scholarly journals New Protection Scheme Based on Coordination with Tie Switch in an Open-Loop Microgrid

Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4756
Author(s):  
Hun-Chul Seo
Keyword(s):  
Wavelet Transform ◽  
Power Supply ◽  
Fault Location ◽  
Current Flow ◽  
Open Loop ◽  
Electromagnetic Transients ◽  
Protection Relay ◽  
Protection Scheme ◽  
Small Loop ◽  
Simulation Results

Owing to the increase in renewable energy, microgrids (MGs) are increasing. A MG has a small loop-type grid configuration. In the loop MG, challenges in protection such as maloperation of protection relay may occur owing to bidirectional current flow. Herein, we propose a new protection scheme in the loop MG. Considerations for protection in loop MG and fault characteristics are analyzed. Based on these, a new index to solve the considerations for MG protection are proposed using a wavelet transform. Furthermore, the new protection scheme based on the coordination with tie switch using the proposed new index is proposed. To verify the proposed scheme, the MG and the proposed scheme are modeled using the electromagnetic transients program and MATLAB. Various simulations according to the fault location and the success/failure of fault section separation are performed. Simulation results indicate that the power supply on the original feeder can be maintained by proposed method.

scholarly journals Systematization of the Simulation Process of Transformer Inrush Current Using EMTP

2019 ◽  
Vol 9 (12) ◽  
pp. 2398 ◽  
Author(s):  
Hun-Chul Seo ◽  
Gi-Hyeon Gwon
Keyword(s):  
Computer Simulation ◽  
Computer Simulations ◽  
Electromagnetic Transients ◽  
Inrush Current ◽  
Large Magnitude ◽  
Test Report ◽  
Protection Relay ◽  
Simulation Process ◽  
System Operator ◽  
Simulation Results

An inrush current is generated when a transformer is energized. This current has a large magnitude and rich harmonics, thereby causing mal-operation of the protection relay. Therefore, the development of countermeasures against inrush current is necessary, and this study has been performed by computer simulations. However, it is difficult for a power system operator to perform a computer simulation as it is difficult to determine what data should be selected and entered. Therefore, this paper establishes the simulation process of transformer inrush current using the Electromagnetic Transients Program (EMTP). Two methods to simulate the transformer inrush current are described in detail. Based on the actual 154 kV transformer test report in Korea, the simulation results of the inrush current using the two methods are discussed.

Development of Adaptive Distance Relay for STATCOM Connected Transmission Line with Wavelet Transform and ANN

2014 ◽  
Vol 705 ◽  
pp. 237-242
Author(s):  
Ramchandra P. Hasabe ◽  
Anil P. Vaidya
Keyword(s):  
Neural Network ◽  
Wavelet Transform ◽  
Transmission Line ◽  
Fault Location ◽  
Reactive Power ◽  
Distance Protection ◽  
Distance Relay ◽  
Protection Relay ◽  
Distance Protection Relay ◽  
Transmission Line Protection

A new scheme to enhance the solution of the problems associated with Transmission line protection with Statcom connected is presentedin this paper.Static Synchronous Compensator (STATCOM) is a shunt type FACTS device connected at the midpoint of the transmission line to maintain the voltage atdesired level by injecting/absorbing the reactive power. This connection affects the performance of distance protection relay during line faults. Thefault detectionis carried out byusingenergy of the detail coefficients of the phase signals and artificial neutral network algorithm used for fault distance location for all thetypes of faults for transmission line. For each type of fault separate neural network is prepared for finding out the fault location.

scholarly journals WT-ANN based fault discrimination for transmission system

2018 ◽  
Vol 7 (1.8) ◽  
pp. 144
Author(s):  
P Venkata Lakshmi ◽  
P N. S. Poojitha ◽  
Y Srinivasrao
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Wavelet Transform ◽  
Power System ◽  
Transmission Line ◽  
Transmission Lines ◽  
Power Supply ◽  
Protection Scheme ◽  
Efficient Protection ◽  
Continuous Power

