Voltage insecurity is a most vital problem that the modern power systems are imposed off. Timely and accurate assessment of voltage security is necessary to detect post-contingency voltage problems in order to prevent a large scale blackout. The paper presents machine learning techniques based on CART algorithm and probabilistic decision tree based strategy for estimation of voltage security. T...

This paper reports the successful fabrication of a GaN-on-Si high electron mobility transistor (HEMT) with a 1702 V breakdown voltage (BV) and low current collapse. The strain and threading dislocation density were well-controlled by 100 pairs of AlN/GaN superlattice buffer layers. Relative to the carbon-doped GaN spacer layer, we grew the AlGaN back barrier layer at a high temperature, resulti...

AlGaN/GaN/AlN quantum-well field-effect transistors have been demonstrated. By replacing a semi-insulating GaN epilayer with a highly resistive AlN epilayer in the device structure, parasitic conduction in the GaN epilayer, leakage current through the GaN epilayer, and the channel electrons spillover into the GaN epilayer have been completely eliminated and the drain current collapse has been r...

The traditional control method has a low margin of indoor voltage stability, which can easily lead to collapse, and the effect is not ideal. An automatic distributed for low-voltage electricity system based on modal symmetry algorithm proposed. In order improve stability margin, decoupling between characteristics regions was analyzed. Based analysis results, robustness faults zone scheme were c...

This paper presents a simple method for estimation of additional load as a factor of the existing load that may be drawn before reaching the point of line maximum loadability of radial distribution system (RDS) with different realistic load models at different substation voltages. The proposed method involves a simple line loadability index (LLI) that gives a measure of the proximity of the pre...

We present a population density and moment-based description of the stochastic dynamics of domain Ca-mediated inactivation of L-type Ca channels. Our approach accounts for the effect of heterogeneity of local Ca signals on whole cell Ca currents; however, in contrast with prior work, e.g., Sherman et al. (1990), we do not assume that Ca domain formation and collapse are fast compared to channel...

The power system becomes more severe under contingency conditions. In general, the contingencies may be outage of transmission lines or generators. To identify the effect of outages on system security, the contingency analysis is one of the analytical tools. The congestion on a system must be manages using generation rescheduling and with the proper control of the compensation equipments. The t...

40 LLE Review, Volume 89 The response of a superconductor to the injection of current pulses depends directly on the quasiparticle dynamics1 since the carriers injected from the external circuit are normal (unpaired) electrons that disturb the quasiparticle–Cooperpair dynamical equilibrium. Most commonly, a current pulse with an amplitude higher than the sample critical current Ic is used (supe...

Abstract Voltage instability is a serious phenomenon that can occur in power system because of critical or stressed conditions. To prevent voltage collapse caused by such instability, accurate prediction necessary for planning and operation. This paper proposes novel index ( NCPI ) to assess the stability conditions lines. The effectiveness applicability proposed are investigated on IEEE 30-bus...

Motivated by the very recent fabrication of sub-10-nm-wide semiconducting graphene nanoribbons X. Li et al., Science 319, 1229 2008 , where some of their band gaps extracted from transport measurements were closely fitted to density-functional theory predictions for magnetic ordering along zigzag edges that is responsible for the insulating ground state, we compute current-voltage I-V character...