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To meet the zero-carbon electricity generation target as part of the sustainable development goals (SDG7), remote industrial microgrids worldwide are considering the uptake of more and more renewable energy resources, especially solar PV systems. Estimating the grid PV hosting capacity plays an essential role in designing and planning such microgrids. PV hosting capacity assessment determines the maximum PV capacity suitable for the grid and the appropriate electrical location for PV placement. This research reveals that conventional static criteria to assess the PV hosting capacity fail to ensure the grid’s operational robustness. It hence demands a reduction in the theoretical hosting capacity estimation to ensure grid compatible post-fault voltage and frequency recovery. Energy storage technologies, particularly fast-responsive batteries, can potentially prevent such undesirable scenarios; nevertheless, careful integration is required to ensure an affordable cost of energy. This study proposes a novel methodical techno-economic approach for an off-grid remote industrial microgrid to enhance the PV hosting capacity by integrating battery energy storage considering grid disturbance and recovery scenarios. The method has been validated in an industrial microgrid with a 2.6 MW peak demand in a ready-made garment (RMG) factory having a distinctive demand pattern and unique constraints in remote Bangladesh. According to the analysis, integrating 2.5 MW of PV capacity and a 1.2 MVA battery bank to offset existing diesel and grid consumption would result in an energy cost of BDT 14.60 per kWh (USD 0.1719 per kWh). For high PV penetration scenarios, the application of this method offers higher system robustness, and the financial analysis indicates that the industries would not only benefit from positive environmental impact but also make an economic profit.

The primary reason for interconnections among different power grids is to reduce the overall economic costs as well as increase reliability and security of supplying electricity services. Thus, for electrical power flow from one power system or grid to another power system or grid a simple, reliable and low cost interconnection is needed. In this paper, a flexible ac power transmission link technology has been proposed for linking two asynchronous independent power systems. The proposed flexible asynchronous ac link (FASAL) system essentially consists of a rotating transformer which is put in the ac tie line between two separate power systems or grids. It controls the power transmission between these power systems which are asynchronous under some or all operating conditions. The direction and the magnitude of power flow is controlled by controlling voltage and/or frequency. Simulink model of proposed FASAL system has been developed for the analytical study and the result verifies the power transfer capability of the proposed system. Index Terms--Flexible asynchronous ac link, power system interconnection, transfer of power, freely rotating asynchronous machine.

For early fault detection and health monitoring of low speed machines the instantaneous angular speed (IAS) measurement with high resolution and accuracy is required. The results show that IAS measurement is much more superior to the conventional methods i.e. analyzing acoustic waveforms, temperature variations, and vibrations etc. However accurate IAS measurement becomes very difficult due to slow and noisy response of the rotary transducers for low speed rotating machines. In the proposed technique, a fast rotating magnetic field (RMF) is used to measure the IAS for low-speed machines. An independent ac source is used to generate a balanced threephase ac voltage, which is applied to the stator windings of a synchro whose rotor is coupled with the rotating member or rotor of a motor. The RMF in the air gap generates emf in the rotor of synchro whose frequency depends upon the slip speed. Since the RMF revolves at a speed, several times the speed of the rotating member or the rotor of motor, hence the IAS measurement becomes very fast and accurate. The proposed scheme is tested successfully for instantaneous change of speed within a range of 0 to 2 rpm.

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