Load frequency control for a distributed grid system involving wind and hydro power generation

An optimal mix of solar PV, wind and hydro power for a low-carbon electricity supply in Brazil

In this paper, the influence of a Superconducting Magnetic Energy Storage (SMES) unit on the performance of the Automatic Generation Control (AGC) is investigated. In which, the self-tuning Fuzzy PI Controller (FPIC) associated with the Automatic Generation Control (AGC) is proposed for the improvement of Load Frequency Control (LFC) in wind farm integrated large power system consisting of thermal and hydro power plants. The effects of the self-tuning FPIC in AGC on SMES control is compared with that of optimized fixed gain PI controlled AGC. The computer simulation of the two-area interconnected power system shows that the self-tuning fuzzy PI control scheme of AGC is very effective for SMES control to damp out of the oscillations caused by load disturbances in one or both of the areas and it is also seen that the proposed controlled AGC including SMES performs more effective primary frequency control compared to optimized fixed gain PI controlled AGC including SMES.

Feasibility analysis of mini hydropower and thermal power plants at Hindiya barrage in Iraq

The wind power generation is increasing in many countries as a result of decreasing technology costs, active government policies for renewable energy sources, environmental concerns, etc.. This paper investigates the impact of wind power generation on ATC (available transmission capacity) calculation. In order to determine the maximum incremental MW transfer possible between two parts of a power system without violating any specified limits, ATCs are calculated. When calculating ATC values, it is necessary to assume production and consumption pattern in power system. Production of wind power depends on the wind speed, which is a random variable and it is impossible to forecast exactly the production of wind power that is needed for the ATCs calculation. In order to investigate influence of the stochastic wind power production on the ATCs value, computer model of Croatian electric power system is made in Power World Simulator. ATCs are calculated for southern part of Croatian power system in which besides wind power, hydro power plants are only type of power generation. Available wind speed measurements are used as input data for wind power production. The results of the ATC calculation for different scenario of wind power production and location in the Southern Croatian power system are presented and discussed in the paper.

Maiden Application of Integral-Tilt Integral Derivative with Filter (I-TDN) Control Structure for Load Frequency Control

Power systems are inherently water dependent. Future energy development needs to jointly consider the interaction between power and water systems, especially the stream dynamics related to both water temperature and availability. Such connection is particularly pronounced in thermal and hydro power plants, where once-through cooling systems face disruptions from high intake water temperature and water scarcity, and hydropower generation is affected by drought conditions. Equally important is the impact of power system operations on water temperature and availability. For instance, warm water discharged from thermal power plants can increase water temperature, while cool water released from reservoir bottoms can cause temperature declines. Additionally, hydropower operations can alter water availability through changes in reservoir storage. Despite the importance of those factors, existing electricity capacity expansion models typically do not fully consider such feedbacks between stream dynamics and power system operations, as they lack the capability to accurately represent cascade reservoir operations and cooling processes for thermal power plants at sufficiently high spatial-temporal resolutions. To address this research gap, we develop an integrated model coupling a hydrological model (Community Water Model, CWatM), a stream temperature model (River Basin Model, RBM), and a novel electricity capacity expansion model (Pathways for Renewable Energy Planning coupling Short-term Hydropower OperaTion, PREP-SHOT, https://github.com/PREP-NexT/PREP-SHOT) to better represent the two-way feedback between stream dynamics and power system operations. The coupled model, applied in Mainland Southeast Asia featured by a diverse array of hydropower reservoirs and thermal power plants, supports informed, sustainable, and environmentally friendly planning for future energy development in the region.

The contribution of wind power in conventional generation is increasing rapidly now-a-days. Hence a better understanding of wind power plants is required. But the wind power plants generally containing induction generators exhibit a rather different behavior than the conventional power plants which use synchronous generators. The purpose of this paper is to analyze and study transient stability of a wind farm based on conventional fixed speed Induction generator when it has been integrated with a weak grid. A comparative analysis of the transient stability improvement of a FSIG wind plant has been done, when it is supported with FACTS like S.V.C and STATCOM of equal ratings. Single case of transient condition i.e. a three phase fault has been studied by simulation. With the increase in demand of power and decrease of fossil fuels, mankind has been forced to search alternative sources for the generation of electricity. Wind power in spite of being stochastic in nature has proved itself as a viable solution to this problem. As the wind turbine technology is developing at a good pace, more and more wind power plants are being integrated with the conventional form of generation. With the increase in the ratio of wind generation to conventional generation, several problems related with integration of wind farms have emerged. These problems are due to distinct properties of the generators used with the conventional form (Thermal & Hydro) of generation and wind based generation (1)-(4). In thermal and hydro power based generation synchronous generators are used while in wind based generation mostly induction generators are used. Induction and synchronous generators do not exhibit similar behavior during power system stresses (transients). Moreover, increase in wind power based generation requires a reliable transmission system for power evacuation to the load centers. As the wind farms are mainly concentrated in far flung and rural areas their interconnection with the grid becomes a problem. This problem is mainly due to the existence weak transmission grids in the rural areas (1)-(4). Earlier when the share of wind power generation as compared with the conventional generation was low, during transient conditions; whenever the power system reached on the verge of instability the wind farm was disconnected from the grid and was reconnected when transients passed away. But as the share of wind power in the conventional generation increased, the practice of disconnecting the wind farms from the rest of the grid led to the drop in frequency of the power system. So now-a- days even if a fault occurs in the power system somewhere near the wind farms, they still remain connected with the grid for a critical time period. This phenomenon is called fault ride through (FRT) in wind farms (5). This paper has studied a transient condition (fault) in a grid connected fixed speed induction generator based wind farm and its fault ride through performance. A comparison of the performance of fact devices like static var compensators (svc) and static synchronous compensators (statcom) in improving the transient stability of wind farms during fault is also done.

