harmony search algorithm

Maintaining the voltage profile of the power system within the appropriate bound has been a key factor for the proper operation of system equipment, especially during disturbances. However, due to the uncertainty of the load powers and the limitation in equipment ratings, achieving this goal has become a challenge. High voltage substations play an important role in voltage control, because these substations can be a primary connection point between the high voltage transmission network and the distribution system. The nature of local voltage control, the variety of control tools and the interaction between them, have made this type of control difficult. In this paper, a centralized voltage/reactive power control method is presented based on phasors measured by PMUs installed in grid substations. In this method, the tap changing of transformers and step switching of capacitor banks have been determined by the central controller based on system voltages and network equations. In addition, the appropriate values of the operating point of the generators have been carried out based on economic dispatch in each period of optimization. The consistent and efficiency of the proposed method have been investigated through simulation in MATLAB software environment.

Nowadays, distributed generation (DG) is widely used in power systems. However, the use of DGs has caused new challenges in different aspects of power system operation, one of which is the effect of DGs on the optimal load shedding. Load shedding is a remedial action triggered after disturbances such line tripping. In fact, due to the line outage, the power flowing through other lines will increase which may cause protection systems to operate to trip the overloaded lines and in severe cases result in the system collapse. In this paper, a general load shedding method is proposed to prohibit the system from moving toward collapsing and helping the system to restore in the presence of DGs. In the proposed method, firstly the most critical line whose outage leads to the minimum values of stability indices is determined. Then, after putting this line out of service, harmony search algorithm is used to find the minimum amount of load shedding as well as the optimal location of DGs so that the loadability of the system is maximized preventing the system to collapse. The efficacy of the proposed methodology is demonstrated through applying it on IEEE 14 and 30-bus systems using various scenarios.

Wireless sensor networks are a large number of sensor nodes with limited energy in a scattered geographically limited area. Due to limited resources in wireless sensor networks, increasing the lifetime of the networks by reducing energy consumption is always considered. More nodes to send data to the central station energy consumption. Sequential routing based on clustering, this responsibility falls on the head, and this increases the energy consumption of cluster heads. In recent years later all the energy of cluster heads, routing protocols and a lot of clustering is proposed. The purpose of this study, the combination of clustering and routing in order to extend the lifetime of this type of network. For clustering of genetic algorithm with fixed and harmony search algorithm is used for routing. Customize search algorithm for routing in harmony, three criteria neighborhood, reducing energy consumption and proper distribution of energy consumption is taken into account. Harmony algorithm is proposed to establish a proper balance between the criteria listed will generate more efficient routes. Finally change the routing cluster heads in each round will be balancing energy consumption between nodes per cluster. The results of the tests show the superiority of 2.14% proposed increase in messaging as well as 24.84% Lifetime network protocol is DEEC.