Distributed Generation (DG) has changed the power generation system to small-scale instead of large-scale generation. The demanding issue with the interconnection of DG is the detection of unintended islanding in a network. Several methods proposed in the literature show drawbacks such as high non-detection zones (NDZ) and higher tripping time. In this paper, the IEEE 13 bus distribution network with DGs like wind and solar power plants is integrated at two buses. Islanding is detected by utilizing data from a micro-synchrophasor located at the distribution grid and the DG. The micro-synchrophasor-based unintended islanding detection algorithm is based on parameters such as voltage, rate of change of voltage, frequency, rate of change of frequency, voltage phase angle difference and the rate of change of the voltage phase angle difference between the utility and the islanded grid. The proposed islanding detection algorithm discriminates between islanding and non-islanding conditions and is highly efficient under zero power mismatch conditions. The proposed method has null NDZ and satisfies the IEEE 1547 standard for DG tripping time. The effectiveness of the proposed IDM was verified when there are multiple DGs in the islanded grid. Also, the proposed method does not require additional hardware as it can be incorporated in digital relays with synchrophasor functionality.
Summary
This paper presents a simple and effective method for detection of complex power quality disturbances using S‐transform amplitude matrix. In this work, classification of complex power quality disturbances has been implemented using a rule‐based decision tree for different noise levels, such as with no noise, 30‐dB noise, and 45‐dB noise. The S‐transform is distinct, which provides a frequency‐dependent resolution with direct relationship to the Fourier spectrum. The features obtained from S‐transform amplitude matrix are dissimilar, clear, and immune to noise. According to a rule‐based decision tree, 7 types of single power disturbance and 16 types of complex power disturbance are well identified in this work. The proposed work is simulated using MATLAB simulation, and the various results are found, which detect the single and complex power quality disturbances; and it proves that the proposed method is effective and unaffected against noise.
New modified carrier‐based level shifted pulse width modulation approaches for single‐phase trinary dc source fed cascaded H‐bridge inverters are proposed in this article. In order to suppress the lower order harmonics, the carrier frequency is often tuned higher. However, switching and electromagnetic interference (EMI) problems have a significant influence on the functioning and controlling of the inverter at higher carrier frequency ranges. A new carrier is designed to address the aforementioned issues. To prove the effectiveness of the proposed carrier, this paper provides comparison results of conventional triangular carrier and a new developed carrier. Furthermore, utilizing the most popular phase disposition (PD) level shifted pulse width modulation approach with a new carrier with the similar modulation indices and switching frequency, to improve the fundamental voltage magnitude and shift the dominant harmonics into three times that of the existing traditional carrier‐based level shifted pulse width modulation approaches. The effectiveness and feasibility of the proposed new modified carrier‐based level shifted pulse width modulation approach have been proven by using MATLAB simulation and prototype results.
The metamaterial sensor antenna is numerically designed to detect breast cancer using breast cancer cell lines, especially relying on the electrical characteristics of breast cancer cells, and designed antenna is measured and the results are observed. The metamaterial sensor antenna is a simple and efficient antenna which is designed using the Minkowski fractal curve with a ring-shaped Split Ring Resonator (SRR). The SRR is chosen because of its inductive and capacitive resonating properties. In addition, the Minkowski fractal curve is used as a defective ground structure to improve sensor sensitivity and selectivity. The numerical investigations are based on different iterations of the Minkowski fractal curve. In that iteration, the third iteration of the Minkowski fractal gives better results. The designed antenna is tested with breast cancer cell lines, and it resonates at a frequency of 2.35, 2.42, and 2.52 GHz for different dielectric constants and conductivity. The simulated design antenna is tested with different cancer cell lines like MDA-MB-231, MCF-7, and HS758-T to ensure its performance and selectivity. The measured result of the fabricated antenna shows that the antenna design resonates at the same frequency as the simulated antenna results.
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