A Protection Scheme for Standard Equipment to Avoid Harmful Random Large Current

2013 ◽  
Vol 834-836 ◽  
pp. 1642-1647
Author(s):  
Shu Zhe Qi ◽  
Wei Han ◽  
Song Bin Zhou ◽  
Chang Li ◽  
Ke Jia Huang
Keyword(s):  
Transient State ◽  
Transient Signal ◽  
Test Results ◽  
Danger Signal ◽  
Standard Equipment ◽  
Protection Scheme ◽  
Large Current ◽  
Current Sampling ◽  
Short Time

In the process of detecting and calibrating for power equipments, it appears a phenomenon that standard equipment is damaged by harmful random large current from tested equipment. This danger signal mainly occurs in the transient state of tested equipment, i.e., in a short time after starting to output new set current. This paper proposes a method for protecting standard equipment to eliminate damage caused by random large current. Its content mainly describes one of the key parts of this scheme including accurately sampling and transient signal removing intelligently in details. Design the related current sampling circuit, test results show that the resolution of circuit can reach to 10mA, which satisfies the work well.

A reliable islanding identification mechanism for DC microgrid using PCC transient signal

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Satyavarta Kumar Prince ◽  
Kaibalya Prasad Panda ◽  
Shaik Affijulla ◽  
Gayadhar Panda
Keyword(s):  
Circuit Breaker ◽  
Rate Of Change ◽  
Transient Signal ◽  
Test Cases ◽  
Detection Zone ◽  
Dc Microgrid ◽  
Dc Microgrids ◽  
Protection Scheme ◽  
Point Of Common Coupling ◽  
Current Sampling

Abstract The islanding detection is a major problem for both AC and DC Microgrids. Failure to do so may result in problems such as system instability, increased non-detection zone, out-of-phase reclosing, personnel safety, and power quality deterioration. To address this issue, this paper presents a reliable island identification method for DC Microgrids that employs a Cumulative Sum of Rate of change of Voltage (CSROCOV) to reduce the non-recognition region. The proposed islanding protection scheme employs point of common coupling (PCC) transient signal to detect islands events. The voltage, power, and current sampling are accumulated from the PCC of the distributed generation terminals. The proposed scheme detects islanding in three test cases with varying power mismatching conditions, while non-islanding events are classified as capacitor switching and faults. The system is modelled and simulated in the MATLAB/Simulink environment, then islanding conditions are applied by turning off the main circuit breaker. Simulation results are presented to verify the methodology under different test cases. The robustness of the proposed scheme is also validated against measurement noise.

scholarly journals Fault Detection in DC Microgrids Using Short-Time Fourier Transform

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 277
Author(s):  
Ivan Grcić ◽  
Hrvoje Pandžić ◽  
Damir Novosel
Keyword(s):  
Fourier Transform ◽  
Fault Detection ◽  
Operating Conditions ◽  
Time Signal ◽  
Short Time Fourier Transform ◽  
Dc Microgrid ◽  
Protection Scheme ◽  
Simulink Model ◽  
Battery Energy ◽  
Short Time

Fault detection in microgrids presents a strong technical challenge due to the dynamic operating conditions. Changing the power generation and load impacts the current magnitude and direction, which has an adverse effect on the microgrid protection scheme. To address this problem, this paper addresses a field-transform-based fault detection method immune to the microgrid conditions. The faults are simulated via a Matlab/Simulink model of the grid-connected photovoltaics-based DC microgrid with battery energy storage. Short-time Fourier transform is applied to the fault time signal to obtain a frequency spectrum. Selected spectrum features are then provided to a number of intelligent classifiers. The classifiers’ scores were evaluated using the F1-score metric. Most classifiers proved to be reliable as their performance score was above 90%.

scholarly journals Condition Assessment of Solar Modules by Flash Test and Electroluminescence Test

Coatings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1361
Author(s):  
István Bodnár ◽  
Dávid Matusz-Kalász ◽  
Rafael Ruben Boros ◽  
Róbert Lipták
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
Solar Power ◽  
Test Results ◽  
Performance Reduction ◽  
Solar Power Plants ◽  
Operational Errors ◽  
Hungarian State ◽  
Short Time ◽  
Real State

The Hungarian society and the Hungarian state are constantly increasing their solar capacity. More and more solar power plants are being put into operation. The largest of these has a 100 MW peak capacity. Such power plants do not require constant maintenance. However, in the case of low productivity, a conditional assessment is required. The reason for production loss can also be manufacturing, installation, and operational errors. A flying drone was used for finding failures by thermographic scouting. Furthermore, electroluminescent (EL) and flash tests give a comprehensive view of the real state of the modules in a mobile laboratory. We had the opportunity to summarize these test results of more than a thousand modules operating in a solar power plant. The report on the power plant shows that a significant part of the modules became unusable in a short time. After four years, 10% of the 260 Wp modules suffered a performance reduction of more than 10%.

scholarly journals Analysis on the Possibility of Eliminating Interference from Paraseismic Vibration Signals Induced by the Detonation of Explosive Materials

