Grid Interface Research Articles

Study on improved control strategy of virtual synchronous generator

Virtual synchronous generator (VSG) control technology for photovoltaic, energy storage, wind power, and other new energy to provide flexibility in the grid interface characteristics, is conducive to improving the stability of the power system, and has been widely considered by many scholars. Firstly, an improved VSG control method is proposed through simulation and analysis, which realizes the complete decoupling of the frequency response time constant and the inertia quantity of the active power control loop and reduces the complexity of the parameter design of the VSG system. Secondly, to avoid the frequent action of the VSG system caused by small-scale frequency change perturbation, this study proposes a VSG frequency optimization control method for VSG frequency control with rated angular velocity ωset feedforward composed of multivariate factors when considering a primary frequency regulation dead zone. Thirdly, the impact of VSG parameter design on the system is investigated through the system response characteristics of power scheduling, primary frequency regulation at the grid connection, and the small-signal dynamic characterization of the improved VSG. Finally, Simulation and experimental verification yielded an active power overshoot of 7% and a maximum frequency deviation of 0.17 Hz for the improved system. The improved control method resulted in an improvement of 0.1 s in the frequency response time and a reduction of 0.15 Hz in the oscillation amplitude. The response speed of the improved control method is much better, while the oscillation amplitude is reduced to meet the grid's regulation requirements. The simulation and experimental analysis verify the feasibility of the improved VSG control method.

High performance P300 spellers using GPT2 word prediction with cross-subject training

ABSTRACT Amyotrophic lateral sclerosis (ALS) severely impairs patients’ ability to communicate, often leading to a decline in their quality of life within a few years of diagnosis. The P300 speller brain–computer interface (BCI) offers an alternative communication method by interpreting a subject’s EEG response to flashing characters presented on a grid interface. This paper addresses the common speed limitations encountered in training efficient P300-based multi-subject classifiers by introducing innovative ‘across-subject’ classifiers. We leverage a combination of the second-generation Generative Pre-Trained Transformer (GPT2) and Dijkstra’s algorithm to optimize stimuli and suggest word completion choices based on subjects’ typing history. Additionally, we employ a multi-layered smoothing technique to accommodate out-of-vocabulary (OOV) words. Through extensive simulations employing random sampling of EEG data from multiple subjects, we demonstrate significant speed enhancements in typing passages containing rare and OOV words. These optimizations result in approximately 10 % improvement in character-level typing speed and up to 40 % improvement in multi-word prediction. We demonstrate that augmenting standard row/column highlighting techniques with layered word prediction yields close-to-optimal performance. Furthermore, we explore both ‘within-subject’ and ‘across-subject’ training techniques, showing that speed improvements are consistent across both approaches.

Three-dimensional lattice Boltzmann flux solver for three-phase/component flow

In this article, an immiscible three-phase/three-component lattice Boltzmann flux solver (TPLBFS) based on diffusion interface method is proposed, which can achieve three-phase flow simulation with high density ratio (1:1000). This model quickly solved (1) the flux at the grid interface using the lattice Boltzmann method (LBM) solution format and (2) the Navier–Stokes (NS) equation and Cahn–Hilliard (CH) equation using a unified format. Compared to LBM, TPLBFS can be applied to unstructured networks. Moreover, TPLBFS can independently add or remove source items and has high secondary development features. Its outstanding computing power has been demonstrated by multiple two-dimensional/three-dimensional (2D/3D) examples, including 2D liquid lens as well as 3D bubble absorption and bubble rising in a three-phase system.

