Showing papers on "Base load power plant published in 2017"

DC Microgrid Technology: System Architectures, AC Grid Interfaces, Grounding Schemes, Power Quality, Communication Networks, Applications, and Standardizations Aspects

Abstract: To meet the fast-growing energy demand and, at the same time, tackle environmental concerns resulting from conventional energy sources, renewable energy sources are getting integrated in power networks to ensure reliable and affordable energy for the public and industrial sectors However, the integration of renewable energy in the ageing electrical grids can result in new risks/challenges, such as security of supply, base load energy capacity, seasonal effects, and so on Recent research and development in microgrids have proved that microgrids, which are fueled by renewable energy sources and managed by smart grids (use of smart sensors and smart energy management system), can offer higher reliability and more efficient energy systems in a cost-effective manner Further improvement in the reliability and efficiency of electrical grids can be achieved by utilizing dc distribution in microgrid systems DC microgrid is an attractive technology in the modern electrical grid system because of its natural interface with renewable energy sources, electric loads, and energy storage systems In the recent past, an increase in research work has been observed in the area of dc microgrid, which brings this technology closer to practical implementation This paper presents the state-of-the-art dc microgrid technology that covers ac interfaces, architectures, possible grounding schemes, power quality issues, and communication systems The advantages of dc grids can be harvested in many applications to improve their reliability and efficiency This paper also discusses benefits and challenges of using dc grid systems in several applications This paper highlights the urgent need of standardizations for dc microgrid technology and presents recent updates in this area

Fast-Frequency Response Provided by DFIG-Wind Turbines and its Impact on the Grid

Abstract: This paper presents a methodology for the analysis of frequency dynamics in large-scale power systems with high level of wind energy penetration by means of a simplified model for DFIG-based wind turbines. In addition, a virtual inertia controller version of the optimized power point tracking (OPPT) method is implemented for this kind of wind turbines, where the maximum power point tracking curve is shifted to drive variations in the active power injection as a function of both the grid frequency deviation and its time derivative. The proposed methodology integrates the model in a primary frequency control scheme to analyze the interaction with the rest of the plants in the power system. It is also proven that, under real wind conditions, the proposed version of the OPPT method allows us to smooth the wind power injected into the grid, thereby reducing frequency fluctuations.

Coordinated Distributed MPC for Load Frequency Control of Power System With Wind Farms

Abstract: Load frequency control (LFC) is crucial for the operation and design of modern electric power systems. This becomes quite challenging, as more wind power is included into the power system. This paper proposes a coordinated distributed model predictive control (DMPC) for the LFC of a power system that includes inherently variable wind-power generations. This DMPC communicates power system measurement and prediction data, and considers the information of other controllers for their local objective to realize effective coordination. The controllers solve the optimization problem while considering given constraints, e.g., generation rate constraints, wind speed, pitch angle, and load input constraints for each area. Since the wind-power output depends largely on the wind speed, different optimization modes for the DMPC were used. Both simulation and experimental tests of a four-area interconnected power system LFC, which consists of thermal plants, hydro units, and a wind farm, demonstrate the improved efficiency of the coordinated DMPC.

Genetic Algorithm Based Demand Side Management for Smart Grid

Abstract: Electricity usage at electricity rush hour (peak hour) may vary from each and every service area such as industrial area, commercial area and residential area. Equalizing the power consumption in industry may lead to the utilization of power in other service areas in an efficient way. Although industries have comparably lesser number of power consuming device types than other service areas the power consumption is quite high. To meet the demands rising in the industry, shiftable loads (devices) can be redistributed equally to all the working time slots based on the average power utilization. It can be done in a flexible manner by shaping the loads using Demand Side Management (DSM) technique in Smart Grid. The main objective is to minimize the power utilization during the electricity rush hour by effectively distributing the power available during off-peak hour. Evolutionary algorithm can be well adapted to problems where optimization is the core criteria. Any maximization or minimization problem can be solved efficiently using evolutionary algorithm. Hence, to obtain the optimized fitness function of load redistribution in industry Genetic Algorithm in Demand Side Management (GA-DSM) is chosen and it has benefited with an overall reduction of 21.91% which is very remarkable. In addition to this the evaluation of the fitness function using GA-DSM is carried out in other two industrial dataset models (steel plant and wind power plant) which is unavailable so far in the literature.

