Wind Power Forecasting Techniques

A Wind penetration Secure level Assessment Tool (WSAT) is currently being developed by EirGrid Pic and Powertech Labs Inc that will help maximising use of its wind power generation while maintaining secure operation of the Irish power system. The tool is based on voltage and transient security analysis of transfers between wind and conventional power generation. In on-line WSAT application WSAT obtains modified power flow snap-shot file from SCADA/EMS and runs real-time voltage and transient stability assessment of mentioned transfers. When one of the security criteria limits is reached, the amount of corresponding wind generation with agreed margin is considered as wind generation limit according to this criterion. At present three such criteria are used for steady-state analysis of base case and N-l contingencies: thermal limits of the equipment, voltage levels of the buses and voltage collapse; and one criterion for dynamic analysis: transient frequency drop below set limit for three-phase faults on the system cleared within assumed clearance times and/or loss of conventional generation. With getting more experience with WSAT we will be adding other criteria, e.g. voltage steps, voltage changes etc. WSAT also automatically estimates wind generation limits for next 24 hours using topology data from most recent snapshot file and generation schedule from Reserve constrained unit commitment program.

Nowadays, solar and wind power generation is an important part of the power sources in many countries all over the world. However, due to the variability and uncertainty of these sources, stable operation of the power system with large solar and wind power penetration is a big challenge for system operators. In order to enhance the contribution efficiency of solar and wind power in the power market, a strong ancillary service system is essential and must be reasonable priced. The ancillary services considered in this paper are spinning reserve, non-spinning reserve. In addition, a model for calculating and comparing generation costs for energy and ancillary services, with and without penetration of solar and wind power in the power market have been proposed. Consequently, this model has been developed and validated with a case study. The results show that in a power system with large proportion integration of solar and wind power, the energy and ancillary services generation costs for the power system are high. Besides, the feed-in tariffs of solar and wind power are more expensive than the traditional electricity generation, which leads to high locational marginal prices of the electricity market.

According to the characteristics of double fed asynchronous generator rotor energy flow, research and design based on the DSP control with two-way flow of energy function of Dual PWM converter and discusses the grid side converter control method of Dual PWM converter in particular. The wind turbine simulation model is established by using the electromagnetic transient PSCAD/EMTDC software. The simulation system is used to simulate the P, Q decoupling control and maximum wind energy tracking control of the generator. Wind is a natural phenomenon generated by the solar radiation heat, the earth's surface caused by uneven heating of the atmosphere. It is estimated that only 1% of the wind on the ground will be able to meet the needs of the world's energy. With the continuous improvement of the level of wind power generation technology, the cost of wind power gradually reduced, considering environmental benefits, the cost will be close to the cost of coal-fired power generation. Therefore, great efforts to develop wind energy as the representative of the renewable energy and new energy, to achieve sustainable development, has become the consensus of the whole society, strategic choice to solve the energy crisis and environmental problems. 2.Overview of control technology of doubly fed wind power gener ation Wind power is the kinetic energy contained in the natural wind into electrical energy in the process, the wind turbine wind energy capture and convert it into mechanical energy, driven by rotary generator, and the generator for converting mechanical energy conversion into electrical energy. As countries around the world pay more attention to wind power, wind power has become the world's fastest, most widely studied and applied new energy technology. With the development of wind power technology, wind turbine, wind turbine generator, converter and its control system and the way of the wind turbine, there are different types of. Among them, the doubly fed wind power generation system due to the converter control capacity is small, the speed of operation range wide characteristics become currently the world's most widely used VSCF wind power generation system. Variable speed constant frequency generator in asynchronous generator rotor side applied three-phase low frequency current to realize AC excitation, the output power is constant frequency and constant voltage amplitude, frequency, phase of the exciting current control. At the same time, the active power and reactive power decoupling control of the generator is realized by using the vector control technology. Control active power capable of adjusting the rotation speed of the wind turbine, to capture the maximum wind power tracking control; regulation of reactive power adjustable power factor and improve the dynamic and static stability of the wind turbine and power system operation. In addition, the VSCF wind power generation technology, so to achieve good flexible connection between the generator and power grid system, compared with the traditional constant speed constant frequency generation system easier to achieve grid connected operation and operation

This paper presents the development of the wind power system and low voltage ride through (LVRT) techniques for doubly -fed induction generator (DFIG) wind energy system. In recent years, wind power has been developing rapidly. As the wind power penetration from large scale wind turbines has been increasing rapidly in the transmission system, there is a higher requirement for the frequency stability and power generation efficiency of the wind power generation system, and the power grid puts forward higher continuous operation requirements for the grid connected wind turbine in the power grid fault and demand that the wind power generator has to ride through the grid faults, especially the grid voltage dips. This overview mainly introduces DFIG and low voltage ride through technology in the wind power generation system. This paper introduces respectively their development, control strategies and future trend.

