IRANIAN ELECTRIC INDUSTRY JOURNAL OF QUALITY AND PRODUCTIVITY (IEIJQP)
Year:2018 | Volume:6 | Issue:2 (12) |Papers Count:11

Sometimes، high-voltage transmission lines passes from an area that there is impossible to build a distribution network، or building a substation is not cost-effective in that location. In this paper، a novel system is proposed that can be delivered the power via the overhead guard wire. The case study is a 400kV high-voltage transmission line with a Telecommunication site with low power consumption. In this proposed system، the electromagnetic induction of voltage of phase conductors on overhead guard wires is used to generate the power. In this case، one of the guard wires can be detached from the ground to use this induced voltage as a voltage source for feeding the loads. Since load voltage should remain relatively stable، an Inductance Variable Auto-Controle´ e a` Entrefers (IVACE) regulator is used for this purpose. Different contingency conditions such as switching and short circuit are applied to evaluate the performance of the IVACE regulator. Simulations are carried out using Electromagnetic Transients Program (EMTP) software. Also، the impacts of the length of the detached overhead guard wires from the ground are investigated on the induced voltage. Moreover، the effect of the switching and short circuit on the output voltage is tested in the absence and presence of the regulator. The robustness and effectiveness of the proposed approach is verified through simulation study.

Planning and construction of charging station are important aspect of promoting the development of electric vehicle. Considering the interactions between power and transportation industries، charging station planning require a systematic consideration of relevant issues including: traffic network characterizes، charging demand and electric network constraint. The scope of this study is optimal sitting and sizing of fast charging stations in distribution network considering uncertainties. Firstly، a stochastic model based on queueing theory and user equilibrium based traffic assignment model is developed for electric vehicle charging demand. Then، annual cost of investment and energy losses is minimized under chance constrained framework. The probabilistic aspect of problem are solved using point estimation method and Gram-Charlier expansion. In Addition، to consider uncertainties in final decision making، probabilistic dominance models are introduced. Finally، planning result of coupled distribution and traffic systems are presented to illustrate the performance of the proposed approach.

Power Systems are continuously exposed to large and small disturbances. Disturbances can stimulate the electrical modes of power system and produce transient oscillations in system quantities. The precise modeling of all equipment including loads is very important for power system stability analysis. In this paper، the effect and importance of different load models on the load angle stability of a typical power network are first shown. It will be shown that Dynamic load model is necessary for stability analysis. Then، the parameters of the chosen dynamic model are estimated using unscented Kalman Filter (UKF) and "Event Playback" method. Voltage and frequency of the busbar after occurrence of an event are injected to the bus and the parameters are estimated.

Using of DFIG-Based wind turbine in distribution network is increasing day by day. Despite different advantages of DFIG such as ease controllability، low cost and ability to work in different wind speeds، they are very sensitive to the grid voltage drop and when a fault occurs، the rotor current is increased and this may leads to damage the DFIG power electronics converters. Also، voltage swell caused by large loads switching off، large capacitor banks energizing and unbalanced faults may damage the DFIG converters. Dou to necessity of compliance of grid codes، a novel approach is proposed in this paper to improve the low voltage ride through (LVRT) and high voltage ride through (HVRT) capability of the DFIG in microgrid by using superconducting magnetic energy storage (SMES) and superconductive fault current limiter (SFCL)، simultaneously. The simulation is carried out by using PSCAD/EMTDC software and the simulation resultsillustrate the effectiveness of proposed approach to improve fault ride through capability of DFIG in microgrid during voltage swell and voltage sag.

The penetration level of distributed generation (DG) units in distribution system has rapidly increased in recent years. Due to the environmental concerns، interest has also grown in utilizing electric vehicles (EV) in the transportation sector، which would also result in increased electricity demand; however، modern electric vehicles can be used as energy storage units in V2G (vehicle-to-grid) operation mode. In this paper، the day-ahead energy scheduling of a microgrid consisting of a set of distributed generation units and electric vehicles has been studied. To this end، considering the uncertainty of photovoltaic outputs، a two-stage mixed-integer stochastic programming framework has been developed. The microgrid operator، using the proposed method، is able to fix some decisions optimally in a way that minimize the expected operating costs، while the accurate amount of uncertain parameters will be revealed later. The proposed day-ahead optimization has been implemented in GAMS and the results have been analyzed in a case study situation.

