scholarly journals An Irregular Current Injection Islanding Detection Method Based on an Improved Impedance Measurement Scheme

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2474 ◽  
Author(s):  
Menghua Liu ◽  
Wei Zhao ◽  
Qing Wang ◽  
Songling Huang ◽  
Kunpeng Shi
Keyword(s):  
Distributed Generation ◽  
Detection Method ◽  
Impedance Measurement ◽  
Current Injection ◽  
Detection Methods ◽  
Impedance Change ◽  
Islanding Detection ◽  
Measurement Scheme ◽  
Voltage Change ◽  
Injection Methods

One class of islanding detection methods, known as impedance measurement-based methods and voltage change monitoring-based methods, are implemented through injecting irregular currents into the network, for which reason they are defined in this paper as irregular current injection methods. This paper indicates that such methods may be affected by distributed generation (DG) unit cut-in events. Although the network impedance change can still be used as a judgment basis for islanding detection, the general impedance measurement scheme cannot separate island events from DG unit cut-in events in multi-DG operation. In view of this, this paper proposes a new islanding detection method based on an improved impedance measurement scheme, i.e., dynamic impedance measurement, which will not be affected by DG unit cut-in events and can further assist some other equipment in islanding detection. The simulations and experiments verify the stated advantages of the new islanding detection method.

scholarly journals Compatibility Issues with Irregular Current Injection Islanding Detection Methods and a Solution

Energies ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1467 ◽  
Author(s):  
Liu ◽  
Zhao ◽  
Wang ◽  
Huang ◽  
Shi
Keyword(s):  
Fundamental Frequency ◽  
Distributed Generation ◽  
Phase Difference ◽  
High Frequency ◽  
Low Frequency ◽  
Current Injection ◽  
Detection Methods ◽  
Islanding Detection ◽  
Injection Methods ◽  
Terminal Voltage

Islanding detection methods, based on injecting high-/low-frequency currents or negative sequence fundamental frequency currents and observing the resultant responses, are collectively referred to as irregular current injection methods in this paper. In multi-distributed generation (DG) operation, if there is no restriction to the phase of injected irregular currents, the currents at the same frequency may cancel each other out, and then their convergent current may be too small to cause a detectable response, for which reason islanding detection will be severely affected. Accordingly, this paper raises a compatibility issue, which requires the phase difference between any two injected irregular currents to be within a certain interval. In response to this issue, a solution is proposed. According to this solution, the terminal voltage of DG units is referenced to conduct irregular currents injection, and only certain high-frequency currents are used as injected currents. If this solution is adopted by as many manufacturers as possible, the effect and reliability of such methods will be greatly improved.

scholarly journals Over/Undervoltage and Undervoltage Shift of Hybrid Islanding Detection Method of Distributed Generation

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Manop Yingram ◽  
Suttichai Premrudeepreechacharn
Keyword(s):  
Control System ◽  
Distributed Generation ◽  
Hybrid Method ◽  
Detection Method ◽  
System Simulation ◽  
Detection Methods ◽  
Islanding Detection ◽  
Active Method ◽  
Passive Method ◽  
Simulation Results

The mainly used local islanding detection methods may be classified as active and passive methods. Passive methods do not perturb the system but they have larger nondetection zones, whereas active methods have smaller nondetection zones but they perturb the system. In this paper, a new hybrid method is proposed to solve this problem. An over/undervoltage (passive method) has been used to initiate an undervoltage shift (active method), which changes the undervoltage shift of inverter, when the passive method cannot have a clear discrimination between islanding and other events in the system. Simulation results on MATLAB/SIMULINK show that over/undervoltage and undervoltage shifts of hybrid islanding detection method are very effective because they can determine anti-islanding condition very fast.ΔP/P>38.41% could determine anti-islanding condition within 0.04 s;ΔP/P<-24.39% could determine anti-islanding condition within 0.04 s;-24.39%≤ΔP/P≤ 38.41% could determine anti-islanding condition within 0.08 s. This method perturbed the system, only in the case of-24.39% ≤ΔP/P ≤38.41% at which the control system of inverter injected a signal of undervoltage shift as necessary to check if the occurrence condition was an islanding condition or not.

