harmony search algorithm (hsa)

This research article describes the frequency regulation of an interconnected power system that includes wind energy systems and thermal non-reheat systems, with a proportional integral derivative (PID) controller optimized using metaheuristic algorithms such as Genetic-Algorithm (GA), Harmony-Search-Algorithm (HSA), Bat-Algorithm (BA), and Flower-Pollination-Algorithm (FPA). With the demand for precisely efficient energy systems growing, system engineers are increasingly looking for the finely optimized control solution that also has the benefit of faster convergence and avoids entrapment in local minimal. To minimize the fitness function which is based on ITAE (Integral of Time multiplied Absolute Error) criteria composed of frequency and tie-line power changes, we have obtained an optimum solution in terms of PID controller gain values using the metaheuristics optimizing techniques. Change in frequency in area 1, deviation in tie-line power, and change in frequency in area 2 obtained from different techniques are compared. The results obtained by simulating MATLAB/Simulink convey that PID controller gain values optimized using the HSA technique provide better dynamic performance compared to BA, FPA and GA techniques. The simulation results have been experimentally validated using hardware-in-loop (HIL) on a real-time simulator based on field-programmable gate arrays (FPGA). The HSA optimized PID controller is used to investigate the robustness of the system by Step-Load-Perturbation (SLP) and Random Step Load Pattern (RSLP). Results obtained by running simulation also show that the HSA optimized PID controller for the same optimized gain value can withstand the SLP and RSLP variation made in the system.

Flexible AC transmission system devices can function efficiently, powerfully and economically in congestion management through the control of the lines transmission power and the voltage of the power systems buses. However, the congestion management of power systems may affect the transient stability or network voltage stability and also reduce the system security. Therefore, constructing congestion management requires the consideration of power system stability. In this paper, a multi-objective Fuzzy structure is employed so as to obtain the optimal locating and sizing of unified power quality conditioner-phase angle control for the congestion management so that it optimizes total operating cost, voltage and transient security. In order to achieve the above goals, unified power quality conditioner-phase angle control placement has been performed using Fuzzy method. Using Fuzzy inference system, triple objective functions are expressed in terms of a single objective function and optimized with the Harmony search algorithm. To illustrate the effectiveness of the proposed approach, this method is implemented in MATLAB software for the congestion management of England's new network with 39 buses. The results indicate that using the proposed method, congestion management is done optimally, which not only does not reduce system security, but also increases the its security margin.

Due to the increasing interest on renewable sources in recent years, the studies on integration of distributed generation to the power grid have rapidly increased. In order to minimize line losses of power systems, it is crucially important to define the size and location of local generation to be placed. Minimizing the losses in the system would bring two types of saving, in real life, one is capacity saving and the other one is energy saving. In this paper, our aim would be optimal distributed generation allocation for voltage profile improvement and loss reduction in distribution network. Harmony Search algorithm (HSA) was used as the solving tool; the problem is defined and objective function is introduced according to losses, security and cost indices. The applied load flow method is based on the equivalent current injection that uses the bus-injection to branch-current (BIBC) and branch-current to bus-voltage (BCBV) matrices which were developed based on the topological structure of the distribution systems. This method is executed on 13 bus unbalanced distribution system and show robustness of this method in optimal and fast placement of DG, efficiency for improvement of voltage profile, reduction of power losses and cost.

Some applications of FACTS devices prove them proper and effective instruments for controlling the technical parameters of power systems. Applying a suitable objective function to optimal placement of FACTS devices plays a very important role in economic improvement of a power market. In this paper, an effective method has been presented for optimal placement of FACTS devices in order to increase the voltage stability and to decrease the losses considering the investment cost of the FACTS devices and the total fuel cost of the power system. Therefore, the Harmony Search Algorithm (HSA) is applied in this paper for simultaneous locating as well and for determining the sizes of both the series and parallel devices (SSSC, STATCOM) in a multi-objective structure. Since the optimization is multi-purpose, a fuzzy system is used in order to find the best solution. The effectiveness of the proposed method is demonstrated using the modified 30-bus IEEE test system. Comparing the results achieved by the suggested algorithm with those of the PSO and GA, the proper efficiency of the presented algorithm will be enforced.