Energy harvesting also called power harvesting or power scavenging is the technique by which power is derived from external resources .Solar Energy System (SES) plays vital role in renewable energy systems. In this paper the need, types, Active and Passive Solar System, first generation solar system, second generation solar systems, third generation solar systems, advantages and disadvantages of SES was discussed. Additionally, basics of Hydrogen Energy harvesting, NGs harvesting, geothermal energy harvestings, Tidal Energy Harvesting, Wind Energy Harvesting, Thermal Energy harvesting and Nuclear Energy Harvesting was discussed with neat circuit and images. Advantages and Disadvantages of Energy Harvesting are listed. This paper would be helpful for UG students to study the concept of energy harvesting from various sources. Keywords: Nuclear Energy, Nuclear Power Plant(Nuclear reactions ,nuclear fission, nuclear fusion), Hydro power plant, Thermal Energy, Nanoparticles, Tidal Energy, Energy Harvesting, Geothermal energy, Thermal Power plant Cite this Article Selva Vengatesh M., Rajanbabu A., Thangamuniyandi C., Ganesan J. Energy Harvesting Technology and its Potential applications – A Mini Review. Journal of Nuclear Engineering & Technology . 2019; 9(3): 33–43p.

In power system any unpredictable variations of consumption load will cause fluctuation in frequency and the transferred power between the lines. Load frequency control is one of the main problems in the power system which synchronizes with automatic generation control. Checking the different factors that cause unbalance in power system is necessary and one of the important factors of them is the load that randomly varies. In this paper, a three area power system in deregulated environments with participation of synchronized generation of wind with Doubly Fed Induction Generator (DFIG), hydro and thermal power plants are studied. The load in this power system is considered as a random variable which periodically and randomly has frequency of 0.25 around nominal amount. Fluctuations are caused due to considering load as a random variable and using wind-powered turbine with DFIG in power system. To improve the response of power system, the optimal fuzzy logic, PID controller and FACTS devices will be used. Imperialist Competitive Algorithm (ICA) has been used for optimizing the parameters of a fuzzy logic controller. PID Controller parameters have been optimized with three intelligent algorithms, ICA, Genetic Algorithm (GA) and Particle Swarm Optimization (PSO) Algorithm and the results will be compared with each other. With comparison the result it is observed that in the case of using optimal fuzzy logic controller (OFLC) we have the fastest response with the minimum over shoot and under shoot, also in this case the transferred power between the areas is settled in the lowest value. The results show a significant reduction in losses in transmission lines.

This paper deals with the combined automatic voltage control (AVR) and automatic load frequency control (ALFC) of an unequal three-area three-source system. Area-1, area-2 comprises of thermal, diesel and hydro plant, and area3 comprises of gas, diesel and thermal plant. A maiden attempt has been made to apply a Tilt-integral-derivative (TID) as secondary controller in both AVR and ALFC loops. A nature inspired metaheuristic algorithm called shuffled frog leaping algorithm (SFLA) is successfully applied for ALFC and AVR studies. Investigations are carried out by considering 1% SLP in area-1 considering integral double derivative (IDD), proportional-ID (PID) and TID controller reveals the better responses with TID controller in terms of settling time and oscillations magnitude. Moreover, the superiority of SFLA technique is tested with cuckoo search and firefly algorithms in terms of dynamic responses and convergence characteristics. Furthermore, the system dynamic responses are compared with and without considering nonlinearities like GRC, GDB as a realistic approach. Sensitivity analysis reveals that SFLA optimized TID controller gains and parameters at nominal conditions are found to be robust against discrepancy in system loading conditions and inertia.