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6401
Author(s):  
Józef Pyra ◽  
Maciej Kłaczyński ◽  
Rafał Burdzik
Keyword(s):  
Acoustic Waves ◽  
Vibration Signal ◽  
Test Results ◽  
Subtraction Method ◽  
Reverberation Chamber ◽  
Explosive Materials ◽  
Short Time ◽  
Spectral Subtraction Method ◽  
The Impact ◽  
Made In

This article presents the results of studies on the impact of acoustic waves on geophones and microphones used to measure airblasts carried out in a reverberation chamber. During the tests, a number of test signals were generated, of which two are presented in this article: frequency-modulated sine (sine sweep) waves in the 30–300 Hz range, and the result of detonating 3 g of pyrotechnic material inside the chamber. Then, based on the short-time Fourier transform, the spectral subtraction method was used to remove unwanted disruption interfering with the recorded signal. Using MATLAB software, a program was written that was calibrated and adapted to the specifics of the measuring equipment based on the collected test results. As a result, it was possible to clean the signals of interference and obtain a vibration signal propagated by the substrate. The results are based on signals registered in the laboratory and made in field conditions during the detonation of explosive materials.

Research on Demodulation Algorithm of PCM/FM Signal

2014 ◽  
Vol 532 ◽  
pp. 142-146
Author(s):  
Gang Fu ◽  
Yue Feng ◽  
Guang Zhi Wu ◽  
Li Ping Wang
Keyword(s):  
Fourier Transform ◽  
Energy Spectrum ◽  
Test Results ◽  
Short Time Fourier Transform ◽  
Software Algorithms ◽  
Digital Detection ◽  
Signal Demodulation ◽  
Short Time

According to the characteristics of PCM/FM signal demodulation, the research based on short-time Fourier transform STFT software resolving method. First detected using STFT f1 and f0 corresponding spectrum energy, according to the comparison of two energy spectrum of element. Software demodulation system is discussed in detail the synchronous digital detection and software algorithms, analysis of demodulation performance of the algorithm. The simulation and test results verify the effectiveness of the method.

scholarly journals IMPLEMENTATION OF MULTI-CRITERIA MOVING AVERAGE CROSSOVER INDICATORS AS THE BASIS FOR TECHNICAL ANALYSIS DECISION MAKING AT THE FUTURES EXCHANGE

2019 ◽  
Vol 19 (1) ◽  
pp. 91
Author(s):  
Zian Ibnu Zain Al Abidin Al Bahsan ◽  
Karmilasari Karmilasari
Keyword(s):  
Foreign Exchange ◽  
Moving Average ◽  
Technical Analysis ◽  
Decision Makers ◽  
Test Results ◽  
Double Crossover ◽  
Existing Problems ◽  
Short Time ◽  
Foreign Exchange Trading ◽  
Crossover Method

The purpose of this paper is to minimize the risk of trading option and futures through conducting technical analysis utilizing Double Crossover Method. Hence, it tries to seek the answer on some problems such as: foreign exchange tradingwithout having to make official and uncomplicated investments, trading without having to spend a lot of time, testing double crossover methods in a short time, and how to determine the most effective double crossover methods with multi-criteria considerations. Four methods were used which included the review, pre-testing, testing, and drawing conclusions. Based on the results of these stages, it was found that MT4 FXDD, SMA 5 - 10 pairs on H4 Timeframes, Expert Advisors, and Backtesting were the answers to the existing problems. Based on the aforementioned results, there are some suggestion for general investors, this strategies support their activities on getting real and efficient foreign exchange trading facilities without Joining procedural and official investments in the futures exchange; utilizing efficient decision makers tools in trading to avoid or minimize the loss, applying the most effective Double Crossover Method priority used as a technical analysis in trading foreign exchange based on test results. At last, this study explains the application of the double crossover method, which is a method that utilizes two moving average lines to generate a more effective and accurate trading signal for making decision and minimizes losses compared to the use of a single moving average. Keywords—F31 Foreign Exchange; G13 Futures Pricing; F17 Trade Forecasting and Simulation; E22 Investment. Abstrak Tujuan dari artikel ini yaitu untuk meminimalkan risiko trading option and futures melalui penggunaan analisis teknis dengan menggunakan Metode Double Crossover. Oleh karena itu, penelitian ini mencoba mencari jawaban pada beberapa masalah terkait dengan hal berikut yaitu: bagaimana melakukan perdagangan valuta asing tanpa harus melakukan investasi resmi dan tidak rumit, bagaimana melakukan perdagangan tanpa harus menghabiskan banyak waktu, bagaimana menguji metode Double Crossover dalam waktu singkat, dan bagaimana menentukan metode Double Crossoveryang paling efektif dengan pertimbangan multi-kriteria. Empat metode digunakan yang meliputi tinjauan, pra-pengujian, pengujian, dan menarik kesimpulan. Berdasarkan hasil dari tahap-tahap ini, ditemukan bahwa jawaban dari masalah yang dicari dalam penelitian ini secara berurutan yaitu menggunakanaplikasi MT4 FXDD, SMA 5 - 10 pasang pada H4 Timeframes, Expert Advisors, dan Backtesting adalah. Berdasrakan hasil diatas, ada beberapa saran bagi investor atau masyarakat umum, strategi ini mendukung kegiatan mereka dalam mendapatkan fasilitas perdagangan valuta asing yang nyata dan efisien tanpa bergabung dengan investasi resmi dan penuh prosedural di bursa berjangka; Memanfaatkan alat pembuat keputusan yang efisien dalam perdagangan untuk menghindari atau meminimalkan kerugian, menerapkan prioritas Metode Double Crossover paling efektif yang digunakan sebagai analisis teknis dalam perdagangan valuta asing berdasarkan hasil tes. Nilai terpenting dari penelitian ini menjelaskan penggunaan metode double crossover, yaitu metode yang memanfaatkan dua garis moving average untuk menghasilkan sinyal perdagangan yang lebih efektif dan akurat dalam pengambilan keputusan dan meminimalkan kerugian dibandingkan dengan penggunaan single moving average. Kata Kunci— Valuta Asing (F31); Harga Saham (G13); Perkiraan dan Simulasi Perdagangan (F17); Investasi (E22).

