grid control cooperation – coordination of secondary control · coordination of secondary...

Prof. Dr. techn. G. Scheffknecht

Institute of Combustion and Power Plant Technology

Exchange of balancing services ‐ Market design and modelling, AmsterdamOctober 28, 2010

Dipl.-Ing. Pavel ZolotarevUniversity of Stuttgart

Grid Control Cooperation –

Coordination of Secondary Control

2

Introduction

Continental Europe power system - synchronously interconnected control areas

Load and power generation from renewable sources cannot be predicted accurately.

In order to ensure the power system stability power generation must be continuously adjusted to power demand by load-frequency control.

3

Introduction

Continental Europe power system - synchronously interconnected control areas

Load and power generation from renewable sources cannot be predicted accurately.

In order to ensure the power system stability power generation must be continuously adjusted to power demand by load-frequency control.

Secondary Control (SC):• Stationary restores the power balance of a control area • Control variable – actual power interchange of a control area• Horizontal structure:

− One controller implemented in each control area− No coordination of secondary control power (SCP) activation

4

Secondary Control Loop

Power balance of a control area

Control deviation: Area Control Error (ACE)

Power Balance

ACE

5




Control area short – positive SCP demandControl area long – negative SCP demand

Secondary Controller

Power Balance

ACE

SCP-request

6






SC Power Plant Units

Power Balance

SCP

ACE

SCP-request

7





Dimensioning of necessary SCP reserves and their activation is conducted with respect to technical and economic criteria for one

control area!



Power Balance

SCP

ACE

SCP-request

8

Interconnected Power System



Power Balance

SCP

ACE

SCP-request

Control Area A

9




Power Balance

SCP

ACE

SCP-request

Control Area A

Power Balance



SCP

ACE

SCP-request

Control Area C



Power Balance

SCP

ACE

SCP-request

Control Area B

other control areas

Technical and financial benefit through Grid Control Cooperation!

10

Index

1. Grid Control Cooperation Modules

2. Technical Concept

3. Example from Operation

4. Implementation in Germany

5. Summary

11

Index





5. Summary

12

Module 1

Module 1:

Inherent in the system: concurrently short and long control areas activate SCP with different signs.

Counteracting SCP avoidance

Less control energy needed (lower energy costs)

Grid Control Cooperation

13

Module 2

Module 2:

Control areas must cover the risk of power imbalances with SCP reserves.

Risk distribution and joint dimensioning of SCP reserves

Lower SCP reserves needed (lower costs)


Module 1:Counteracting SCP avoidance

14

Module 3

Module 3:

SCP reserves must be procured.

Joint cross-border procurement

Overall cheapest SCP is bought

Higher supply but stable demand could lead to lower prices



Module 2:Joint dimensioning of SCP reserves

15

Module 4

Module 4:

SCP is activated under consideration of energy costs (e.g. with respect to a merit order list).

Cross-border cost optimal SCP activation

Possible market based effects on control energy price

Module 3:Joint SCP procurement




16

Grid Control Cooperation Modules

Module 4:Cross-border cost-optimal SCP activation





17

Index





5. Summary and Outlook

18







19




Module 3:Joint SCP procurementonly organizational



20




Power Balance

SCP

ACE

SCP-request

Control Area A

Power Balance



SCP

ACE

SCP-request

Control Area C



Power Balance

SCP

ACE

SCP-request

Control Area B

other control areas

Technical and financial benefit through Grid Control Cooperation!

21

Secondary Control Optimization



Power Balance

SCP

ACE

SCP-request

Control Area A

Power Balance



SCP

ACE

SCP-request

Control Area C



Power Balance

SCP

ACE

SCP-request

Control Area B

other control areas

SC-Optimization

correction

correction

correction

correction

SCP demand SCP demand

SCP demand SCP demand

22

Integration into Secondary Control Structure

int,aP -

K f∆int,setP Secondary Controller Secondary ControlledPower Plant Units

sc,setP-ACEP

existing

sc,aP

distint,aP

-

23


int,aP -


sc,setP-ACEP

existing

sc,aP

24


-

corr,2 corr,3 corr,, , , iP P P

SC-Optimization

corr,1P

int,aP


sc,setPACEP

existing

newdemand,1P

demand,2 demand,3 demand,, , , iP P P

sc,aP-

25


- -


SC-Optimization

corr,1P

int,aP


sc,setPACEP

existing

newdemand,1P


sc,aP

Definition of SCP demand?

