Method of Judging the Energy Measurement Device Error Wiring Based on Checking Tables

2010 ◽  
Vol 139-141 ◽  
pp. 2247-2251
Author(s):  
Xing Zhong Zhang
Keyword(s):  
Phase Angle ◽  
Energy Measurement ◽  
Test Results ◽  
Measurement Device ◽  
Electric Parameter ◽  
Simple Method ◽  
Line Voltage ◽  
Three Phase ◽  
Working Efficiency

Focused on the complexity and Time-consuming of judging the error wiring of the energy measurement device, It extracts a series of electric parameter tables including phase angle table, such as the voltage sequence table, the line voltage location table, phase angle transform table, and phase angle table. And proposes a simple method of judging the error wiring of Three-phase three-wire error wiring of two components energy measurement device. The method based only on the four tables, inspectors only need to look-up the tables in accordance with the measured dates and get the error wiring instead of drawing vector plots. Because these tables root from vector plots. It greatly simplifies inspectors to judge wiring mistake, improves the working efficiency and makes the test results more accurate.

A Study on DG Control Strategy and Grid Protection

2014 ◽  
Vol 521 ◽  
pp. 204-212
Author(s):  
Xin Chao Wang ◽  
Chen Xin Yang
Keyword(s):  
Load Capacity ◽  
Short Circuit ◽  
Current Source ◽  
Islanding Detection ◽  
Test Results ◽  
Total Load ◽  
Line Voltage ◽  
Negative Sequence ◽  
Three Phase ◽  
Negative Sequence Current

DG integration reduces the selectivity and sensitivity of grid relay protection. A new control algorithm is proposed. It shows that the negative sequence current will not be affected by DG when the DG is designed as a symmetric three-phase current source. In this case, the negative sequence characteristic can be utilized for grid protection during short-circuit faults. If DGs maximum power capacity is restricted to be lower than total load capacity, DG terminal line-voltage and the negative sequence voltage can be used as the criteria for islanding detection. Then it is possible to cutoff DG in order to fulfill the reclosing requirement. A complicated simulation system is designed using PSCAD/EMTDC program. Different short-circuit faults are simulated to verify the proposals. The test results confirm well with the conclusions.

scholarly journals The impact of supply phase shift on the three phase induction motor operation

2019 ◽  
Vol 39 (3) ◽  
pp. 270-282 ◽  
Author(s):  
Aderibigbe Adekitan ◽  
Ayodeji S. O. Ogunjuyigbe ◽  
Temitope R. Ayodele
Keyword(s):  
Phase Shift ◽  
Induction Motor ◽  
Phase Angle ◽  
Positive Sequence ◽  
Test Results ◽  
Three Phase ◽  
Sequence Components ◽  
Angle Shift ◽  
Motor Operation ◽  
The Impact

The performance of a three-phase induction motor operating under supply unbalance conditions has been the focus of many research works using various methods. Most of the studies have focused majorly on voltage magnitude unbalance without due analysis to determine the effect of deviations in the supply phase angle from the 120° phase to phase displacement. This research investigates the significance of supply phase shift on the performance of a three-phase induction motor by applying a novel phase shift unbalance definition to the zero, negative and positive sequence components model of the motor. The test results reveal that when both phase angle shift and voltage magnitude unbalance occur simultaneously during motor operation the effect of the phase shift dominates over the effects of the voltage magnitude unbalance. This study shows that phase angle unbalance has a severe consequence on three phase motor performance.

