Active anti-islanding method for PV system using reactive power control

Wavelet-Based Islanding Detection in Grid-Connected PV Systems

“…In this case, a controlled disturbance is introduced at the PCC, and when the islanding condition occurs, the disturbance forces the detection method threshold [28], [29], and as a consequence, the NDZ is minimized or avoided. Diverse methods, such as impedance measurement or detection [30]- [32], slip-mode frequency shifting (SMS) [33], active and reactive power variations [34], and active frequency drift [35], have been proposed; however, as drawbacks, they introduce a disturbance at the PCC, and interaction between DPGSs must be considered [36]. Hybrid methods combine the effectiveness of passive and active approaches and can be applied as an alternative [37].…”

Islanding detection scheme for distributed generation systems using modified reactive power control strategy

“…In order to drive the frequency to OUF threshold during islanding, many active detection techniques are proposed in the literature. The harmonic current injection and harmonic distortion-based technique [5,10], active frequency drift [11], frequency shift [12,13], impedance detection [14], automatic phase shift [15], Sandia voltage shift [16], correlation-based technique [17], negative sequence current injection [18], and reactive power variation [19,20] are significant contributions to the active islanding detection techniques. Among active detection techniques, the techniques based on the objective of varying the reactive power output of the controller are the effective ways to drive the frequency to hit its OUF threshold.…”

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

“…Figure 1 shows the circuit diagram of the grid-connected inverter for ESS with a critical load. When an islanding occurs the inverter for ESS should detect the islanding within 2 seconds and disconnect the inverter from the grid according to IEEE 1547 and 929 standards [2][3][4][5]. During the clearing time the magnitude and frequency of voltage across the critical load may vary as shown in Figure 2, since the voltage is determined by the amount of the injected power and load condition.…”