Diode rectifier unit(DRU)-based high-voltage direct current(HVDC)transmissionsystems areeffectivein achieving the stableandeconomical operation of offshore *** theuncontrollable characteristicsof DRUs,a grid-forming(G...
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Diode rectifier unit(DRU)-based high-voltage direct current(HVDC)transmissionsystems areeffectivein achieving the stableandeconomical operation of offshore *** theuncontrollable characteristicsof DRUs,a grid-forming(GFM)strategy forwind-turbine converters isnecessary to support offshore AC voltageand ***,the active power-synchronization control in traditional GFM converters is unsuitable for DRU-based GFM ***,the stability issue for DRU-based HVDC systems involving DRU-based GFM and grid-following(GFL)converters has not yet been *** solve these issues,this study begins with the characteristics of a DRU-based HVDC system and presents a control scheme for DRU-based GFM converters for power ***,the dq-frame impedance model of the DRU-based GFM converteris proposed for the stability analysis of the entire HVDC ***,a simulation platform is built to verify the model accuracy and system stability.
To ensure frequency stability in powersystems with high wind penetration,the doubly-fed induction generator(DFIG)is often used with the frequency fast response control(FFRC)to participate in frequency ***,a certain o...
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To ensure frequency stability in powersystems with high wind penetration,the doubly-fed induction generator(DFIG)is often used with the frequency fast response control(FFRC)to participate in frequency ***,a certain output power suppression amount(OPSA)is generated during frequency support,resulting in the frequency modulation(FM)capability of DFIG not being fully utilised,and the system’s unbalanced power will be increased during speed recovery,resulting in a second frequency drop(SFD)in the ***,the frequency response characteristics of the powersystem with DFIG containing FFRC are ***,based on the analysis of the generation mechanism of OPSA and SFD,a combined wind-storage FM control strategy is proposed to improve the system’s frequency response *** strategy reduces the effect of OPSA and improves the FM capability of DFIG by designing the fuzzy logic of the coefficients of FFRC according to the system frequency index in the frequency support *** the speed recovery stage,the energy storage(ES)active power reference value is calculated according to the change of DFIG rotor speed,and the ES output power is dynamically adjusted to reduce the ***,taking the IEEE 39-bus test system as an example,real-time digital simulation verification was conducted based on the RTLAB OP5707 simulation *** simulation results showthat theproposedmethodcan improve theFMcapabilityofDFIG,reduce the SFDunder thepremise of guaranteeing the rapid rotor speed recovery,and avoid the overshooting phenomenon so that the systemfrequency can be quickly restored to a stable state.
Electrical tree degradation is one of the main causes of insulation failure in high-frequency *** tree degradation is studied on pure epoxy resin(EP)and MgO/EP composites at frequencies ranging from 50 Hz to 130 *** r...
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Electrical tree degradation is one of the main causes of insulation failure in high-frequency *** tree degradation is studied on pure epoxy resin(EP)and MgO/EP composites at frequencies ranging from 50 Hz to 130 *** results show that the tree initiation voltage of EP decreases,while the growth rate and the expansion coefficient increase with ***,the bubble phenomenon at high frequencies in EP composites is *** with trap distribution character-istics within the material,the intrinsic mechanism of epoxy composites to inhibit the growth of the electrical tree at different frequencies is *** can be concluded that more deep traps and blocking effect are introduced by doping nano-MgO into EP bulks,which can improve the electrical tree resistance performance of EP composites in a wide frequency range.
The article designs a new type of bridge circuit with a controlled source—when the resistance on the bridge arm of the controlled source bridge circuit meets the bridge balance condition, and the bridge branch contai...
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The article designs a new type of bridge circuit with a controlled source—when the resistance on the bridge arm of the controlled source bridge circuit meets the bridge balance condition, and the bridge branch contains only one Current-controlled Current Source (CCCS), a Voltage-controlled Current Source (VCCS), a Current-controlled Voltage Source (CCVS), or a Voltage-controlled Voltage Source (VCVS), the circuit is called a controlled bridge circuit, which has the characteristics of bridge balance. Due to the relationship between the controlled source and the bridge arm, the sensitivity of the components on the bridge is higher mathematically and logically. When applied to measurement, engineering, automatic control, and other fields, the controlled bridge circuit has higher control ac-curacy. Mathematical derivation and simulation results prove the correctness of the bridge balance conclusion and the special properties of this bridge when applied to the measurement field.
Photovoltaic(PV)and battery energy storage systems(BESSs)are key components in the energy market and crucial contributors to carbon emission reduction *** systems can not only provide energy but can also generate cons...
