A practical method of reliability weak links mining for distribution network based on multidimensional analysis

With the development of intelligent distribution networks and access to distributed energy, the solving the problem of timely and accurate determination of the operating state of the distribution network is an urgent task. Based on an improved analysis of the principle components of the network and statements of a self-organizing neural network, this article proposes the method to evaluate the operating state of medium- and low-voltage distribution networks. At the first step, the system of evaluating indices of the network is formed by advanced component analysis. The evaluation system is grounded on four aspects, including safety, reliability, quality and economy. Next, the self-organizing neural network is used to identify and clean up the data regarding the operating state of the distribution network. At the next step, the indicators are modeled at all levels; the entropy method is applied to calculate the total weight of all indicators. Then the value of each indicator is found and the weak links of the distribution network are determined. At the final stage, the comprehensive assessment of the real operation of the distribution network in Guangxi province is carried out. As shown, the method can effectively reduce the effect of abnormal data and subjectivity factor on the results of evaluating the state of the distribution network. That confirms the feasibility and practicability of the proposed method. References 22, figures 6, tables 6.

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A Practical Method of Pressure Optimization for Water Distribution Network

Transactions of the Society of Instrument and Control Engineers ◽

10.9746/sicetr1965.19.233 ◽

1983 ◽

Vol 19 (3) ◽

pp. 233-240

Author(s):

Makoto TSUKIYAMA

Keyword(s):

Water Distribution ◽

Distribution Network ◽

Water Distribution Network ◽

Practical Method

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Optimal Investment Decision of Distribution Network With Investment Ability and Project Correlation Constraints

Frontiers in Energy Research ◽

10.3389/fenrg.2021.728834 ◽

2021 ◽

Vol 9 ◽

Author(s):

Jianping Yang ◽

Yue Xiang ◽

Zeqi Wang ◽

Jiakun Dai ◽

Yanliang Wang

Keyword(s):

Portfolio Optimization ◽

Power Grid ◽

Distribution Network ◽

Regional Distribution ◽

Weak Links ◽

Investment Efficiency ◽

Project Portfolio ◽

Dynamic Adjustment ◽

Investment Projects ◽

Benefit Evaluation

Power grid enterprises are faced with a serious mismatch between limited investment capacity and numerous investment projects. How to accurately match the weak links with investment projects according to the power system diagnosis is the key to improve investment accuracy. On the basis of an investment-oriented label, a project portfolio optimization framework with coherent diagnosis–evaluation–optimization is proposed in this study. First, a two-layer index system for investment benefit evaluation is established, which considers unit investment efficiency and macroinvestment benefit. Second, by weighing the diagnosis results of power grid and the biased investment environment, the benefit evaluation of the project is implemented as the basis of project portfolio optimization. To meet different investment demands, two combination optimization models of maximizing investment benefit and minimizing investment cost are established considering the coupling benefit relationship and time series relationship between projects. Finally, a case study is conducted for a regional distribution network. The proposed framework has been proven to be able to effectively cope with different investment needs and realize the dynamic adjustment of the scheme in the whole investment cycle.

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The role of differential phase contrast in electron microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100108027 ◽

1978 ◽

Vol 36 (1) ◽

pp. 176-177

Author(s):

E.M. Waddell ◽

J.N. Chapman ◽

R.P. Ferrier

Keyword(s):

Phase Contrast ◽

Practical Method ◽

Position Vector ◽

Differential Phase ◽

Pure Phase ◽

Differential Phase Contrast ◽

The Difference ◽

Image Position ◽

First Moment

Dekkers and de Lang (1977) have discussed a practical method of realising differential phase contrast in a STEM. The method involves taking the difference signal from two semi-circular detectors placed symmetrically about the optic axis and subtending the same angle (2α) at the specimen as that of the cone of illumination. Such a system, or an obvious generalisation of it, namely a quadrant detector, has the characteristic of responding to the gradient of the phase of the specimen transmittance. In this paper we shall compare the performance of this type of system with that of a first moment detector (Waddell et al.1977).For a first moment detector the response function R(k) is of the form R(k) = ck where c is a constant, k is a position vector in the detector plane and the vector nature of R(k)indicates that two signals are produced. This type of system would produce an image signal given bywhere the specimen transmittance is given by a (r) exp (iϕ (r), r is a position vector in object space, ro the position of the probe, ⊛ represents a convolution integral and it has been assumed that we have a coherent probe, with a complex disturbance of the form b(r-ro) exp (iζ (r-ro)). Thus the image signal for a pure phase object imaged in a STEM using a first moment detector is b2 ⊛ ▽ø. Note that this puts no restrictions on the magnitude of the variation of the phase function, but does assume an infinite detector.

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A new type of defect structure in 124-superconducting oxide revealed by HREM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100089779 ◽

1991 ◽

Vol 49 ◽

pp. 1092-1093

Author(s):

R. Sharma ◽

B.L. Ramakrishna ◽

N.N. Thadhani ◽

D. Hianes ◽

Z. Iqbal

Keyword(s):

Shock Wave ◽

Defect Structure ◽

Neutron Radiation ◽

Weak Links ◽

Defect Structures ◽

New Materials ◽

New Type ◽

Current Densities ◽

Processing Techniques ◽

Microstructural Studies

After materials with superconducting temperatures higher than liquid nitrogen have been prepared, more emphasis has been on increasing the current densities (Jc) of high Tc superconductors than finding new materials with higher transition temperatures. Different processing techniques i.e thin films, shock wave processing, neutron radiation etc. have been applied in order to increase Jc. Microstructural studies of compounds thus prepared have shown either a decrease in gram boundaries that act as weak-links or increase in defect structure that act as flux-pinning centers. We have studied shock wave synthesized Tl-Ba-Cu-O and shock wave processed Y-123 superconductors with somewhat different properties compared to those prepared by solid-state reaction. Here we report the defect structures observed in the shock-processed Y-124 superconductors.

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