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.

Laboratory Test of Current Transformer Operates under Harmonic Conditions

2015 ◽  
Vol 793 ◽  
pp. 222-225
Author(s):  
Indra Nisja ◽  
A.Z. Abdullah ◽  
S. Masri ◽  
S. Hardi
Keyword(s):  
Power System ◽  
Laboratory Test ◽  
Harmonic Distortion ◽  
Current Transformer ◽  
Total Harmonic Distortion ◽  
Current Harmonics ◽  
Secondary Current ◽  
Primary Current

This research focused on the effect of harmonic to the performance of current transformer (CT) operates under harmonic conditions. Due to the increasing of harmonic in power system, the CT did not perform well. The CT may saturates due to the presence of voltage and current harmonics. In this project, a laboratory test was conducted to investigate and analyze the influence of harmonics to the CT performance. This CT has been test with different Total Harmonic Distortion Current (THDi) at primary side and constant primary current. The experiment result shows the secondary current CT errors will increases when THDi increases.

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.

scholarly journals SRF based Shunt Active Power Filter Integrated with Microgrid for Harmonics Mitigation

2019 ◽  
Vol 8 (12) ◽  
pp. 869-874
Keyword(s):  
Power System ◽  
Distribution System ◽  
Electrical Power ◽  
Harmonic Distortion ◽  
Active Power Filter ◽  
Active Power ◽  
Electrical Power System ◽  
Shunt Active Power Filter ◽  
Current Harmonics ◽  
Power Filter

“The increased penetration of Distributed Energy Resources (DER) is inspiring the entire design of conventional electrical power system. “A Microgrid (MG) includes distributed generation, loads, energy storage, and a control system that is competent of working in grid-connected mode and/or islanded mode. Power quality (PQ) problems are one of the major technical challenges in MG power system. To get better PQ of energy supply, it is essential to analyze the harmonics distortion of the system. Moreover, harmonic distortion in a MG networks has significantly reduced PQ, which affects the stability of the system. In order to diminish the harmonics, shunt active power filter (SAPF) has been extensively useful and it is verified to be the best solution to current harmonics. The present paper proposes the mitigation of harmonics of a MG system using shunt active power filter (SAPF). However, the SAPF is employed for reimbursing the harmonics concurrently in the distribution system. The proposed model is developed in MATLAB/Simulink and the result obtained validates the superiority of proposed technique over others in terms of harmonics elimination.”

New Method to Identify CT Saturation Based on EMD

2013 ◽  
Vol 721 ◽  
pp. 488-491 ◽  
Author(s):  
Wen Hua Xia ◽  
Mao Fa Gong ◽  
Guo Liang Li ◽  
Jian Yu Zhang ◽  
Xin Cheng
Keyword(s):  
Sine Wave ◽  
Current Transformer ◽  
New Method ◽  
Projection Area ◽  
Differential Protection ◽  
Intrinsic Mode Functions ◽  
Secondary Current ◽  
Mode Decomposition ◽  
Gravity Coefficient ◽  
Aperiodic Component

Aiming at the problem that Current Transformer (CT) affects differential protection, this paper proposes a new method to identify CT saturation based on Empirical Mode Decomposition (EMD). Differential current can be decomposed into few Intrinsic Mode Functions (IMFs) by EMD. When CT is linear transfer, the current waveform is nearly a sine wave, and it only contains one dominant IMF. However, CT saturation leads to the distortion of secondary current which contains at least two dominant IMFs. From the defined projection area on t-axis of each IMF and the specific gravity coefficient, the number of dominant IMF can be got. Thus CT saturation can be identified. Theoretical analysis and simulation results show that this method can identify CT saturation of different degree. It is convenient to achieve and hardly to be affect by aperiodic component.

scholarly journals Performance of current transformer operate under harmonic condition and their effects on transformer differential protection