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Photovoltaic(PV)and battery energy storage systems(BESSs)are key components in the energy market and crucial contributors to carbon emission reduction *** systems can not only provide energy but can also generate considerable revenue by providing frequency regulation services and participating in carbon *** study proposes a bidding strategy for PV and BESSs operating in joint energy and frequency regulation markets,with a specific focus on carbon reduction benefits.A two-stage bidding framework that optimizes the profit of PV and BESSs is *** the first stage,the day-ahead energy market takes into account potential real-time forecast *** the second stage,the real-time balancing market uses a rolling optimization method to account for multiple ***,a real-time frequency regulation control method is proposed for the participation of PV and BESSs in automatic generation control(AGC).This is particularly relevant given the uncertainty of grid frequency fluctuations in the optimization model of the real-time balancing *** control method dynamically assigns the frequency regulation amount undertaken by the PV and BESSs according to the control interval in which the area control error(ACE)*** case study results demonstrate that the proposed bidding strategy not only enables the PV and BESSs to effectively participate in the grid frequency regulation response but also yields considerable carbon emission reduction benefits and effectively improves the system operation economy.
An MPPT control strategy based on the combination of adaptive nonlinear mutation particle swarm optimization algorithm is proposed. The algorithm uses the tanh function to control the inertia weight, balances the abil...
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The grid connection of a high proportion of re-newable energy generation increases the uncertainty in power ***,the flexibility margin of different energy sources needs to be quantified to cope with the uncertainty ch...
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The grid connection of a high proportion of re-newable energy generation increases the uncertainty in power ***,the flexibility margin of different energy sources needs to be quantified to cope with the uncertainty change and maintain the dynamic balance of powersystem *** this paper,first,the flexibility characteristics of source,net,load and power and load community(PLC)are *** dynamic equilibrium relationship among them is briefly ***,taking into full consideration the complex output characteristics of different energy sources and combining their respective flexibility characteristics,a quantitative model of the power source flexibility margin for thermal power,hydro-power,gas power and concentrating solar power is established.A quantitative model for a power source flexibility margin in PV and wind power based on blind number theory is ***,the calculation method of theoretical power generation capacity,which can reflect different characteristics of output power of various energy sources,is *** actual output power of each power source in each period is ***,a case study shows that the model and method can consider the operating characteristics of different types of power sources,and quickly and accurately quantify the adjustable range of flexibility margins of each power source at different periods of time,which can provide an important basis for evaluating the capacity of renewable energy consumption and the optimal operation of multi-energy powersystems(MEPSs).
Currently,both regulated and deregulated power trading exist in China’s powersystem,which has caused imbalanced funds in the electricity *** this paper,a simulation analysis of the electricity market with wind energ...
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Currently,both regulated and deregulated power trading exist in China’s powersystem,which has caused imbalanced funds in the electricity *** this paper,a simulation analysis of the electricity market with wind energy resources is conducted,and the calculation methods of unbalanced funds are investigated *** detail,the calculation formulas of unbalanced funds are illustrated based on their definition,and a two-track electricity market clearing model is ***,the concept of the dual-track system is explained,and the specific calculation formulas of various types of unbalanced funds are ***,considering the renewable energy consumption,the market clearing model based on DC power flow is constructed and solved;by combining fitting methods of mid-and long-term curves,the unbalanced funds are calculated based on clearing results and formulas.
The current existing problem of deep learning framework for the detection and segmentation of electrical equipment is dominantly related to low *** of the reliable,safe and easy-to-operate technology provided by deep ...
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The current existing problem of deep learning framework for the detection and segmentation of electrical equipment is dominantly related to low *** of the reliable,safe and easy-to-operate technology provided by deep learning-based video surveillance for unmanned inspection of electrical equipment,this paper uses the bottleneck attention module(BAM)attention mechanism to improve the Solov2 model and proposes a new electrical equipment segmentation ***,the BAM attention mechanism is integrated into the feature extraction network to adaptively learn the correlation between feature channels,thereby improving the expression ability of the feature map;secondly,the weighted sum of CrossEntropy Loss and Dice loss is designed as the mask loss to improve the segmentation accuracy and robustness of the model;finally,the non-maximal suppression(NMS)algorithm to better handle the overlap problem in instance *** results show that the proposed method achieves an average segmentation accuracy of mAP of 80.4% on three types of electrical equipment datasets,including transformers,insulators and voltage transformers,which improve the detection accuracy by more than 5.7% compared with the original Solov2 *** segmentation model proposed can provide a focusing technical means for the intelligent management of powersystems.
Due to the slow dynamic power-regulation characteristics of the electrolyser(EL),a novel integrated three-port DC/DC converter topology based on a phase-shifted full-bridge converter and dual active-bridge converter i...
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Due to the slow dynamic power-regulation characteristics of the electrolyser(EL),a novel integrated three-port DC/DC converter topology based on a phase-shifted full-bridge converter and dual active-bridge converter is proposed in this ***,the proposed converter can achieve a fast auxiliary response to the *** topology has the features of single-stage conversion,high system integration and compatibility with multiple operation *** operational principles and a hybrid modulation scheme of the proposed converter are analysed in *** addition,the power-transmission characteristics of each port and the soft-switching range are *** these bases,six operation modes suitable for a hydrogen energy-storage system are *** simulation and a 2-kW scaled-down experimental prototype are established to verify the feasibility and effectiveness of the proposed topology in different operation modes.
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