Transient currents can severely impact the operation of weak or islanded grids. Inrush current electromagnetic compatibility challenges, due to their unpredictable and intermittent nature, are very difficult to identify. Using multi-point synchronised measurements, analysis is performed on an inverter. The supply powers various loads that are observed during cold start as well as under load switching conditions. Inrush event triggered failure probability is linked to non linear and average load levels.

In high-power industrial applications such as air-cooled condenser fans, excessive mechanical gear failures highlight a need to investigate possible alternatives. In this study, the concentric magnetic gear (CMG) is evaluated as a potential replacement for traditional mechanical gear. For a more objective comparison between the CMG and mechanical gear, a CMG is optimally designed in accordance with the performance specifications of an existing mechanical gear. The design is further refined for performance improvements taking into account mechanical strength requirements. Based on the design a CMG prototype is manufactured and experimentally evaluated against its mechanical counterpart under the same operating conditions. The performance of both gears achieved efficiency in the mid 90% range. The mechanical gear slightly outperformed the CMG under rated operating conditions. The large unbalanced magnetic forces within the CMG are likely responsible for the larger than expected no-load losses. With the advantage of overload protection, reduced maintenance requirements, the CMG could be a valid replacement for the mechanical gear.

Peak loads determine the rated capacity of islanded grid power supplies. This often results in non-optimal running conditions in terms of cost, efficiency or size footprint. Presented in this paper is a method of in-depth analysis of very fast submillisecond transient behaviour performed between sub-systems and supply in a low-inertia grids. Using this method, time domain measurements can be analysed to potentially achieve electromagnetic compatibility. Synchronised current and voltage measurements are possible, with offsets in the sub-milliseconds and high sample rates of tens of Mega-samples per second. A demonstration of a weak grid is presented showing effects of linear and non-linear loads on the supply source and power quality.

Increased power electronics converters on microgrid supplies result in large inrush currents which are not appropriately limited by present-day standards, especially devices commonly switched in large clusters. The currents drawn by switching large clusters, such as LED lights, or systems dominated by power electronics converters are shown by measurement as well as simulations to have worrying trends for electromagnetic compatibility. Superposition of currents from many low power devices, especially in low inertia micro-grids, can significantly impact the stability of the supply and may cause interference or high probability of complete grid failure.

Power systems and loads are becoming more complex with the implementation of micro-grids and non-linear power electronics loads. Intermittent and rapidly changing load and supply behavior calls for measurement strategies which are adaptable and able to comprehensively analyze new technical challenges. In this paper, such a device is presented, with measurement bandwidth of mega-samples per second and multiple channel and location measurement capabilities optimized for micro-grid and low frequency (DC -150 kHz). A micro-grid reliability test is conducted and presented where fast changing load conditions results in grid failure.