The development of wind power generation can promote the transformation of energy structure and the green development of the economy. The land is the spatial carrier of wind power generation projects, which has a basic supporting role for wind power generation. This paper analyzes the situation of land utilization for wind power generation, sorts out relevant national policy documents, and summarizes the problems existing in the implementation of wind power projects, which is of great significance for promoting the development of the wind power industry. The results showed that the installed capacity of wind power and electricity generation increased rapidly in the past decade. The land supplied area for wind power generation reached its peak in 2016 and then fluctuated, with the land supplied area decreasing but the power generation efficiency improving. In the process of wind power land utilization in China, there are some problems, such as the insufficient connection between industry planning and territorial spatial planning, lack of coordination mechanism between government departments for examination and approval, lack of land standards, prominent problems in the use of stock land and the renewal and renovation of old wind farms, and complicated land requisition compensation. Based on this, the paper puts forward corresponding countermeasures and suggestions from the aspects of territorial space planning, land use examination and approval, land use standard, utilization of stock land, popularization and application of land saving technology and land saving mode.

Hydrogen production by wind and solar hybrid power generation is an important means to solve the strong randomness and high volatility of wind and solar power generation. In this paper, the permanent magnet direct-drive wind turbine, photovoltaic power generation unit, battery pack, and electrolyzer are assembled in the AC bus, and the mathematical model of the wind-solar hydrogen storage coupled power generation system and the simulation model in PSCAD/EMTDC are established. An energy coordination control strategy is designed. After simulation, the proposed control strategy can effectively reduce the rate of curtailment of wind and solar power, and stabilize the fluctuation of wind and solar power generation. It verifies that the established model is correct and the control strategy is effective and feasible.

The intermittent nature of wind power presents special challenges for utility system operators when performing system economic dispatch, unit commitment, and deciding on system energy reserve capacity. Also, participation of wind power in future electricity markets requires more systematic modeling of wind power. It is expected that the installed energy capacities from wind sources in the United States will increase by up to 20% by the year 2020. New York Independent System Operator (NYISO), General Electric (GE), and Automatic Weather Stations Inc., (AWS) conducted a project for the future of wind energy integration in the United States. They stated that NY State has 101 potential wind energy sites and it should be able to integrate wind generation up to at least 10% of system peak load without further expansion (GE report 2005). In order to integrate wind power systematically, it is necessary to solve the technical challenges as well as policy regulation designs. Some of these polices have been updated to allow increased intermittent renewable energy by settling imbalances in generation rulemakings and portfolio standards, where the most commonly used one at this time is the production tax credit portfolios. Due to intermittent nature of wind power, forecasting methods become a powerful tool and of great importance to many power system applications that include uncertainties in generation outputs. The recent work has discussed several methods to develop wind power forecasting algorithms to anticipate the degrees of uncertainty and variability of wind generation. (C. Lindsay & Judith, 2008) use an auto-regressive moving average model to estimate the next ten-minute ahead production level for a hypothetical wind farm and investigate the possibility of pairing wind output with responsive demand to reduce the variability in the net wind output. In (Kittipong M. et al., 2007), the authors develop an Artificial Neural Network (ANN) model to forecast wind generation power with 10-min resolution. Current and previous wind speed and wind power generation are used as input parameters to the network where the output from the ANN is the wind generation power. (M. S. Miranda & R. W. Dunn, 2006) predicted one-hour-ahead of wind speed using both an auto-regressive model and Bayesian approach. (D. Hawkins & M. Rothleder, 2006), discuss operational concerns with increased amount of wind energy in the Day-aheadand Hourahead-Market for CAISO in California. They emphasize the importance of forecasting accuracy for unit commitment and ancillary services and the implications of load following or supplemental energy dispatch to rebalance the system every five minutes. In (Alberto F. at el., 2005), the authors propose a probabilistic method to estimate the forecasting error for

An integrated development environment based situational awareness for operational reliability evaluation in wind energy systems incorporating uncertainties

The battery energy storage system (BESS) is the current typical means of smoothing intermittent wind or solar power generation. Such BESS hybrid power systems require a suitable control strategy that can effectively regulate power output levels and battery state of charge (SOC). This paper presents the results of a wind/PV/BESS hybrid power system simulation analysis under taken to improve the smoothing performance of wind and Photovoltaic (PV) power generation and the effectiveness of battery SOC control. A wavelet based power smoothing method is presented for reducing output power fluctuations of wind/PV hybrid power generation systems and regulating the battery SOC. The effectiveness of the proposed method was verified using MATLAB/SIMULINK software.

