An Islanding Detection Method for Inverter-Based Distributed Generators Based on the Reactive Power Disturbance

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.

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A Nondestructive Islanding Detection Method Based on Adaptive and Periodic Disturbance on Reactive Power Output of Inverter-Based Distributed Generation

Journal of Applied Mathematics ◽

10.1155/2014/132348 ◽

2014 ◽

Vol 2014 ◽

pp. 1-11 ◽

Cited By ~ 2

Author(s):

Xiaolong Chen ◽

Yongli Li

Keyword(s):

Distributed Generation ◽

Power Output ◽

Reactive Power ◽

Detection Method ◽

Test System ◽

Rate Of Change ◽

Islanding Detection ◽

Unity Power Factor ◽

Periodic Disturbance ◽

Strategy Transformation

In order to detect islanding nondestructively, an islanding detection method for microgrid is proposed based on adaptive and periodic disturbance on the reactive power output of inverter-based distributed generation (DG). The first two parts of the disturbance in a cycle form a symmetric triangular shape and the disturbance can adaptively adjust its peak value and cycle time for two purposes. One is to minimize the total amount of the disturbance. The other is to guarantee that the absolute value of the rate of change of frequency (ROCOF) is constant during islanding, which can be utilized to be a criterion to detect islanding. The method can be applied on the DG either operating at a unity power factor or generating both active and reactive power simultaneously. Moreover, it helps to avoid the serious transient process during control strategy transformation of the DG for microgrid islanded operation. According to the anti-islanding test system in the IEEE Std. 929-2000 and IEEE Std. 1547-2003, several study cases are carried out in the PSCAD/EMTDC environment. The simulation results show that the proposed method can detect islanding rapidly and nondestructively. Moreover, it also performs effectively for the system with multiple DGs.

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Grid Connected Inverter for Current Control by Using Anti-Islanding Technique

International Journal of Power Electronics and Drive Systems (IJPEDS) ◽

10.11591/ijpeds.v9.i2.pp926-932 ◽

2018 ◽

Vol 9 (2) ◽

pp. 926

Author(s):

B V Rajanna ◽

K S Srikanth

Keyword(s):

Critical Loads ◽

Reactive Power ◽

Detection Method ◽

Current Control ◽

Control Mode ◽

Islanding Detection ◽

Voltage Variation ◽

Clearing Time ◽

Indirect Current Control ◽

Grid Connected Inverter

The inverter with critical loads should be able to provide critical loads with a stable and seamless voltage during control mode change as well as clearing time. The indirect current control has been proposed for providing stable voltage with critical load during clearing time and seamless control mode transfer of inverters. However, the islanding detection is difficult since with the indirect current control the magnitude and frequency of voltage do not change when the islanding occurs. The conventional anti-islanding method based on the magnitude and frequency of voltage variation cannot apply to the indirect current control. This paper proposes an islanding detection method for the indirect current control. The proposed islanding detection method can detect the islanding using reactive power perturbation and observation when the frequency and magnitude of voltage don’t vary during clearing time. In order to verify the proposed anti-islanding method, the experimental results of a 600W three-phase inverter are provided.

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