2018 ◽  
Vol 159 ◽  
pp. 02075
Author(s):  
Indra Nisja
Keyword(s):  
Power Transformer ◽  
Harmonic Distortion ◽  
Current Transformer ◽  
Power Transformers ◽  
Actual Condition ◽  
Differential Protection ◽  
Nonlinear Load ◽  
Primary Power ◽  
Transformer Differential Protection ◽  
Secondary Power

This paper focused to determine the performance of Current Transformer (CT) operates under harmonics condition and their effects on transformer differential protection. A laboratory test has been implemented to determine the error produced by both CT and power transformer when operating under harmonic condition. The test was performing with the actual condition, where the power transformer is connected to an adjusted nonlinear load, so that the test can be conducted with several levels of total harmonic distortion current (THDi). The results shows, for THDi ranging from 16.70% to 40.88% the maximum errors occurred on CT at secondary power transformers is 27.21% and CT at primary power transformers is 8.12%. This error resulted in differential current flow 0.17A and relay trip without any fault. In this study it was found that the relays started to operate incorrectly on THDi 31.5%.

scholarly journals Studying the Effect of Non-Linear Loads Harmonics on Electric Generator Power Rating Selection

2017 ◽  
Vol 13 (18) ◽  
pp. 548 ◽  
Author(s):  
Ahmed EL Sebaay ◽  
Mahmoud Ramadan ◽  
Maged A. Abu Adma
Keyword(s):  
Power System ◽  
Power Supply ◽  
Harmonic Distortion ◽  
Synchronous Generator ◽  
Electric Power System ◽  
Variable Frequency Drive ◽  
Current Harmonics ◽  
Electric Generator ◽  
Harmonic Currents ◽  
Non Linear

Non-linear loads connected to an electric power system produce Harmonic currents, harmonics are introduced into the system in the form of currents whose frequencies are the integral multiples of the fundamental power system frequency (50/60 Hz). The harmonic currents interact with the supply system impedance causing distortions in supply output voltage and current, which has a very bad effect on all other loads connected to the system and the power supply itself, such as overheating, increasing powers losses in the system, and malfunction of protection and control devices connected to the system. This paper presents a study to analyze the effect of voltage and current harmonics resulting from non-linear loads such as variable frequency drive, uninterruptable power supply, and battery chargers on operation and power rating of synchronous generator. The study introduces an optimized method for selecting the suitable generator power rating to withstand harmful harmonics effects for a safe operation of the generator, saving its lifetime, and to improve the power quality of the power system. The method depends on analyzing the effect of increasing the supply generator power rating on the THVD produced from non-linear loads harmonics connected to the system. By calculating the THVD for each case of a generator power rating, a mathematical relationship between generator power rating and TVHD can be found. So, the relationship between generator power rating and total harmonic distortion in the power system will be discussed clearly.

Dependence of Current Harmonics of Greenhouse Irradiators on Supply Voltage

2020 ◽  
pp. 85-88 ◽  
Author(s):  
Nadezhda P. Kondratieva
Keyword(s):  
Mathematical Models ◽  
Supply Voltage ◽  
Harmonic Distortion ◽  
Feasibility Studies ◽  
Power Losses ◽  
Voltage Level ◽  
Supply Networks ◽  
Current Harmonics ◽  
Cable Lines ◽  
Harmonic Composition

The article describes the results of the study concerning the effect of the voltage level on current harmonic composition in greenhouses irradiators. It is found that its change affects the level of current harmonics of all types of the studied greenhouse irradiators. With decrease of nominal supply voltage by 10 %, the total harmonic distortion THDi decreases by 9 % for emitters equipped with high pressure sodium lamps (HPSL), by 10 % for emitters with electrode-less lamps and by 3 % for LED based emitters. With increase of nominal supply voltage by 10 %, THDi increases by 23 % for lighting devices equipped with HPSL, by 10 % for irradiators with electrode-less lamps and by 3 % for LED based emitters. Therefore, changes of supply voltage cause the least effect on the level of current harmonics of LED based emitters and then the emitters with electrode-less lamps. Change of the level of supply voltage causes the greatest effect on the level of current harmonics of HPSL based irradiators. Mathematical models of dependence of THDi on the level of supply voltage for greenhouse emitters equipped with LED, electrode-less lamps and HPSL lamps were formulated. These mathematical models may be used for calculations of total current when selecting transformers and supply cable lines for greenhouse lighting devices, for design of new or reconstruction of existing irradiation systems of greenhouse facilities, and for calculation of power losses in power supply networks of greenhouse facilities during feasibility studies for energy saving and energy efficiency increasing projects.