Comparative study of dynamic response by three types of energy storage systems for grid studies: A Microgrid Laboratory experimental-based study

Implementing Energy Storage Systems (ESS) is increasingly significant in power electrical systems. This is attributed to their ability to store surplus electricity generated by renewable energy sources such as wind and solar, contributing to the balance between generation and demand. Literature studies indicate that this practice enhances network stability and diminishes the need for expensive redesigns in infrastructure. This paper presents an exhaustive experimentation-based study of the dynamic response provided by three energy storage system technologies: supercapacitors, Lithium-Ion batteries, and Vanadium redox flow batteries, technologies with significant academic, research, and industrial interests nowadays. The objective of this research is the experimental evaluation of the performance of such technologies in real electrical system operations, focusing on determining the efficiency of charge and discharge, as well as the tracking of active and reactive power achieved through the associated grid interface. The experimental tests performed in a microgrid laboratory show these technologies’ advantages and limitations in different grid-integration applications, with the Lithium-Ion battery-based ESS demonstrating the highest efficiency and faster power response. The results achieved and reported in the article can serve as an essential input for researchers and technology developers to feed their models with more precise parameters and data that might provide results closer to the actual behaviour of the studied prototypes. The methodological framework used in this research is descriptive, experimental, and quantitative.

Integrated wellbore-reservoir modeling based on 3D Navier–Stokes equations with a coupled CFD solver

The occurrence of fluid flow near a wellhead is the major concern of the petroleum industry, as pressure drop, loss of formation, and other variables of interest are mostly affected in this region. The fluid flows from the hydrocarbon reservoir to the wellbore can be characterized as laminar to turbulent; thus, it is important to model this phenomenon with the integrated wellbore-reservoir model. Using 3D Navier–Stokes equations, an integrated wellbore-reservoir model is created in this study, and it incorporates the formation damage zone. For the porous-porous and porous-fluid interfaces, the General Grid Interface (GGI) approach is applied in conjunction with the conservative mass flux interface model. Model equations are solved using a velocity-pressure coupling solver that is pressure-based. For reliable and quick results, the system of equations is solved using an algebraic multigrid approach. The pressure diffusivity equation’s analytical solution under steady-state flow circumstances is used to validate the model. The integrated wellbore-reservoir model is applied to different reservoir scenarios, for example, different production rates, formation zones, and reservoir formation conditions. The results indicate that the present Computational Fluid Dynamics (CFD) model can be extended to simulate the real field scale model. integrated wellbore-reservoir modeling based on 3D Navier–Stokes equations with efficient computational techniques can lead the field of petroleum industries to advance current knowledge.

Simulation test of 50 MW grid-connected “Photovoltaic+Energy storage” system based on pvsyst software

With the implementation of the national “double carbon” strategy, the installed capacity of new energy power generation continues to grow, and stable photovoltaic power generation solutions have received increasing attention. The PV + energy storage system with a capacity of 50 MW represents a certain typicality in terms of scale, which is neither too small to show the characteristics of the system nor too large to simulate and manage. This study builds a 50 MW “PV + energy storage” power generation system based on PVsyst software. A detailed design scheme of the system architecture and energy storage capacity is proposed, which is applied to the design and optimization of the electrochemical energy storage system of photovoltaic power station. Based on the results of PVsyst operation simulation test, the operation performance of 50 MW “PV + energy storage” power generation system is explored. The results show that the 50 MW “PV + energy storage” system can achieve 24-h stable operation even when the sunshine changes significantly or the demand peaks, maintain the balance of power supply of the grid, and save a total of 1121310.388 tons of CO2 emissions during the life cycle of the system. The various parts of the system, including the photovoltaic array, the energy storage unit and the grid interface, demonstrated efficient collaborative performance in the simulation environment of PVsyst.The analysis of power generation shows obvious seasonal changes. The unit power generation is higher from March to September, and the more the power generation is the overall annual power generation shows good consistency and predictability under the regulation of the energy storage system. Through the analysis of different operating scenarios, the key parameters that affect the system performance are further determined, such as lighting conditions, battery storage capacity, power consumption device efficiency. For lighting conditions, the total radiation amount of the incident lighting surface takes the most proportion in the interval of 380–900 W/m2 and 25-60kwh/m2/Bin. The simulation test also reveals the important role of energy storage unit in power grid demand peaking and valley filling, which has an important impact on balancing the instability of photovoltaic power generation and improving the system response ability.