26


- -

SC-Optimization


corr,1P

int,aP


sc,setPACEP

-ACE corr,1P P−


existing

newdemand,1P

sc,aP

Demand = ACE without correction

27


- -

SC-Optimization


corr,1P

int,aP


sc,setPACEP

-ACE corr,1P P− sc,aP


existing

newdemand,1P

sc,aP

Demand = ACE without correction and without activated SCP

28


- -

SC-Optimization


corr,1P

int,aP


sc,setPACEP



existing

newdemand,1P

sc,aP

distint,aP

-


29


- -

SC-Optimization


corr,1P

int,aP


sc,setPACEP



existing

newdemand,1P

sc,aP

distint,aP

-

+


Demand contains no information fromclosed control loop –

Stability is guaranteed!

30


- -

SC-Optimization


corr,1P

int,aP


sc,setPACEP



existing

newdemand,1P

sc,aP

import/export boundson/off switch

31

Index






32

Grid Control Cooperation in Germany

TNG

TPS

Four control areas• Amprion GmbH (AMP)• TenneT TSO GmbH (TTG)• 50Hertz Transmission GmbH (50Hz)• EnBW Transportnetze AG (TNG)

AMP

50HzTTG

TNG

33



December 2008: Grid Control Cooperation launched by TNG,

50Hz and TTG Control areas remain independent

University of Stuttgart

AMP

50Hz

TNG

TTG

34

Example from Operation

0 5 10 15 20 25 30 35 40 45 50 55 60-400

-200

0

200

400

600

800

1000

1200

1400

SCP demands

MW

min.

TNG demand 50Hz demand TTG demand

0 5 10 15 20 25 30 35 40 45 50 55 60-400

-200

0

200

400

600

800

1000

1200

1400

35

Counteracting SCP Demands

SCP demands counteracting counteractingcounteractingcounteracting

MW

min.

TNG demand 50Hz demand TTG demand

36

Netted Demand

Netted SCP demand of all participants

0 5 10 15 20 25 30 35 40 45 50 55 60600

800

1000

1200

1400

1600

+ 1500 MW

+ 640 MW

MW

min.

GCC demand

37

TNG Demand


0 5 10 15 20 25 30 35 40 45 50 55 60-200

-100

0

100

200

300

400

500

600

700

800MW

min.

TNG demand

38



0 5 10 15 20 25 30 35 40 45 50 55 60-200

-100

0

100

200

300

400

500

600

700

800MW

min.

TNG demand TNG Module 1

39



0 5 10 15 20 25 30 35 40 45 50 55 60-200

-100

0

100

200

300

400

500

600

700

800MW

min.


Saved energy!

40



0 5 10 15 20 25 30 35 40 45 50 55 60-200

-100

0

100

200

300

400

500

600

700

800MW

min.


Cross-border cost optimization?

41

Goal: Cost Optimal Netted Demand Coverage


0 5 10 15 20 25 30 35 40 45 50 55 60600

800

1000

1200

1400

1600

+ 1500 MW

+ 640 MW

MW

min.

GCC demand

Cost optimization only for positive SCP demand needed

42

Positive Merit Order List

+ 640 MW

+ 1500 MW

Merit Order List Position

Available in TNG [MW]

Available in TTG [MW]

Available in 50Hz [MW]

Available in Total [MW]

1 20 0 0 20

2 0 55 0 75

3 40 0 0 115

4 0 160 0 275

5 160 0 0 435

6 0 35 0 470

7 320 0 0 790

8 0 0 433 1223

9 428 0 0 1651

(minimum demand)

(maximum demand)

Lowest energy price

Highest energy price

43

Positive Merit Order List

Coverage of minimum SCP demand (always activated)

Coverage of maximum SCP demand

Merit Order List Position

Available in TNG [MW]

Available in TTG [MW]

Available in 50Hz [MW]

Available in Total [MW]

1 20 0 0 20

2 0 55 0 75

3 40 0 0 115

4 0 160 0 275

5 160 0 0 435

6 0 35 0 470

7 320 0 0 790

8 0 0 433 1223

9 428 0 0 1651

+ 640 MW

+ 1500 MW

(minimum demand)

(maximum demand)

Lowest energy price

Highest energy price

44

TNG Demand and Module 1


0 5 10 15 20 25 30 35 40 45 50 55 60-200

-100

0

100

200

300

400

500

600

700

800MW

min.


