electrical FrequencySLC Loadbank: Voltage, Magnitude in p.u.

DIg

SILE

NT

Active Power Frequency

Voltage

SIMULATION: DUMP LOAD (SLC)

13

500.0400.0300.0200.0100.000.000 [s]

0.80

0.60

0.40

0.20

0.00

-0.20

Trf 50366: Psum WT1Trf 50366: Qsum WT1

Switching of capacitor bank

Active Power

Reactive Power

SIMULATION: WINDTURBINE

14

500.0400.0300.0200.0100.000.000 [s]

0.250

0.125

0.000

-0.125

-0.250

-0.375

Synchronous Condenser: Total Reactive Power in p.u.Qctrl: Ref

500.0400.0300.0200.0100.000.000 [s]

0.050

0.025

0.000

-0.025

-0.050

-0.075

-0.100

Synchronous Condenser: Total Active Power in p.u.

500.0400.0300.0200.0100.000.000 [s]

1.0250

1.0125

1.0000

0.9875

0.9750

0.9625

0.9500

Synchronous Condenser: Electrical FrequencySynchronous Condenser: Voltage, Magnitude in p.u.

500.0400.0300.0200.0100.000.000 [s]

2.50

2.00

1.50

1.00

0.50

0.00

-0.50

Selector: icSynchronous Condenser: Current, Magnitude in p.u.

DIg

SIL

EN

T

Active Power

Reactive Power

Frequency

Voltage

Switching of capacitor bank

SIMULATION: SYNCHRONOUS CONDENSER

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60 kV 10 kV 0,4 kV

Billund Hejnsvig

VOB AGB

BID HEJ

STI BIS

KLN GLB FUG CHP TRØ GRØ MØL

KT22 KT21

HEJ GEN1

HEJ GEN2

HEJ SC

HEJ SLC

HEJ WT1

HEJ WT2

HEJ WT3

HEJ WT4

BID GEN1

BID GEN2

BID GEN3

CEN SØK

KT21

KVV

Cell Controller

Mini Island

MEASUREMENT RESULTS

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MEASUREMENT TEST 1: „MINI ISLAND“ FREQUENCY

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MEASUREMENT TEST 1: „MINI ISLAND“ VOLTAGE

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60 kV 10 kV 0,4 kV

Billund Hejnsvig

VOB AGB

BID HEJ

STI BIS

KLN GLB FUG CHP TRØ GRØ MØL

KT22 KT21

HEJ GEN1

HEJ SC

HEJ SLC

HEJ WT1

HEJ WT2

HEJ WT3

BID GEN1

CEN SØK

KT21

KVV

Cell Controller

MEASUREMENT TEST 2: ISLAND OPERATION

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MEASUREMENT TEST 2: ISLAND OPERATION FREQUENCY

At time of island, cell generation (which includes over 1 MW of wind power) exceeds load by 470 kW.

Frequency increases immediately, but SLC and CHP governors react to compensate.

During island, cell frequency fluctuates as wind generation varies from 800 to 1350 kW. Cell Controller reacts and maintains cell within all grid code given boundaries.

Cell reconnected to grid.

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MEASUREMENT TEST 2: ISLAND OPERATION SYNCHRONIZATION

Once a reconnection to the grid is requested, the Cell Controller brings cell frequency and voltage phase within range of grid values. The Master Synchronizer reconnects only when cell frequency and voltage phase are sufficiently close to the grid values.

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60 kV 10 kV 0,4 kV

Billund Hejnsvig

VOB AGB

BID HEJ

STI BIS

KLN GLB FUG CHP TRØ GRØ MØL

KT22 KT21

HEJ GEN1

HEJ WT1

HEJ WT2

HEJ WT3

BID GEN1

CEN SØK

KT21

KVV

Cell Controller

MEASUREMENT TEST 3: IMPORT/EXPORT CONTROL

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Billund CHP

Hejnsvig CHP

Setpoint

Actual value

MEASUREMENT TEST 3: IMPORT/EXPORT CONTROL

23 1 hour

Grid connected import/export control (virtual generator operation)

Emergency transfer to sustained hybrid island operation

Islanded wind only operation with SC and SLC

ACHIEVED TEST RESULTS

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CONCLUSIONS

A utility scale smart grid concept has been successfully demonstrated. Lessons learned from the project: • By adding ICT to the system a higher security of supply can be achieved, however it also

adds new sources of failure.

• Modelling and simulations are powerful tools to test new control strategies before going into the field. In case of island operation dynamic simulations are necessary!

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THANK YOU FOR YOUR ATTENTION!