Lattice Boltzmann model on unstructured grids for radiative transfer in graded-index media

The lattice Boltzmann method (LBM) has already been extended to radiative transfer. Radiative transfer in graded-index media is of great interest in many practical processes and is particularly challenging to solve. Currently, some lattice Boltzmann (LB) models have been developed for radiative transfer in graded-index media. These LB models are limited to uniform Cartesian grids and only applicable to simple geometries, thus limiting its application to practical processes. Here we develop a LB model on unstructured grids for radiative transfer in graded-index media. We adopt the relationship between the equilibrium distribution function and the radiative intensity in the standard LB model to establish this LB model on unstructured grids. In this unstructured LB model, the key is that the equilibrium distribution function is reconstructed on the interface of the unstructured grids. This unstructured LB model can solve the radiative transfer equation of graded-index media directly without using the streaming process on each lattice, thus significantly shortening the computational time compared to the standard LB model. This unstructured LB model allows for a simple and efficient geometrical implementation of complex boundaries for radiative transfer in graded-index media. Numerical results show that this unstructured LB model is well suited for radiative transfer in graded-index media with complex geometries and has good accuracy and stability.

Operating modes of grid integrated PV-solar based electric vehicle charging system- a comprehensive review

The impact of air pollution on the world has been highlighted by the World Health Organization (WHO), which has contributed to the growth of emission-free and ecologically friendly transportation options such as electric vehicles (EVs). Between 2019 and 2020, EV sales climbed by 43%, and by 2025, 14 million EVs are expected to be sold worldwide. On the other hand, EVs have drawbacks such as expensive batteries, short lifespans, lack of EV dependability, limited driving range, and long charging periods. Integrating renewable energy sources (RESs) such as biomass, solar, and wind power into EV charging infrastructures is gaining popularity. PV solar-powered EV charging has benefits like cheaper fuel costs, easier installation, less demand on the grid for power, and cost savings. Hybrid and on-board charging systems offer benefits such as reduced weight, faster charging, and improved communication protocols. On-board chargers have higher energy transfer but are more expensive and difficult to integrate with charging stations. Off-board charging systems include public, rapid, induction, and home charging stations. Advanced charging management systems can optimize charging to preserve battery life. It is recommended that future research concentrate on the development of sophisticated control algorithms, integration of wireless charging, extension of fast-charging infrastructure, innovation in materials, compatibility with many vehicles, and optimization of grid interface to enhance efficiency and user experience. The charging of electric vehicles in standalone and grid-connected photovoltaic systems is covered in this paper, along with an explanation of the various modes of operation for these systems. There is also a quick explanation of the various kinds of EV chargers, their power capacities, and their specifications. The research and comparisons in this paper are expected to be useful resources for scholars who are interested in learning more about EV charging facilities.

Considerations on Combining Unfolding Inverters with Partial Power Regulators in Battery–Grid Interface Converters

The application of electrochemical cells as a source unit of electrical energy is rapidly growing—used in electric vehicles and other electric mobility devices, as well as in energy supply systems—as energy storage, often together with renewable energy sources. The key element of such systems is the power electronic converter used for DC energy storage and AC grid interfacing. It should be bidirectional to charge and discharge the battery when it is necessary. Two-stage battery interface converters are the most common; their DC-DC stage controls the battery current and adjusts voltage, but the DC-AC stage (inverter or frontend) controls the current in the grid. The use of unfolding inverters in two-stage battery interfaces can have some advantages. In this case, the DC-DC converter produces half-sinewave pulsating voltages and currents, but the unfolding circuit changes the polarity of the voltages and currents and produces no switching losses. Another trend of modern power electronics is the principle of partial power processing. In this case, power electronic converters deal only with a part of the total power; therefore, losses in such converters are reduced. This paper considers combining unfolding frontends with partial power DC-DC converters that enable the further reduction in losses. In this paper, it is shown that such implementation of the partial power conversion principle in semi-DC-AC systems is really possible based on the real-time matching of the voltage of the partial-power DC-DC converter, battery voltage (which depends on its state of charge) and the rectified instantaneous voltage of the AC grid.