Protection of transmission line is a complex in power system as the majority of the faults in power system are transmission faults. A proper protection is needed for transmission line for continuous power supply. To provide a strong as well as an efficient protection scheme, in this paper we are using wavelet technique and artificial neural network. By using these mentioned two techniques we can detect the faults in transmission line and also, we can classify the detected faults. Wavelet transform has strong mathematical, very fast and accurate tools for brief signal inside the transmission lines and synthetic neural network can make a unique between measured sign and associated signal that has different pattern. 

scholarly journals Novel Protection Scheme considering Tie Switch Operation in an Open-Loop Distribution System using Wavelet Transform

Energies ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1725 ◽  
Author(s):  
Hun-Chul Seo
Keyword(s):  
Power Distribution ◽  
Distribution System ◽  
Distribution Systems ◽  
Normal Load ◽  
Open Loop ◽  
Fault Current ◽  
Load Current ◽  
Protection Relay ◽  
Protection Scheme ◽  
Switch Operation

Loop power distribution systems are gaining increasing attention due to improvements in the reliability of the power supply and the connection of distributed generation. With loop distribution systems, there is the possibility of mal-operation of the protection relay because of the existence of the tie switch and bi-directional current injection. In this paper, we propose a novel protection scheme considering the tie switch operation in the open loop power distribution system using wavelet transform. We analyze the possibility of mal-operation of the protection relay as a result of the normal load current after tie switch operation and analyze the characteristics of the normal load current and fault current injection after tie switch operation. Using these results, a new index is proposed to distinguish the normal load current and fault current, and a novel protection scheme based on this new index is proposed. The proposed method is modeled using an electromagnetic transients program and MATLAB, and the various simulations are performed according to the tie switch position, the fault location, and the success or failure of the fault section separation. From the simulation results, we can confirm that the normal load current and the fault current after tie switch operation can be accurately distinguished and the protection relay can accurately operate at only fault conditions.

scholarly journals New Protection Scheme in Loop Distribution System with Distributed Generation

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5897 ◽  
Author(s):  
Hun-Chul Seo
Keyword(s):  
Distributed Generation ◽  
Distribution System ◽  
Power Flow ◽  
Distribution Systems ◽  
Fault Location ◽  
Electromagnetic Transients ◽  
Radial Distribution System ◽  
Protection Scheme ◽  
Protection Method ◽  
Bidirectional Power Flow

Loop distribution systems are increasingly used for reasons such as increased distributed generation (DG) and increased demand for a reliable and high-quality power supply. Because the loop distribution system involves bidirectional power flow, the method for protection of the radial distribution system cannot be applied. Therefore, a protection method is proposed herein for loop distribution systems. In this study, the existence of DG is also considered. According to the proposed method, the fault point is estimated on the basis of the equivalent circuit of the distribution system. Then, the fault section is determined and separated from the distribution system. The separation of DG is determined depending on whether the frequency and voltage are maintained within the steady state ranges. The proposed method is modelled and verified using the Electromagnetic Transients Program. Simulations according to the fault location are performed and analyzed. The results show that the method accurately determines the fault section so that normal power can be supplied to the healthy sections in the distribution system.

A Bandgap Reference with Temperature Coefficient of 13.2 ppm/°C

2014 ◽  
Vol 981 ◽  
pp. 66-69
Author(s):  
Ming Yuan Ren ◽  
En Ming Zhao
Keyword(s):  
Power Supply ◽  
Process Simulation ◽  
Output Voltage ◽  
Operating Temperature ◽  
Cmos Process ◽  
Bandgap Reference ◽  
Analysis Method ◽  
Operation Condition ◽  
Reference Circuit ◽  
Simulation Results

This paper presents a design and analysis method of a bandgap reference circuit. The Bandgap design is realized through the 0.18um CMOS process. Simulation results show that the bandgap circuit outputs 1.239V in the typical operation condition. The variance rate of output voltage is 0.016mV/°C? with the operating temperature varying from-60°C? to 160°C?. And it is 3.27mV/V with the power supply changes from 1.8V to 3.3V.

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