Power system stability analysis under increasing penetration of photovoltaic power plants with synchronous power controllers

Abstract: The utilisation of renewable sources brings many benefits to electric power systems, but also some challenges such as the impact that renewable power plants employing power electronics have on the grid, which is gaining importance as the penetration of this type of generating stations increases, driven by the construction of large wind or solar photovoltaic (PV) power plants. This study analyses the impact of large-scale PV power plants on a transmission grid for different penetration levels. The analysis considers power plants formed by a number of power converters employing synchronous power controllers (SPCs), that allow them to have a harmonious interaction with the grid, and compares their performance with that of conventional power converter controllers, assuming in both cases that the power plants participate in frequency and voltage regulation. The study addresses both the small-signal stability of the system and its response to large disturbances that alter the active power balance and frequency stability. The results of the analysis show that PV power plants using SPCs are able to limit frequency deviations, improve the oscillation damping, and reduce the stress of other generating units, thus having a beneficial impact on the power system.

Solar parallel feed water heating repowering of a steam power plant: A case study in Iran

Abstract: Currently, the use of renewable energies is put on the agenda of most researchers in the field of energy. On the other hand, in many parts of the world, fossil fuel power plants continue to be the main source of electrical power. Increased efficiency of fossil fuel power plants and the use of solar energy lead to recommendation of merging solar farms with the cycle of these power plants. The statistics indicate that the output of fossil fuel power plants in Iran, which currently supply about 93.9% of electricity of the national network, is experiencing a negative growth. On the other hand, according to government plans, part of the generated electricity should be provided from renewable energy sources in the next few years. In this paper, the use of solar energy for integration with power-plant units of Isfahan is investigated. To do this, preheat project of the feed water is investigated on 7 separate scenarios. The results showed that replacing all high-pressure feed water preheaters with solar farm increases the net energy and exergy efficiencies of the power plant by 18.3% compared to the simple cycle which respectively reaches to 45% and 43.91%. Given the importance of reducing emissions of CO 2 pollutants at power plants, reduction level of gas emissions, as well as some economic aspects of the integration of solar farm with the cycle of this power plant has also been evaluated.

Security-Constrained Unit Commitment With Flexible Uncertainty Set for Variable Wind Power

Abstract: Power system operation has recently witnessed major challenges, which are often due to large-scale integrations of wind power generation. In this paper, a two-stage robust security-constrained unit commitment (SCUC) model is proposed for managing the wind power uncertainty in the hourly scheduling of power system generation. Different from previous studies on robust SCUC, which considered a predefined uncertainty set, the proposed method applies a flexible uncertainty set for managing the variable wind power generation. The proposed method seeks a feasible and economic dispatch in the flexible uncertainty set, takes into account wind spillage and load curtailment risks, and makes a tradeoff between the optimal wind power absorption and the economic grid operation. Several case studies are applied to the proposed method and the corresponding solutions are analyzed in the paper. The impacts of major factors, including flexible generation resources and power transmission capacity, on the proposed solution are also discussed. The numerical results demonstrate the merits of the proposed method for managing large variations in the hourly wind power generation and lowering the power system operation cost in uncertain conditions.

