Voltage and current waveform distortion are more prevalent on power systems today related to nonlinear loads. The proliferation of loads of this kind and their interaction with the power supply system is increasing the need to use power monitoring equipment to evaluate electric power quality. Measurements show that waveform harmonics and unbalance are variable over time due to changes in load conditions and in the system configuration. Thus, the electrical engineer has a large amount of data available from each phase, acquired using commercial Analyzers. Therefore, it is necessary to find ways to characterize this group of recorded data, to allow proper evaluation of the situation. Two indices, which can be calculated with these measurements, are proposed in this work: a three-phase total demand distortion index and a total unbalance index. In addition, this paper proposes an easy way to characterize the time-varying data to simplify their representation. The exposed procedures are applied to the data registered from an electrical power system, to show the performance of the proposed methods.

This work proposes a means of reducing maritime transport emissions by combining electric ship propulsion with waste heat recovery systems. This solution was derived from the application of a literature-review based methodology, the findings of which were formulated as a paradigm consisting of a combination of electric ship propulsion with MVDC networks and waste heat recovery systems. This paradigm was then validated through modelling and simulation. Real-time simulations were deployed to evaluate the integration of the heat recovery system, specifically an Organic Rankine Cycle, into the MVDC network of the ship. The results of the simulations showed that an appropriate design of the DC network topology and control system is required for the ship to perform correctly under any scenario. It was concluded that replacing the passive rectifiers of the generators with controlled rectifiers improved the voltage profile of the MVDC network. In addition, it was inferred that the design of the global controller is essential for the integration of the heat recovery system.

The instantaneous reactive power theory (IRPT) has long been utilized for load compensation through active power line conditioners (APLCs). IRPT effectively divides the current vector into two components: the instantaneous power current and the instantaneous reactive current. Among these components, only the former is necessary to transfer instantaneous real power to the load. However, the commonly adopted approach faces challenges when extended to multi-phase systems and their compensation strategy design. This challenge is particularly pertinent today due to the consensus that treating a three-phase system with a neutral wire as a four-conductor system is more appropriate. This paper introduces a formulation of IRPT tailored for multi-phase systems within the framework of geometric algebra (GA). GA is a mathematical structure that defines a single power variable, the instantaneous power multivector, encompassing both instantaneous real power and instantaneous reactive power within a unified mathematical entity. The current components can be directly derived from this power multivector. Additionally, this paper establishes a connection with the original p-q formulations and lays the foundations for time-instantaneous compensation (TIC) and time-average compensation (TAC). Finally, to validate the proposed model, simulation and experimental results from a three-phase four-wire industrial system using a novel approach are presented.