A Novel Islanding Detection Method for Inverter-Based Distributed Generation Systems

2013 ◽  
Vol 318 ◽  
pp. 597-600
Author(s):  
Dong Xie ◽  
Xing Zhang
Keyword(s):  
Power Quality ◽  
Distributed Generation ◽  
Detection Method ◽  
Detection Methods ◽  
Islanding Detection ◽  
Generation System ◽  
Detection Zone ◽  
Renewable Energy Technologies ◽  
Energy Technologies

In the area of renewable energy technologies, islanding of distributed generation system needs to be prevented due to safety reasons and to ensure quality of power supplied to the customers. Several islanding detection methods based on passive and active schemes have been proposed in the literature. Passive methods have a large non detection zone (NDZ), While active schemes degrade power quality. This paper proposed a new passive islanding detection method which combines the Wavelet-transform and neural network techniques. This method can reduce the NDZ to zero without any perturbation that deteriorates the power quality. The simulation results show that the proposed islanding detection method is effective and robust in all kind of conditions.

scholarly journals Research on a novel passive islanding detection method

2021 ◽  
Vol 71 (5&6) ◽  
pp. 91
Author(s):  
Dong Xie ◽  
Dajin Zang ◽  
Peng Gao ◽  
Junjia Wang ◽  
Zhu Zhu
Keyword(s):  
Distributed Generation ◽  
Bp Neural Network ◽  
Detection Method ◽  
Electric Energy ◽  
Detection Methods ◽  
Islanding Detection ◽  
Characteristic Parameters ◽  
Detection Zone ◽  
Voltage Signal ◽  
Simulation And Experiment

In distributed generation systems, islanding detection is a necessary function of grid-connected inverters. In view of the performance disadvantages of traditional passive and active islanding detection methods, this paper proposes a novel passive islanding detection method. The proposed method first extracts characteristic parameters from the inverter output voltage signal and inverter output current signal through lifting wavelet transform, and then conducts the pattern recognition of these extracted characteristic parameters via BP neural network, so as to judge if there is an islanding phenomenon. As verified by the simulation and experiment results, the islanding detection method proposed in this paper is effective, and is featured by high detection speed and small non-detection zone, without affecting electric energy quality; its detection performance has been remarkably improved in comparison with that of traditional islanding detection methods.

scholarly journals The Improvement of an Islanding Detection Method Based on the Perturbation Signal in Case of a Multi-Photovoltaic Operation

2019 ◽  
Vol 9 (19) ◽  
pp. 4054 ◽  
Author(s):  
Thanh Son Tran ◽  
Duc Tuyen Nguyen ◽  
Goro FUJITA
Keyword(s):  
Distributed Generation ◽  
Significant Influence ◽  
Detection Method ◽  
Photovoltaic System ◽  
Detection Methods ◽  
Islanding Detection ◽  
Mathematical Explanations ◽  
Promising Solution ◽  
Simulation Results ◽  
Signal Cancellation

Islanding phenomenon is one of the consequences of the emergence and development of microgrids in the power system. Injected signal cancellation is a common problem in a multi- distributed generation that has a significant influence on active islanding detection methods. In this study, this issue was analyzed by injecting a perturbation signal in the multi-photovoltaic system. Furthermore, the promising solution to eliminate injected signal cancellation was proposed in this paper. The solution was validated through mathematical explanations and simulation results.

scholarly journals A Test Device for Optimize PMU-Based Islanding Detection Technology

2015 ◽  
Vol 10 (2) ◽  
Keyword(s):  
Power Systems ◽  
Power Plants ◽  
Detection Method ◽  
Detection Methods ◽  
Islanding Detection ◽  
Algorithm Optimization ◽  
Test Device ◽  
Photovoltaic Power ◽  
Detection Technology ◽  
Bulk Power

Islanding detection is a necessary function for grid connected distributed generators. Usually, islanding detection methods can be classified as two catalogues: remote detecting methods and local detecting methods. Most of them have limitation and defects when they are applied in photovoltaic power stations. Recently synchronous phasor measuring units (PMU) is proposed to be applied for islanding detecting. Although the islanding detection method is supposed to be applied for traditional bulk power systems, it is also suitable for renewable generation power plants. To do this islanding detection will be implemented on central management unit of photovoltaic power station instead of on grid-tied inverters as traditionally. In implementing, the criteria of this method and the threshold of algorithm are needed to be optimized. This paper develops a test device which can optimize PMU-based islanding detection technology to validate the proposed islanding detection method applying in PV station. Then using simulation to discuss how to set a reasonable threshold for the researched islanding detection method applied in PV stations. Finally the paper provides a platform for the algorithm optimization.

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