Transition of Future Energy System Infrastructure; through Power-to-Gas Pathways

Abstract: Power-to-gas is a promising option for storing interment renewables, nuclear baseload power, and distributed energy and it is a novel concept for the transition to increased renewable content of current fuels with an ultimate goal of transition to a sustainable low-carbon future energy system that interconnects power, transportation sectors and thermal energy demand all together. The aim of this paper is to introduce different Power-to-gas “pathways”, including Power to Hydrogen, Power to Natural Gas End-users, Power to Renewable Content in Petroleum Fuel, Power to Power, Seasonal Energy Storage to Electricity, Power to Zero Emission Transportation, Power to Seasonal Storage for Transportation, Power to Micro grid, Power to Renewable Natural Gas (RNG) to Pipeline (“Methanation”), and Power to Renewable Natural Gas (RNG) to Seasonal Storage. In order to compare the different pathways, the review of key technologies of Power-to-gas systems are studied and the qualitative efficiency and benefits of each pathway is investigated from the technical points of view. Moreover, different Power-to-gas pathways are discussed as an energy policy option that can be implemented to transition towards a lower carbon economy for Ontario’s energy systems.

Stochastic Scheduling of Battery-Based Energy Storage Transportation System With the Penetration of Wind Power

Abstract: Battery-Based Energy Storage Transportation (BEST) is a potential solution for optimizing the power system operations with a high penetration of wind energy. In this paper, we propose a scenario-based stochastic model for the BEST-integrated power system scheduling. In this model, load and wind energy forecasting inaccuracies and random disturbances are modeled in scenario trees using the Monte Carlo simulation method. Random disturbances represent forced outages of both power system and railway system components, including generation units, transmission lines, railway stations, and railway lines. Benders decomposition is adopted to solve the stochastic model. Two BEST-integrated power systems are used to illustrate the proposed model and the performance of the proposed solution algorithm. The first one is a 6-bus power system integrated with a 3-station and 3-line railway network. The second one is the modified IEEE 118-bus power system integrated with a railway network composed of 8 railway stations and 10 rail lines. Simulation results show that the BEST system implementation is a viable option for managing the large-scale integration of wind power which can reduce the curtailment of wind power and accordingly lower the operation cost of power systems.

Robust Scheduling for Wind Integrated Energy Systems Considering Gas Pipeline and Power Transmission N–1 Contingencies

Abstract: The security of natural gas network and the wind power uncertainty bring new challenges for power system operation. This letter develops a robust scheduling model for wind-integrated energy systems with the considerations of both gas pipeline and power transmission N –1 contingencies. The proposed method is robust against wind power uncertainty to ensure that the system can sustain possible N –1 contingency event of gas pipeline or power transmission line. Case studies demonstrate the effectiveness of the proposed model.

Technical impacts of high penetration levels of wind power on power system stability

Abstract: With increasing penetrations of wind generation, based on power-electronic converters, power systems are transitioning away from well-understood synchronous generator-based systems, with growing implications for their stability. Issues of concern will vary with system size, wind penetration level, geographical distribution and turbine type, network topology, electricity market structure, unit commitment procedures, and other factors. However, variable-speed wind turbines, both onshore and connected offshore through DC grids, offer many control opportunities to either replace or enhance existing capabilities. Achieving a complete understanding of future stability issues, and ensuring the effectiveness of new measures and policies, is an iterative procedure involving portfolio development and flexibility assessment, generation cost simulations, load flow, and security analysis, in addition to the stability analysis itself, while being supported by field demonstrations and real-world model validation. WIREs Energy Environ 2017, 6:e216. doi: 10.1002/wene.216 For further resources related to this article, please visit the WIREs website.

Turbine Stability-Constrained Available Wind Power of Variable Speed Wind Turbines for Active Power Control

Abstract: The active power control (APC) of variable-speed wind turbines (VSWT) is increasingly required to support the power system operation and control. Besides control strategies, the power reference also exerts a significant influence upon APC performance. Due to the VSWT instability, the optimistic reference which is usually determined according to the conventional available wind power (AWP) based on maximum power point, cannot be sustainably maintained over the dispatch period. This may results in frequent interruption of power reference tracking. On the other hand, the conservative reference will easily lead to excessive pitch regulation. In this letter, the turbine stability-constrained available wind power is defined and analyzed to sustain the power generation of scheduled wind turbines at a maximum level. Simulation results show that the VSWT dispatched according to the proposed AWP can maintain stable power generation with less pitch action and therefore better support secure and economic power system operations.

