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Material Type: Assignment; Class: Electrical Machine Design; Subject: Electrical and Computer Engr; University: University of Illinois - Urbana-Champaign; Term: Fall 2007;
Typology: Assignments
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Room 339 Everitt Lab Homework 7
Problem 1. [40 points] Impacts of a double-line outage contingency We consider the simultaneous outage of two lines ′and ′′. Let
Δ f denote the changes in the active power line flow on line due to the simultaneous outage of lines
′and
We express Δ f as the linear combination of the pre-outage active power line flows on lines ′and ′′: Δ f = χ ′ f (^) ′+ χ (^) ′′ f (^) ′′ where χ ′and χ ′ ′are called LODF s for two line outage contingencies. Use two different schemes to determine χ ′and χ ′ ′: i ) simultaneous outages ii ) sequential outages Show that the two schemes lead to identical results.
Problem 2. [40 points] UTC evaluation considering two – line outage contingency In the evaluation of the UTC u m,n^ , we have considered the active power line flow constraints for the base case and single line outage contingency cases. Now, we want to take into account also the constraints for contingencies in which two lines are outaged simultaneously. Formulate the optimization problem using the appropriate distribution factors to determine u m,n^ considering the constraints for all the following conditions: i ) the base case ii ) the set of single line outage contingencies for the subset
iii ) the set of double-line outage contingencies for the subset L : each pair of lines in L is outaged simultaneously
Problem 3. [40 points] Impacts of the load levels on the sensitivity matrix
The ISF s are approximations of the sensitivity matrix d d^ fp s(^0 )
whose values depend on the
load level of the system. We investigate the impacts of the nodal injections on the sensitivity matrix by studying the sensitivity of each element in the sensitivity matrix to the injection
vector p : (^) dd p^ ⎡ ⎣ ⎢ (^) d^ d pf n ⎤ ⎦ ⎥ s(^0 )
. We consider a lossless system with the load level close to zero,
i.e., θ (^0 )^ ≈ 0 , p(^0 )^ ≈ 0 ; we assume that the reactance compensation is sufficient at each node so that the voltage magnitude at each node is constant and close to 1.0 p.u. Prove that, if the Jacobian matrix J θ = 0 ,V = 1 is nonsingular, then
d d p
d f d pn
⎦^ ⎥ θ = 0 ,V = 1 ≈^0 ∀^ ^ ∈^ L^ ,^ ∀^ n^ ∈^ N^.
State any additional assumptions that you require.