A Micro-grid Fault Section Positioning Method Based On Fault Steady State Component

Real-time accurate voltage phase angle measurement data has a very important significance to monitor and analyze the power system, and phase angle measurement principle of Fourier transform plays an important role in the theoretical calculations and engineering applications. The dynamic sinusoidal voltage signal contains two parts of the sinusoidal steady-state component and decaying DC component, and the decaying DC component having a continuous spectrum, at the frequency corresponding to the sinusoidal steady-state component must have a non-zero value, making dynamic signal phase than steady signal phase has one extra deviation angle. Considering Fourier transform method and theory of engineering application are different, this paper only considered the application conditions of time truncation, analyzes continuous Fourier transform under a real eigenvalue and a pair of conjugate complex roots condition, then compared with the theoretical calculation, for the two case of limited time integration and theoretical calculation condition, the phase angle difference and influencing factors are given.

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A sliding mode controller-based STATCOM for voltage profile improvement of micro-grids

World Journal of Engineering ◽

10.1108/wje-06-2017-0152 ◽

2018 ◽

Vol 15 (2) ◽

pp. 283-291 ◽

Cited By ~ 1

Author(s):

Swagat Pati ◽

Kanungo Barada Mohanty ◽

Sanjeeb Kumar Kar

Keyword(s):

Steady State ◽

Sliding Mode ◽

Synchronous Generator ◽

Sliding Mode Controller ◽

Voltage Profile ◽

Content Type ◽

Grid Systems ◽

Micro Grid ◽

Micro Grids ◽

Voltage Profile Improvement

Purpose The purpose of this paper is to evaluate the suitability and robustness of sliding mode controller (SMC) for maintaining flat voltage profile at the load bus of two different micro-grid systems using STATCOM. Design/methodology/approach Two micro-grid systems are dynamically modelled and simulated using MATLAB/Simulink. The first micro-grid has a single diesel engine-driven synchronous generator. The second micro-grid has one diesel engine-driven synchronous generator and a doubly fed induction generator-based wind energy conversion system. The STATCOM is connected to the load bus in both the micro-grids. SMC is used for the control of STATCOM for voltage profile improvement of micro-grid. The performance of SMC-based STATCOM is analysed and compared with the performance of conventional PI controller-based STATCOM. Findings The SMCs are more suited for STATCOM control as these are more immune to load disturbances even with the presence of wind energy generators. The voltage deviations and the steady state errors in voltage are less with SMC. Although SMC introduces a bit of steady state error in the dc link voltage of the STATCOM, it is much less than the settling limit of 2 per cent, which is quite acceptable. SMC proves to be better than conventional PI controllers in both the proposed models of micro-grid. Originality/value Design of a robust first-order SMC for a STATCOM is used for voltage profile improvement in two different micro-grid systems.

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Modulation of excitatory amino acid responses in rat dorsal horn neurons by tachykinins

Journal of Neurophysiology ◽

10.1152/jn.1992.68.1.265 ◽

1992 ◽

Vol 68 (1) ◽

pp. 265-286 ◽

Cited By ~ 102

Author(s):

K. I. Rusin ◽

P. D. Ryu ◽

M. Randic

Keyword(s):

Steady State ◽

Substance P ◽

Dorsal Horn ◽

Peak Amplitude ◽

Neurokinin A ◽

Induced Current ◽

Simultaneous Application ◽

Transient Component ◽

Nmda Current ◽

State Component

1. In freshly isolated spinal dorsal horn (DH) neurons (laminae I-III) of the young rat, the effects of tachykinins (substance P, neurokinin A) on inward current induced by excitatory amino acids were studied under whole-cell voltage-clamp conditions. 2. When the cells were clamped to a holding potential of -60 mV, a simultaneous application of N-methyl-D-aspartate (NMDA) (10(-4) M) and substance P (SP) (2 x 10(-9)-10(-7) M) for 10 s reversibly enhanced (by 129.6 +/- 8.2%, mean +/- SE) the peak amplitude of the initial transient component of the NMDA-induced current in approximately 60% of the examined cells and reduced it (to 83.3 +/- 2.7%) in 27% of the cells. In addition, SP produced an increase (by 133.6 +/- 11.7%) or a small decrease (to 85.9 +/- 1.4%) in the steady-state component of the NMDA response. In difference to SP, a simultaneous application of NMDA (10(-4) M) and neurokinin A (NKA) (10(-10)-10(-7) M) reversibly suppressed (to 86.8 +/- 2.1%) the peak amplitude of the NMDA-induced current in 75% of the examined cells. 3. The NMDA-induced currents were modulated by tachykinins not only during the coadministration but up to 20 min after the removal of the peptide. SP potentiated the initial peak NMDA current by 147.9 +/- 8.1% in 78% of examined cells and decreased it (76.3 +/- 5.7%) in 11% of cells. The potentiating effect was concentration-dependent (range: 10(-11)-10(-8) M) and reversible, but it was reduced with repeated applications. In addition, SP increased (by 125.4 +/- 3.6%) or reduced (to 86.0 +/- 1.8%) the steady-state component of the NMDA response. 4. When the single DH neurons were exposed to SP or NKA for 30 s-7 min before the testing of the NMDA responses, tachykinins had two distinct effects on the peak amplitude of the transient component of the NMDA-induced current, consisting of an initial depression (SP: to 64.8 +/- 2.1%; NKA: to 76.3 +/- 4.4%) followed by a potentiation (SP: by 146.6 +/- 6.8%; NKA: by 178.4 +/- 35.2%). The enhancing effect in some cells lasted less than or equal to 1 h. 5. A claimed novel nonselective tachykinin antagonist, spantide II (10(-8) M) coadministered with NMDA (10(-4) M), slightly depressed the peak component of NMDA-induced current. In addition, it effectively blocked the SP-induced potentiation of the responses of DH neurons to NMDA.(ABSTRACT TRUNCATED AT 400 WORDS)

