Hasil untuk "Production of electric energy or power. Powerplants. Central stations"

Fausto Pedro García Márquez, Alfredo Peinado Gonzalo, Mayorkinos Papaelias

LIU Chang, LIU Hongli, CHEN Hongfei, WEI Yang, LIU Xueyuan, CHEN Lipin, XU Ke, YU Juan

[Objective] Building and improving the mid-long-term electricity market between provinces is one of the fundamental links in promoting the development of green electricity and implementing the “dual carbon” goals. However，the randomness of green power output affects the physical feasibility of medium- and long-term clearing schemes for inter-provincial electricity transactions，and the participation of large-scale green power increases the burden of solving the clearing model. This paper proposes a fast-clearing method for mid- to long-term inter-provincial electricity transactions that considers the low-carbon value and stochastic characteristics of green electricity to improve the feasibility of clearing schemes and the efficiency of clearing calculations. [Methods] This paper constructs an inter-provincial electricity mid- to long-term transaction-clearing model that considers the low-carbon value and stochastic characteristics of green electricity. The objective function includes the cost of carbon emissions from power generation and the non-executable electricity penalty established based on the distribution characteristics of green electricity output，enabling clean and low-carbon green electricity to gain an advantage in market competition and improve the enforceability of green electricity-winning bids. Subsequently，an acceleration strategy based on fixed transaction variables is proposed. Based on the calculation results of the period decoupling model，transaction variables with a high probability of not closing are fixed，thereby constructing a smaller-scale clearing model and improving the efficiency of the clearing calculation. [Conclusions] Simulation examples based on actual transaction data from China show that the proposed model can balance the feasibility of the green electricity winning bid quantity and winning bid electricity. In addition，the proposed acceleration strategy can improve the computational efficiency by an average of 1.91 times while ensuring feasibility and accuracy （with an average relative error of only 0.4% compared with the optimal solution in multiple examples）. [Conclusions] This translation accurately reflects the technical meaning and structure of the original Chinese sentence while being fluent and appropriate for an academic context.

ZHANG Yao, QIU Wei, YANG Qiushuang, HUANG Qin, YAO Wenxuan, CAI Xinxin

[Objective] With the gradual evolution of power systems toward a trend of “high share of renewables and high penetration of power electronic equipment”， system oscillations have become more frequent and exhibit wide-frequency characteristics， posing greater challenges to operational security. [Methods] First， a compound intrinsic noise-assisted decomposition （CIND） method is introduced to perform modal decomposition on the wide-frequency information of each generator. Then， a targeted selection method for key wideband oscillation modes is developed based on correlation coefficients and energy. Subsequently， the dissipation energy flow corresponding to each generator is calculated from the key components to locate the oscillation source. [Results] The proposed method is validated on the WECC 179-bus test system and the NE 39-bus system with integrated wind farms. The results show that the localization accuracy remains close to 100% under noise levels of 100， 65， 55， and 45 dB， with single-machine computation time reaching the millisecond level. [Conclusions] Experimental results demonstrate that the method can accurately and effectively localize wideband oscillation sources under various noise conditions， showing good robustness and adaptability.

Muhammad Bilal Ali, Abdullah Altamimi, Syed Ali Abbas Kazmi et al.

LIU Yankun, CHANG Zhongxue, SUN Yongwei, WANG Delong, HUANG Xinyue, JI Xingquan, ZHANG Yumin

[Objective] To address the challenges of low reliability and high cost of fault location in multibranch distribution networks using wavefront detection， this study proposes a novel fault location method based on the line segment detector （LSD） algorithm and modal time differences.[Methods] First， considering that the initial fault wavefront exhibited steep linear characteristics when reaching the busbar， the method converted zero- and line-mode traveling waves into images. Using the LSD algorithm， the sub-pixel-level steep line segments in the images were identified to achieve precise wavefront detection. Next， by leveraging the difference in the propagation speeds of the zero- and line-mode traveling waves over short distribution lines， the fault location was determined solely by measuring the modal time difference of the initial traveling wavefronts at both ends of the main feeder. This approach eliminated the need for measurement devices on branch lines， significantly reducing the cost of fault location. Finally， a multibranch distribution network model was developed using MATLAB/Simulink.[Results] Compared with traditional fault location methods， the proposed method achieved an average error of approximately 6 m， representing an error reduction of approximately 80%. Furthermore， it exhibited accurate wavefront identification even under strong noise conditions of 10 dB.[Conclusions] Simulation results demonstrated that the proposed method achieved high reliability， cost efficiency， and accuracy in fault location.

Liang Xiong, Xiaolian Zhang, Shuo Zhao et al.

