Adaptive Algorithm for Distribution Transformer Protection to Improve Smart Grid Stability

2018 ◽  
Vol 19 (5) ◽  
Author(s):  
D. D. Patel ◽  
Nilesh Chothani ◽  
K. D. Mistry ◽  
Dhaval Tailor
Keyword(s):  
Power System ◽  
Single Phase ◽  
Current Transformer ◽  
Distribution Transformer ◽  
Transformer Protection ◽  
Internal Fault ◽  
Differential Characteristic ◽  
Differential Algorithm ◽  
Distribution Generation ◽  
The Stability

Abstract Due to the presence of Distribution Generation (DG), power system becomes more complicated and stability of power is the main challenging task. Saturation of Current Transformer (CT) imposes great dilemma on differential relaying scheme. This manuscript presents a new differential algorithm for distribution transformer protection which adaptively set its characteristic in the event of CT saturation. The proposed scheme is capable to detect magnetizing inrush condition, high resistance internal fault and discriminate external fault with CT saturation. The validation of the proposed scheme is done by simulating a part of the power system in PSCADTM software and programming in MATLAB software. A Full Cycle Discrete Fourier Transform (FCDFT) is implemented to validate the differential protective scheme for 15 MVA, 66/11 kV distribution transformer. An adaptive concept of the differential characteristic is employed in the algorithm to maintain the stability of relay during external fault with CT saturation. Validation and authenticity of the proposed technique are carried out with various test condition generated under wide variation in system parameters. The result on 2 kVA, 230/110 V, single phase transformer shows that the proposed scheme is capable to discriminate inrush, internal and external fault also with CT saturation conditions.

The Effect of Harmonic Distortion on the Performance of Differential Relay for Distribution Transformer Protection

2015 ◽  
Vol 793 ◽  
pp. 182-186
Author(s):  
Indra Nisja ◽  
M.H. Idris ◽  
M. Syafrudin ◽  
S. Hardi ◽  
M. Isa
Keyword(s):  
Power System ◽  
Harmonic Distortion ◽  
Current Transformer ◽  
Differential Protection ◽  
Residential Areas ◽  
Distribution Transformer ◽  
Current Harmonics ◽  
Secondary Current ◽  
Transformer Protection ◽  
Current Error

This paper aims to analyzing and probing the influences of power system harmonics on a differential relay used for distribution transformer protection. The increased use of nonlinear devices in industry, commercial and residential areas can lead to a significant increase the level of harmonic distortion in the power system. This harmonic has the significant effects to the differential protection systems components such as current transformer (CT) and relay. The CT tends to saturate due to the presence of current harmonics in power system, so it will produce magnitude secondary current error and make the differential relay to miss operations. The harmonic distortion effects on the differential protection have been investigated through laboratory test. To determine the CT errors when operates under harmonic condition, the CT has been test with certain level of THDi. The result of this testing was found that with increasing of the THDi, the magnitude of secondary current error increased and differential relay will operate at no fault conditions.

Research on Error Characteristic of the Protective Current Transformer in High Remanence Environment

2014 ◽  
Vol 1070-1072 ◽  
pp. 1092-1104
Author(s):  
Wei Wei ◽  
Wei Zhen ◽  
Ming Zhong Liu ◽  
Xiao Bin Liang ◽  
Cang Yang Chen
Keyword(s):  
Power System ◽  
Short Circuit ◽  
Electric Energy ◽  
Transfer Characteristic ◽  
Current Transformer ◽  
Error Characteristic ◽  
Electromagnetic Current ◽  
Transient Model ◽  
The Stability ◽  
Safety Operation

Electromagnetic Current Transformer (CT) is one of the main equipment in power system, and the remanence in the measuring or protective windings of CT will influence the stability of the power system. Measuring CT is mainly used for the electric energy measurement in normal working condition, focusing on the steady operation state; while protective CT is usually used in fault or short-circuit condition, and the transient transfer characteristic is of significant important. Considering high remanence operation environment in the power system, the numeric analytical model of CT, which is working in the saturation condition, is depicted in this paper. With analyzing the amount of exciting current caused by remanence and deducing the transfer characteristic of CT, the influence of the remanence on the relay protection and the corresponding precautions are proposed, providing accurate and reliable theoretical basis for the protective CT’s correct action and safety operation after system failure. Finally, the electromagnetic transient model of protective CT (TPY) is built in PSCAD, the simulation result of which shows the validity and practicability of the proposed model.

A review on phase prediction in high entropy alloys

2021 ◽  
pp. 095440622110089
Author(s):  
Vinay Kumar Soni ◽  
S Sanyal ◽  
K Raja Rao ◽  
Sudip K Sinha
Keyword(s):  
Solid Solution ◽  
Phase Formation ◽  
Single Phase ◽  
High Entropy Alloy ◽  
High Entropy Alloys ◽  
Modeling Tools ◽  
High Entropy ◽  
Recent Developments ◽  
Phase Prediction ◽  
The Stability

The formation of single phase solid solution in High Entropy Alloys (HEAs) is essential for the properties of the alloys therefore, numerous approach were proposed by many researchers to predict the stability of single phase solid solution in High Entropy Alloy. The present review examines some of the recent developments while using computational intelligence techniques such as parametric approach, CALPHAD, Machine Learning etc. for prediction of various phase formation in multicomponent high entropy alloys. A detail study of this data-driven approaches pertaining to the understanding of structural and phase formation behaviour of a new class of compositionally complex alloys is done in the present investigation. The advantages and drawbacks of the various computational are also discussed. Finally, this review aims at understanding several computational modeling tools complying the thermodynamic criteria for phase formation of novel HEAs which could possibly deliver superior mechanical properties keeping an aim at advanced engineering applications.