AI-IOT-Based Adaptive Control Techniques for Electric Vehicles

The convergence of Artificial Intelligence (AI) and Internet of Things (IoT) technologies has transformed the field of sustainable transportation planning, notably in the context of Electric Vehicles (EVs). The Problems in all the Existing models are not having proper coordination of optimizing the elements of EV functioning. This research proposes a novel strategy to improving sustainable transportation planning by utilizing AI and IoT. AI-powered algorithms analyze real-time data from IoT sensors installed in EVs and the surrounding environment. These adaptive control algorithms are designed to solve issues including range anxiety, charging infrastructure optimization and energy efficiency. Predictive analytics, route optimization, energy management, and grid interface are all part of the proposed system. Energy management algorithms alter EV settings dynamically to maximize efficiency while taking into account real-time traffic conditions thereby increasing the range extension is upto 2.5% and the total energy efficiency is improved upto 92%. Furthermore, bidirectional connection allowed by IoT devices facilitates the integration of EVs into the energy grid. EVs may engage intelligently in Vehicle-to-Grid (V2G) interactions, providing grid services such as energy delivery during peak demand periods and grid stability.

Variable Speed Wind Energy System Based on a Synchronous Generator with a Three Level Inverter.

The aim of this paper is to show the application of a three level inverter as a grid interface for a variable speed wind energy conversion system. New megawatt wind turbines demand for the connection at higher voltage levels. Multilevel level inverters provide the solution for connecting these wind turbines at voltages over 1 kV. A variable speed wind energy conversion system based on a synchronous generator with a three level inverter has been completely modelled. Then, the dynamic performance of this wind energy conversion system has been studied by simulation. The simulation results show the appropriate behaviour of this system.

An efficient high-gain bidirectional interleaved boost converter for PV integration to DC microgrid.

The design of a power electronic interface for high voltage difference DC buses is a key aspect in DC microgrid applications. A multi-port non isolated interleaved high-voltage gain bidirectional converter, which facilitates bidirectional power transfer and islanded operation in a DC microgrid, is presented in this paper. The forward high-voltage transfer ratio is achieved using a voltage multiplier circuit, and the high-gain step-down power conversion is performed using a resonant power module. A novel power transfer selection algorithm is proposed to control power flow among the interfaces of the RES, ESS, and DC grid converters, which utilizes the net power difference as the basis for switching the converter. The proposed converter is simulated for a 24 V PV source, 12 V battery, and 400 V DC grid interface using MATLAB/SIMULINK. A 200 W hardware prototype is implemented. The simulation results for voltages, currents, and power flow among RES, ESS, and microgrid DC bus proved an excellent voltage regulation, efficient power conversion, and a feasible duty cycle range with high voltage gain. These observations are validated through equivalent experimental results. A comparison is made regarding achieved gain, component sizing, achievable power transfer modes, efficiency, and control complexity with existing converters for DC microgrid applications. The presented topology proved to be a better interface with multiple-mode support with high efficiency.

