Summary:

ABB Suite of Power Transmission Test Cases

Mats LarssonCorporate Research

ABB Switzerland Ltd.

Jan 19, 2004

Collapse Scenario

Line tripping (L3) after 100 s Inherent Load Recovery Tap Changer Tries to Restore Voltage Generator field limit activated at 286 s Collapse

0 100 200 300 4000.9

0.95

1

1.05Tap Controlled Load Generator Voltage

Overload limit

reached

Tap Changer

Control

Control Objectives

Stabilize all voltages within 0.9 - 1.1 p.u.

Use minimal amount of load shedding

Control voltage at bus 4 as close as possible to 1 p.u.

Capacitor and tap changer control can be used freely

“Medium Scale” ABB Test Case

inf

G3

StrongNetwork

Area 1

Area 2

Area 3

• Three copies of small case

• Similar control objectives

• Recovery dynamics in :• load (continuous)

• Transformers (discrete)

Inputs:

• Line impedances (disturbance)

• 3 Capacitors

• 3 Voltage Refs. Transformer (optional)

• 3 Load shedding

Outputs:

• 3 Load voltages

• 2 Generator field voltages

Case 1 – Tripping of Lines

inf

G3

Area 1

Area 2

Area 3

0 100 200 300 400

0.9

1

Vload[2] Vload[3]

0 100 200 300 400

1.6

1.7

1.8 GEfd[2] GEfd[3]

0 100 200 300 400

0

5

10

15 pos[2] pos[3]

Collapse in 400 secs

Case 2 – Cap Switch in Area 2

inf

G3

Area 1

Area 2

Area 3

0 100 200 300 4000.9

0.95

1

1.05Vload[2] Vload[3]

0 100 200 300 4001.6

1.7

1.8GEfd[2] GEfd[3]

0 100 200 300 4002

4

6

pos[2] pos[3]

0 100 200 300 400

0

1

System.C2.step

Cap switch at 100 secs stabilizes

Case 3 – Tap Reference Change (-5%)

inf

G3

Area 1

Area 2

Area 3

0 100 200 300 400

0.94

0.96

0.98

1Vload[2] Vload[3]

0 100 200 300 400

1.6

1.7

1.8GEfd[1] GEfd[2]

0 100 200 300 400

0

2

4

6pos[2] pos[3]

Tap reference at 100 secs stabilizes

Case 4 – Second line trip

inf

G3

Area 1

Area 2

Area 3

0 100 200 300 4000.4

0.6

0.8

1

Vload[2] Vload[3]

0 100 200 300 4001.6

1.65

1.7

1.75

1.8 GEfd[1] GEfd[2]

0 100 200 300 400

4

8

12 pos[2] pos[3]

No longer stable ...

Case 5 – Added load shedding at bus 3

inf

G3

Area 1

Area 2

Area 3

0 100 200 300 400

0.92

0.96

1

Vload[2] Vload[3]

0 100 200 300 4001.5

1.6

1.7

1.8 GEfd[1] GEfd[2]

0 100 200 300 400

0

2

4 pos[2] pos[3]

Additional load shedding stabilizes

Model Complexity

6 disturbance inputs - (0,1,2)

Control inputs:

3 capacitors - (0,1)

3 load shedding – (0,1,2,3)

3 tap voltage refs – (0.8–1.2)

Continuous dynamics:

3 loads (2 dynamic states each)

Discrete dynamics:

3 transformers (3 states each)

2 generator limiters (2 states each)

inf

G3

StrongNetwork

Area 1

Area 2

Area 3

Possible work on new model

Scaling of Model-predictive approaches (ETH, Grenoble?)

Testing of decentralized schemes (Lund, Grenoble)

Requests for customized versions welcome ...

Large scale case – CIGRE Nordic 32

52 Discrete control inputs Load shedding

Generator voltage setpoints

Tap changers

10 Controlled outputs Load voltages

67 Constrained outputs All voltages, generator currents

State-space ~ 1041 nodes

At 10 s – Gen 4062 Trips Lost generation compensated by

hydro units in the north Increased losses in transmission

corridor, lower voltage in southern region

Generators in the south increase reactive power production

Generator Trip – No Emergency Control

4062

1043

4042

4012

0 50 100 1500.8

0.85

0.9

0.95

1

Time (sec)

Vo

ltag

e (

p.u

.)

V1043V4012V4042

0 50 100 1500.8

0.85

0.9

0.95

1

Time (sec)

Vo

ltag

e (

p.u

.)

V1043V4012V4042

0 50 100 1500.8

0.85

0.9

0.95

1

Time (sec)

Vo

ltag

e (

p.u

.)

V1043V4012V4042

At 30 s – Gen 1043 and 4042 at limit Voltage support lost in middle and

southern parts

At 50+ s – Tap changers restore load Further voltage decrease Collapse at 180 s

Generator Trip – Model Predictive Control

0 100 200 300 400 5000.8

0.85

0.9

0.95

1

Time (sec)

Vo

ltag

e (

p.u

.)

V1043V4012V4042

Generator tripTime Control

30 tap T4041-41 +1 step 30 tap T4042-42 +1 step 30 tap T4061-61 +1 step 30 tap T4062-62 +1 step 30 Gen 1043 s.p. -3 steps30 Gen 2032 s.p. +1 step 30 Gen 4021 s.p. +1 step 30 Gen 4041 s.p. +1 step 30 Gen 4042 s.p. -2 steps30 Gen 4047 s.p. +2 steps60 tap T4041-41 +1 step 60 tap T4042-42 +1 step 60 tap T4047-47 -1 step 60 tap T4061-61 +1 step 60 Gen 2032 s.p. +1 step 60 Gen 4021 s.p. +1 step 60 Gen 4041 s.p. +1 step 60 Gen 4047 s.p. +1 step 90 Gen 4021 s.p. +1 step 120 Gen 4041 s.p. +1 step 150 Gen 2032 s.p. +1 step 300 tap T4047-47 -1 step 330 tap T4046-46 -1 step

Constraint Management

200 400 600 800 1000

0.85

0.9

0.95

1

1.05

1.1

Arm

atu

re C

urr

en

ts