Restructuring and deregulation have changed the power system planning and have introduced new objectives and challenges، especially in the field of Transmission Expansion Planning (TEP). On the other hand، the growing demand and shortage of energy and investment resources have caused special attention to the Demand Response (DR) programs. In this paper، dynamic multi-objective transmission expansion planning is carried out under reliability constraints in the market environment and the presence of demand bidding programs and price responsive bids. The novelties of this paper include the participation of demand bidding (DB) programs and price responsive bids in transmission expansion planning، new wholesale electricity market modeling considering the direct participation of DB programs and price responsive bids and finding the optimum amount of DB programs in each year in individual buses. These data can be sent as a signal to the DR suppliers from the market regulated entity to be considered in their long term planning. The proposed algorithm is implemented on the IEEE 24-bus network and its advantages، including reducing the investment cost and congestion and increasing the reliability، are shown.

Demand side managemnt resources always were used as important options in planning and operation. Studies about them were done in some capacity markets and some others like PJM was used from these resources in their capacity markets. But، it is so important that first a study about them should be done and then a structure for using them in the capacity market shpuld be proposed. Participation of demand side management resources in capacity market just must be done by retailers، because of economic and management reasons. So، we must develope a model from retailers' product and the ways of their business in capacity market. This modeling will have the benefits for retailers and consumers. Therefore، in this paper a model for retailers' behavior have been proposed. Numerical studies have been shown the efficiency of the model.

In this paper، a hybrid algorithm has been presented for energy management in multi-microgrid systems considering security constraints. The energy management system is responsible for accurately dispatching the amount of required energy among multiple microgrids and units in a muti-microgerid system. The energy management procedure is done hierarchically، in a way that each microgrid performs a local energy management، which determines surplus and shortage amounts of energy at each time interval. Accordingly، Independent System Operator (ISO)، schedules the units. Each microgrid، contains a wind turbine (WT) and Photovoltaic (PV) panels as renewable and nondispatchable resources and a diesel generator as a dispatchable energy resource. Also an energy storage system (ESS) is responsible for balancing the produced and consumed energy. A demand response program (DRP) is performed through energy management system for the objective of MG load management and flattening the load curve and reducing the operation cost. Finally، the proposed approach is tested on IEEE 33-bus distribution test system، in presence of microgrids، using GAMS and MATLAB softwares. The simulation results would be presented in the final section to show the effectiveness of the proposed algorithm.

In this paper، a load restoration framework is proposed in distribution network، which includes distributed generations and energy storage resources. In this framework، dynamic programming method (DP) has been used as a tool to optimize the distribution system restoration problem. The time and sequence of the feeders (loads) of the distribution network are considered as the optimal steps and the optimal answer to the problem of optimization of the dynamic programming method after the global outage has occurred. The proposed method considers the priority of network loads according to its importance in load restoration problem. At the end، the proposed method is implemented in a real network and its efficient and practical inference is derived from the results.

In this paper a new method for fault detection in microgrids is proposed considering uncertainties of their networks topologies. The new method is realized by wavelet and S transforms. The properties of three phase components and positive، negative and zero sequences of current and voltage waveforms which are used in fault detection، fault location and to determining the occurred fault type are mined by wavelet and S transforms. For this reason that the process of the fault detection in this method is independent from the network topology، so this method is capable to detect occurred faults in all dynamic states of the studied microgrid. To check the ability of the proposed method in fault detection، this method is implemented on a sample microgrid. The simulation results show that the proposed method is capable to distinguish between the occurred faults and the transient distortions in the network. Also the comparison of S transform and wavelet transform shows that although wavelet transform usage exceeds the speed of maintaining a decision، but the accuracy of S transform in differentiate between the occurred states in microgird is the premier property of this transform.

this paper concerns identifying the most impressionable group of customers for participating in demand response programs. this is an important point in energy efficiency policies. in this paper this aim is achieved by combining data-mining and pattern recognition capabilities with energy management and electricity market concepts. besides، graph theory and entropy concepts are utilized as influencing tools. the proposed procedure in this paper is evaluated using a real dataset reated to irish customers electricity consumption and its effectiveness is confirmed.