Interior point methods for power flow optimization with security constraints

• Author: C. Lyra,L. Casacio,A.R.L. Oliveira
• Date: 01 January 2019
• DOI: http://doi.org/10.1111/itor.12279
• Published date: 01 January 2019

Intl. Trans. in Op. Res. 26 (2019) 364–378

DOI: 10.1111/itor.12279

INTERNATIONAL

TRANSACTIONS

IN OPERATIONAL

RESEARCH

Interior point methods for power flow optimization

with security constraints

L. Casacioa,C.Lyra

aand A.R.L. Oliveirab

aSchool of Electrical and Computer Engineering, University of Campinas (UNICAMP), Av. Albert Einstein 400,

13083-852 Campinas, S˜

ao Paulo, Brazil

bApplied Mathematics Department, University of Campinas (UNICAMP), Rua SergioBuarque de Holanda, 651,

13083-859 Campinas, S˜

ao Paulo, Brazil

E-mail: luciana@densis.fee.unicamp.br [Casacio]; chrlyra@densis.fee.unicamp.br [Lyra];

aurelio@ime.unicamp.br[Oliveira]

Received 2 August 2015; received in revised form 30 November2015; accepted 15 February 2016

Abstract

This paper deals with power flow optimization with security constraints, focusing on the problem of short-

term hydroelectric scheduling, called predispatch. Since the energy demand varies throughout the day, the

generation must satisfy daily targets, established by long-term scheduling models. This study considers that

the hydroelectric plants and transmission systems must provide an optimal flow of energy under security

constraints that allow meeting energy demands for normal operating conditions and when disturbances

happen. Algebraic techniques are used to exploit the sparse structure of the problem, targeting the design of

an interior point algorithm, efficient in terms of robustness and computational time. Case studies compare

the proposed approach with a general purpose optimization solver for quadratic problems and an algorithm

for the predispatch problem that does not consider security constraints.The results show the benefits of using

the method proposed in the paper, obtaining optimal power flow that is suitable to consider contingencies,

with numerical stability and appropriate computational time.

Keywords: optimal power flows; security constraints; predispatch problem; convex cost flow; interior point methods;

power systems

1. Introduction

The operations of large powersystems require specialized methods to optimiz e the use of resources,

in order to minimize costs and losses of the generation and the transmission of energy. Furthermore,

the system must be prepared to cope with unexpected events.

Since energy demand varies throughout the day, the generation must follow the variations of the

load. During the predispatch of hydroelectrical systems, the plants should satisfy goals established

through long-term planning. Furthermore, it is necessary to regard,in every time period, the security

C

2016 The Authors.

International Transactionsin Operational Research C

2016 International Federation ofOperational Research Societies

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