As terrestrial oil and gas resources continue to decline, deep-sea oil and gas development has become a strategic priority. A wide range of production equipment must be deployed on the seabed, among which subsea wet-mateable connectors are indispensable. To address the challenges of high pressure, low temperature, and corrosion in deep-sea environments, this study proposes a cooperative sealing strategy between the annular protrusion on the entry casing and a sliding sleeve. The leakage per single mate/demate cycle is quantified under varying insertion speeds and pressure differentials. By examining the effects of protrusion geometry, insertion speed, friction coefficient, and radial compression on sealing performance, the optimal parameters are identified: a friction coefficient of 0.15 and a trapezoidal-rib seal with 0.015 mm radial compression for dynamic sealing, yielding a contact pressure of 27.5 MPa and a mating/demating force of 197.26 N—satisfying the manipulation requirements of a remotely operated vehicle. Hydrostatic pressure tests demonstrate that the dynamic sealing design of the underwater connector achieves a balance between high reliability and low insertion resistance, and the prototype meets the operational requirements for deep-sea service.

Haiwei Jiang, Xing Ji, Yixin Hou et al.

Rouzbeh Haghighi, Ali Hassan, Van-Hai Bui et al.

Mark Henkenjohann, Udo Nolte, Fabian Sion et al.

Incremental nonlinear dynamic inversion (INDI) is a widely used approach to controlling UAVs with highly nonlinear dynamics. One key element of INDI-based controllers is the control allocation realizing pseudo controls using available actuators. However, the tracking of commanded pseudo controls is not the only objective considered during control allocation. Since the approach only works locally due to linearization and the solution is often ambiguous, additional aspects like control efforts or penalizing the deviation of certain states must be considered. Conducting the control allocation by solving a quadratic program this results in a considerable number of weighting parameters, which must be tuned during control design. Currently, this is conducted manually and is therefore time consuming. An automated approach for tuning these parameters is therefore highly beneficial. Thus, this paper presents and evaluates a model-based approach automatically tuning the control allocation parameters of a tiltrotor VTOL using an optimization algorithm. This optimization algorithm searches for optimal parameters minimizing a cost functional that reflects the design target. This cost functional is calculated based on a test mission for the VTOL which is conducted within a simulation environment. The test mission represents the common operating range of the VTOL. The simulation environment consists of an aircraft model as well as a model of the INDI-based controller which is dependent on the control allocation parameters. On this basis, model-based optimization is conducted and the optimal parameters are identified. Finally, successful real-world tests on a 4-degrees-of-freedom testbench using the identified parameters are presented. Since the control allocation parameters can significantly influence the aircraft’s stability, the 4-DOF testbench for the aircraft is required for rapid validation of the parameters at a minimum amount of risk.

Daniel Gonzalez-Delgado, Pablo Jaen-Sola, Erkan Oterkus

Generative design techniques together with the rapid development of additive manufacturing represent a revolution in the field of structural optimisation processes. In this study, a static structural and modal analysis was integrated to drive a multi-objective generative design optimisation process for a 3 MW direct-drive offshore wind turbine electrical generator rotor structure. This novel optimisation approach implements an automated fittest-for-purpose process including a static structural analysis and a modal analysis as the input for the optimisation strategy algorithm, allowing the exploration of a wide range of non-conventional topologies. If compared with the simple generator rotor disc structure, the results obtained using this innovative method achieved over 7% of weight reduction and a 39% increment in the generator operational range with the consequent growth in the wind turbine energy capture capability. Moreover, this approach generates a vast amount of structural analysis information, crucial at an early stage of the development of large-scale projects for a cost-effective scheme.

Tim Slangen, Vladimir Ćuk, Sjef Cobben

Belachew Desalegn, Desta Gebeyehu, Bimrew Tamrat

Larissa Affolabi, Mohammad Shahidehpour, Farrokh Rahimi et al.

Deepsikha Panda, Pratim Kundu, Bharat Singh Rajpurohit

Abstract Islanded microgrid network is sensitive to voltage and frequency fluctuations which becomes more vulnerable in the presence of external disturbance and the intermittent nature of Renewable Energy Sources (RESs). The “Electric Spring” (ES) is one of the most effective and efficient solutions for enhancing operational flexibility and RESs integration. A Self‐Excited Induction Generator (SEIG) based Micro hydro system with ES, non‐critical and critical loads is considered. Both non‐critical and critical loads are connected in 2:1 ratio in parallel with SEIG. The concept of voltage‐sensitive and non‐sensitive loads and the “power demand following the supply” idea have been incorporated for pointing up the contribution of ES. The non‐critical load coupled with a three‐phase inverter acts like an ES and can be operated as a Smart Load (SL). SL can compensate the voltage deviation between demand‐supply side, therefore mitigating the voltage fluctuations. The effectiveness of ES in terms of voltage regulation at the point of standard coupling has been achieved which improved the overall voltage profile of the hybrid microgrid system which can be observed from various test cases. A hardware in loop microgrid experimental platform is established and its results highlight the excellent performance of the proposed method.

Xi‐Lai Liu, Yu‐Chuan Jiang, Jiang‐Tao Huang et al.