Performance of geothermal power plants (single, dual, and binary) to compensate for LHC-CERN power consumption: comparative study

Abstract: The aim of this study is to compare between single flash, dual flash, and binary power plants in terms of the power generated, their performance, and the related cost. The results from the comparison are used to find the best plant type that can be implemented to compensate for the very high power requirements of a large hadron collider (LHC). Using the setting and requirements of the CERN LHC in Geneva, Switzerland, the study uses System Advisor Model software to analyze the implementation of the different plant types. Results show that the binary power plant has the best performance and lowest cost compared with other geothermal power plants analyzed, and there is a reduction in the total power generation cost when using renewable energy sources.

Use of Smart Loads for Power Quality Improvement

Abstract: Electric spring (ES) was originally proposed as a distributed demand-side management technology for making noncritical loads adaptive to the availability of intermittent renewable power generation. The second generation of ES, fed with batteries (ES-2) and associated with a noncritical load, can form a new kind of combined smart load and distributed energy storage technology for smart grids. With its four-quadrant operation, ES-2 is able to offer ancillary grid services in addition to its major functions of voltage and frequency regulation. This paper presents the operating principles and the input current control of ES-2 for power quality improvement such as power factor correction and harmonics reduction. The operating principles and the proposed input current control have been verified with the experimental results obtained from a small-scale power grid. Another weak single-phase power system fed by intermittent wind power is set up to prove the combined operation of ES-2 for power quality improvement and ES-1 (ES with capacitor storage) for voltage stabilization. The experimental results show that ES-2 with input current control can carry out power quality improvement as its ancillary function.

Multi-period integrated natural gas and electric power system probabilistic optimal power flow incorporating power-to-gas units

Abstract: The increasing adoption of gas-fired power plants directly strengthens the coupling between electric power and natural gas systems. Current industrial practice in optimal power flow for electric power systems has not taken the security constraints of gas systems into consideration, resulting in an overly-optimistic solution. Meanwhile, the operation of electric power and natural gas systems is coupled over multiple periods because of the ramp rate limits of power generators and the slow dynamical characteristics of gas systems. Based on these motivations, we propose a multi-period integrated natural gas and electric power system probabilistic optimal power flow (M-GEPOPF) model, which includes dynamic gas flow models. To address the uncertainties originating from wind power and load forecasting, a probabilistic optimal power flow (POPF) calculation based on a three-point estimate method (3PEM) is adopted. Moreover, power-to-gas (PtG) units are employed to avoid wind power curtailment and enable flexible bi-directional energy flows between the coupled energy systems. An integrated IEEE RTS 24-bus electric power system and the Belgian 20-node natural gas system are employed as a test case to verify the applicability of the proposed M-GEPOPF model, and to demonstrate the potential economic benefits of PtG units.

Intermittent Smoothing Approaches for Wind Power Output: A Review

Abstract: Wind energy is one of the most common types of renewable energy resource. Due to its sustainability and environmental benefits, it is an emerging source for electric power generation. Rapid and random changes of wind speed makes it an irregular and inconsistent power source when connected to the grid, causing different technical problems in protection, power quality and generation dispatch control. Due to these problems, effective intermittent smoothing approaches for wind power output are crucially needed to minimize such problems. This paper reviews various intermittent smoothing approaches used in smoothing the output power fluctuations caused by wind energy. Problems associated with the inclusion of wind energy resources to grid are also briefly reviewed. From this review, it has been found that battery energy storage system is the most suitable and effective smoothing approach, provided that an effective control strategy is available for optimal utilization of battery energy system. This paper further demonstrates different control strategies built for battery energy storage system to obtain the smooth output wind power.