A New Electric Power Harmonic Detection Scheme

2013 ◽  
Vol 341-342 ◽  
pp. 1308-1312
Author(s):  
Chao Wang
Keyword(s):  
Power System ◽  
Detection Method ◽  
Frequency Change ◽  
Matlab Simulation ◽  
Harmonic Detection ◽  
Detection Scheme ◽  
The Troubles ◽  
System Protection ◽  
Three Phase ◽  
Intelligent Devices

Microcomputer relay is a kind of intelligent devices used for detecting and protecting power system. Whenever, it quickly calculate whether the power system is wrong or not on the basis of the fundamental and harmonics detected from power system, And according to the calculating results to obviate the troubles, among them, the fundamental and harmonics acquired accurately in time is the most important part of the power system protection process. The basic principle of d-q fundamental and harmonics voltage detection is presented and on this basis a fundamental and harmonics detection method of presumption the transformation frequency is put forward. The results of the theoretical analysis and MATLAB simulation indicate that the d-q method in this paper can precisely detect the voltage and frequency change of the power system in time, whether the distortion voltage or not in three-phase power system .

A Survey on Detecting Methods for Harmonic of Power System

2012 ◽  
Vol 614-615 ◽  
pp. 907-910
Author(s):  
Xue Song Zhou ◽  
Guang Zhu Chen ◽  
You Jie Ma
Keyword(s):  
Power System ◽  
Reactive Power ◽  
Detection Method ◽  
Response Speed ◽  
Development Trend ◽  
Detection Methods ◽  
Detection Accuracy ◽  
Harmonic Detection ◽  
Advantages And Disadvantages ◽  
Power System Harmonics

This paper describes Detecting Methods for Harmonics of power system has been considered one of the serious harms for power system. The research of harmonics has obtained high attention among people. The researches of harmonics detection have many methods, such as Based on Fryze theory of harmonic power detection, Instantaneous reactive power theory detection method, Fourier Transformation harmonic detection method, wavelet transform detection method, neural networks harmonic detection method etc. Aiming at harmonic detection, the different detection methods of power system harmonics are summarized and compared. This paper reviews the existing harmonic detection methods, and discuss their advantages and disadvantages in terms of detection accuracy and response speed, and finally summarizes the development trend of the harmonic detection method.

scholarly journals Increment of Fault Current due to integration of Distributed Generation and its impact on Distribution Network Protection

2021 ◽  
Author(s):  
Haymanot Takele Mekonnen
Keyword(s):  
Power System ◽  
Distributed Generation ◽  
Distribution System ◽  
Distribution Network ◽  
Fault Current ◽  
Power System Protection ◽  
Power Distribution System ◽  
System Protection ◽  
Network Protection ◽  
Three Phase

Abstract BackgroundOne of the new technologies in generating power near the distribution system is called distributed generation which has supportive and destructive characteristics to the power system protection. One of the destructive characteristics of distributed generation is increasing the level of fault current to the protective equipment of the power system. In addition to increment of fault, it also alters the radial nature of the power distribution system and cause the power bidirectional rather than unidirectional. Integration of distributed generation to the distribution network causes increment of fault current effect, reliability drop, and affects security of protection system. The level of failure of protection be contingent on type, size, location and number of distributed generation. This fault current can cause a great damage to the electrical equipment with the miss operations of protective devices. The main aim of this paper is analysis of the fault current level to the protection of distribution network due to the integration of distributed generation which concerns on solar distributed generation, wind distributed generation and combination of solar and wind distributed generations at a time. This paper conducts the analysis for the increment of fault current by the integration of distributed generation and its impact on distribution network protection. ResultsThe analysis and the modeling are conducted on the 15KV distribution network of the radial feeder in Debre Markos town. This paper has covered the ling to ground, line to line and three phase fault analysis and their impact on the protection of distribution system for the wind and solar distributed generation types. After the integration of the distributed generation the fault current is increased by 0.529KA for three phase, 0.74KA for line to ground, 0.467KA for line to line and 0.523KA for line to line to ground. ConclusionsThis paper confirms designing distribution network without forecasting the future demand of electric power users give the protection equipment additional requirement. As the result, the fault current after the integration of distributed generation to the distribution network have great value in terms of power system protection.

Research on Harmonic Detection Methods of Electrified Railway

2011 ◽  
Vol 301-303 ◽  
pp. 1740-1743
Author(s):  
Xiang Zheng Xu ◽  
Wei Wan
Keyword(s):  
Power System ◽  
Real Time ◽  
Detection Method ◽  
Detection Methods ◽  
Harmonic Suppression ◽  
Harmonic Detection ◽  
Electric Railway ◽  
Electrified Railway ◽  
Traction Power Supply ◽  
Traction Power

This paper introduces the characteristics of the traction power system of electric railway, and explores the harms to the power system caused by electric railway and the necessity of harmonic suppression of traction power supply system. In order to achieve real-time detection and compensation for harmonic waves of electric railway traction power system, this paper provides an improved harmonic detection method with initial compensating angle of delay time. Detection method is simple, and has better real-time, it can be used to detect selective harmonic for electrified railway.

