Reactive power optimization
View Patent ↗Var optimization (VARO) is a subsystem of a voltage and var optimization (VVO) system that processes a capacitor switching optimization problem. The VARO is a self contained process that may work stand alone or in conjunction with a Voltage Regulation Optimization (VRO) system to provide integrated VVO solutions. The VARO system takes network inputs and calculates optimal settings for distribution network capacitor banks.
1. A computer program product for determining optimal capacitor bank switching in a distribution network, comprising: a non-transitory computer readable medium having computer readable code embedded therein, the computer readable code comprising:
program instructions that receive a network model and builds a set of controls S c and a set of conductors S b in the network model;
program instructions that solve a base case unbalanced load flow for a base network;
program instructions that determine initial current values I i d (0), I i q (0) for each conductor S b in the base case;
program instructions that initialize the load flow model to an initial case and, for each control in S c ;
program instructions that perturbs the capacitor status for each control in S c and determines a new load flow for the model with the perturbed capacitor status;
program instructions that calculate new currents I i d , I i q for each conductor in S b using the new load flow and determine current sensitivity vectors S d , S q according to ΔI i d =I i d −I i d (0),ΔI i q =I i q −I i q (0);
program instructions that constructs, using the initial load flow solution and the current sensitivity vectors S d , S q , a mixed integer quadratically constrained quadratic optimization problem (MIQCQP);
program instructions that solve said MIQCQP to output optimal control settings for S c ; and
program instructions that output said optimal control settings.
2. The computer program product according to claim 1 wherein said MIQCQP is calculated according to:
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wherein i=index of a conductor in S b ;
I i d =real part of the complex current through i-th conductor;
I i q =imaginary part of the complex current through i-th conductor;
r i =resistance of the i-th conductor in S b ; S i d , S i q =current sensitivity vectors; U =control variable vector; U lb =lower bound of the control variable vector; and U ub =upper bound of the control variable vector.
3. A method for determining optimal capacitor bank switching in a distribution network, the method comprising:
receiving a network model and builds a set of controls S c and a set of conductors S b in the network model;
solving a base case unbalanced load flow for a base network;
determining initial current values I i d (0), I i q (0) for each conductor S b in the base case;
initializing the load flow model to an initial case and, for each control in S c ;
perturbing the capacitor status for each control in S c and determines a new load flow for the model with the perturbed capacitor status;
calculating new currents I i d , I i q for each conductor in S b using the new load flow and determine current sensitivity vectors S d , S q according to ΔI i d =I i d −I i d (0),ΔI i q =I i q −I i q (0);
constructing, using the initial load flow solution and the current sensitivity vectors S d , S q , a mixed integer quadratically constrained quadratic optimization problem (MIQCQP);
solving said MIQCQP to output optimal control settings for S c ; and
outputing said optimal control settings.
4. The method according to claim 3 wherein said MIQCQP is calculated according to:
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I
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d
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q
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q
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∀
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∈
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b
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l
b
≤
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≤
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ub
u
∈
n
wherein i =index of a conductor in S b ;
I i d =real part of the complex current through i-th conductor;
I i q =imaginary part of the complex current through i-th conductor;
r i =resistance of the i-th conductor in S b ;
S i d , S i q =current sensitivity vectors;
U=control variable vector;
U lb =lower bound of the control variable vector; and
U ub upper bound of the control variable vector.