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Explore ABB's suite of power transmission test cases, including scenarios related to voltage collapse. This includes tap-controlled load generators, line tripping, load recovery, and generator field limit activation. The goal is to stabilize all voltages, minimize load shedding, and control voltage within specific limits.
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Summary:ABB Suite of Power Transmission Test Cases Mats Larsson Corporate Research ABB Switzerland Ltd. Jan 19, 2004
Tap Controlled Load Generator Voltage 1.05 Overload limit reached 1 0.95 Tap Changer Control 0.9 0 100 200 300 400 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
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 • 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
Collapse in 400 secs Case 1 – Tripping of Lines Vload[2] Vload[3] 1 0.9 0 100 200 300 400 GEfd[2] GEfd[3] 1.8 1.7 1.6 0 100 200 300 400 pos[2] pos[3] 15 10 5 0 0 100 200 300 400
Cap switch at 100 secs stabilizes Case 2 – Cap Switch in Area 2 Vload[2] Vload[3] 1.05 1 0.95 0.9 0 100 200 300 400 GEfd[2] GEfd[3] 1.8 1.7 1.6 0 100 200 300 400 pos[2] pos[3] 6 4 2 0 100 200 300 400 System.C2.step 1 0 0 100 200 300 400
Case 3 – Tap Reference Change (-5%) Vload[2] Vload[3] 1 0.98 0.96 0.94 0 100 200 300 400 GEfd[1] GEfd[2] 1.8 1.7 1.6 0 100 200 300 400 pos[2] pos[3] 6 4 2 0 0 100 200 300 400 • Tap reference at 100 secs stabilizes
Case 4 – Second line trip Vload[2] Vload[3] 1 0.8 0.6 0.4 0 100 200 300 400 GEfd[1] GEfd[2] 1.8 1.75 1.7 1.65 1.6 0 100 200 300 400 pos[2] pos[3] 12 8 4 0 100 200 300 400 • No longer stable ...
Case 5 – Added load shedding at bus 3 Vload[2] Vload[3] 1 0.96 0.92 0 100 200 300 400 GEfd[1] GEfd[2] 1.8 1.7 1.6 1.5 0 100 200 300 400 pos[2] pos[3] 4 2 0 0 100 200 300 400 • 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)
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
Generator Trip – No Emergency Control 4012 • 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 • At 30 s – Gen 1043 and 4042 at limit • Voltage support lost in middle and southern parts 4042 • At 50+ s – Tap changers restore load • Further voltage decrease • Collapse at 180 s 1043 4062
Generator Trip – Model Predictive Control Generator trip 1 0.95 Voltage (p.u.) 0.9 0.85 V1043 V4012 V4042 0.8 0 100 200 300 400 500 Time (sec)
Constraint Management 1.1 1.05 1 Armature Currents 0.95 0.9 0.85 200 400 600 800 1000