محسن سیماب

In this article, the control method of the economic predictive model for the use of the efficiency tariff of the photovoltaic backup system, diesel generator and microgrid, connected to the grid using the closed loop control system, the optimal open loop control, and also through the control and strengthening of the primary open loop has been The main goal of this study is to minimize the power grid energy and fuel costs by evaluating the limits related to the level of fuel level in diesel fuel tanks. In addition to complying with the restrictions among the controllable variables, this control method also meets the load requirements. In order to obtain the benefits of feedback and predict the optimal power timing as a back-up energy system control problem, as well as the diesel generator connected to the microgrid, it is modeled based on the linear programming structure. Specifically, analysis is divided into two groups. The first case in the alternative model is when: outage occurs between 7 AM and 6 PM and the other in the grid energy state occurs when the grid is available for more than 24 hours. Energy performance shows, cost savings and income, in the control of daily economic forecasting model has improved. As long as, daily energy saving is up to 52%, while diesel energy is up to 85%. Optimum operation control can be well associated with uncertainty and disturbance in the result.

The capability of a neuro-fuzzy control approach for frequency fluctuation damping in an isolated hybrid microgrid (IHMG) system (DEG/WTG /PV/FC/ESSs) is investigated in this paper. Due to the intermittent behavior of renewable energy sources (RESs) like wind turbines and photovoltaic arrays and the time-varying nature of demands, frequency fluctuation is more likely, specifically in the grid-connected mode. Model parametric uncertainties as well as load changes, wind power, and solar irradiation variations are the main uncertainty sources of the IHMG system. In the suggested approach, a neuro-fuzzy output feedback controller with three inputs that are inspired by PID control is designed considering the power balance between demands and generations, by optimizing fuzzy membership functions’ locations. The proposed controller is compared with two popular other methods on the investigated IHMG system in terms of time-domain characteristics. The outcome illustrates remarkable merit compared to the state-of-the-art methods in the presence of simultaneous disturbances and the model parametric uncertainties.

Using bidirectional parallel converters improves system reliability as they can bypass faults. Therefore, the bidirectional parallel converters structure is adopted for the DC micr ogrid connected to the grid. There is a circulating current between the bidirectional parallel converters that limits the overall capacity of the system and can damage switching devices. To solve this problem, in this paper, the mechanism of generating circulating current on the AC side when several bidirectional parallel converters work together was taken into consideration with the effect of constant power loads by the droop strategy Pdc-vdc2-f to share DC power and network frequency adaptation. The PI coefficients of the bidirectional parallel converters controller were optimized by online genetic algorithm and neural networks and updated with system conditions. Both the stable and dynamic relationships between Pdc and vdc2 are linear and did not create constant power loads of unstable poles for the system. The results indicated that compared with conventional idc-vdc droop control, the proposed Pdc-vdc2-f strategy can increase dc power control and system stability, consequently increasing the dc voltage regulation dynamics.

The issue of unit commitment (UC) is one of the most important issues in the electricity market, and with the smartening and restructuring of networks which its goals and variables have undergone changes. In this paper, solving and modeling the problem of unit commitment by considering smart networks is proposed. As we know, in smart grids, there are new issues such as demand side management and energy storage systems (batteries) as well as new goals such as reducing the environmental pollution of the units that must be considered. In this paper, the issue of unit commitment with demand side management modeling along with optimal charging and discharging of battery storage system with the aim of minimizing the economic costs of units and batteries and environmental pollution is presented. The proposed model is a Mixed Integer Linear Programming (MILP) model that is solved using powerful commercial software such as Gurobi and guarantees optimal global solutions. The proposed model is implemented on two standard IEEE 6 and 118 bus networks, the results of which show the efficiency of the proposed model.

Today, the use of distributed generation resources connected to the network has remarkable growth therefore network-connected to the converters must be able to provide services beyond the injection of power into network, including maintaining network stability. In this paper the control and management of energy for battery wind, photovoltaic and diesel connected to a three-phase network by activating the current limitation under unbalanced fault has been introduced. In this method injected currents are limited to a certain amount along the faults Also, the operation mode without tracking the maximum power point for the converter is included. This state is activated during severe faults, when the converter cannot control Maximum power of the system. Therefore, in a microgrid with, the operation of a fuzzy logic-based controller the transformation operation of DC to DC converter control is performed sparsely by two-way battery and distributed generation resources management. Also proportional resonance controller is used due to its proper performance. In fact, with the use of reference current generation, sinusoidal current with a total harmonic distortion (THD) value of less than 5% is injected. The results show that the control strategy along with energy management with multiple energy generation resources is able to limit and maintain DC link voltage within an acceptable range in addition to The existence of an asymmetric fault. Therefore, the fault crossing operation has been performed correctly without the operation of the protection relays and secondly in comparison with microgridsolely with the presence of one photovoltaic production source the process of injecting active and reactive power in the upstream network is more appropriate.