Investigation of a Low-Speed Commutation Voltage Shock Problem in Three-Level ANPC Inverter with Hybrid Modulation Mode

With the development of the photovoltaic industry; there will be an increasing demand for efficient, high-power density, and low-cost grid interface converters. Compared with two-level inverters, multilevel inverters have the following advantages: (1) lower device voltage ratings; (2) better output filtering spectrum; (3) lower electromagnetic interference (EMI) noise; and (4) higher switching speed capability. However, the complex switching circuit of the multilevel inverter will bring more parasitic inductance, resulting in severe switching overvoltage (ringing). Especially in order to reduce the cost of the inverter, using the long-loop modulation mode, the commutation loop will introduce more parasitic inductance, which will make the overvoltage more serious. Consider that commonly used overvoltage absorption schemes are effective only for overvoltage or suppression of oscillations. Therefore, a new overvoltage absorption circuit is proposed in this paper, which can not only alleviate the overvoltage and ringing phenomena but also suppress the effect of voltage jumps during low-frequency switching on high-frequency input voltage. This overvoltage absorption circuit is characterized by low overvoltage, fast ringing damping, and minimum capacitance. Experiments and simulations are conducted to verify the effectiveness of this overvoltage absorption circuit using a three-level ANPC inverter as a prototype. The results show that the proposed overvoltage absorption circuit can significantly reduce the overvoltage level, shorten the oscillation time, and reduce the voltage difference between the upper and lower DC bus capacitors.

Enhancing power control in doubly fed induction generator based wind turbines: a performance comparison of fuzzy logic and sliding mode control methods

Abstract Effective power regulation is critical for ensuring the stability and performance of Doubly Fed Induction Generator (DFIG)-based wind turbines. This study conducts a comparative study between two control methodologies: fuzzy logic control (FLC) and sliding mode control (SMC), to regulate power in DFIG-based wind turbines. The paper emphasizes the importance of power regulation in wind turbines and its impact on grid stability, presents mathematical equations governing DFIG-based wind turbine systems, encompassing machine equations, power equations, and control objectives related to power regulation. A comprehensive model of the DFIG-based wind turbine system is developed, accounting for dynamic machine behavior and grid interface considerations. The modeli ng process integrates relevant electrical and mechanical components, along with power regulation control strategies. Subsequently, FLC and SMC control methodologies are developed and implemented to regulate desired power. Detailed discussions on controller design and tuning are provided, aligning with specific power control requirements. The results highlight SMC’s effectiveness in achieving precise power regulation within DFIG-based wind turbines, showcasing its superior response characteristics. The study offers valuable insights into the advantages and trade-offs associated with each control approach, aiding researchers and practitioners in selecting the most suitable control methodology for their operational needs. In summary, this paper contributes to the field of wind turbine control systems through a comparative study of FLC and SMC controllers, focusing on regulating power in DFIG-based wind turbines. The findings demonstrate SMC’s superior performance in response, enhancing our understanding of control methodologies for optimizing wind turbine performance and grid integration in sustainable energy systems.

Unsteady Reynolds-Averaged Navier–Stokes Simulations of a Ducted Wind Turbine

Abstract An unsteady Reynolds-averaged Navier–Stokes model on body-fitted meshes in a commercial package (SimericsMP+) with a mismatched grid interface is used to study fluid dynamics around a ducted wind turbine. The model is validated by studying turbulent flow past a marine propeller. The nondimensional thrust and torque coefficients are compared against experimental data and results from a large eddy simulation model. Both coefficients are found to be within 3% of experimental results. Following this validation, the impact of different tip speed ratios on the ducted wind turbine's fluid dynamics is assessed. The optimal tip speed ratio is found to be the design value of 3.93 with a maximum power coefficient of 0.465 based on the duct exit area. The corresponding thrust coefficient is found to be 1.02 based on the rotor area. Lower tip speed ratios experience larger flow separation on the duct interior. Higher tip speed ratios decrease the size of the low-velocity region behind the hub. The ducted wind turbine's performance at design conditions is compared to an open rotor. The ducted wind turbine increases the power coefficient by 96% over the open rotor. The impact of hub size on the ducted wind turbine is also studied by simulating a smaller hub with 77% diameter. At the design tip speed ratio, the smaller hub has a power coefficient of 0.417. The maximum power coefficient is found to be 0.446 at a higher tip speed ratio of 4.5.