Reliable Analysis on Fast Valving of Ultra-Supercritical Unit Under Transient Fault Conditions

2017 ◽  
Author(s):  
Yu Cai ◽  
Wei Li ◽  
Bao Zhang ◽  
Wenjian Wu ◽  
Deren Sheng ◽  
...  
Keyword(s):  
Power System ◽  
Steam Turbine ◽  
Dynamic Model ◽  
Transient Stability ◽  
Power Grid ◽  
Load Shedding ◽  
Control Mode ◽  
Normal Operation ◽  
Transient Fault ◽  
The Stability

Fast valving of ultra-supercritical unit has great effects on over-speed prevention, load-shedding control, transient stability analysis of electrical system and other security problems. The purpose of fast valving is to maintain the stability of power system once fault or load shedding of unit occurs in the electric power system. Therefore, it is of great significance to study the reliability of fast valving for ultra-supercritical unit. In this paper, the KU ( short shedding) logic condition of SIEMENS T3000 system is analyzed as the research object of fast valving. The unit can be avoided over speed by monitoring the unit load and fast valving under faulty grid conditions based on the KU control. A series of measures will be taken after KU is triggered, for instance the governing valving will be closed quickly and the DEH (digital electro-hydraulic) control of the steam turbine will be switched to speeding control mode. On the other hand, the unit will return to normal operation if the transient fault of power grid disappears. The key contributions of this thesis include three parts: Firstly, based on the analysis of control characteristics of ultra-supercritical unit and protective logic and triggered conditions of KU function, a novel dynamic model by coupling the fast valving of steam turbine and the transient stability of generator is established by applying the PSCAD software. Then, the dynamic response process of ultra-supercritical unit is simulated and calculated by adopting the coupling dynamic model when KU function is triggered. Also the influence factors and reliability of fast valving are analyzed under transient fault conditions. Finally, two optimized measures by increasing the time delay and the speed of quantitative judgment are put forward to reduce risks and avoid the misoperation of signal distortion which may be caused by the power transmitter under transient fault conditions. The results of this study can not only help to evaluate the reliability of fast valving function scientifically in power grid transient fault, but also guide the technicians to analyze the stability of the power grid.

scholarly journals Optimal Location and Design of TCSC controller For Improvement of Stability

2011 ◽  
pp. 210-215
Author(s):  
Swathi Kommamuri ◽  
P. Sureshbabu
Keyword(s):  
Power System ◽  
Optimization Problem ◽  
Low Frequency ◽  
System Stability ◽  
Simulation Environment ◽  
Swarm Optimization ◽  
Stability Performance ◽  
Low Frequency Oscillations ◽  
Simulation Results ◽  
The Stability

Power system stability improvement by a coordinate Design ofThyristor Controlled Series Compensator (TCSC) controller is addressed in this paper.Particle Swarm Optimization (PSO) technique is employed for optimization of the parameterconstrained nonlinear optimization problem implemented in a simulation environment. The proposed controllers are tested on a weakly connected power system. The non-linear simulation results are presented. The eigenvalue analysis and simulation results show the effectiveness and robustness of proposed controllers to improve the stability performance of power system by efficient damping of low frequency oscillations under various disturbances.

scholarly journals Multi-machine transient stability by using static synchronous series compensator

2020 ◽  
Vol 11 (3) ◽  
pp. 1249
Author(s):  
Nur Ashida Salim ◽  
Nur Diyana Shahirah Mohd Zain ◽  
Hasmaini Mohamad ◽  
Zuhaila Mat Yasin ◽  
Nur Fadilah Ab Aziz
Keyword(s):  
Power System ◽  
Transient Stability ◽  
Single Phase ◽  
Power Transmission ◽  
System Stability ◽  
Phase System ◽  
Proportional Integral ◽  
Before And After ◽  
In Series ◽  
Static Synchronous Series Compensator

<span lang="EN-US">Transient stability in power system is vital to be addressed due to large disturbances that could damage the system such as load changes and voltage increases. This paper presents a multi-machine transient stability using the Static Synchronous Series Compensator (SSSC). SSSC is a device that is connected in series with the power transmission line and produces controllable voltage which contribute to a better performance in the power system stability. As a result, this research has observed a comparison of the synchronization of a three-phase system during single-phase faults before and after installing the SSSC device. In addition, this research investigates the ability of three different types of controllers i.e. Proportional Integral (PI), Proportional Integral Derivation (PID), and Generic controllers to be added to the SSSC improve the transient stability as it cannot operate by itself. This is because the improvement is too small and not able to achieve the desired output. The task presented is to improve the synchronization of the system and time taken for the voltage to stabilize due to the fault. The simulation result shows that the SSSC with an additional controller can improve the stability of a multi-machine power system in a single phase fault.</span>

Simulation Design of Transformer Differential Protection Based on Mat Lab

2013 ◽  
Vol 722 ◽  
pp. 282-286
Author(s):  
Hong Hua He
Keyword(s):  
Simulation Model ◽  
Relay Protection ◽  
Fault Current ◽  
Differential Protection ◽  
Protection Device ◽  
Simulation Design ◽  
Transformer Protection ◽  
Internal Fault ◽  
Simulation Results ◽  
Transformer Differential Protection

The microprocessor-relay protection device has gradually replaced regular simulation relay protection it is also difficult to visually determine protection device malfunction or tripping. Therefore, the use of the Mat lab toolbox to build transformer differential protection simulation model, the simulation results show that two-line ratio brake can correctly identify internal fault current, and rapidly remove fault, and the system also can provide convenient for microprocessor transformer protection.

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