This paper presents the design and implementation of iPONICS: an intelligent, low-cost IoT-based control and monitoring system for hydroponics greenhouses. The system is based on three types of sensor nodes. The main (master) node is responsible for controlling the pump, monitoring the quality of the water in the greenhouse and aggregating and transmitting the data from the slave nodes. Environment sensing slave nodes monitor the ambient conditions in the greenhouse and transmit the data to the main node. Security nodes monitor activity (movement in the area). The system monitors water quality and greenhouse temperature and humidity, ensuring that crops grow under optimal conditions according to hydroponics guidelines. Remote monitoring for the greenhouse keepers is facilitated by monitoring these parameters via connecting to a website. An innovative fuzzy inference engine determines the plant irrigation duration. The system is optimized for low power consumption in order to facilitate off-grid operation. Preliminary reliability analysis indicates that the system can tolerate various transient faults without requiring intervention.

The development of large-scale photovoltaic (PV) plants in rural areas is constantly increasing. However, the knowledge of performing and installing lightning and surge protection in large-scale PV plants is still premature. The main objective of this paper is to provide a method for assessing the external lightning protection and earthing designs that may be installed in large-scale solar applications. Consequently, the method and models presented in this paper may assist engineers to perform a comparison between the use of isolated and nonisolated lightning protection systems, and second to select suitable surge protection equipment.

The presence of direct current (DC) offset and harmonics–interharmonics (HIHs) in grid voltage input signal of phase‐locked loop (PLL) results in inaccurate controller response. The inaccuracies are due to the low‐ and high‐frequency oscillations that appear in the PLL estimated phase, amplitude and frequency. The suppression of fundamental frequency oscillations caused by DC offset (DO) in the input voltage signal must be carried out without compromising the dynamic response of the system. The use of low‐pass filters, for example, results in undesirable, slow response. This study proposes an accurate and fast decoupling of fundamental frequency oscillations using a mathematic‐cancellation decoupling cell. Higher‐frequency oscillations generated by HIHs are eliminated by a different harmonic compensation network (HCN) that is also proposed in this study. The performance of conventional techniques is limited because they eliminate only specifically selected harmonics. The proposed PLL, however, eliminates any number of HIHs present in the grid with the least computational complexity and without any prior knowledge. Furthermore, its advanced features provide accurate synchronisation under any abnormal grid condition at the lowest computational complexity when compared with the existing state‐of‐the‐art PLLs. The advanced performance of the proposed HIHDO‐PLL is verified through simulation and experimental results.