Songsak Chusanapiputt

A solution to the Optimal Power Flow using Artificial Bee Colony algorithm

Optimal Power Flow (OPF) is one of the most vital tools for power system operation analysis, which requires a complex mathematical formulation to find the best solution. Conventional methods such as Linear Programming, Newton-Raphson and Non-linear Programming were previously offered to tackle the complexity of the OPF. However, with the emergence of artificial intelligence, many novel techniques such as Artificial Neural Networks, Genetic Algorithms, Particle Swarm Optimization and other Swarm Intelligence techniques have also received great attention. This paper described the use of Artificial Bee Colony (ABC), which is one of the latest computational intelligence to solve the OPF problems. The results show that solving the OPF problem by the Artificial Bee Colony can be as effective as other swarm intelligence methods in the literature.

Optimal SVC and TCSC Placement for Minimization of Transmission Losses

Proper placement of static VAR compensator (SVC) and thyrlstor controlled series compensator (TCSC) reduces transmission losses, increases the available capacity, and improves the voltage profile. This paper presents an optimal placement of SVC and TCSC to determine SVC and TCSC locations and control parameters for minimization of transmission loss. Optimal location method utilizes the sensitivity of total real power transmission loss with respect to the control parameters of devices and multiply with new equation. The new equation of SVC is sum of reactive power flow that has relationship with bus and the new equation of TCSC is sum of real power loss that has relationship with transmission line. The method of optimal control parameters utilizes the interior point method for the minimizing real power loss. The results have been obtained on IEEE 14 bus, IEEE 30 bus, and IEEE 57 bus test system. Test result shows that both SVC and TCSC can determine optimal placement.

Diversity control approach to ant colony optimization for unit commitment problem

This paper presents a new method to solve the constrained unit commitment problem by applying ant colony optimization (ACO) based on the diversity control approach. The pheromone updating rule is modified to control the diversification by adopting a simple mechanism for random selection in ACO. The proposed method is tested on the 10-unit test system with a scheduling time horizon of 24 hours. The numerical results show an economical saving in the total operating cost when compared to the previous literature results. Moreover, two types of the proposed diversity control technique have the features of easy implementation and a better convergence rate superior to a standard ACO.

Reactive tabu search for optimal power flow under constrained emission dispatch

This paper presents an efficient method to obtain the optimal power flow (OPF) problem under constrained emission dispatch by applying reactive tabu search (RTS) algorithm. The RTS is developed as a derivative-free optimization technique in solving constrained emission OPF problem significantly reduces the computational burden with the strategies that make the search process robust and fast. The effectiveness of the proposed approach has been demonstrated through the IEEE 30-bus, 6-generator, test system. The simulation results reveal that the proposed RTS can yield highly optimal solution and tan reduce computational execution time superior to a standard tabu search. Moreover, the proposed method provides better solution than previous literatures with promising results.

A hybrid cultural-based Bee Colony Algorithm for solving the optimal power flow

Optimal Power Flow (OPF) is one of the most vital tools for power system operation analysis, which requires a complex mathematical formulation to find the best solution. Conventional methods such as Linear Programming, Newton-Raphson and Non-linear Programming were previously offered to tackle the complexity of the OPF. However, with the emergence of artificial intelligence, many novel techniques such as artificial intelligence and swarm intelligence approaches have also received great attention. This paper described the use of Cultural-based Bee Colony to solve the OPF problems. The results show that solving the OPF problem by the Cultural-based Bee Colony are more effective than other swarm intelligence methods in the literature.

Hybrid ant system/priority list method for unit commitment problem with operating constraints

This paper presents a new method to solve unit commitment problem with operating constraints using a hybrid ant system/priority list method (HASP). The proposed methodology employs ant system in cooperating with the priority list method to find unit commitment solution as means of mutually combining the advantages of them in that a flexibility of the priority list method is reinforced, while AS algorithm can gain the benefit of using bias information for improving its performance during search process. The simulation results show that the proposed HASP is capable of obtaining satisfactory solution within reasonable computational time. Moreover, the proposed HASP can be extensively applied to handle the ramp rate limits and the operating reserve constraint, which are important for modern power system operation.

A solution to unit commitment problem using hybrid ant system/priority list method

This paper presents a new method to solve unit commitment problem with operating constraints using a hybrid ant system/priority list method (HASP). The proposed methodology employs ant system in cooperating with the priority list method to find unit commitment solution as means of mutually combining the advantages of them in that a flexibility of the priority list method is reinforced, while AS algorithm can gain the benefit of using bias information for improving its performance during search process. The simulation results show that the proposed HASP is capable of obtaining satisfactory solution within reasonable computational time.

Increasing of Dynamic Thermal Rating of Transmission Line

The thermal rating of transmission lines has been known for a long time that it is over designed. The rating can be increased through an application of dynamic thermal rating methods, which consider the real time state of each parameter rather than those of the worst case. The paper is focused the basic concepts for the dynamic thermal rating of transmission line, and considered how it is calculated and how it impacts to the system during operation. Finally, by considering of each parameter as random variable with an appropriated probability distribution, the obtained results from the proposed method have been shown.

Relativity Pheromone Updating Strategy in Ant Colony Optimization for Constrained Unit Commitment Problem

This paper presents a development of the enhanced ant colony optimization (EACO) based on a novel approach of the relativity pheromone updating strategy (RPUS) for solving constrained unit commitment problem which cooperates with the candidate path management module (CPMM) embedded the effective repairing heuristic module (ERHM) in reducing search space and recovering a feasible optimality region so that a high quality solution can be acquired in a very early iterative. The adoption of RPUS not only enhances the search convergence of EACO, but also provides relatively pheromone information that is suitably exploited for a good guidance of search process. The EACO algorithms have been performed on a test system up to 100 generating units with a scheduling time horizon of 24 hours. The numerical results show better economical saving in the total operating cost when compared to the previous literature results. Furthermore, the proposed EACO topology can remarkably speed up the computation time of ant colony optimization algorithms, which is favorable for a large-scale UC problem implementation.

The Line P-Q Curve for Steady-State Voltage Stability Analysis

Generally, resistances and susceptance of transmission lines are neglected in determining voltage stability limit. Differently, this paper includes such parameters to form the P-Q curve analyzed as a rotated parabola. In the region inside the line P-Q curve, a power system can operate normally, but in the outside the system operation is impossible. The line voltage collapse coefficient is determined by using the concept of the line P-Q curve. This coefficient can be used to find weak lines in the power system. It relates to the minimal distance of the P-Q boundary curve, the probability of safe load transmission and the probability of positive bus influence on load transmission. The minimal distance and the probability of safe load transmission can be determined by equations in this paper. While the probability of positive bus influence on load transmission is given from the exact post-contingency analysis with a P-V curve. The lower the values of line voltage collapse coefficient, the weaker the transmission line. The threshold of line voltage collapse is shown in this paper. The proposed method is tested on the modified IEEE 14-bus test system. The result shows that some transmission lines would be monitored carefully to prevent voltage collapse. In practice, this method can detect the weak lines. We can solve the voltage collapse problem before it occurs.