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Thesis Proposal

Reactive Power Market Clearing Scheme

By: Ting ZhangSupervisor: Dr. B. Venkatesh

23 November 2006

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Outline

Introduction

Objective

Problem Statement

Progress to date

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Introduction Reactive power supply plays an important role in the power

system.

In former deregulated power system: supply of real and reactive power was charged in a composite fashion.

After deregulation of power systems, supply of real power andancillary services such as reactive power support have to beunbundled & priced independently.

CompositePower Supply

Real Power Supply

Ancillary Servicesincluding reactive power

supply

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Reactive power market is established to trade reactive power. In this market, there are vendors and customers.

Fig. 2 A schematic representation of a reactive power market

Introduction

GenerationSystems

TransmissionSystem

DistributionSystems

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Introduction

Elements of the power system that have to befinancially compensated for their participation in the

reactive market :*Generators*Shunt reactive elements

*Transformers

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Objective

The main objective of reactive power market clearingscheme in the deregulated power system is to

minimize the total cost of reactive power supplywhile benefiting from transmission loss minimizationand maintaining an acceptable voltage profile.

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Objective

Cost from Generator:P

Q Leading Lagging If 2Rf

Ia2Ra

OpportunityCosts

Fig. 3 Reactive power cost components

OpportunityCosts

A B C

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Objective

Aggregating these costs, a total cost curve for reactive power output of a synchronous generator is shown inFig. 4 :

Constraints that should besatisfied:

Fig.4 The i th generator reactive power cost curve

1UGk

ik

QA QB QC QG

Leading Lagging

QGC

UG i1 UG i2 UG i3 UG i4

k ik ik i

k ik ik QG*UGQGQG*UG

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Objective

The cost of reactive power generation can beexpressed as below:

NG

1i k ik ik ik iik UG*KGoUG*QG*KG

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Objective Cost from Compensators:

Cost of reactive power output from controllableVAR sources can be expressed in general as:

Fig.5 VAR source reactive power cost curve

NS

1iiiii US*KSoKS*QS

QSi

QSCi KSi

KSoi

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Objective

Cost from transformers :Cost of shifting taps of transformers can be expressedin general as:

NTR

1iii UT*KTo

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Problem Statement The non-linear mixed integer formulation can be

stated as below:OBJ =

+

+

+ KL*PL(X , Y , d

NG

1i k ik ik ik iik UG*KGoUG*QG*KG

NS

1iiiii US*KSoKS*QS

NTR

1iii UT*KTo

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Problem Statement

Subject to: Control Vector Constraints Dependent Vector Constraints Power Flow Constraints

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Progress to date

Formulate the mathematical model of a Mixed Integer LP (MILP) of reactive power optimization in

deregulated system.

Coding of MILP using MATLAB.

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Thank you!