A two-stage electroencephalogram (EEG) source tomography method is proposed. First, the layer recursive algorithm (LRA) is developed to calculate the cortical potentials from the scalp potentials by using the finite v...
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Energy crisis and environmental concerns have led to the rapid development of renewable energy sources(RES). However, the fluctuating and unpredictable nature of RES reduce the reliability of the powersystems. Using ...
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Energy crisis and environmental concerns have led to the rapid development of renewable energy sources(RES). However, the fluctuating and unpredictable nature of RES reduce the reliability of the powersystems. Using compressed air energy storage(CAES) is one of the main solutions to this problem. In this paper, three typical operation modes of CAES are adopted to improve the flexibility of the wind-CAES hybrid system, and a risk-constrained economic dispatch model considering the uncertainty of wind power and the part-load characteristics of CAES is proposed. Scenario generation and reduction technique is applied to model the uncertainties and a piecewise linearization method is used to incorporate the part-load features into the mixed integer linear programming model. The effectiveness of the proposed methodology is studied in a modified IEEE RTS 24-bus system.
The transient pressure process, which determined the gas blasting in the interrupter of SF6 circuit breaker, have attracted the attention of designer and developer for long time. In this investigation, a onload SF6 in...
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ISBN:
(纸本)9781457712739
The transient pressure process, which determined the gas blasting in the interrupter of SF6 circuit breaker, have attracted the attention of designer and developer for long time. In this investigation, a onload SF6 interrupter pressure measurement method was established with piezoresistive pressure transducer and insulating-tube. The pressures in the puffer cylinder, at the upstream, throat and downstream of nozzle have been measured. The difference of gas blowing characteristics between N2 and SF6 has been pointed out. The insulating-tube can effectively protect the pressure transducer from the high voltage and high temperature during on-load interrupting. It was found that the arc process can cause high frequency oscillations to superimpose upon the pressure waveforms during on-load interrupting.
Design is the key of lightning protection of transmission lines, and lightning protection analysis is the base to estimate the lightning protection behaviors of transmission line and the effect of lightning protection...
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Design is the key of lightning protection of transmission lines, and lightning protection analysis is the base to estimate the lightning protection behaviors of transmission line and the effect of lightning protection measures for transmission line. We mainly discussed the development states and the existed problems in lightning protection analysis of transmission line in the world, presented the analysis methods on the lightning backflash and shielding failure of transmission line and their comprehensive applications, and proposed the suitable models and methods for lightning protection analysis of transmission line. The whole-wave- progress analysis model should be applied to calculate the lightning transient characteristics of transmission line when the lightning strikes the tower or the overhead ground wires of transmission line;different analysis methods, such as electrogeometric method, the leader propagating model and the fractal model, should be used to calculate the shielding failure behaviors of transmission line. The lightning protection analysis of transmission lines should consider the micro-typological characteristics and the area difference of lightning parameters along transmission line, and comprehensively estimate the lightning protection behaviors of transmission line sections.
When there is power supply shortage or emergency event in power system, orderly power utilization needs to be applied to cut down electricity demand to maintain power supply for important electricity consumers. Curren...
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The CLLC converter is widely used in bidirectional power conversion systems. The conventional control method for CLLC converter is pulse frequency modulation (PFM) method. However, PFM method can not realize smooth bi...
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ISBN:
(数字)9781728153018
ISBN:
(纸本)9781728153025
The CLLC converter is widely used in bidirectional power conversion systems. The conventional control method for CLLC converter is pulse frequency modulation (PFM) method. However, PFM method can not realize smooth bidirectional power switching, because the driver signals for the primary and the secondary side switches are asymmetric. This paper proposed a voltage-fed control method for CLLC and Synchronous Rectified (SR) Buck two stage converters, which can realize the automatic and smooth bidirectional power switching for CLLC stage. In the proposed control method, the PWM signals for both the primary and the secondary switches are the same. The effectiveness of the proposed voltage-fed control method is verified by experiments.
In recent years, as the consumption rate of renewable energy has increased, the impact of renewable energy on the power grid has also increased. Currently, distribution network system operators and transmission line s...
ISBN:
(数字)9781728116754
ISBN:
(纸本)9781728116761
In recent years, as the consumption rate of renewable energy has increased, the impact of renewable energy on the power grid has also increased. Currently, distribution network system operators and transmission line system operators are unable to acquire and control the operational status of renewable energy sources such as wind power photovoltaics. These phenomena pose a significant challenge to the safety and stability of the operation of the power system. The virtual power plant is a feasible solution, based on the data acquisition terminal of advanced communication technology, decentralized control or centralized control of DER. Based on the virtual power plant, this paper aggregates three types of resources, wind power, photovoltaic, and electric vehicles, which are typical on the supply side and the demand side. Then, the virtual power plant is regarded as a whole to accept the dispatching instructions of the power grid, formulate the operational strategy of the internal resources of the virtual power plant, and participate in the peaking service.
Lightning is a major cause of power interruptions in power transmission *** the Leader Progression Model is an advanced method to evaluate the shielding failure probability of transmission *** the surface electric fie...
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Lightning is a major cause of power interruptions in power transmission *** the Leader Progression Model is an advanced method to evaluate the shielding failure probability of transmission *** the surface electric field on phase conductors and ground wires precisely is important, because the surface electric field has great effect on the upward leader *** this paper, the influence of lightning current and some other factors on surface electric field were analyzed.
The rapid increase of voltage sourced converter brings the great development of the multi-terminal DC technology, both in the DC transmission and DC distribution fields. However, because of the weak impedance characte...
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The rapid increase of voltage sourced converter brings the great development of the multi-terminal DC technology, both in the DC transmission and DC distribution fields. However, because of the weak impedance characteristic of the VSC-HVDC system, how to suppress and clear DC fault currents becomes a challenge. Considering the stability, the response speed and the system structure, it is not possible to apply excessive inductance at the DC side, hence, the current limiting effectiveness is relatively restricted. On the one hand, with the effective properties, Resistive type Superconducting Fault Current Limiter (R-SFCL) becomes an effective device to solve the problem of VSC-HVDC system under DC faults. On the other hand, because of dynamic energy-impedance characteristics of R-SFCL, the fixed impedance selection method at a certain time to carry out dynamic current limiting analysis is no longer applicable. Therefore, the DC fault current research and R-SFCL characteristic are comprehensively analyzed firstly in this paper. Based on that, a smoothing inductance determination method is proposed to cut off the DC fault current by DC breaker and ensure the continuous operation of remaining parts. Finally, based on a multi-terminal DC system simulation, the improvement and effectiveness of the proposed method are validated.
Compared with other conventional energy sources, renewable energy, which results in less pollution and has numerous resources, is a significant factor in addressing the current issues of the serious environmental poll...
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Compared with other conventional energy sources, renewable energy, which results in less pollution and has numerous resources, is a significant factor in addressing the current issues of the serious environmental pollution and the resource depletion. Large-scale renewable energy connected to the grid could lead to a the change of the morphological structure and the operation modes of energy transmission. While current power grid evolution models did not consider the characteristics of renewable energy in the evolution strategy. The expansion mechanism of the future transmission network with a high proportion of renewable energy is studied in this paper. The operation cost including renewable energy curtailment are optimized using the production simulations, where the stochastic and intermittent of wind and solar energy are modeled. And the dual variable information is adopted to drive the grid upgrading. The expansion strategies for power grid of Zhejiang province in China are analyzed to balance the construction cost and curtailment cost of renewable energy.
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