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

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.

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Manop Yingram ◽  
Suttichai Premrudeepreechacharn

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.


Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2474 ◽  
Author(s):  
Menghua Liu ◽  
Wei Zhao ◽  
Qing Wang ◽  
Songling Huang ◽  
Kunpeng Shi

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.


2013 ◽  
Vol 732-733 ◽  
pp. 646-652
Author(s):  
Jian Liu ◽  
Hou Hui Fang ◽  
Xian Feng Li

This paper puts forward a novel islanding detection method based on q-axis disturbance signal injection. This method, by introducing q-axis disturbance signal injection, makes the RLC load generate frequency offset to detect the island in the case that the power network is disconnected due to certain fault.The introduced q-axis disturbance signal injection method is connected with reactive power variation and frequency variation whose values are close to zero when photovoltaic system is operated in grid-connected mode. Therefore, the suggested method has the advantage of tiny harmonic distortion and good power quality. The simulation results based on the MATLAB/Simulink software show that the novel islanding detection method can detect the island in 1 second and has little effects on the system under the condition of the set parameters.


2013 ◽  
Vol 318 ◽  
pp. 597-600
Author(s):  
Dong Xie ◽  
Xing Zhang

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.


2021 ◽  
Vol 71 (5&6) ◽  
pp. 91
Author(s):  
Dong Xie ◽  
Dajin Zang ◽  
Peng Gao ◽  
Junjia Wang ◽  
Zhu Zhu

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.


2013 ◽  
Vol 748 ◽  
pp. 453-456
Author(s):  
Chen Xin Li ◽  
Qi Ping Yuan

Islanding detection is a very essential function for a photovoltaic grid-connected system. Islanding phenomenons not only damage to equipment, but also endanger to the safety of the maintenance personnel. Passive islanding detection methods that use alone have considerable non-detection zone (NDZ); active islanding detection methods that use alone are that join disturbance to system, but the disturbance will cause system instability [1]. In this paper, an over/under voltage and over/under frequency detection method combines with an improved active power perturbation detection method are proposed. The photovoltaic system can be reduced non-detection zone (NDZ) with improved the power quality and reduced the total harmonic distortion (THD) through this method.


2012 ◽  
Vol 614-615 ◽  
pp. 815-818
Author(s):  
Xue Song Zhou ◽  
Jia Rui Wu ◽  
You Jie Ma

With the increasing of the capacity of grid-connected photovoltaic (PV) power system, islanding detection becomes more prominent and significant. At present, islanding detection methods used in grid-connected photovoltaic system can be divided into passive detection methods and active detection methods these two categories, which can also be divided into a variety of methods. This paper shows a comprehensive review of islanding detection methods, classifies the methods of islanding detection, analyzes the principles and characteristics of various islanding detection methods, indicates their appropriate situations, and pointes out the prospect of islanding detection methods. In practical applications, according to the actual situation, selects one or more islanding detection methods can attain better detection effect.


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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