When high-impedance faults(HIFs)occur in resonant grounded distribution networks,the current that flows is extremely weak,and the noise interference caused by the distribution network operation and the sampling error ...
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When high-impedance faults(HIFs)occur in resonant grounded distribution networks,the current that flows is extremely weak,and the noise interference caused by the distribution network operation and the sampling error of the measurement devices further masks the fault ***,locating a fault section with high sensitivity is *** existing technologies,this study presents a novel fault feature identification framework that addresses this *** framework includes three key steps:(1)utilizing the variable mode decomposition(VMD)method to denoise the fault transient zero-sequence current(TZSC);(2)employing a manifold learning algorithm based on t-distributed stochastic neighbor embedding(t-SNE)to further reduce the redundant information of the TZSC after denoising and to visualize fault information in high-dimensional 2D space;and(3)classifying the signal of each measurement point based on the fuzzy clustering method and combining the network topology structure to determine the fault section *** simulations and field testing confirm that the proposed method accurately detects the fault location,even under the influence of strong noise interference.
Rapid and accurate static voltage stability assessment is crucial for the safe operation of large-scale interconnected power grids. Existing methods have failed to effectively filter key input variables in massive mea...
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The distributed capacitance of the line becomes larger as the scale of wind farms,the transmission voltage level,and the transmission distance ***,the error of the traditional time-domain distance protection scheme ba...
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The distributed capacitance of the line becomes larger as the scale of wind farms,the transmission voltage level,and the transmission distance ***,the error of the traditional time-domain distance protection scheme based on the R-L model,which ignores the distributed capacitance of the line,becomes ***,the error of the time-domain fault location method based on the R-L model,especially the maximum error range,is theoretically analyzed in this *** this basis,a novel fault location method based on the RL and Bergeron models is ***,a fast time-domain distance protection scheme is *** the proposed scheme,the error in the fitting calculation is used to construct a weight matrix,and an algorithm for solving the time-domain differential equations is designed to improve the calculation speed and *** with the traditional frequency-domain distance protection scheme,the proposed scheme is independent of the power supply characteristics;thus,it is suitable for wind farm transmission *** addition,compared with the traditional method based on the R-L model,the proposed scheme effectively avoids the negative influence of the distributed capacitance of the line,which significantly improves the operating *** types of faults are simulated by PSCAD/EMTDC to verify the effectiveness and superiority of the proposed scheme.
The setting work of backup protection using steady-state current is tedious,and mismatches occasionally occur due to the increased proportion of distributed generations(DGs)connected to the power ***,there is a practi...
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The setting work of backup protection using steady-state current is tedious,and mismatches occasionally occur due to the increased proportion of distributed generations(DGs)connected to the power ***,there is a practical need to study a backup protection technology that does not require step-by-step setting and can be adaptively *** paper proposes an action sequence adaptive to fault positions that uses only positive sequence fault component(PSFC)*** the influence of DGs,the unified time dial setting can be obtained by selecting specific *** protection performance is improved by using the adjacent upstream and downstream protections to meet the coordination time interval in the case of metallic faults at the near-and far-ends of the ***,the expression and implementation scheme for inverse-time backup protection(ITBP)based on the unified characteristic equation is *** results show that this scheme can adapt to DG penetration scenarios and can realize the adaptive coordination of multi-level relays.
The nuclear event risk(NER)is an important and disputed factor that should be reasonably considered when planning the pathway of nuclear power development(NPD)to assess the benefits and risks of developing nuclear pow...
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The nuclear event risk(NER)is an important and disputed factor that should be reasonably considered when planning the pathway of nuclear power development(NPD)to assess the benefits and risks of developing nuclear power more *** paper aims to explore the impact of nuclear events on NPD pathway *** influence of nuclear events is quantified as a monetary risk component,and an optimization model that incorporates the NER in the objective function is *** optimize the pathway of NPD in the lowcarbon transition course of power supply structure evolution,a simulation model is built to deduce alternative NPD pathways and corresponding power supply evolution scenarios under the constraint of an exogenously assigned carbon emission pathway(CEP);moreover,a method is proposed to describe the CEP by superimposing the maximum carbon emission space and each carbon emission reduction(CER)component,and various CER components are clustered considering the emission reduction characteristics and resource endowments of different power generation technologies.A case study is conducted to explore the impact of NER and its risk valuation uncertainty on NPD pathway *** method presented in this paper allows the impact of nuclear events on NPD pathway planning to be quantified and improves the level of coordinated optimization of benefits and risks.
With the large-scale integration of renewable energy such as wind power and photovoltaics, the power grid now exhibits characteristics of low inertia and reduced anti-interference ability. Consequently, it presents si...
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Due to the fact that a high share of renewable energy sources(RESs)are connected to high-voltage direct current(HVDC)sending-end AC power systems,the voltage and frequency regulation capabilities of HVDC sending-end A...
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Due to the fact that a high share of renewable energy sources(RESs)are connected to high-voltage direct current(HVDC)sending-end AC power systems,the voltage and frequency regulation capabilities of HVDC sending-end AC power systems have *** has resulted in potential system operating problems such as overvoltage and overfrequency,which occur simultaneously when block faults exist in the HVDC *** this study,a steady-state voltage security-constrained optimal frequency control method for weak HVDC sending-end AC power systems is *** integrated virtual inertia control of RESs is employed for system frequency *** dynamic reactive power compensation devices are utilized to control the voltage of all nodes meet voltage security ***,an optimization model that simultaneously considers the frequency and steady-state voltage security constraints for weak HVDC sending-end AC power systems is *** optimal control scheme with the minimum total cost of generation tripping and additional dynamic reactive power compensation required is obtained through the optimization *** are conducted on a modified IEEE 9-bus test system and practical Qing-Yu line commutated converter based HVDC(LCC-HVDC)sending-end AC power system to verify the effectiveness of the proposed method.
The management of massive security and stability control devices (SSCD) configured for power grids is relatively decentralized, and there is an urgent need for refinement and intensification. Focusing on the purpose o...
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Flexible interconnection of low-voltage distribution station area with power electronic device can realize dynamic capacity increase and coordination. When three-phase four-leg converter is used as a flexible intercon...
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With the increasing penetration rate of distributed renewable energy and more complexity of grid, it is essential to keep a secure voltage profile for the safety, stability and economy of the power system. A reactive ...
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