We present a constructive approach to obtain information about the compactness and shape of large-scale lowest excitations in disordered systems by studying order parameter fluctuations (OPF) at low temperatures. We show that the parameter G that measures OPF is 1/3 at T = 0 provided the ground state is unique and the probability distribution for the lowest excitations is gapless and with finit...

This paper presents two new Particle swarm optimization methods to solve optimal power flow (OPF) in power system incorporating flexible AC transmission systems (FACTS). Two types of FACTS devices, thyristor-controlled series capacitor (TCSC) and thyristor controlled phase shifting (TCPS), are considered. In this paper, the problems of OPF with FACTS are solved by using particle swarm optimizat...

Optimal Power Flow (OPF) is one of the main functions of Power Generation Operation and Control. It determines the optimal settings of generating units, bus voltage, and transformer tap and shunt elements in Power System with the objective of minimizing total production costs or losses while the system is operating within its security limits. The aim of this paper is to propose a methodology (G...

This paper presents a novel probabilistic optimization algorithm for simultaneous active and reactive power dispatch in power systems with significant wind power integration. Two types of load and wind-speed uncertainties have been assumed that follow normal and Weibull distributions, respectively. A PV bus model for wind turbines and the wake effect for correlated wind speed are used to achiev...

This paper proposes an artificial bee colony (ABC) algorithm for solving optimal power flow (OPF) problem. The objective of the OPF problem is to minimize total cost of thermal units while satisfying the unit and system constraints such as generator capacity limits, power balance, line flow limits, bus voltages limits, and transformer tap settings limits. The ABC algorithm is an optimization me...

Modern power networks often have partitioned structures, with disjoint parts of the network being operated by competing agents. It is therefore of significant interest to be able to solve the Optimal Power Flow (OPF) problem for the entire network in a distributed manner without requiring significant exchange of sensitive operational information between rival operators. For networks whose regio...

Different energy infrastructures, such as electricity, natural gas and local district heating systems utilized for the energy supply are most often planned and operated independently of each other. This paper addresses the optimization of combined electricity and natural gas networks. The couplings between the two energy infrastructures are taken into account with the novel concept of energy hu...

Optimal power flow (OPF) over power transmission networks poses challenging large-scale nonlinear optimization problems, which involve a large number of quadratic equality and indefinite quadratic inequality constraints. These computationally intractable constraints are often expressed by linear constraints plus matrix additional rank-one constraints on the outer products of the voltage vectors...

Introduction: Optimal power flow (OPF) is an enhanced form of the economic dispatch (ED) optimisation problem where both active and reactive powers are treated as control variables and adjusted to minimise generation cost while observing associated power flow constraints. The constraints include but are not limited to thresholds on bus voltages, reactive power generation and the thermal ratings...

Under the competitive environments, power companies may calculate optimal power flow (OPF) in many occasions: especially for such real time applications as contingency analysis and congestion management. However, caused by congestions, etc., it is not guaranteed that OPF has the feasible solution in every calculation case. This paper proposes a new optimal power flow calculation model applicabl...