scholarly journals Effect of Temperature on Material Properties of Carbon Fiber Reinforced Polymer (CFRP) Tendons: Experiments and Model Assessment

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1025 ◽  
Author(s):  
Fei Zhou ◽  
Jiwen Zhang ◽  
Shoutan Song ◽  
Dong Yang ◽  
Chao Wang
Keyword(s):  
Steady State ◽  
Material Properties ◽  
Elevated Temperatures ◽  
Transient State ◽  
Fiber Reinforced Polymer ◽  
Test Results ◽  
Concrete Members ◽  
Frp Composites ◽  
Reinforced Polymer ◽  
State Test

Material properties at elevated temperatures are important factors in the fire safety design and numerical analysis of concrete members strengthened with fiber reinforced polymer (FRP) composites. Most of the previous research mainly focused on tensile strength and elastic modulus in conventional steady state temperature tests. However, the transient state test method is more realistic for strengthening concrete structures. At the same time, the coefficient of thermal expansion of FRP composites is also one of the important factors affecting concrete members at elevated temperatures. This paper presents a detailed experimental investigation on the longitudinal thermal expansion deformation, and the mechanical properties of carbon FRP (CFRP) tendons with 8 mm diameter in the steady state and transient state. The results indicate that longitudinal deformation of CFRP tendons is negative at high temperature; in addition, the transient state test results of CFRP tendons are slightly higher than the steady state test results. The final part of this paper assesses the accuracy of different empirical models. Furthermore, a new equation calculating the properties of CFRP composites at elevated temperatures is presented with the numerical fitting technique, which is in good agreement with the experimental results.

Indexing 5-Axis Machining Process Design Support System Shortening Die Fabrication Lead Time

2012 ◽  
Vol 523-524 ◽  
pp. 392-397
Author(s):  
Yoshihiko Yamada ◽  
Toshiyuki Okita ◽  
Yoshimasa Kuwano
Keyword(s):  
Support System ◽  
Process Design ◽  
Lead Time ◽  
Machining Process ◽  
Test Results ◽  
Tool Orientation ◽  
Global Competitiveness ◽  
Complex Thinking ◽  
Design Support System ◽  
Short Time

In recent years, due to intensified global competitiveness in die machining, further reduction of lead time, lower costs and higher accuracy are in demand. 5-axis machining is receiving attention as a means to solving these issues. However, differing to the conventional 3-axis machining, complex thinking tasks such as determining tool orientation while considering interference are required in the process design phase prior to machining, which not only places pressure on even those experienced workers, but also consumes a significantly longer amount of time than that required for the actual machining itself. Accordingly, with the aim of shortening the overall lead time from machining process design through to machining itself, we have developed a support system which makes highly efficient indexing 5-axis machining process design possible in a short time even for inexperienced workers. This report presents the algorithms contrived and calculation test results.

a Taskboard System Based On Website (Case Study: CV Nukegraphic Indonesia)

Tech-E ◽  
2018 ◽  
Vol 1 (2) ◽  
pp. 10
Author(s):  
Ceng Giap Yo ◽  
Dennie
Keyword(s):  
Information Technology ◽  
Test Results ◽  
Work Process ◽  
Web Based ◽  
Task List ◽  
The Status ◽  
Short Time ◽  
A Company ◽  
Made In

CV. Nukegraphic Indonesia as one of the fast growing website in Indonesia would require a lot of support, including support in the field of Information Technology. Recording task list that still use manual systems, often prevent the processing of information about the details of the status of the task and the status of projects ongoing or already completed in the form of a percentage of each project, as well as recording task that still use paper media is also considered only will lead to waste in paper usage. Recording task that is only made in the scope of the company's staff also hinder the work process of the company when staff are outside the company. The method used in the manufacture of a web-based application taskboard this form of collecting data through observation and questionnaires were distributed in the scope of the company. The test results of these applications concluded that with the application taskboard-based website is an account executive can find out information about the details of the status and the status of the project in a short time, because the data processing has been made into a computerized provided through the application, both an account executive and members are also more easy in knowing the task that must be done even though it is outside the company. With this application is expected to help the performance of employees in a company to be more productive

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