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Energy storage systems (ESSs) are the key elements to improve the operation of power systems. On the other hand, these elements challenge the power system planners. The difficulties arise as a result of the ESSs' economic and technological features. The cycle life of ESSs is a critical aspect that influences the choices made during expansion planning processes. In this manuscript, we have focused on a new model for the expansion planning of ESSs considering the impacts of technical properties, such as the cycle life and depth of discharge. For this purpose, the proposed model consists of the hourly operation planning of ESSs in the sample days of year. A new indicator is proposed to determine the daily charging/discharging cycles of ESSs. Numerical results show the ability of the proposed model to determine the optimal technology and capacity of ESSs.

Wireless sensor networks are as series sensor node in very small dimensions with the capability of sensing the surrounding environments, processing the data which is sensed; and, sharing the data between each other in wireless form. Despite numerous capabilities of these nodes, as their energy is supplied by batteries with limited power, they have limited life. In fact, the restrictions in the energy of nodes and the life span of a network poses as one of the important challenges in (using) these networks. The sensor nodes shall have the characteristics of low consumption capability; thus, in designing the nodes hardware, one must try to use designs and parts with low consumption. Furthermore, providing the sleep mode for the whole node or each section separately is highly important. Therefore, we suggest a combo-switch in which, the Micro—Electromechanical switch is used as a MOSFET switch functions as a gate MOSFET driver with the applicability of energy collection systems. The Power Administration Circuits which use combo-switch have the capacity of very low loss and no leakage, autonomous property and high current transmission capability. The measurements show solar energy collection circuits that use combo-switches collect energy without any power supply sources and voltage source, they charge the battery or drive resistive load. The current leakage during energy collection is very low; therefore, power administration which uses the proposed combo switch could serve as an ideal solution for autonomy of wireless sensor nodes in smart grid systems.

This paper proposes the application of a hierarchical fuzzy system (HFS) based on multi-input power system stabilizer (MPSS) and also Static Var Compensator (SVC) in multi-machine environment.The number of rules grows exponentially with the number of variables in a conventional fuzzy logic system. The proposed HFS method is developed to solve this problem. To reduce the number of rules the HFS consists of a number of low-dimensional fuzzy systems in a hierarchical structure. In fact, by using HFS the total number of involved rules increases only linearly with the number of input variables. In the MPSS, to have better efficiency an auxiliary signal of reactive power deviation (ΔQ) is added with ΔP+ Δω input type Power system stabilizer (PSS). Phasor model of SVC is described and used in this paper. The performances of MPSS, Conventional power system stabilizer (CPSS), hierarchical Fuzzy Multi-input Power System Stabilizer (HFMPSS) and the proposed method in damping inter-area mode of oscillation are examined in response to disturbances. By using digital simulations the comparative study is illustrated. It can be seen that the proposed PSS is performing satisfactorily within the whole range of disturbances.