Voltage Control in Power Systems:Voltage Control in Power Systems:Preliminary ResultsPreliminary Results

T. Geyer, G. Ferrari-Trecate, T. Geyer, G. Ferrari-Trecate, M. Morari

Automatic Control LaboratoryAutomatic Control LaboratorySwiss Federal Institute of Technology (ETH)Swiss Federal Institute of Technology (ETH)

in collaboration with

Mats LarssonMats Larsson

ABBABB

Optimal Control ProblemOptimal Control Problem

Subject to Dynamics (in MLD form):

Soft constraints on bus voltages :

Receding Horizon ControlReceding Horizon Control

P re d ic te d o u tp u ts

M a n ip u la te d ( t+ k )uIn p u ts

t t+ 1 t+ m t+ p

fu tu rep a s t

t+ 1 t+ 2 t+ 1 + m t+ 1 + p

Optimize at time t (with new measurements) Only apply the first optimal move u(t) Repeat the whole optimization at time t +1 Advantage of on-line optimization: Feedback!

Tuning of Cost FunctionTuning of Cost Function

Violation of soft constraints is penalized by:

Choose weight R on u such that:

No constraint violation: nominal control: > ultc voltage reference

> capacitor bank

Constraint violation: emergency control: > all controls including load-shedding

Preliminary ResultsPreliminary Results

ConclusionsConclusions Control problem:

MPC is able to stabilize the load voltage V4m

with N=2 and Ts=15sec

without using load-shedding

solution time 8sec..2min (PC with 1GHz)

but: there remains a control error

Outlook: observer

model reduction

reachability analysis

large-scale problem