One way to mitigate the variability of wind and solar power generation is to install the corresponding plants in nearby locations. For example, in Kuwait, the facility at Shagaya Renewable Energy Park is located in a desert area with both photovoltaic panels and wind turbines that allow the continuous generation of renewable energy throughout the day. The National Center for Atmospheric Research (NCAR) has developed a system to generate probabilistic wind and solar predictions for the Shagaya facility. These predictions are based on the analog ensemble technique that post-processes the wind speed and solar irradiance predictions based on a combination of multiple models including the Weather Research and Forecasting (WRF) numerical model. The ensemble forecasts have 20 members and are generated independently at each wind and solar power production facility. Here we present a method based on the Schaake Shuffle (SS) technique to pair the ensemble members from the independent systems to obtain a unique ensemble prediction of the aggregated wind and solar generation. After reordering through the SS technique, the corresponding paired solar and wind power members can be summed to build a unique ensemble of combined generation that is statistically consistent, as verified by the presented metrics.

Impacts of large-scale wind and solar power integration on California׳s net electrical load

In this paper, an application artificial neural network (ANN) and adaptive neuro-fuzzy inference system (ANFIS) are presented to predict the heat transfer rate and effectiveness in the corrugated plate heat exchangers. First, the thermal performances of the corrugated plate heat exchangers were evaluated experimentally. Experimental data were used for training and testing network. The results of the ANN are compared with the ANFIS in which the same data sets are used. The ANN model is slightly better than ANFIS. The coefficient of multiple determination (R2) values obtained when unknown data were used to the networks were 0,999636 for heat transfer rate and 0,999565 for effectiveness, which is very satisfactory. This demonstrates that the neural network presented can help the engineers and manufacturers predict the thermal characteristics of corrugated plate heat exchangers under various operating conditions.

This paper proposes a renewable energy hybrid power system that is based on photovoltaic (PV) and wind power generation and is equipped with Superconducting Magnetic Energy Storage (SMES). Wind and solar power generation are two of the most promising renewable power generation technologies. They are suitable for hybrid systems because they are environmentally friendly. However, like most renewable energy sources, they are characterized by high variability and discontinuity. They generate a fluctuating output voltage that damages the machines that operate on a stable supply. Therefore, the energy storage system SMES with the function to reduce output voltage fluctuation problems is introduced. SMES is found to be the most effective energy storage device as a result of its quick time response, high power density, and high energy conversion efficiency. In this paper, modeling of a hybrid system with SMES is built using MATLAB/Simulink. Blocks such as the wind model, PV model, and energy storage model are built separately before combining into a complete hybrid system with SMES. Varying wind speed and solar irradiance values are taken as the input parameters. The obtained results from the simulation reveal that a system with SMES is more reliable than a system without SMES.

Many sources of renewable energy, including solar, wind, and ocean wave, offer significant advantages such as no fuel costs and no emissions from generation. However, in most cases these renewable power sources are variable and non-dispatchable. The utility grid is already able to accommodate the variability of the load and some additional variability introduced by sources such as wind. However, at high penetration levels, the variability of renewable power sources can severely impact the utility reserve requirements. This paper presents an analysis of the interaction between the variability characteristics of the utility load, wind power generation, solar power generation, and ocean wave power generation. The results show that a diversified variable renewable energy mix can reduce the utility reserve requirement and help reduce the effects of variability.

The PV and wind power generation have a disadvantage of unstable power output, resulting negative impact on utility and micro grid operation. The battery energy storage system is the effective means of smoothing wind or solar power generation fluctuations. For effective regulation of power output levels and state of charge (SOC) of battery require a suitable control strategy. This paper presents the results of wind/photovoltaic (WPPV) hybrid power system simulation analysis using PSCAD to improve the smoothing problem of wind/PV/BESS hybrid power generation fluctuations.