While hydropower in California is one the main sources of renewable energy, population growth has continuously increased demand for energy. In addition, recent droughts reduced the amount of available water behind the hydropower dams to provide the water head needed to run the turbines in hydropower plants. A more sustainable alternative, instead of developing new infrastructure, is to enhance the daily operation of reservoirs to support hydropower generation. This study suggests a new optimal operation policy for Folsom Reservoir in California and hydropower plants, which maximizes hydropower generation and reduces flood risk. This study demonstrates the application of the cellular automata (CeA) approach to optimize the daily hydropower operation of Folsom Reservoir. The reservoir operation is a nonlinear problem, where the hydropower generation and elevation-area-storage functions are the main nonlinearity to accurately represent the daily operation of the system. Moreover, the performance of the CeA approach under two extreme climate conditions, wet and dry, was evaluated and compared to the operation during normal conditions. Results showed that the CeA approach provides more efficient solutions in comparison to the commonly used evolutionary optimization algorithms. For the size of the non-linear optimization problem designed in this study, CeA outperformed genetic algorithm for finding optimal solutions for different climate conditions. Results of CeA showed that although the annual average inflow to the reservoir during the dry period was about 30% less than the normal condition, CeA offered about a 20% reduction in average hydropower generation. The new operation policy offered by CeA can partly compensate for the loss of the snowpack in California’s Sierra Nevada under a warming climate. The approach and its outcomes support an informed decision-making process and provide practical reservoir operational guideline to remediate the adverse effects of hydroclimatic changes in the future.

Hydropower generation is world best source of renewable energy and is continuously playing a tremendous job in energy requirement. To cope up with day by day increasing demand in electric energy, it is very essential to keep the hydropower plants in sustainable operational condition. To achieve this, the maintenance strategies based on Reliability, Availability and Maintainability (RAM) analysis play a pivotal role in sustainability of the hydropower plants. In our case study various critical components of hydropower plant were identified such as turbine, governor and generator. The causes and effects of various failures in the critical components were identified using Failure Mode Effect Analysis (FMEA) and Fault tree Analysis (FTA). The main role in the study is presenting a RAM model which helps in evaluating different levels of performance in Hydropower plant. Finally, the RAM parameters were evaluated and their outcomes were suggested to find the convenient maintenance intervals. The results of the proposed model revealed that the critical flaws of the hydrogenation process such as turbines, governors and generator should to be taken on priority basis to achieve the high level of reliability and safety. The results of present framework is to achieve the high level of reliability, hence, the main flaws of the hydrogenation process such as turbines, governors and generator should to be taken on priority basis. The proposed study could be valuable for improving the availability and safety of the critical equipment in hydropower plant. As a consequence, the results of present study could be beneficial for other hydro generating facilities to achieve the sustainable maintenance and operation programs in electricity generation systems.

A reliable approach based on a multi-verse optimization algorithm (MVO) for designing load frequency control incorporated in multi-interconnected power system comprising wind power and photovoltaic (PV) plants is presented in this paper. It has been applied for optimizing the control parameters of the load frequency controller (LFC) of the multi-source power system (MSPS). The MSPS includes thermal, gas, and hydro power plants for energy generation. Moreover, the MSPS is integrated with renewable energy sources (RES). The MVO algorithm is applied to acquire the ideal parameters of the controller for controlling a single area and a multi-area MSPS integrated with RES. HVDC link is utilized in shunt with AC multi-areas interconnection tie line. The proposed scheme has achieved robust performance against the disturbance in loading conditions, variation of system parameters, and size of step load perturbation (SLP). Meanwhile, the simulation outcomes showed a good dynamic performance of the proposed controller.

The characteristic of the united power system of Ukraine, based on thermal, nuclear and hydro power plants, as well as on alternative and renewable sources, is carried out. The structure of power system potential indicates a lack of maneuver capacity, some plants are of low mobility. Thermal power is in critical condition due to expired service time of the main technological equipment, additionally, it is a huge source of emissions of harmful substances into the environment. An attempt to use them to cover peak loads only worsens their critical state.It is suggested to restore thermal power on the basis of combined steam and gas power plants. Moreover, for operation of gas section it is necessary to use working substance, which is formed in an additional furnace by heating the compressed air with heat from combustion of some part of coal flow, which subsequently enters the main furnace. The steam and gas generation branches are parallel connected, which extends the range of power change (increasing its maneuverability.) Gas generation increases mobility (rate of power change). For combustion of organic fuel, oxygen enriched atmospheric air is fed, and a nitrogen-based fraction can form a working substance for gas generation. With such an organization of combustion the coefficient of excess air can be ignored, which enables to reduce the volume of flue gases. The membrane separation of atmospheric air into fractions - one en-riched with oxygen, and another with nitrogen, improves the environmentalperformance of a power plant, while increasing its power and economic indices. On the example of the boiler unit TP-92 the basic parameters of a power plant are checked by a calculation method. It is confirmed that the proposed technical solutions point to the correctness and validity of the assumptions. Analysis of the existing technical level of scientific research increases confidence in perspective of the selected direction.

Difference between grid connections of large-scale wind power and conventional synchronous generation