A Design of Different-Frequency Grounding Resistance Meter

2014 ◽  
Vol 668-669 ◽  
pp. 762-766
Author(s):  
Chun Yan Xu ◽  
Wu Ai ◽  
Jing Tao Wu
Keyword(s):  
Power Systems ◽  
Large Scale ◽  
Grounding Resistance ◽  
The Core ◽  
Current Voltage ◽  
Military Facilities ◽  
Software Filtering ◽  
Ground Grid ◽  
A Current ◽  
Electrical Source

This paper introduces a design of different-frequency grounding resistance meter using MCU 80C196KB as the core. This instrument generates a current with a different frequency at about 120Hz to be injected into the ground grid. By adopting current-voltage method, the design enables an accurate measurement of the grounding resistance of large-scale ground grid, such as, power systems, architectural buildings, military facilities, and airports. The instrument controls the output of different-frequency electrical source by using MCU and DDS techniques. Moreover, the utilization of RMS-DC devices simplifies its data acquisition and data processing. In addition, the application of hardware and software filtering technology reduces the measurement error which may be caused by frequency interference, measuring disturbing between lead wires.

Is economic inequality a universal evil?

2019 ◽  
pp. 91-106 ◽  
Author(s):  
Rostislav I. Kapeliushnikov
Keyword(s):  
Quantitative Data ◽  
Large Scale ◽  
Economic Inequality ◽  
The State ◽  
Fair Play ◽  
Left Wing ◽  
Ordinary People ◽  
The Public ◽  
Discursive Power ◽  
A Current

Using published estimates of inequality for two countries (Russia and USA) the paper demonstrates that inequality measuring still remains in the state of “statistical cacophony”. Under this condition, it seems at least untimely to pass categorical normative judgments and offer radical political advice for governments. Moreover, the mere practice to draw normative conclusions from quantitative data is ethically invalid since ordinary people (non-intellectuals) tend to evaluate wealth and incomes as admissible or inadmissible not on the basis of their size but basing on whether they were obtained under observance or violations of the rules of “fair play”. The paper concludes that a current large-scale ideological campaign of “struggle against inequality” has been unleashed by left-wing intellectuals in order to strengthen even more their discursive power over the public.

Overview of Subsynchronous Oscillation in Grid-connected Wind Farm

2020 ◽  
Vol 13 (7) ◽  
pp. 969-979
Author(s):  
Xu Pei-Zhen ◽  
Lu Yong-Geng ◽  
Cao Xi-Min
Keyword(s):  
Power Systems ◽  
Wind Turbine ◽  
Large Scale ◽  
Wind Farm ◽  
Wind Farms ◽  
Induction Generator ◽  
Future Research ◽  
Stable Operation ◽  
Subsynchronous Oscillation ◽  
Different Types

Background: Over the past few years, the subsynchronous oscillation (SSO) caused by the grid-connected wind farm had a bad influence on the stable operation of the system and has now become a bottleneck factor restricting the efficient utilization of wind power. How to mitigate and suppress the phenomenon of SSO of wind farms has become the focus of power system research. Methods: This paper first analyzes the SSO of different types of wind turbines, including squirrelcage induction generator based wind turbine (SCIG-WT), permanent magnet synchronous generator- based wind turbine (PMSG-WT), and doubly-fed induction generator based wind turbine (DFIG-WT). Then, the mechanisms of different types of SSO are proposed with the aim to better understand SSO in large-scale wind integrated power systems, and the main analytical methods suitable for studying the SSO of wind farms are summarized. Results: On the basis of results, using additional damping control suppression methods to solve SSO caused by the flexible power transmission devices and the wind turbine converter is recommended. Conclusion: The current development direction of the SSO of large-scale wind farm grid-connected systems is summarized and the current challenges and recommendations for future research and development are discussed.

scholarly journals Identification of Efficient Sampling Techniques for Probabilistic Voltage Stability Analysis of Renewable-Rich Power Systems

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2328
Author(s):  
Mohammed Alzubaidi ◽  
Kazi N. Hasan ◽  
Lasantha Meegahapola ◽  
Mir Toufikur Rahman
Keyword(s):  
Monte Carlo ◽  
Stability Analysis ◽  
Power Systems ◽  
Large Scale ◽  
Voltage Stability ◽  
Sampling Technique ◽  
Coefficient Of Determination ◽  
Sampling Techniques ◽  
Quasi Monte Carlo ◽  
Efficient Sampling

This paper presents a comparative analysis of six sampling techniques to identify an efficient and accurate sampling technique to be applied to probabilistic voltage stability assessment in large-scale power systems. In this study, six different sampling techniques are investigated and compared to each other in terms of their accuracy and efficiency, including Monte Carlo (MC), three versions of Quasi-Monte Carlo (QMC), i.e., Sobol, Halton, and Latin Hypercube, Markov Chain MC (MCMC), and importance sampling (IS) technique, to evaluate their suitability for application with probabilistic voltage stability analysis in large-scale uncertain power systems. The coefficient of determination (R2) and root mean square error (RMSE) are calculated to measure the accuracy and the efficiency of the sampling techniques compared to each other. All the six sampling techniques provide more than 99% accuracy by producing a large number of wind speed random samples (8760 samples). In terms of efficiency, on the other hand, the three versions of QMC are the most efficient sampling techniques, providing more than 96% accuracy with only a small number of generated samples (150 samples) compared to other techniques.

scholarly journals Wind power integration into the automatic generation control of power systems with large-scale wind power

2014 ◽  
Vol 2014 (10) ◽  
pp. 538-545 ◽  
Author(s):  
Abdul Basit ◽  
Anca Daniela Hansen ◽  
Mufit Altin ◽  
Poul Sørensen ◽  
Mette Gamst
Keyword(s):  
Power Systems ◽  
Wind Power ◽  
Large Scale ◽  
Automatic Generation ◽  
Automatic Generation Control ◽  
Wind Power Integration ◽  
Generation Control
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