Large-Scale Cluster Parallel Strategy for Regularized Lattice Boltzmann Method with Sub-Grid Scale Model in Large Eddy Simulation

As an improved method of the lattice Boltzmann method (LBM), the regularized lattice Boltzmann method (RLBM) has been widely used to simulate fluid flow. For solving high Reynolds number problems, large eddy simulation (LES) and RLBM can be combined. The computation of fluid flow problems often requires a large number of computational grids and large-scale parallel clusters. Therefore, the high scalability parallel algorithm of RLBM with LES on a large-scale cluster has been proposed in this paper. The proposed parallel algorithm can solve complex flow problems with large-scale Cartesian grids and high Reynolds numbers. In order to achieve computational load balancing, the domain decomposition method (DDM) has been used in large-scale mesh generation. Three mesh generation strategies are adopted, namely 1D, 2D and 3D. Then, the buffer on the grid interface is introduced and the corresponding 1D, 2D and 3D parallel data exchange strategies are proposed. For the 3D lid-driven cavity flow and incompressible flow around a sphere under a high Reynolds number, the given parallel algorithm is analyzed in detail. Experimental results show that the proposed parallel algorithm has a high scalability and accuracy on hundreds of thousands of cores.

Numerical Simulation of the Conjugate Heat Transfer of a “Fluid–Solid Body” System on an Unmatched Grid Interface

Recently, when modeling transient problems of conjugate heat transfer, the independent construction of grid models for fluid and solid subdomains is increasingly being used. Such grid models, as a rule, are unmatched and require the development of special grid interfaces that match the heat fluxes at the interface. Currently, the most common sequential approach to modeling problems of conjugate heat transfer requires the iterative matching of boundary conditions, which can significantly slow down the process of the convergence of the solution in the case of modeling transient problems with fast processes. The present study is devoted to the development of a direct method for solving conjugate heat transfer problems on grid models consisting of inconsistent grid fragments on adjacent boundaries in which, in the general case, the number and location of nodes do not coincide. A conservative method for the discretization of the heat transfer equation by the direct method in the region of inconsistent interface boundaries between liquid and solid bodies is proposed. The proposed method for matching heat fluxes at mismatched boundaries is based on the principle of forming matched virtual boundaries, proposed in the GGI (General Grid Interface) method. A description of a numerical scheme is presented, which takes into account the different scales of cells and the sharply different thermophysical properties at the interface between liquid and solid media. An algorithm for constructing a conjugate matrix, the form of matrix coefficients responsible for conjugate heat transfer, and methods for calculating them are described. The operability of the presented method is demonstrated by the example of calculating conjugate heat transfer problems, the grid models of which consist of inconsistent grid fragments. The use of the direct conjugation method makes it possible to effectively solve both stationary and non-stationary problems using inconsistent meshes, without the need to modify them in the conjugation region within a single CFD solver.

Aberrant AI creations: co-creating surrealist body horror using the DALL-E Mini text-to-image generator

The emergence in 2022 of surreal and grotesque image sets created using the free online AI text-to-image generator DALL-E Mini (Craiyon) prompts our analysis of their aesthetic content and connections to preexisting media forms and trends in digital culture. DALL-E Mini uses an unfiltered database of images from the internet to create new images based on a user’s text prompt, often resulting in misshapen bodies and impossible scenarios. Despite its technological limitations, DALL-E Mini’s popularity as a meme-making tool is visible on social media platforms, where crowd-sourced images are shared and experimentation with the tool is encouraged. Through comparison with existing artistic practices and formats (creative automata, surrealism, body horror, celebrity memes), we argue that DALL-E Mini creations can be understood as human-AI co-creations and forms of aesthetic mimicry. Building on the ideas of surrealists such as André Breton, we propose that DALL-E Mini’s images, prompts and the grid interface adhere to surrealism’s historical interests in the unconscious, the uncanny, and the collaborative ‘exquisite corpse’ parlour game. We also consider DALL-E Mini’s relevance to the category of ‘AI Arts’, Patricia De Vries’s call for more research that relates algorithms to the broader artistic and cultural contexts in which they are embedded (2020), and the ‘authoring’ of celebrity bodies as data (Kanai, 2016). Our theorisation of DALL-E Mini is supported by examples drawn from social media and personal experiments with the generator. Overall, we propose that internet users’ experimentation with DALL-E Mini corresponds with a cultural moment in which AI imaging technologies are eliciting excitement and anxiety. The outputs are revealed to be reliant on users’ pop cultural knowledge, with DALL-E Mini allowing for a playful, co-creative algorithmic practice, wherein contemporary anxieties about digital labour, (post)digital culture, biopolitics, and global issues are redirected into surreal visual storyworlds.