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Steady-State Component of Three-Dimensional Slab-on-Grade Foundation Heat Transfer

Journal of Solar Energy Engineering ◽

10.1115/1.1346677 ◽

2000 ◽

Vol 123 (1) ◽

pp. 18-29 ◽

Cited By ~ 3

Author(s):

Pirawas Chuangchid ◽

Moncef Krarti

Keyword(s):

Steady State ◽

Heat Loss ◽

Parametric Analysis ◽

Three Dimensional ◽

Thermal Characteristics ◽

U Value ◽

Rectangular Slab ◽

Steady State Heat ◽

Profile Estimation ◽

State Component

General semi-analytical solutions for the steady-state heat conduction problems for circular and three-dimensional rectangular slab-on-grade floors with uniform insulation are presented. The soil temperature field, and the total slab heat loss are presented and analyzed using the Interzone Temperature Profile Estimation (ITPE) technique. A parametric analysis is conducted to determine the effect of thermal insulation U-value, slab size, and water table depth on the total slab heat loss. In particular, it was found that the total slab heat loss is independent of its shape but is strongly affected by the slab size and thermal characteristics.

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Influence of Micro-Grid in Steady State Performance of Primary Distribution System

Research Journal of Applied Sciences Engineering and Technology ◽

10.19026/rjaset.6.4126 ◽

2013 ◽

Vol 6 (5) ◽

pp. 819-824 ◽

Cited By ~ 3

Author(s):

K. Buayai ◽

T. Kerdchuen

Keyword(s):

Steady State ◽

Distribution System ◽

Micro Grid ◽

Steady State Performance

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Acetylcholine-activated ionic currents in parasympathetic neurons of bullfrog heart

Journal of Neurophysiology ◽

10.1152/jn.1990.63.5.1052 ◽

1990 ◽

Vol 63 (5) ◽

pp. 1052-1059 ◽

Cited By ~ 5

Author(s):

N. Tateishi ◽

D. K. Kim ◽

N. Akaike

Keyword(s):

Steady State ◽

Rapid Change ◽

Reversal Potential ◽

External Solution ◽

Ionic Currents ◽

Hill Coefficient ◽

Equilibrium Potential ◽

Inward Rectification ◽

Parasympathetic Neurons ◽

State Component

1. The electrical and pharmacologic properties of acetylcholine (ACh)-induced current (IACh) were studied in the parasympathetic neurons isolated from bullfrog heart with the use of the concentration-clamp technique, which allows intracellular perfusion and rapid change of external solution within 2 ms under the single-electrode voltage-clamp condition. 2. The IACh consisted of an initial transient peak component and a successive steady-state plateau component. Both currents increased in a sigmoidal fashion with increasing ACh concentration. The dissociation constant (Kd value) and the Hill coefficient for each component were 2.2 X 10(-5) M and 1.6, respectively. 3. In the K(+)-free solution, the reversal potential (EACh) of IACh was close to the Na+ equilibrium potential (ENa). The current-voltage (I-V) relation showed inward rectification at positive potentials. 4. Nicotine mimicked only the peak component of IACh. However both peak and steady-state components were blocked nonselectively by the nicotinic blockers d-tubocurarine and hexamethonium. 5. Carbamylcholine (CCh) mimicked the steady-state component of IACh. The steady-state component was selectively inhibited by atropine at concentrations 1,000 times lower than that required for inhibition of the peak component. The steady state was blocked equally by either pirenzepine (M1 blocker) or AF-DX-116 (M2 blocker). 6. It was concluded that the IACh consisted of a peak component having double exponential activation and inactivation, mediated through the nicotinic actions, and a steady-state component having no inactivation, mediated through the muscarinic action.

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