• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.9
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• pp.1315-1322
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• 2015

This paper proposes an active islanding detection method for the BESS (Battery Energy Storage System) with 3-phase inverter which is connected to the AC grid. The proposed method adopts the DDSRF (Decoupled Double Synchronous Reference Frame) PLL (Phase Locked-Loop) so that the independent control of positive-sequence and negative-sequence current is successfully carried out using the detected phase angle information. The islanding state can be detected by sensing the variation of negative-sequence voltage at the PCC (Point of Common Connection) due to the injection of 2-3% negative-sequence current from the BESS. The proposed method provides a secure and rapid detection under the variation of negative-sequence voltage due to the sag and swell. The feasibility of proposed method was verified by computer simulations with PSCAD/EMTDC and experimental analyses with 5kW hardware prototype for the benchmark circuit of islanding detection suggested by IEEE 1547 and UL1741. The proposed method would be applicable for the secure detection of islanding state in the grid-tied Microgrid.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1684-1686
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• 2005

As photovoltaic(PV) power generation systems become more common, it will be necessary to investigate islanding detection method for PV systems. Islanding of PV systems can cause a variety of problems and must be prevented. However, if the real and reactive power of load and PV system are closely matched, islanding detection by passive methods becomes difficult. Also, most active methods lose effectiveness when there are several PV systems feeding the same island. The active frequency drift positive feedback method(AFDPF) enables islanding detection by forcing the frequency of the voltage in the island to drift up or down. In this paper the research for the minimum value of chopping fraction gain applied digital phase-locked-loop(DPLL) to AFDPF considering output power quality and islanding prevention performance are performed by simulation and experiment in IEEE Std 929-2000 islanding test.

• Journal of IKEEE
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• v.22 no.3
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• pp.539-547
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• 2018

Grid-connected inverter is required to cut off the power supplied to the grid at the islanding condition, immediately. For this reason, an islanding detection is an indispensable function for grid-connected distributed generation system. Slip-Mode frequency Shift (SMS) islanding detection method is very popular method to determine the grid state. SMS method supplies the reactive power to the load according to the grid frequency. In the islanding condition of grid, this injected reactive power pulls out the grid frequency from the allowable range, then the inverter system can detect the islanding condition of the grid. The SMS method can detect the islanding state well and does not generate any harmonics of the grid current. However, the reactive power would be generated and the power quality is reduced even though the grid is not islanding condition, but normal condition. In this paper, a modified SMS method is proposed to remove the reactive power in the normal condition. The performance of the proposed method is evaluated by 600W single phase inverter experimental results.

• 한국태양에너지학회:학술대회논문집
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• 2009.11a
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• pp.297-302
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• 2009

As the grid-connected photovoltaic power conditioning systems (PVPCS) are installed in many residential areas, these have raised potential problems of network protection on electrical power system. One of the numerous problems is an Islanding phenomenon. In this paper, active frequency drift (AFD) method, one of the anti-islanding analyzed by current magnitude compensation and calculation of RMS value of the output power.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.634-636
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• 2008

This paper proposes a frequency detection method based on an advanced zero-crossing technique. Zero-crossing method for detecting frequency is one of the most widely used methods today. Although it is simple to apply, it requires extra hardware in implementation due to its limitations in accuracy. The proposed method models the error generated during zero crossing linearization and compensated for it in real time which makes it simple and accurate. The validity of the method and its applicability in anti-islanding detection of distributed generators was confirmed through simulation.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.555-558
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• 2002

The general ways of the anti-islanding can be classified into the active method and passive method. The passive method which use only the voltage information when power failure occurs has much possibility of the wrong detection. And the active method detects the change of the voltage frequency as instantaneously changing the frequency of the inverter output current. Therefore, in this paper, the method to inject arbitrary order harmonics into controlled current is proposed. In this method islanding can be detected by measuring the amount of load voltage of injected harmonics order. And as a current control method predictive control method is used, which make actual current accurately to track reference current by Instantaneously computing converter output voltage and has fast response in transient state. This parer proposed method was verified by simulation.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.4
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• pp.57-62
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• 2010

Renewable energy and smart grid become the focus of attention of industry. The smart grid is an intelligent system which maximizes the efficiency of energy and it needs to monitor the amount of power generation and power consumption continuously. Remote Monitoring System(RMS) is very useful for monitoring the power generation and consumption, but mostly they are implemented on the wire communication. In this paper, we propose a wireless sensor network based remote power monitoring system. And as an application, a new anti-islanding method with the proposed RMS is presented. An experimental micro grid system is implemented to verify the proposed RMS and anti-islanding method.

• Proceedings of the KIEE Conference
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• summer
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• pp.217-219
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• 2004

The installation of small sized dispersed generation(DG) units operating in parallel with the utility supply presents several technical problems for the protection and control of the system. One of the critical concerns is the occurrence of islanding. Hence, this paper propose the Digital Universal Relay(DUR) including anti-islanding function as DG interconnection interface. The existent islanding detection algorithms are examined. And the most effective and reliable method of those is modified for DUR application. The modified algorithm is evaluated through the modeling of the test system by PSCAD/EMTDC.

• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.2
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• pp.160-167
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• 2009

To detect islanding mode when the grid is being tripped is a major safety issue in the Utility Interactive Photo Voltaic (UIPV) system. In this paper, analytical design method is suggested for AFD & RPV method under IEEE 929-2000 recommended islanding test condition. We have discussed that there is a same point. we injected reactive component of the current by AFD & RPV methods, but the current reference generated is other waveform. Possible if amount of reactive components in this methods are same each method, there is happened same rates frequency variation. To verify the validity of the analytical comparison, this paper presents simulation and experimental results from single phase, 3[kW] inverter for the transformerless UIPV system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.1
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• pp.127-136
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• 2013

The islanding detection and prevention function in the important performance of the grid-connected inverter is the essential details which should be considered for worker's safety to maintain the system. This paper tries to suggest the active frequency shake islanding detection technique in the grid-connected PV generation system using sunlight. The existing active frequency drift method algorithm is described to suggest active frequency shake method algorithm. And, the algorithm which can reduce the non-detection zone, improve THD, and improve the detection speed in comparison with the existing algorithm is suggested. And we applied the proposed algorithm to the 3kW grid-connected photovoltaic inverter generation and verified the feasibility of the technique through the simulation and experiments.