A Design of Circuit and its Application of the Power Frequency Voltage Linear Superposition Method

2012 ◽  
Vol 220-223 ◽  
pp. 1564-1572
Author(s):  
Qiang Song ◽  
Feng Pan
Keyword(s):  
Measuring Circuit ◽  
Superposition Method ◽  
Linear Network ◽  
Voltage Transformer ◽  
Linear Superposition ◽  
Voltage Ratio ◽  
Voltage Coefficient ◽  
In Series ◽  
Power Frequency ◽  
Calibration Techniques

In order to improve the power frequency voltage ratio standard calibration techniques to meet the application of UHV power grid，a measuring circuit based on power frequency voltage linear superposition method was proposed. A three-port network was fromed by connecting two shielding voltage transformer with the same rated voltage ratio in series. The voltage coefficient of a voltage transformer was tested by double voltage method based on the proportionality and superposition of the linear network. The measuring circuit based on power frequency voltage linear superposition method can prevent the shielding error of the voltage transformer during the mearurment, making it used in voltage ratio standard self-calibration system with higher voltage and precision. The test has proved the feasibility and accuracy of circuit of power frequency voltage linear superposition method.

Measure Characteristic of UHV Power Frequency Voltage Ratio Standard

2011 ◽  
Vol 354-355 ◽  
pp. 1210-1215
Author(s):  
Feng Zhou ◽  
Min Lei ◽  
Xiao Dong Yin ◽  
Shu Han Zhang
Keyword(s):  
Measuring Method ◽  
Voltage Measurement ◽  
Voltage Transformer ◽  
Ratio Measurement ◽  
Measurement Traceability ◽  
Voltage Ratio ◽  
Voltage Coefficient ◽  
National Power ◽  
Power Frequency ◽  
Better Than

In order to meet the urgent needs of voltage measurement traceability and transfer in the construction of ultra-high voltage power grid, 1000kV series standard voltage transformer is developed as the standard instrument, and then its measurement characteristics is tested. According to the theory and construction of the series power frequency voltage ratio standard, semi-insulating transformer voltage summation is proposed to make the voltage ratio measurement of SSTV whose accuracy can reach the 0.02 level trace to the source of national power frequency ratio standard of 500kV successfully. The compatibility is better than compared to traditional voltage coefficient measuring method.

Evaluating Shakedown for Structures Based on the Element Bearing-Ratio

2011 ◽  
Vol 137 ◽  
pp. 16-23 ◽  
Author(s):  
Wei Zhang ◽  
Lu Feng Yang ◽  
Chuan Xiong Fu ◽  
Jian Wang
Keyword(s):  
Yield Criterion ◽  
Solution Procedure ◽  
Superposition Method ◽  
Linear Superposition ◽  
Non Linear Programming ◽  
Elastic Plastic ◽  
Non Linear ◽  
Efficiency And Effectiveness ◽  
Linear Programming Formulation ◽  
Element Bearing

Based on Melan’s theorem, an improved numerical solution procedure for evaluating shakedown loads by non-linear superposition method is presented, and the relationship between the classical non-linear programming formulation of shakedown problem and the numerical method is disclosed. The stress term in classical optimization problem is replaced by the element bearing-ratio (EBR) in the procedure, and series of residual EBR fields can be generated by the D-value of the elastic-plastic EBR fields and the elastic EBR fields at every incremental loading step. The shakedown load is determined by performing the incremental non-linear static analysis when the yield criterion is arrived either by the elastic-plastic EBR fields or residual EBR fields. By introducing the EBR, the proposed procedure can be easily used to those complex structures with multi-material and complicated configuration. The procedure is described in detail and some numerical results, that show the efficiency and effectiveness of the proposed method, are reported and discussed.

Strain field reconstruction of crossbeam structure based on load-strain linear superposition method

2021 ◽  
Author(s):  
Yangyang Cheng ◽  
Zhaohua Li ◽  
Guangjun Wang ◽  
Chang Peng ◽  
Lei Zhang ◽  
...  
Keyword(s):  
Strain Field ◽  
Superposition Method ◽  
Linear Superposition ◽  
Field Reconstruction

scholarly journals Hydraulic Fracture Propagation in a Poro-Elastic Medium with Time-Dependent Injection Schedule Using the Time-Stepped Linear Superposition Method (TLSM)

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6474
Author(s):  
Tri Pham ◽  
Ruud Weijermars
Keyword(s):  
Hydraulic Fracture ◽  
Fracture Propagation ◽  
Fracture Network ◽  
Time Dependent ◽  
Reservoir Rock ◽  
Hydraulic Fractures ◽  
Superposition Method ◽  
Stress Concentrations ◽  
Linear Superposition ◽  
Dynamic Fractures

The Time-Stepped Linear Superposition Method (TLSM) has been used previously to model and analyze the propagation of multiple competitive hydraulic fractures with constant internal pressure loads. This paper extends the TLSM methodology, by including a time-dependent injection schedule using pressure data from a typical diagnostic fracture injection test (DFIT). In addition, the effect of poro-elasticity in reservoir rocks is accounted for in the TLSM models presented here. The propagation of multiple hydraulic fractures using TLSM-based codes preserves infinite resolution by side-stepping grid refinement. First, the TLSM methodology is briefly outlined, together with the modifications required to account for variable time-dependent pressure and poro-elasticity in reservoir rock. Next, real world DFIT data are used in TLSM to model the propagation of multiple dynamic fractures and study the effect of time-dependent pressure and poro-elasticity on the development of hydraulic fracture networks. TLSM-based codes can quantify and visualize the effects of time-dependent pressure, and poro-elasticity can be effectively analyzed, using DFIT data, supported by dynamic visualizations of the changes in spatial stress concentrations during the fracture propagation process. The results from this study may help develop fracture treatment solutions with improved control of the fracture network created while avoiding the occurrence of fracture hits.

scholarly journals Optimization and Experimental Study of the Semi-Closed Short-Gap Arc-Extinguishing Chamber Based on a Magnetohydrodynamics Model

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3335 ◽  
Author(s):  
Wenbin Jia ◽  
Wenxia Sima ◽  
Tao Yuan ◽  
Ming Yang ◽  
Potao Sun
Keyword(s):  
High Speed ◽  
Basic Structure ◽  
Optimization Method ◽  
Original Structure ◽  
Arc Plasma ◽  
Zero Crossing ◽  
In Series ◽  
Power Frequency ◽  
Motion Characteristics ◽  
Current Zero

The multi-chamber arc-extinguishing structure (MAS), which consists of a lot of semi-closed short-gap arc-extinguishing chambers (SSAC) in series, can be used in parallel gap lightning protection devices to improve the ability to extinguish power frequency follow current. The arc-extinguishing ability of single SSAC directly affects the arc-extinguishing performance of the whole MAS. Therefore, the arc-extinguishing performance of MAS can be improved by optimizing single SSACs. A two-dimensional model of the arc plasma in a SSAC is built based on the magneto-hydrodynamic (MHD) theory. The motion characteristics of an arc in the SSAC are simulated and analyzed. An optimization method of the SSAC structure is proposed. Finally, an impact test platform is built to verify the effectiveness of the optimized SSAC structure. Results show that the short-gap arc forms a high-speed airflow in the SSAC and the arc plasma sprays rapidly to the outlet until the arc is extinguished at its current zero-crossing point. The amplitude of airflow velocity in the optimized structure can be increased to about 8-fold the velocity in the basic structure. Experiments also show that the dissipation time of an arc in the optimized SSAC is 79.2 μs, which is much less than that in the original structure (422.4 μs).

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