Table 3 Comparison of signal processing methods
From: Shifting of research trends in islanding detection method - a comprehensive survey
Signal processing method | Ref. | DG type | Multiple DG considered | Analyzed signal | Run on time | Strength of the method | Shortcoming of the method |
|---|---|---|---|---|---|---|---|
CWT | 63 | – | – | Target DG voltage | 0.6 | Coefficients for all scales and transformations is obtained | Computational burden |
DWT | 65 | PV | No | PCC voltage | 17–26 ms | Better low frequency resolutions | Computational complexity |
67 | PV | No | PCC frequency | 2.5 power freq cycle | |||
68 | PV | No | Target DG voltage | 2.5Â cycle (0.05Â s) | |||
WPT | 74 | Wind | No | ROCOP at DG | 200Â ms | Equal resolution for low and high frequency | Time-frequency localization decrease with increase in decomposition levels. |
ST | 73 | PV and wind | Yes | PCC voltage negative sequence | 26Â ms | Provides simplified multiresolution | Fails in localization of momentary phenomenon |
77 | PV, fuel cell and wind | Yes | PCC voltage negative sequence | – | |||
HST | 71 | PV, fuel cell and wind | Yes | PCC voltage | – | Better time and frequency resolutions for high and low frequency | Window may not incorporate all signals |
73 | PV and wind | Yes | PCC voltage negative sequence | 22Â ms | |||
TTT | 71 | PV, fuel cell and wind | Yes | PCC voltage | – | Better understanding of time-local properties of the time series | Inappropriate low-frequency Localization |
73 | PV and wind | Yes | PCC voltage negative sequence | 25Â ms | |||
HHT | 84 | Inverter based | Yes | PCC voltage | Less than 2Â cycles | Provides physical representation of data | Less suitable for close frequency components signals |
MM | 73 | PV and wind | Yes | PCC voltage negative sequence | 22Â ms | Less computational complexity | Reconstruction of the original signal is not possible |