Presence Of Wind Power Generation Research Articles

A short-term wind-hydrothermal operational framework in the presence of pumped-hydro storage

Short-term operation is one of the most significant aspects of power systems operation and planning and it mainly includes resource scheduling including renewable and non-renewable energy sources. The mentioned problem is modeled as an optimization problem with one or more objectives depending upon the priorities of the decision maker (system operator) and several equality and inequality constraints. In this respect, this paper proposes a short-term operational model for the hydrothermal power systems in the presence of wind power generation and pumped-hydro storage (PHS) units. The problem is formulated as a single-objective optimization problem that aims to minimize the total operating cost including the fuel cost of thermal units. The problem has been comprehensively investigated through five case studies where the first case study is used for the sake of validation. Then, the other case studies assessed the impacts of wind power generation, PHS unit, and uncertainty on the problem. The five case studies are as follows: Case 1: Short-term hydrothermal (STH) scheduling which aims to minimize the total cost. Case 2: Deterministic short-term hydrothermal-wind (STHTW) scheduling which aims to minimize the total cost. Case 3: Stochastic wind-hydro-thermal scheduling that seeks to minimize the total cost taking into consideration the uncertainty of the wind power generation. Case 4: Deterministic wind-hydro-thermal scheduling in the presence of the PHS unit with the total cost minimization as the objective function. Case 5: Stochastic wind-hydro-thermal scheduling in the presence of the PHS unit that is used to evaluate the impact of uncertainty of wind power generation with the total cost minimization as the objective function. It is noteworthy that the first three case studies have been formulated using a non-linear programming (NLP) model and solved using the CONOPT solver in GAMS. Case studies 4 and 5 have been presented using a mixed-integer non-linear programming (MINLP) model and solved using the DICOPT solver in GAMS. A sensitivity analysis has also been carried out to assess the system's performance with different loading conditions. In this respect, the total cost and PHS operation with different amounts of load demand were evaluated and the results have been presented and discussed.

A protection scheme for distribution utility grid with wind energy penetration

The impact of fault circumstances on distribution grid parameters in the presence of wind power generation is explored in this research. A protection algorithm (PA) is also proposed for detecting faulty events by using the proposed wind fault index, which is computed by analysing current signals using the Wigner distribution function and the Stockwell transform (ST). The sort of fault is determined by the number of faulty phases found. The zero sequence currents introduced to identify the ground’s involvement in a fault event are analysed to calculate a wind ground fault index. Single phase to the ground, double phase to the ground, double phase, three-phases, and three phases to the ground faults are all investigated fault events. It has been determined that PA outperforms discrete Wavelet Transform and ST-based approaches in terms of fault estimation time and noise effect. The study was conducted on the IEEE-13 bus test feeder, which was connected to wind power plants (WPPs).

Wind Speed Clustering Using Linkage-Ward Method: A Case Study of Khaaf, Iran

The use of renewable energy for providing electricity is growing rapidly. Among others, wind power is one of the most appealing energy sources. The wind speed has direct impact on the generated wind power and this causes the necessity of wind speed forecasting. For better power system planning and operation, we need to forecast the available wind power. Wind power is volatile and intermittent over the year. For getting better insight and a tractable optimization problem for different decision making problems in presence of wind power generation, it is required to cluster the possible wind power generation scenarios. This article presents probabilistic wind speed clustering prototype for wind speed data of Khaaf, Iran. This region is known as one of the high potential wind sites in Iran and several wind farm projects is planned in this area. The average speed of wind for a ten-minute period measured at height of 40m over a year (2008) is used for clustering. From the result of this research, the most appropriate probabilistic model for the wind speed can be obtained.

Stochastic assessment and enhancement of voltage stability in multi carrier energy systems considering wind power

Voltage instability is one of the main problems of power systems operation. Hence, voltage stability margin is kept within a sufficient range by several costly procedures such as load shedding. Coupling the electrical and natural gas systems by energy hub is a useful way to keep system voltage within a proper range following contingencies in the system. This paper proposes a new approach for assessment and enhancement of the power system voltage stability in the presence of wind power generation, as well as electrical and heat demands uncertainty. A stochastic programming method is adopted to handle the uncertainties of the wind power generation and demands. The proposed methodology shows that coupled operation of the electrical and gas systems in the presence of renewable resources can provide flexibility for the system along with a decrease in the operational cost in both regular cases and post-contingency conditions. In comparison with previous methods to enhance the power system voltage stability, in the proposed model the natural gas system could help power system to supply electrical demand without any voltage stability problem, where there is no load curtailment in some contingencies while in other cases, load curtailment is reduced dramatically which results in undeniable reduction of the total operation cost. Load margin is considered as voltage stability index, and the proposed framework is implemented on the IEEE 14-bus electrical system and 17-node natural gas system to indicate its applicability and appropriateness.

Frequency-constrained unit commitment problem with considering dynamic ramp rate limits in the presence of wind power generation

An increased use of variable generation technologies such as wind power generation can have important effects on system frequency performance during normal operation as well as contingencies. This has led to new challenges for system operators in terms of improving frequency characteristics during contingencies. This subject is stated within the framework of frequency-constrained unit commitment problem (FCUCP) in this study by augmenting the frequency characteristic in the multi-thermal units. The ramp rate is proposed as dynamic constraint, and FCUCP is solved efficiently by binary particle swarm optimization (BPSO) based heuristic optimization algorithms. The influence of the proposed ramping on FCUCP is simulated, and it can be shown that the costs of the system under considering practical limitations that are solved by BPSO are minimized.

