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When a hexagonal converter (Hexverter) is applied to high-power renewable energy generation such as offshore low-frequency transmission, using traditional PID control to ensure the stable global operation and strong robustness of the system is difficult due to the random fluctuation of renewable energy, system parameter uptake, its non-linear characteristics, and the possible unbalanced grid situation. This paper proposes a non-linear passivity-based control (PBC) strategy for Hexverter under an unbalanced grid. First, the passivity and stability of Hexverter objects are analyzed based on PBC theory. The unbalanced PBC strategy of Hexverter is then designed and derived. Three control objectives are designed according to different control requirements. Finally, the simulation system of the Hexverter under an unbalanced grid is built on Matlab/Simulink to verify the effectiveness and superiority of the proposed unbalanced PBC method. The simulation results show that the proposed method has fewer control parameters, faster response, lower harmonic content, and better overall control effect than PID control. [ABSTRACT FROM AUTHOR]

This paper presents application guidelines for a new generic plant controller model that can be used for renewable plant dynamic system analysis that may include the control of static compensators (STATCOMs), static var compensators (SVCs), and/or energy storage devices. The authors originally presented the need for such a model to the Western Electricity Coordinating Council (WECC) and contributed to various stages of the new model development led by WECC. As Independent System Operators (ISOs)/Regional Reliability Organizations (RTOs)/Transmission Service Providers (TSPs) are moving toward acceptance and use of generic models only the authors have for the first time applied this new model for an operating renewable plant. The new model was configured, parameterized, and tuned to control two STATCOMs and multiple switched capacitors/reactors to represent a master/auxiliary control strategy as implemented in the plant. Dynamic simulations show that the configured and parameterized model is performing properly as expected. This tuned model was submitted to the system operator for compliance with the interconnection requirements of the plant. This is the first submission of the new generic model for this type of control for a renewable project. The submitted model is appropriate for dynamic simulations, which are routinely performed by ISOs/RTOs/TSPs in system impact studies or transmission planning studies. This paper provides useful guidelines in applying this new model for similar projects. [ABSTRACT FROM AUTHOR]

In order to relieve the influence of wind power uncertainty on power system operation, demand response and robust stochastic theory are introduced to build a stochastic scheduling optimization model. Firstly, this paper presents a simulation method for wind power considering external environment based on Brownian motion theory. Secondly, price-based demand response and incentive-based demand response are introduced to build demand response model. Thirdly, the paper constructs the demand response revenue functions for electric vehicle customers, business customers, industry customers and residential customers. Furthermore, robust stochastic optimization theory is introduced to build a wind power consumption stochastic optimization model. Finally, simulation analysis is taken in the IEEE 36 nodes 10 units system connected with 650 MW wind farms. The results show the robust stochastic optimization theory is better to overcome wind power uncertainty. Demand response can improve system wind power consumption capability. Besides, price-based demand response could transform customers’ load demand distribution, but its load curtailment capacity is not as obvious as incentive-based demand response. Since price-based demand response cannot transfer customer’s load demand as the same as incentive-based demand response, the comprehensive optimization effect will reach best when incentive-based demand response and price-based demand response are both introduced. [ABSTRACT FROM AUTHOR]

The deployment of Renewable Energy Sources (RES) is driving modern power systems towards a fundamental green transition. In this regard, there is a need to develop models to accurately capture the variability of wind and solar photovoltaic (PV) power, at different geographical and temporal scales. This paper presents a general methodology based on meteorological reanalysis techniques allowing to simulate aggregated RES time series over large geographical areas. It also introduces a novel PV conversion approach based on aggregated power curves in order to capture the uncertainty associated to the technical characteristics of individual installations spread across large regions. The proposed methodology is validated using actual power data in Europe and can be applied to represent intermittent generation in network development plans, reliability and market studies, as well as operational guidelines. [ABSTRACT FROM AUTHOR]

This paper presents a scenario-based simulation analysis of the operation of the insular power system of Crete, Greece, on an hour-by-hour basis aiming at the evaluation of the impact of high Renewable Energy Sources (RES) penetration on the short-term power system scheduling. The possibility of introducing a pumped-storage plant as a storage facility to alleviate the negative effects of increased RES generation on the short-term operation is also investigated. The renewable generation impact is evaluated in terms of specific system indicators. An integrated software tool that performs annual simulation of the insular power system with hourly granularity aiming at the minimization of the total production cost while respecting the system and various generating unit operating constraints is used. Simulation results for the year 2015 provide quantitative assessment of the insular power system performance regarding its short-term operation under large-scale RES penetration and valuable conclusions are drawn. [ABSTRACT FROM AUTHOR]

Renewable energies are a central element in the search for energy sustainability, so they are becoming a substantial component of the energy scenario of every country, both as systems connected to the grid or in stand-alone applications. Feasibility of these renewable energy systems could be necessary not only in their application in isolated areas, but also in systems connected to the grid, in this last case when their contribution reaches a substantial fraction of the total electricity demand. To overcome this reliability problem, hybrid renewable systems could become essential and activities to optimize their design should be addressed, both in the simulation and in the experimental areas. In this paper, a laboratory to simulate and verify the reliability of hybrid renewable systems is presented and its application to the feasibility analysis of multicomponent systems including photovoltaic panels, wind generator and biomass gasification plant, plus energy storage in a battery bank, are described. [ABSTRACT FROM AUTHOR]

