After the carbon peaking and carbon neutrality goals were determined, industrial zones with high energy consumption began investigating their own carbon emission paths and formulating carbon emission reduction strateg...
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The configuration for substation robot inspection task includes the following steps: configuring inspection object, scanning map package, building wireless AP, establishing database, etc. Previous work mostly relies o...
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Substation supervisory control is an essential part of power grid monitoring system. Besides the power flow between substations, the running states of the devices in substations are important to the staff in power gri...
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Capacitance current has significant effect on long-distance fault of high-voltage transmission line, and the current single-ended quantity location algorithm can hardly eliminate the effect of capacitance current unde...
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The replacement of thermal power units with renewable energy power generation equipment like wind and photovoltaics has decreased the inertia level of power systems and weakened the frequency stability of the power gr...
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Due to its different characteristics from traditional synchronous generator, grid-forming converter (GFM-converter) affects the transient characteristics of the system when it is linked to the power grid. The mathemat...
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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...
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 interconnection device, there is no need to the isolation transformer, which can reduce the volume and cost of the system, but it will generate circulating current on the ground line. According to the main circuit topology of the system, the average circuit model of ground circulating current is established, and the influencing factors of ground circulating current are deduced. The low-frequency circulating current suppression strategy based on the average duty cycle control of the fourth leg and the high-frequency circulating current suppression method based on the DC side common mode inductor are proposed respectively for the low frequency and high frequency components of the ground circulating current. Finally, the simulation results show the effectiveness of the proposed average circuit model and the suppression method.
The dynamic equivalent of large power grid needs to calculate the dynamic aggregation of equivalent generator parameters for a given synchronous units group. In this paper, the weighted aggregation method commonly use...
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The dynamic equivalent of large power grid needs to calculate the dynamic aggregation of equivalent generator parameters for a given synchronous units group. In this paper, the weighted aggregation method commonly used in engineering is reviewed, and the deficiency of capacity weighting method is pointed out, then a direct parameters calculation method for dynamic equivalent generator based on EEAC and the unit-grid phasor diagram is proposed. Its key techniques are to using the complementary-cluster center-of-inertia relative motion transformation (CCCOI-RM) provided by the EEAC method, the initial value of the power angle for corresponding equivalent generator of the coherent generators group at the fault moment is calculated, and the impedance parameters of the equivalent generator are solved step by step by different forms of unit-grid phasor equations according to the feature that the power angle cannot be changed abruptly before and after the fault moment. Compared with the weighted aggregation calculation method, the proposed method is simpler and has a clearer physical concept. Simulation results based on the real power grids verify the effectiveness of the proposed method.
Calculating the most reliable maximum flow(MRMF)from the edge cache node to the requesting node can provide an important reference for selecting the best edge cache node in a content delivery network(CDN).However,SDBA...
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Calculating the most reliable maximum flow(MRMF)from the edge cache node to the requesting node can provide an important reference for selecting the best edge cache node in a content delivery network(CDN).However,SDBA,as the current state-of-the-art MRMF algorithm,is too complex to meet real-time computing *** paper proposes a set of MRMF algorithms:NWCD(Negative Weight Community Deletion),SCPDAT(Single-Cycle Preference Deletion Approximation algorithm with Time constraint)and SCPDAP(Single-Cycle Preference Deletion Approximation algorithm with Probability constraint).NWCD draws on the“flow-shifting”algorithm of minimum cost and maximum flow,and further defines the concept of negative weight *** algorithm continuously deletes the negative weight communities,which can increase reliability while keeping the flow constant in the residual *** is proven that when all negative weight communities are deleted,the corresponding maximum flow is the *** tries to approach the optimal solution to the greatest extent possible within the limited time,while SCPDAP tries to reach the probability threshold in the shortest amount of *** of these adopt the strategy of first deleting single-cycle communities(which contribute more to the reliability with lower time cost).Experiments show that,compared with SDBA,NWCD combined with the probabilistic pruning achieves an order of magnitude improvement in time cost,while SCPDAT and SCPDAP demonstrate better time performance and increased applicability.
When large-power disturbances occur in power grids, the system frequency will shift greatly, and there may be obvious spatial-temporal distribution characteristics. By analyzing the single-machine frequency response c...
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