45

TNG Module 1 and Module 4

0 5 10 15 20 25 30 35 40 45 50 55 60-200

-100

0

100

200

300

400

500

600

700

800

SCP demand, Module 1 and Module 4 correction signals

MW

min.

TNG demand TNG Module 1 TNG Module 4

0 5 10 15 20 25 30 35 40 45 50 55 60-200

-100

0

100

200

300

400

500

600

700

800

46

TNG – Effect of Correction Signal

MW

min.

TNG demand

SCP demand, correction signals and demand after correction

TNG Module 1 TNG Module 4 TNG corrected demand

47

50Hz – Effect of Correction Signal

MW

min.

50Hz demand 50Hz corrected demand

SCP demand and demand after correction

0 5 10 15 20 25 30 35 40 45 50 55 60-200

-100

0

100

200

300

400

500

48

TTG – Effect of Correction Signal

SCP demand and demand after correction

MW

min.

TTG demand TTG corrected demand

0 5 10 15 20 25 30 35 40 45 50 55 600

200

400

600

800

1000

1200

1400

49

Goal: Cost Optimal Netted Demand Coverage


0 5 10 15 20 25 30 35 40 45 50 55 60600

800

1000

1200

1400

1600

+ 1500 MW

+ 640 MW

MW

min.

GCC demand

50

Result of Grid Control Cooperation

Netted SCP demand of all participants and sum of secondary controller outputs

0 5 10 15 20 25 30 35 40 45 50 55 60600

800

1000

1200

1400

1600MW

min.

GCC demand Sum of secondary controller outputs

The sum of SCP activation = Netted GCC demand!

51

Index






52






AMP

TNG

50HzTTG

53





May 2010: AMP joins the Grid Control Cooperation

AMP

TNG


50HzTTG

54

Timeline of Implementation

Nov. Dec. Jan. Feb. Mar. Apr. May. Jun. Jul. Aug. Sep. Oct.

20092008

Module 1 Module 2 Module 3 Module 4

Module 1: Counteracting SCP avoidance (December 2008)

Common balancing energy price for participating control areas (May 2009)

Module 2: Joint dimensioning of SCP reserves (June 2009)

Module 3: Joint procurement (July 2009)

Module 4: Cross-border cost optimization (October 2009)

Common balancing energy price

55

Estimated Cost Savings for Germany


20092008

Module 1 Module 2 Module 3 Module 4

Module 1: Counteracting SCP avoidance (December 2008) – approx. 120 mil. € pa.

Common balancing energy price for participating control areas (May 2009)

Module 2: Joint dimensioning of SCP reserves (June 2009) – approx. 140 mil. € pa.

Module 3: Joint procurement (July 2009)

Module 4: Cross-border cost optimization (October 2009)

Common balancing energy price

double digit mil. € savings

56

Index



3. Modelling


5. Summary

57

Summary

Grid Control Cooperation:• Counteracting SCP avoidance (Module 1)• Joint dimensioning of SCP reserves (Module 2)• Joint SCP procurement (Module 3)• Cross-border cost-optimal SCP activation (Module 4)

58

Summary


Coordination of secondary control while maintaining the independence of participating control areas and power system stability

Congestion management system allows restriction power interchange within the Grid Control Cooperation framework

59

Summary


Coordination of secondary control while maintaining the independence of participating control areas and power system stability

Congestion management system allows restriction power interchange within the Grid Control Cooperation framework

Implementation in Germany:• Cost savings: approximately 300 mil. € pa.• Common balancing energy price• Harmonization of SCP market

60

The End

Thank you!

