NASHRIYYAH -I MUHANDISI -I BARQ VA MUHANDISI -I KAMPYUTAR -I IRAN, A- MUHANDISI -I BARQ
Year:2014 | Volume:12 | Issue:2|Papers Count:9

In this paper, the long-term dynamics of an electricity market is modeled, considering the load uncertainty. Moreover, the generation side uncertainties, including the uncertainties of the generators availabilities, the hydro generations and the wind generations are observed. The problem is analyzed by the System Dynamics (SD) method. Also, the effects of capacity payment on power market dynamics, with and without uncertainties, are modeled and analyzed. The simulation results show how the uncertainties may affect the long-term behavior of a power market. Moreover, it is shown how the effect of uncertainties on market dynamics, may be improved through capacity payment.

Bayesian Networks (BNs) as a strong framework for handling probabilistic events have been successfully applied in a variety of real-world problems, but they have received little attention in the area of composite power systems reliability assessment. Reliability assessment by BN provides some additional capabilities in comparison to conventional methods, both at the modeling and at the analysis levels. At the modeling level, several restrictive assumptions, implicit in the conventional methods, can be removed. At the analysis level, a variety of applicable reliability-based analysis which is hardly achievable in conventional methods, can be conveniently performed. This paper proposes a methodology based on Minimal Cutsets (MCs) to apply BNs to composite power system reliability modeling, reliability assessment and reliability-based analysis.To have a more accurate BN model, a new method of MC determination for composite power system is proposed. Bayesian structure is extracted, based on the determined MCs. Bayesian parameters are defined based on the logical relationships of nodes. To make the proposed method applicable to large composite power systems, virtual nodes are proposed and combined with Bayesian model. Also, a variety of reliability-based analyses are presented which are hardly achievable in conventional methods. The proposed method is validated by applying to RBTS and comparing the results with other reliability analysis methods. The proposed methodology is applied to the Reliability Test System (RTS), to show its feasibility in large networks.

This paper proposes a comprehensive framework for distributed energy resource (DER) expansion planning from investors’ viewpoint based on a combination of dynamic programming algorithm and game theory. In this framework, different aspects of DER planning i.e. their uncertainties, risks, pollution, etc. are included. Wind turbines, gas engines and demand response (DR) programs are considered as DERs in this study. The intermittent nature and uncertainty of wind power generation and also uncertainty of demand response programs will cause the investors to consider risk in their investment decisions. In order to overcome this problem, a modified model has been derived to study the regulatory intervention impacts on wind expansion planning and implementing DR programs. Dynamic programming method is utilized for this problem solving and in each step, the Nash equilibrium point is calculated using Cournot model. A model based on intermittent nature of wind power generation and uncertainties of DR programs is developed which can calculate the optimal investment strategies. The effectiveness of the proposed model is proved through implementing on a test system.

Energy exchange among the electricity markets is a new issue in modern power systems. This issue, especially in Europe, has been identified as a market coupling. In this paper, a framework for congestion management and clearing of multiple electricity markets, in which the market participants can place their bids simultaneously in different markets across an interconnection, is proposed. In this framework, the markets dispatch the energy and the reserve, independently. A central coordinator entity, then, runs the allocation of transmission capacity among the electricity markets. Three methods for simultaneous clearing of the energy and reserve are also proposed. The possibility of implementation of the proposed methods in multiple markets is discussed. The numerical results for three-area 15-bus and IEEE RTS-96 test systems in a triple-market case are presented, to demonstrate the effectiveness of the proposed approach as compared with the other approaches.

Most wind turbines, photovoltaic and fuel cells need a DC/AC converter as an interface for connection to the main grid. Power electronics based distributed generation resource has two parts: power circuit and control circuit of converter. In this paper, a new method which is based on current control by using internal model control method is presented, in order to control active and reactive power of power electronics interfaced distributed generation resource. The main benefit of using internal model control method is that it can reduce number of required parameters for PI controller tuning to one parameter which is desired closed-loop band width (a). It should be mentioned that parameter a can be computed regarding response rise time. Therefore, values of KI and KP can be determined with the selection of desired band width. So, the system can be designed just with the selection of one parameter (rise time tr). The proposed control method can be used in micro-grids containing power electronic interfaced DGs, in both modes of operation (connected to grid and islanded micro-grid).

In this paper, a new control method is proposed for extracting the maximum power of wind turbines equipped with Permanent Magnet Synchronous Generator (PMSG), which is connected to the grid via a matrix converter. The method calculates the optimal rotation speed of wind turbine and finds the optimal operation point by hill climbing method. The proposed method is simple and it does not need to use some complex methods such as field oriented and rotor position estimation. Wind turbine speed, electrical torque and consequently maximum output power of wind turbine are obtained by the perfect control of output phases and amplitudes of matrix converter. Moreover, the maximum power is injected to the grid under unity power factor. The proposed method is simulated in MATLAB programming software and the obtained results approve the validity of the method.

In this paper, a new structure composed of a negative capacitance and resistance is presented in order to increase gain and bandwidth of distributed amplifiers. The proposed structure is used at the gate transmission line of the distributed amplifier and the obtained circuit has been simulated using 0.13mm CMOS model. The negative capacitance at the gate transmission line decreases parasitic effects of gain cells and increases amplifier bandwidth and accordingly increases voltage gain. The generated negative resistance decreases transmission lines losses and increases bandwidth. Simulated voltage gain is 15dB with ±0.5odB gain flatness over 0.5-49 GHz frequency band. Circuit input and output are matched with 50Ω resistance; and input and output return losses are -8.15 dB and -9.2 dB, respectively. This circuit has a noise figure less than 4.6 and its power consumption is 99 mW from 1.8 V power supply.

In this paper, a quarter car active suspension system with a hydraulic actuator, has been controlled by sliding mode coupled with an adaptive approach. To deal with all kinds of uncertainty arising from the effect of external perturbation or the any nonlinear behavior system, sliding mode control has been used. In the proposed method the sliding surface, by using an optimal strategy to minimize the optimal cost function is derived, so the result is a logarithmic sliding surface. Adaptive algorithms proposed in this paper because of the nonlinear variability by time and not bounded uncertainty in the system. While the effects of parameter uncertainties and external disturbances to system performance have been dramatically reduced, the stability of control system proves based on the Lyapanof theory. The proposed control method has been done on a quarter car active suspension system with a hydraulic actuator. Simulation results of the proposed method show that the activation of suspension system by the proposed method increases its performance compare with the passive suspension system.

The paper presents a geometry-based MIMO channel model for outdoor-to-indoor applications. The propagation channel model is derived when indoor scatterers are located on a hollow-disk around the user and a distribution of outdoor scatterers exists between the base station and the user. The closed-form Cross-Correlation Function (CCF) is derived for the aforementioned scenario. This function depends on various parameters of interest including the distance between the base station and the user, the spacing among antennas elements, and the directions of the antennas elements. The numerical CCF values are obtained with Radiowave Propagation Simulator (RPS) software for the building of Electrical and Computer Engineering School at the University of Sistan and Baluchestan. The results show that considering the outdoor scatterers increases the accuracy of the CCF and the capacity computation significantly.