The problem of unit commitment (UC) or in other words, the issue of placing the units in orbit is a very important optimization problem, the exact solution of which can lead to a significant reduction in operation costs. In general, UCchr('39')s goal is to minimize the total cost of production units by considering the constraints of the units and the system during the intended period. In fact, UC is divided into two issues. First, there is the issue of determining the on or off mode of production units for each hour, which is usually 24 hours, and the second is the distribution of economic dispatch between production units. Considering both problems at the same time will complicate the solution. It should also be noted that the difficulty of the problem also increases in proportion to the number of production units as well as the constraints considered. As mentioned, unit cost is typically the primary goal of minimizing UC issues. This paper considers smart grids, one of whose goals is reducing environmental pollution in addition to reducing costs. Therefore, this paper considers UC problem-solving in smart grids by considering the pollution of production units, so a multi-objective function is selected for minimization. On the other hand, with the introduction of smart grids, the existence of energy storage systems (ESS) in the network is also considered. This paper suggests optimal charging and discharging of energy storage systems, too. Another issue modeled in this paper is the issue of demand response in smart grids. Demand response program modeling allows grid demands to be shifted within the specified range at different times of the day. The proposed model is a mixed integer linear programming model (MILP) that has been tested to validate the performance of the proposed model, i.e., 4-unit and 10-unit systems with storage resources. To solve the proposed model, a powerful Gurobi solver is used. This solver also guarantees optimal global solutions and can get optimal solutions in the shortest time. In the end, the simulation results showed that modeling the problem of optimizing the charge and discharge of the energy storage system, along with the problem of demand-response management in the issue of unit participation, is very effective in reducing operating costs and reducing pollution. On the other hand, due to the linear nature of the problem, the proposed model can be solved in larger dimensions of the power systems.

Dynamic Voltage Restorer (DVR) is one of the voltage compensation equipment. Voltage quality injected by of this equipment depends on the quality of DC link voltage and the type of control system modulation. The photovoltaic array can be used to store the DC link of this equipment. To increase the output voltage of the photovoltaic array to the required DC voltage level, a standard boost chopper is used which reduces the quality of the compensator voltage due to the high voltage ripple. Using well-designed choppers such as interleave can in addition to increasing the photovoltaic array voltage, reduce the ripple DC link voltage and thus the harmonic content of the voltage injected by the compensator. Applying appropriate pulse bandwidth modulation to the control system of this equipment can also be effective in reducing harmonic content and improving voltage quality. In this paper, in order to reduce the total harmonic distortion (THD) of the compensator injected voltage and consequently to improve the load voltage quality, the interleave boost converter at DC compensator link and the hysteresis modulation in the controller scheme of this hybrid compensator are used and the simulation results are presented. The result of the proposed system is compared with the results of the hybrid compensator based on conventional boost chopper and sinusoidal modulation.The simulations are done using Matlab/Simulink.

In this paper, a multi-level benchmarking method is presented for assessing efficiency of electrical distribution companies’ expenditures. Proposed method considers mutual cooperation of capital expenditure (CAPEX) and operational expenditure (OPEX) for improving quality and decreasing energy losses. Firstly, weighted fuzzy c-means clustering (WFCM) is used by proposed method to find similar companies. Then, proposed method utilizes data envelopment analysis (DEA) and slack analysis in multi levels and through creating pseudo competition between companies, estimates companies’ efficiency scores and slacks in their expenditures. Finally, proposed IBRS is applied on Iranian distribution companies and its results are discussed.

In trading electrical energy in deregulated power systems, violation of operation constraints such as transmission lines flow limits is possible. These conditions have been called “congestion”. One of the most important responsibility of Independent System Operator (ISO) is congestion management in a manner that all the system equipments be operated in their nominal ranges. In this paper, using topological generation distribution factor, participation of each generator in power flow in each line is calculated. Then, by means of decomposition of nodal price and mentioned factor, the effect of generation in each bus on the locational marginal price in all buses of the system are calculated. And the congestion price is calculated based on re-dispatch in constant demand. In this paper a new method is introduced to dedicate congestion price to each generator and by this method a fair congestion cost allocation is implemented. The method has been tested on IEEE 24-bus test system and the results have been demonstrated.