# Simplicity# Stability# Back-up plan# Cost savings# Market impact# Extension

AMP

VE-TTPS

TNG

Stuttgart


20092008

Module 1 Module 2 Module 3 Module 4Common balancing energy price

Module 4:Cost-optimal SCP activation





SecondaryController


Power Balance

SCP

ACE

SCP-request

Control Area A

Power Balance


SecondaryController

SCP

ACE

SCP-request

Control Area C

SecondaryController


Power Balance

SCP

ACE

SCP-request

Control Area B

other control areas

SC-Optimization

correction

correction

correction

correction

demand demand

demand demand

Powergrid 08.06.2010

- -

SC-Optimization


corr,1P

int,aP


sc,setPACEP



existing

newdemand,1P

sc,aP

import/export boundson/off switch

scheduled power plant units

secondary controller

Σ

secondary controlled power plant units

schedule

- -

-

- primary controlled power plants and

self-regulating effect

Σ

Σ

ΣK f∆

int,setP

sc,setP

sc,aP

ACEP

demandPcorrP

2,schedP

1,schedP

f∆

−load genP P

3,schedP

loadP

genP

int,aP

-

genP

zP

61

Modelling of Power Systems at IFK

12 oW

0o

12oE 24oE

36o E

30 oN

36 oN

42 oN

48 oN

54 oN Nonlinear, dynamic model of the ENTSO-E CE power system including: > 1000 power plant units > 3000 dynamic loads > 7000 transmission lines > 900 transformers Investigation of dynamic and stationary power

system behavior 400 kV 220 kV HDVC

Wide Area Monitoring: 8 frequency measuring units in Europe:

• Sevilla, Madrid, Aalborg, Gliwice, Zagreb, Timisoara, Athens and Stuttgart

2 frequency measuring units in Africa:• Algiers/Algeria + Sfax/Tunesia

19 frequency measuring units in Turkey

Summary Dynamic Load-Frequency Model

Control Area 1

Control Area n

Control Area 2

Control Area k

Rest

62

Summary dynamic load-frequency behavior of a synchronous network:

……


Control Area 1

Control Area n

Control Area 2

Control Area k

Rest

63


−load genP P

……


Control Area 1

Control Area n

Control Area 2

Control Area k

Rest

Summarized Network

Dynamics

64


f∆

−load genP P

……


Control Area 1

Control Area n

Control Area 2

Control Area k

Rest

SC-Optimization

Summarized Network

Dynamics

f∆

demand corr,P P

65


……

−load genP P

Control Area Model

schedule

66

Control Area Model

Σschedule

Σ

2,schedP

1,schedP

3,schedP

GenP

67

primary controlled power plants and




Σ

Σ

Control Area Model

Σschedule

-Σ

68





Σ

Σ

2,schedP

1,schedP

−load genP P

3,schedP

loadP

genP

genP

Control Area Model

Σschedule

-

-Σ

zP

69





Σ

Σ

2,schedP

1,schedP

−load genP P

3,schedP

loadP

genP

genP

Control Area Model

Σschedule

-

-Σf∆

zP

70





Σ

Σ

2,schedP

1,schedP

−load genP P

3,schedP

loadP

genP

genP

Control Area Model


Σschedule

- -

-Σf∆

71

-





Σ

Σ

sc,setPACEP

2,schedP

1,schedP

−load genP P

3,schedP

loadP

genP

int,aP

genP

zP

K f∆

int,setP

Control Area Model



Σ


schedule

- -

-



Σ

Σ

Σ

sc,setP

sc,aP

ACEP

demandPcorrP

2,schedP

1,schedP

f∆

−load genP P

3,schedP

loadP

genP

72

int,aP

-

genP

zP

K f∆

int,setP

Control Area Model



Σ


schedule

- -

-



Σ

Σ

Σint,setP

sc,setP

sc,aP

ACEP

demandPcorrP

2,schedP

1,schedP

f∆

−load genP P

3,schedP

loadP

genP

73

int,aP

-

genP

zP

control area disturbance from measurements

K f∆

74

Remarks

Control area model can be used to represent a balancing group

Dynamic power plant models:• linear approximations for input-output behavior (“TSO perspective”),• or detailed, nonlinear models for investigations of load-frequency control impact on

power plant units (“power plant perspective”)− different power plant types (coal-fired, hydraulic, nuclear etc.)− different operating modes (turbine in control, steam generator in control)

Simplifications with respect to the focus of investigations are possible

75

Remarks

Control area model can be used to represent a balancing group

Dynamic power plant models:• linear approximations for input-output behavior (“TSO perspective”),• or detailed, nonlinear models for investigations of load-frequency control impact on

power plant units (“power plant perspective”)− different power plant types (coal-fired, hydraulic, nuclear etc.)− different operating modes (turbine in control, steam generator in control)

Simplifications with respect to the focus of investigations are possible

Model validation based on comparison of simulated and published secondary control energy and costs:

• Simulation tends to overestimate activated control energy (and thus costs)• Overestimation error is smaller than 10%

grid control cooperation – coordination of secondary control · coordination of secondary...

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