A Phase Locked Loop Method for Low Voltage Ride-Through Control in Three-Phase Three-Wire Photovoltaic Grid System

2013 ◽  
Vol 415 ◽  
pp. 174-179
Author(s):  
Bao Ding ◽  
Gong Zhang ◽  
Yong Ming Zhang ◽  
Liang Zhao
Keyword(s):  
Phase Angle ◽  
Low Voltage ◽  
Phase Locked Loop ◽  
Grid System ◽  
Line Voltage ◽  
Low Voltage Ride Through ◽  
Loop Method ◽  
Synchronous Reference Frame ◽  
Automatic Phase ◽  
Three Phase

Low voltage ride through (LVRT) is regarded as one of the biggest challenges in photovoltaic grid equipments designing, manufacturing and control technology. The fast and accurate automatic phase locked control is the premise to achieve photovoltaic grid low voltage ride through. Considering that the traditional phase locked loop method is difficult to adapt the performance requirements of low voltage ride through (LVRT) in three-phase three-wire photovoltaic grid system, this paper presents a new three-phase unbalanced phase locked loop method. Improved second order generalized integral orthogonal signal generator (SOGI-OSG) is used for line voltage detection; Synchronous reference frame for phase locked loop (SRF-PLL) is used for line voltage phase locked and phase angle detection; Heron formula and Sine theorem is adopted to calculate the three-phase phase voltage amplitude and phase angle. Research results show that when grid voltage dips, this phase locked loop method can detect the fault signal accurately. It provides a technical support for photovoltaic grid low voltage ride through system.

Calculation of the Phase-Angle-Jump for Voltage Dips in Three-Phase Systems

2015 ◽  
Vol 30 (1) ◽  
pp. 480-487 ◽  
Author(s):  
Ying Wang ◽  
Math H. J. Bollen ◽  
Xian-Yong Xiao
Keyword(s):  
Phase Angle ◽  
Three Phase ◽  
Voltage Dips ◽  
Phase Systems

scholarly journals Frequency adaptive sliding fourier transform for synchronizing VSI to the grid

2019 ◽  
Vol 10 (2) ◽  
pp. 1034 ◽  
Author(s):  
Osama M. Arafa ◽  
M. E. Abdallah ◽  
Ghada A. Abdel Aziz
Keyword(s):  
Fourier Transform ◽  
Phase Angle ◽  
Phase Detector ◽  
Spectral Leakage ◽  
Double Frequency ◽  
Harmonic Rejection ◽  
Three Phase ◽  
Stationary Reference Frame ◽  
Filtering Technique ◽  
Phase Setting

Sliding Discrete Fourier Transform (SDFT) is very efficient regarding computational load and it possesses a very fast phase angle detection with excellent harmonic rejection at nominal frequency. However, at off-nominal frequency, SDFT generates errors in both magnitude and phase angle due to spectral leakage. This paper introduces a workaround for Fourier Transform to handle this disability under off-nominal frequency while avoiding variable-rate sampling. Sliding Fourier Transform (SFT) is used as a phase detector for a phase-locked loop whose output frequency is used to drive the SFT. The paper revisits the mathematics of Fourier Transform (FT) in a three-phase setting via a time-domain approach to show a newly proposed filtering technique for the double-frequency oscillation just by summing the FT sine/cosine filter outputs of the three individual phases. Also, the analysis aims to determine and correct the phase and magnitude errors under offnominal frequency operation. The proposed technique (SFT-PLL) is tested in real time on dSPACE DS1202 DSP using voltage vectors that are pregenerated to simulate the most adverse grid conditions. The testing scenarios compare the performance of the SFT-PLL with that of the Decoupled Stationary Reference Frame PLL (dαβPLL). The results prove that SFT-PLL is superior to dαβPLL.

Effect to Online Energy Measurement Device for Long-Pulse Laser by Laser Pulse Width

2010 ◽  
Vol 37 (4) ◽  
pp. 1088-1092 ◽  
Author(s):  
魏继锋 Wei Jifeng ◽  
关有光 Guan Youguang ◽  
周山 Zhou Shan ◽  
彭勇 Peng Yong ◽  
胡晓阳 Hu Xiaoyang ◽  
...  
Keyword(s):  
Laser Pulse ◽  
Pulse Laser ◽  
Pulse Width ◽  
Energy Measurement ◽  
Measurement Device ◽  
Laser Pulse Width ◽  
Long Pulse
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