The Selective Harmonic Detection for the Integration Photovoltaic Generation and Active Power Filter

2011 ◽  
Vol 58-60 ◽  
pp. 781-786
Author(s):  
Yan Dan Lin ◽  
Li Qing Tong ◽  
Yao Jie Sun
Keyword(s):  
Control Strategy ◽  
Detection Method ◽  
Active Power Filter ◽  
Active Power ◽  
Positive Sequence ◽  
Harmonic Detection ◽  
Power Filter ◽  
Three Phase ◽  
Frequency Domains ◽  
And Control

To improve the utilization of the inverter of the photovoltaic grid connected systems and decrease the harmonic of the grid, a novel selective harmonic detection method based on the synchronous rotator frame is proposed. Utilizing three-phase Park transform, the rotator vector is transferred to the static vector, and the synchronous harmonic is separated and acquired. The characteristic of negative and positive sequence harmonic is fleetly and exactly presented in all frequency domains. Additional, a new control strategy based on this harmonic detection is proposed for the integration photovoltaic grid connected generation and active power filter. Validity and practicality of the proposed selective harmonic detection method and control strategy are proved.

A Current Harmonic Detection Method via Input Observer

2014 ◽  
Vol 548-549 ◽  
pp. 655-658 ◽  
Author(s):  
Po Li ◽  
Di Bin Huang ◽  
Peng Wang
Keyword(s):  
Power Systems ◽  
Detection Method ◽  
Current Signal ◽  
Matlab Simulation ◽  
Harmonic Detection ◽  
Current Harmonic ◽  
Active Power Filters ◽  
Power Filters ◽  
Error System ◽  
A Current

The current harmonic detection method is an important part in the control of active power filters used in power systems, since inaccuracy in harmonic detection yields to incorrect compensation. In this paper, an input observer for current harmonic detection is proposed. Firstly, a integral unit of the measured current signal is introduced to establish an augment function,then based on the augment system an observer is deduced. By constructing a Lyapunov function, the stabilization of the error system between the augment system and its observer is proved, which means the observed current harmonic approaches their real values. Finally, the proposed method is validated by Matlab simulation.

An Improved ip-iq Harmonic Detection Algorithm

2012 ◽  
Vol 588-589 ◽  
pp. 864-867
Author(s):  
Xue Hai Cui
Keyword(s):  
Real Time ◽  
Single Phase ◽  
Harmonic Component ◽  
Detection Algorithm ◽  
Matlab Simulation ◽  
Harmonic Detection ◽  
Two Phase ◽  
Time Performance ◽  
Three Phase ◽  
Simulation Results

This paper introduces the the basic principle of ip-iq harmonic detection algorithm and puts forward a method of harmonic detection for the single-phase circuit. This method eliminates the three-phase to two-phase and two-phase to the three-phase coordinate transformation, thus effectively reduces the computation ; moreover it has the advantages of good real-time performance and makes the digital control easy. Matlab simulation results show that this method can detect the harmonic component of single-phase and three-phase current accurately and in real-time.

scholarly journals An Improved Specific Harmonic Detection Method Based on Adaptive Cancellation Principle

2021 ◽  
Vol 256 ◽  
pp. 02043
Author(s):  
Lei Wang ◽  
Sun Pan ◽  
Sun Jun ◽  
Liang Yan ◽  
Xie Hai Lang ◽  
...  
Keyword(s):  
Steady State ◽  
Detection Method ◽  
Tunable Filter ◽  
Harmonic Amplitude ◽  
Harmonic Suppression ◽  
Matlab Simulation ◽  
Harmonic Detection ◽  
Suppression Effect ◽  
Feedback Error ◽  
Adaptive Cancellation

When the active power filter (APF) and the tunable filter are used for specific harmonic suppression, the accurate single harmonic current detection module is one of the key links to ensure its harmonic suppression effect. An improved single harmonic detection method based on the principle of adaptive cancellation has been proposed, which does not have some of the problems of traditional algorithms, for instance the feedback error is not accurate enough, and the contradiction between tracking speed and steady-state accuracy. This method can accurately and quickly detect the harmonic amplitude and phase angle, and can be flexibly applied to the harmonic detection of three-phase and single-phase systems. Through theoretical analysis and MATLAB simulation, it is proved that the method can guarantee a higher steady-state accuracy and a faster tracking speed.

scholarly journals A rapid harmonic detection method for grid-connected photovoltaic when three-phase voltage is unbalanced

2021 ◽  
Author(s):  
Tiezhou Wu ◽  
An Wang ◽  
Yawen Xu
Keyword(s):  
Phase Angle ◽  
Detection Method ◽  
Positive Sequence ◽  
Harmonic Detection ◽  
Phase Voltage ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Negative Sequence ◽  
Three Phase ◽  
Low Pass

Abstract By using power electronic devices, photovoltaic grid-connected power generation may inject harmonics into the power system. As the photovoltaic grid-connected inverter has the same basic structure as the active power filter, so the unified control of the photovoltaic grid and active filtering can be achieved. When the current unified control system compensates harmonics of the grid side, it mainly uses ip-iq harmonic detection method, which is based on instantaneous reactive power theory. When the three-phase voltage is unbalanced, the method has a large voltage phase angle detection error and the signal of the low-pass filter tracking system is long, detection time delay and even failure occur. This paper proposes an improved fast harmonic detection method. When phase deviation or amplitude change occurs to the three-phase voltage, the positive and negative-sequence voltages are simultaneously park transformed. The negative-sequence component is filtered by the current average module to obtain the fundamental amount of the voltage, then the phase angle of the positive-sequence voltage is accurately calculated to improve the harmonic current detection accuracy. Through the study of the integral method, it is found that the least common multiple of each harmonic period can be used as the integral interval, and the integral value is also zero, so the detection delay time is reduced by replacing the low-pass filter with an integration module. The simulation results show that the proposed harmonic detection algorithm can accurately detect harmonics when the three-phase voltage is unbalanced, and about 0.057 s improve the harmonic detection speed compared with the commonly used ip-iq method.

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