Inter-turn fault stability enrichment and diagnostic analysis of power system network using wavelet transformation-based sample data control and fuzzy logic controller

2021 ◽  
pp. 014233122110070
Author(s):  
Arunesh Kumar Singh ◽  
Abhinav Saxena ◽  
Nathuni Roy ◽  
Umakanta Choudhury
Keyword(s):  
Fuzzy Logic ◽  
Power System ◽  
Wavelet Transformation ◽  
Fuzzy Logic Controller ◽  
Power Transformer ◽  
Harmonic Distortion ◽  
Inrush Current ◽  
Data Control ◽  
Sample Data ◽  
Z Transformation

In this paper, performance analysis of power system network is carried out by injecting the inter-turn fault at the power transformer. The injection of inter-turn fault generates the inrush current in the network. The power system network consists of transformer, current transformer, potential transformer, circuit breaker, isolator, resistance, inductance, loads, and generating source. The fault detection and termination related to inrush current has some drawbacks and limitations such as slow convergence rate, less stability and more distortion with the existing methods. These drawbacks motivate the researchers to overcome the drawbacks with new proposed methods using wavelet transformation with sample data control and fuzzy logic controller. The wavelet transformation is used to diagnose the fault type but contribute lesser for fault termination; due to that, sample data of different signals are collected at different frequencies. Further, the analysis of collected sample data is assessed by using Z-transformation and fuzzy logic controller for fault termination. The stability, total harmonic distortion and convergence rate of collected sample data among all three methods (wavelet transformation, Z-transformation and fuzzy logic controller) are compared for fault termination by using linear regression analysis. The complete performance of fault diagnosis along with fault termination has been analyzed on Simulink. It is observed that after fault injection at power transformer, fault recovers faster under fuzzy logic controller in comparison with Z-transformation followed by wavelet transformation due to higher stability, less total harmonic distortion and faster convergence.

PI and Fuzzy-Controlled 3-Phase 4-Wire Interleaved Buck Active Power Filter with Shoot-Through Elimination for Power Quality Improvement using RTDS Hardware

2014 ◽  
Vol 15 (2) ◽  
pp. 177-194 ◽  
Author(s):  
Anup Kumar Panda ◽  
Ranjeeta Patel
Keyword(s):  
Control Strategy ◽  
Fuzzy Logic Controller ◽  
Supply Voltage ◽  
Harmonic Distortion ◽  
Active Power Filter ◽  
Active Power ◽  
Current Harmonics ◽  
Power Filter ◽  
Power Quality Improvement ◽  
Real Time Digital Simulator

Abstract In this paper, shoot-through current elimination DC–AC converter circuit has been presented with the application of active power filter (APF). The intuitive analysis of the shoot-through in the conventional DC–AC converter has been reported first. Interleaved buck (IB) converter is adopted to eliminate the shoot-through current, thereby increasing the reliability of the interleaved buck–based active power filter (IB-APF). The 3-phase 4-wire IB-APF eliminates the current harmonics produced by the load just as a conventional one does and are innately immune to “shoot-through” phenomenon, with the elimination of special protection features required in conventional inverter circuits. A comparison has been made about the compensation capabilities of the IB-APF with the PI and fuzzy logic controller (FLC) used by id–iq control strategy under different supply voltage conditions. The id–iq control strategy used for extracting the three-phase reference current for IB-APF, evaluating their performance here in MATLAB/Simulink environment and also implemented using real-time digital simulator hardware (OPAL-RT hardware). The RTDS result verifies that the total harmonic distortion percentage of the source current can be reduced below 5% according to IEEE-519 standard recommendations on harmonic limits.

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