1. ABB Summary: ABB Suite of Power Transmission Test Cases Mats Larsson Corporate Research ABB Switzerland Ltd. Jan 19, 2004

2. 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 0100200300400 0.9 0.95 1 1.05 Tap Controlled LoadGenerator Voltage Overload limit reached Tap Changer Control

3. 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

4. “ Medium Scale” ABB Test Case 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

5. Case 1 – Tripping of Lines 0100200300400 0.9 1 Vload[2]Vload[3] 0100200300400 1.6 1.7 1.8 GEfd[2]GEfd[3] 0100200300400 0 5 10 15 pos[2]pos[3]  Collapse in 400 secs

6. Case 2 – Cap Switch in Area 2 0100200300400 0.9 0.95 1 1.05 Vload[2]Vload[3] 0100200300400 1.6 1.7 1.8 GEfd[2]GEfd[3] 0100200300400 2 4 6 pos[2]pos[3] 0100200300400 0 1 System.C2.step  Cap switch at 100 secs stabilizes

7. Case 3 – Tap Reference Change (-5%) 0100200300400 0.94 0.96 0.98 1 Vload[2]Vload[3] 0100200300400 1.6 1.7 1.8 GEfd[1]GEfd[2] 0100200300400 0 2 4 6 pos[2]pos[3]  Tap reference at 100 secs stabilizes

8. Case 4 – Second line trip 0100200300400 0.4 0.6 0.8 1 Vload[2]Vload[3] 0100200300400 1.6 1.65 1.7 1.75 1.8 GEfd[1]GEfd[2] 0100200300400 4 8 12 pos[2]pos[3]  No longer stable...

9. Case 5 – Added load shedding at bus 3 0100200300400 0.92 0.96 1 Vload[2]Vload[3] 0100200300400 1.5 1.6 1.7 1.8 GEfd[1]GEfd[2] 0100200300400 0 2 4 pos[2]pos[3]  Additional load shedding stabilizes

10. 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)

11. Possible work on new model  Scaling of Model-predictive approaches (ETH, Grenoble?)  Testing of decentralized schemes (Lund, Grenoble)  Requests for customized versions welcome...

12. 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 ~ 10 41 nodes

13.  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  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

14. Generator Trip – Model Predictive Control 0100200300400500 0.8 0.85 0.9 0.95 1 Time (sec) Voltage (p.u.) V1043 V4012 V4042 Generator trip

15. Constraint Management 2004006008001000 0.85 0.9 0.95 1 1.05 1.1 Armature Currents