Showing 4 results for Kiani
M. Kiani, A. Abdolali,
Volume 9, Issue 1 (March 2013)
Abstract
This paper presents a general formulation to investigate the scattering from Multilayer Lossy Inhomogeneous Metamaterial Planar Structure (MLIMPS) with arbitrary number of layers and polarization. First, the dominating differential equation of transverse components of electromagnetic fields in each layers derived. Considering the general form of solution of the differential equations and the boundary conditions of the problem a set of linear equations is obtained. By solving these equations, the electromagnetic fields in all layers and reflection and transmission coefficients are calculated. This method is applied in an interesting example for two bi-layered structures with inhomogeneous conventional material and metamaterial profile for constitutive parameters. Results which are presented in example are useful for constructing general duality between conventional material and metamaterials.
A. R. Moradi, Y. Alinejad-Beromi, K. Kiani,
Volume 13, Issue 1 (March 2017)
Abstract
Congestion and overloading for lines are the main problems in the exploitation of power grids. The consequences of these problems in deregulated systems can be mentioned as sudden jumps in prices in some parts of the power system, lead to an increase in market power and reduction of competition in it. FACTS devices are efficient, powerful and economical tools in controlling power flows through transmission lines that play a fundamental role in congestion management. However, after removing congestion, power systems due to targeting security restrictions may be managed with a lower voltage or transient stability rather than before removing. Thus, power system stability should be considered within the construction of congestion management. In this paper, a multi-objective structure is presented for congestion management that simultaneously optimizes goals such as total operating cost, voltage and transient security. In order to achieve the desired goals, locating and sizing of series FACTS devices are done with using components of nodal prices and the newly developed grey wolf optimizer (GWO) algorithm, respectively. In order to evaluate reliability of mentioned approaches, a simulation is done on the 39-bus New England network.
N. Kiani, M. Afsahi,
Volume 15, Issue 2 (June 2019)
Abstract
In this paper, a compact 6.8/7.6 GHz diplexer is provided with the help of substrate integrated waveguide (SIW) structures. The use of this structure is for satellite communication systems. The designed diplexer includes a T-junction. In addition, our structure consists of two SIW filters of the type of bandpass. The relative bandwidth of the upper channel is 3.3% at the center frequency of 7.6 GHz and its lower channel is 3.7% at the center frequency of 6.8 GHz. The proposed diplexer offers a great benefit in terms of size decrease. In addition, it displays an optimal insertion loss. While giving the low return loss. Ultimately, the designed structure displays ideal rates of isolation and rejection. The diplexer incorporates a planar form and can be simply integrated with to the integrated circuits of the microwave. The insertion and return losses are 1.8 dB and 15d B in the lower band and they are 1.9 dB and 17 dB in the upper band. Simulations have been implemented with CST Microwave Studio. The Diplexer is completely built into a standard printed circuit board (PCB) procedure. A very favorable compromise is reached among the results of the construction and the measurement, which is the evidence of the proposed method.
H. Kiani Rad, Z. Moravej,
Volume 15, Issue 3 (September 2019)
Abstract
In this paper, a new method is conducted for incorporating the forecasted load uncertainty into the Substation Expansion Planning (SEP) problem. This method is based on the fuzzy clustering, where the location and value of each forecasted load center is modeled by employing the probability density function according to the percentage of uncertainty. After discretization of these functions, the location and value of each of the new load centers are determined based on the presented fuzzy clustering based algorithm. A Genetic Algorithm (GA) is used to solve the presented optimization problem in which the allocations and capacities of new substations as well as the expansion requirements for the existing ones are determined. With the innovative presented method, the impact of uncertainty of the power and location of the predicted loads on the results of SEP is measured, and finally, it is possible to make a proper decision for the SEP. The significant features of this method can be outlined as its applicability to large-scale networks, robustness to load changes, the comprehensiveness and also, the simplicity of applying this method to various problems. The effectiveness of proposed method is demonstrated by application on a real sub-transmission system.