Real-Time Power-Hardware-in-the-Loop Implementation of Variable-Speed Wind Turbines

This paper presents the real-time (RT) power-hardware-in-the-loop (PHIL) emulation of the two most popular variable-speed wind turbines (WT): the doubly-fed induction generator WT with partial-scale power converter and the permanent-magnet synchronous machine WT with full-scale power converter. RT-PHIL emulation offers a realistic, controlled, and easily reconfigurable test environment for analyzing grid integration problems, in which classic tools frequently show a lack of capacity. The proposed discrete-time models and implementation methodology result in creation of platform-independent models suitable for application on any RT platform. A voltage-source converter is used as PHIL power interface between the RT simulation and a microgrid testbed. This test environment is of interest for verification of high-level control strategies for wind farms and for evaluation of the response of hardware systems, such as active filters or static synchronous compensators (STATCOMs) connected to a grid (or microgrid) in presence of wind power generation. The RT discrete models of both WTs are demonstrated in a grid-connection experiment.

Three powerful nature-inspired algorithms to optimize power flow in Algeria's Adrar power system

This paper is intended to solve the optimal power flow (OPF) dispatch in the presence of wind power generation (WPG) in the Adrar power system. Towards this aim, the performances of three powerful meta-heuristic algorithms-namely, the cuckoo search algorithm (CSA), firefly algorithm (FFA), and flower pollination algorithm (FPA) are investigated. The proposed algorithms are applied to best capture the active power produced with the minimum value of a multi-objective function. This latter includes: the fuel cost, the NOx emissions, and the imbalance cost of the WPGs. Furthermore, considering the uncertainties governing wind resources, the maximum wind power output is estimated using the wind speed carrying maximum energy. It was found that all algorithms perform well in providing accurate solutions. Interestingly, the convergence is reached in the first 135 iterations. A remarkable outcome of the present work is that CSA outperforms FPA and FFA. CSA has proved itself to be a great tool to optimize Adrar's power flow system in term of iterations and computational time.

Simultaneous planning of plug-in hybrid electric vehicle charging stations and wind power generation in distribution networks considering uncertainties

Recently, plug-in hybrid electric vehicles (PHEV) are becoming more attractive than internal combustion engine vehicles (ICEV). Hence, design and modeling of charging stations (CSs) has vital importance in distribution system level. In this paper, a new formulation for PHEV charging stations is presented with the strategic presence of wind power generation (WPG). This study considers constraints of the system losses, the regulatory voltage limits, and the charge/discharge schedule of PHEV based on the social behavior of drivers for appropriate placement of PHEV charging stations in electricity grid. The role of CSs and WPG units must be correctly assessed to optimize the investment and operation cost for the whole system. However, the wind generation owners (WGOs) have different objective functions which might be contrary to the objectives of distribution system manager (DSM). It is assumed that aggregating and management of charge/discharge program of PHEVs are smartly carried out by DSM. This paper presents a long-term bi-objective model for optimal planning of PHEV charging stations and WPG units in distribution systems which simultaneously optimize two objectives, namely the benefits of DSM and WGO. It also considers the uncertainty of load growth, electricity price and PHEV access to the charging station using Mont-Carlo simulation (MCS) method. Initial state of charge uncertainty is also modeled based on scenario approach in PHEV batteries and wind turbine power generation using weibull distribution. Non dominated sorting genetic algorithm (NSGA-II) is used to solve the optimization problem. The simulation has been conducted on the nine-bus system.

Implementation of Dynamic Line Rating in a Sub-Transmission System for Wind Power Integration

Based on conventional static line rating method, the actual current carrying capability of overhead conductors cannot be judged. Due to continuous increment in electricity demand and the difficulties associated with new line constructions, the overhead lines are therefore required to be rated based on a method that should establish their real-time capability in terms of electricity transmission. The method used to determine the real-time ampacity of overhead conductors not only can enhance their transmission capacity but can also help in allowing excessive renewable generation in the electricity network. In this research work, the issues related to analyzing an impact of wind power on periodical loading of overhead line as well as finding its static and dynamic ampacities with line current are investigated in detail. Moreover, the investigation related to finding a suitable location for the construction of a 60 MW wind farm is taken on board. Thereafter, the wind park is integrated with a regional grid, owned by Fortum Distribution AB. In addition to that, the electricity generated from the wind park is also calculated in this project. Later on, the work is devoted to finding the static and dynamic line ratings for “VL3” overhead conductor by using IEEE-738-2006 standard. Furthermore, the project also deals with finding the line current and making its comparison with maximum capacity of overhead conductor (VL3) for loading it in such a way that no any violation of safe ground clearance requirements is observed at all. Besides, the line current, knowing the conductor temperature when it transmits the required electricity in the presence of wind power generation is also an important factor to be taken into consideration. Therefore, based on real-time ambient conditions with actual line loading and with the help of IEEE-738-2006 standard, the conductor temperature is also calculated in this project. At the end, an economic analysis is performed to evaluate the financial advantages related to applying the dynamic line ratings approach in place of traditional static line ratings technique across an overhead conductor (VL3) and to know how much beneficial it is to temporarily postpone the rebuilding and/or construction of a new transmission line. Furthermore, an economic analysis related to wind power system is taken into consideration as well to get familiar with the costs related to building and connecting a 60 MW wind farm with the regional grid.

Probabilistic Load Flow Including Wind Power Generation

In this paper, a procedure is established for calculating the load flow probability density function in an electrical power network, taking into account the presence of wind power generation. The probability density function of the power injected in the network by a wind turbine is first obtained by utilizing a quadratic approximation of its power curve. With this model, the DC power flow of a network is calculated, considering the probabilistic nature of the power injected or consumed by the generators and the loads.