A Novel Algorithm for Optimal Operation of Hydrothermal Power Systems under Considering the Constraints in Transmission Networks

Thang Nguyen,Nguyen Quynh,Bach Dinh,Le Dai,Minh Duong

doi:10.3390/en11010188

Thang Nguyen, Nguyen Quynh + Show 3 more

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https://doi.org/10.3390/en11010188

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Abstract

This paper proposes an effective novel cuckoo search algorithm (ENCSA) in order to enhance the operation capacity of hydrothermal power systems, considering the constraints in the transmission network, and especially to overcome optimal power flow (OPF) problems. This proposed algorithm is developed on the basis of the conventional cuckoo search algorithm (CSA) by two modified techniques: the first is the self-adaptive technique for generating the second new solutions via discovery of alien eggs, and the second is the high-quality solutions based on a selection technique to keep the best solutions among all new and old solutions. These techniques are able to expand the search zone to overcome the local optimum trap and are able to improve the optimal solution quality and convergence speed as well. Therefore, the proposed method has significant impacts on the searching performances. The efficacy of the proposed method is investigated and verified using IEEE 30 and 118 buses systems via numerical simulation. The obtained results are compared with the conventional cuckoo search algorithm (CCSA) and the modified cuckoo search algorithm (MCSA). As a result, the proposed method can overcome the OPF of hydrothermal power systems better than the conventional ones in terms of the optimal solution quality, convergence speed, and high success rate.

Highlights

Optimal power flow (OPF) is a complex problem for the operation of a power system due to its dependence on many equality and inequality constraints, such as the limit of active and reactive powers of electric generators, transformer tap positions, switchable capacitor banks, bus-voltage values, and capacity of lines transmission [1]
The hydrothermal scheduling (HTS) problem is relatively different from the optimal power flow (OPF) problem since the thermal and hydro units are included in power systems
The load of the first subinterval is fixed at values of the IEEE 30 buses system but the load of the second is reduced to 85% of the first subinterval

Summary

Introduction

Optimal power flow (OPF) is a complex problem for the operation of a power system due to its dependence on many equality and inequality constraints, such as the limit of active and reactive powers of electric generators, transformer tap positions, switchable capacitor banks, bus-voltage values, and capacity of lines transmission [1]. A solution is considered an optimal result if it gives the minimum fuel cost for all thermal units while satisfying all dependent variables and constraints. The hydrothermal scheduling (HTS) problem is relatively different from the OPF problem since the thermal and hydro units are included in power systems. The target of the HTS problem is to minimize the fuel cost of the thermal units in various scheduled sub-intervals while satisfying all constraints in the generators’ capacities, the balance of power systems, as well as limitations of water discharge, water balance, etc. The optimal operation of hydrothermal systems is divided into many sub-intervals, which is more complicated than a single sub-interval in the OPF problem

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Discussion

Conclusion