Firing behavior of lead-containing and lead-free metallization silver paste for monocrystalline silicon solar cells

In this work, PbO-TeO2-Bi2O3-SiO2 lead-containing glass and TeO2-Bi2O3-ZnO-Li2O lead-free glass were synthesized in order to investigate the difference between them and find out the reason why lead-free paste can't be used on monocrystalline wafer commercially. Their flowability and reactivity with SiNx were characterized. Lead-free glass presents lower flow temperature, better wettability and stronger etching ability to SiNx than lead-containing glass. Button test was carried out and large white particles was identified on the interface for lead-free glass. These results indicates the excessive flowability and etching to SiNx for lead-free glass. The morphology of grid line and interface between silver electrode and silicon wafer were investigated on dependence of temperature. The lead-containing and lead-free glasses went through similar evolution of silver sintering and interface microstructure with lead-free glass better facilitating silver sintering through liquid phase sintering due to its lower flow temperature. The thicker glass layer and more Ag crystallites with large size can be observed from cross-sectional micrographs for lead-free glass. Therefore, lead-free paste exhibits lower Voc and FF than lead-containing glass owing to its ecxessive corrosion of SiNx, thicker glass layer and large Ag crystallites.

Numerical Study of the Internal Fluid Dynamics of Draft Tube in Seawater Pumped Storage Hydropower Plant

Pumped storage hydropower plants are renewable energy systems that are effective in saving energy and solving electricity peak-on shortage. Seawater pumped storage hydropower plants are a novel type of pumped storage hydropower plant specifically supplying electric power for ocean islands with the support of solar energy and wind energy. Compared with traditional pumped storage hydropower plants that are constructed on the mainland, seawater pumped storage hydropower plants should take the influence of the complex marine environment, such as extreme waves and winds, into consideration. Taking the characteristics of waves near islands in the East China Sea as an example, we explored the transient hydraulic characteristics in the draft tube of a pump turbine under wave disturbance using a sliding grid interface and the detached eddy simulation (DES) turbulence model. By analyzing the characteristics of unsteady flow in the draft tube, the vortex characteristics under the Q criterion, the frequency characteristics of the pressure pulsation, the evolution law of the internal fluid, and the propagation law of the pressure pulsation were explored. For the situation without wave disturbance, an obvious eccentric vortex in the straight cone section of the draft tube was observed in the case where the opening of the guide vane was small. With the increase in the opening of the guide vane, the eccentric vortex gradually dissipated. For the situation with wave disturbance, the main frequency of the draft tube equaled the frequency of the wave disturbance, the maximum pressure pulsation at the selected monitoring points increased 5 to 15 times, and the superposition of the wave pressure pulsation signals and the draft tube pressure pulsation produced more low-frequency, high-amplitude pressure pulsation signals. Even though the pressure pulsation frequency spectrum varied a lot, the frequency domain of the pressure pulsation without wave disturbance still existed. In addition, the wave disturbance merely varied with the pressure of the draft tube. The influence of wave disturbance on the pressure distribution in the draft tube was relatively small. The results can provide a reference for the operation of seawater pumped storage hydropower plants.