Abstract Small‐molecule electrooxidation‐boosted water electrolysis (WE) is an energy‐saving method for hydrogen (H2) production. Herein, PdPt bimetallenes (PdPt BMLs) are obtained through the simple galvanic replacement reaction. PdPt BMLs reveal 2.93‐fold enhancement in intrinsic electroactivity and 4.53‐fold enhancement in mass electroactivity for the formate oxidation reaction (FOR) with respect to Pd metallenes (Pd MLs) at 0.50 V potential due to the synergistic effect. Meanwhile, the introduction of Pt atoms also considerably increases the electroactivity of PdPt BMLs for hydrogen evolution reaction (HER) with respect to Pd MLs in an alkaline medium, which even exceeds that with the use of commercial Pt nanocrystals. Inspired by the outstanding FOR and HER electroactivity of bifunctional PdPt BMLs, a two‐electrode FOR‐boosted WE system (FOR‐WE) is constructed by using PdPt BMLs as the cathode and the anode. The FOR‐WE system only requires an operational voltage of 0.31 V to achieve H2 production, which is 1.48 V lower than that (ca. 1.79 V) with the use of the traditional WE system.

Zezhou WANG, Mingming ZHANG, Fengqiang QIAN et al.

With increasing PV connected to MV distribution network, the problem of node voltage fluctuation and network loss is becoming more and more serious. Taking the communication conditions and calculation capabilities of MV distribution networks into account, a centralized regulation optimization strategy for distributed PV connected to MV distribution network is proposed to realize the suppression of voltage fluctuation and excessive network loss. Firstly, the impacts of PV integration on node voltage and network loss are analyzed. Then, a multi-objective optimal control model is established, with the power flow balance equation, node voltage, branch current and system operation as constrains, and with the minimal network loss, minimal voltage fluctuation and maximum consumption of DGs as objective. In addition, the commercial CPLEX is used to solve the model. Finally, the effectiveness of the proposed model is verified through case simulation. The results show that the proposed model can effectively reduce the voltage fluctuation and network loss, reasonably allocate the output of DGs and ensure the utilization of PV in a reasonable range.

Shumin Chen, Junda Li, Lingfang Li

Dan Huang, Huadong Sun, Jian Zhang et al.

Abstract Increasing penetration of renewable energy sources (RESs) into power systems has brought new challenges to guarantee transient voltage stability (TVS) of the system, due to complex and different characteristics of the RES compared with the synchronous generator. The related theories to the TVS for power systems with RES (PSRESs) are incomplete, and it is difficult to construct accurate physical model of the PSRES by using traditional TVS analysis method. Here a novel data mining‐based approach for extracting key factors that affect the TVS of a PSRES is put forward. The original Relief algorithm is modified to deal with the imbalance of sample size between stable and unstable samples of the practical data set and improve the calculation accuracy. Then, a data mining scheme based on the modified Relief algorithm is presented to acquire key factors affecting the TVS. With the proposed scheme, the influence degrees of different factors on the TVS can be evaluated quantitatively by their weighting values, and then the key factors as well as the influence patterns can be determined. Test results which are conducted on the modified IEEE‐39 test system with RESs are presented to demonstrate the accuracy and efficiency of the proposed method.

Zongzheng Zhao, Yixin Liu, Li Guo et al.

The large-scale integration of renewable energy sources (RESs) brings huge challenges to the power system. A cost-effective reserve deployment and uncertainty pricing mechanism are critical to deal with the uncertainty and variability of RES. To this end, this paper proposes a novel locational marginal pricing mechanism in day-ahead market for managing uncertainties from RES. Firstly, an improved multi-ellipsoidal uncertainty set (IMEUS) considering the temporal correlation and conditional correlation of wind power forecasting is formulated to better capture the uncertainty of wind power. The dimension of each ellipsoidal subset is optimized based on a comprehensive evaluation index to reduce the invalid region without large loss of modeling accuracy, so as to reduce the conservatism. Then, an IMEUS-based robust unit commitment (RUC) model and a robust economic dispatch (RED) model are established for the day-ahead market clearing. Both the reserve cost and ramping constraints are considered in the overall dispatch process. Furthermore, based on the Langrangian function of the RED model, a new locational marginal pricing mechanism is developed. The uncertainty locational marginal price (ULMP) is introduced to charge the RES for its uncertainties and reward the generators who provide reserve to mitigate uncertainties. The new pricing mechanism can provide effective price signals to incentivize the uncertainty management in the day-ahead market. Finally, the effectiveness of the proposed mechanism is verified via numerous simulations on the PJM 5-bus system and IEEE 118-bus system.

Muhammad Sumair, Tauseef Aized, Syed Asad Raza Gardezi

The aim of this work is to compare the wind data extrapolated by 1/7 th wind power law and site-specific wind power law for wind power potential estimation at Shahbandar. Both the Wind shear exponents (WSE) and local air density values were calculated using measured wind data at 10 and 30 m heights and they were found minimum in summer and maximum in winter. Weibull distribution was applied with a newly developed method to estimate the Weibull parameters whose accuracy was tested using coefficient of determination which was more than 95%. Technical analysis of energy generation was conducted which showed that GE1 and GE2 turbines have highest yield and capacity factors respectively while B3 and V5 has corresponding minimum values. Comparison showed that 1/7 th wind power estimates lower values of wind potential than site-specific wind power law. Moreover, comparison of predicted data with measured data shows that site-specific wind power law estimates data more accurately.