This paper introduces a new proposed design and optimization simulation program for the techno-economic sizing of a stand-alone hybrid photovoltaic/wind/diesel/ battery energy system using the iterative optimization. The main function of the new proposed simulation program is to determine the optimum size of each component of a hybrid renewable energy system for the lowest price of generated energy and the lowest value of dummy energy at highest reliability. An accurate methodology for pairing between five Saudi Arabia sites and ten wind turbines from different manufacturers to maximize energy production and minimize the price of the generated power is introduced. This methodology changes the penetration ratio of the renewable energy sources in certain increments to meet the load requirements of the sites under study. A detailed economic methodology to obtain the price of the generated energy is introduced. The new proposed simulation program is implemented in flexible fashion, which is not possible for the market-available software, such as HOMER, INSEL, TRNSYS, and RETScreen. The results obtained from the new proposed simulation program are compared with those from genetic algorithm and HOMER software to evaluate the effectiveness of the proposed program. Many valuable results can be extracted from the proposed program to assist researchers and decision makers. [ABSTRACT FROM AUTHOR]

This paper addresses power management strategies, including technical issues and control methodologies, for a wind-dominated hybrid remote area power supply (RAPS) system. The system consists of a doubly fed induction generator, a diesel generator, a hydrogen-based generation scheme, and mains loads. The goal is to maximize power extraction from the wind generator under generation uncertainty. For active power management, a hydrogen-based generation scheme consisting of an electrolyser and a fuel cell system is integrated to the RAPS system. Developed control strategies contribute to achieve the following objectives: 1) load side voltage and frequency regulation; 2) maximum power extraction from wind; and 3) regulating diesel generator operation at low load conditions. Simulation studies with a real-life data set are used to evaluate the proposed architecture and prove the control objectives, and it has been observed that all the proposed objectives are met within satisfactory limits. [ABSTRACT FROM PUBLISHER]

SUMMARY This paper investigates Japan's long-term energy outlook to 2050 taking into consideration the massive deployment of solar photovoltaic (PV) systems and wind power generation under a nuclear energy scenario. The extensive introduction of PV systems and wind power systems is expected to play an important role in enhancing electricity supply security after the Fukushima nuclear power accident, which has increased the uncertainty of the future additional construction of nuclear power plants in Japan. Against this background, we develop an integrated energy assessment model composed of both an econometric energy demand and supply model and an optimal power generation mix model. The latter model is able to explicitly analyze the impact of output fluctuations for various renewable energy sources at a detailed time resolution of 10 min on 365 consecutive days, incorporating the role of stationary battery technology. The simulation results reveal that intermittent fluctuations derived from a high penetration level of those renewables are controlled by quick load following operation by natural gas combined cycle power plants, pumped-storage hydro power, stationary battery technology, and output suppression of PV and wind power generation. The results show as well that massive penetration of renewables does not necessarily require a comparable scale of stationary battery capacity. Additionally, in the scenario, which assumes the decommissioning of nuclear power plants with a lifetime of over 40 years, the required PV capacity in 2050 amounts to more than double the PV installation potential in both buildings and abandoned farmland areas. [ABSTRACT FROM AUTHOR]

Due to their weak nature, such as low inertia, offshore energy hubs are prone to unprecedented fast dynamic phenomena. This can lead to undesired instability problems. Recent literature, with main focus on onshore systems, suggests that electrolysers could be an attractive option to support wind generators in the mitigation of balancing problems. This paper presents an Electromagnetic Transient (EMT) model for real-time simulation based study of the dynamics of active power and voltage responses of offshore hubs due to wind speed fluctuations. The purpose of this study was to ascertain the ability of an electrolyser to support an offshore energy hub under different scenarios and with different locations of the electrolyser. Two locations of Proton Exchange Membrane (PEM) electrolysers were considered: centralised (at the AC common bus of the hub) or distributed (at the DC link of the wind turbines). Numerical simulations conducted in RSCAD® on a 2 GW offshore hub with 4 × 500 MW wind power plants and 330 or 600 MW PEM electrolysers show that electrolysers can effectively support the mitigation of sudden wind speed variations, irrespective of the location. The distributed location of electrolysers can be beneficial to prevent large spillage of wind power generation during the isolation of faults within the hub. [ABSTRACT FROM AUTHOR]

Improving the safety and stability of power systems by adjusting the controllable load to improve the wind power integration has become a hot research topic. However, the methodology of accurately controlling the load and fundamentally improving the wind power integration capacity has yet to be studied. Therefore, this paper proposes an intelligent regulation method for a controllable load. This method takes the new energy consumption assessment as feedback, and it combines the wind power acceptance assessment and scheduling plan to form the internal and external loop control structure, and it derives the controllable load intelligent regulation architecture. The load curve is decomposed by an interactive load observer, and the load curve is adjusted by the interactive load controller according to a given standard, thereby improving the new energy acceptance capability. Finally, based on the actual grid operation data of a provincial power grid in Northeastern China, the source grid load balancing process and the interactive load regulation model of the wind power system are simulated. The above method verifies the validity and rationality of the proposed method. [ABSTRACT FROM AUTHOR]