Small craft. Electrical systems. Extra-low-voltage d.c. installations

2017 ◽  
Keyword(s):  
Low Voltage ◽  
Electrical Systems ◽  
Small Craft

scholarly journals A Systematic Method for the Design of Earthing System for Low-voltage Installations

2019 ◽  
Vol 8 (3S) ◽  
pp. 12-15
Keyword(s):  
Low Voltage ◽  
Low Cost ◽  
Computer Software ◽  
National Standards ◽  
Design Parameters ◽  
Electrical Systems ◽  
Fault Currents ◽  
Standards And Regulations ◽  
Earthing Systems ◽  
Industry Needs

Earthing system plays an essential role in electrical systems in terms of safety for people in the vicinity against the hazard of electric shocks as well as protection and proper operation of equipment during the incidence of electric faults by providing a low-impedance path that can dissipate fault currents to the conductive mass of earth. Engineers are faced with the design of adequate earthing systems that comply with national standards and regulations which apparently incorporate a variety of earthing methods and various formulae to obtain the design parameters such as the earthing resistance and conductor size. Manual calculation of such parameter makes the design quite laborious, tedious, and time-consuming but could conceivably be performed much quicker by a computer software. This paper presents a proposed step-by-step approach for the design of a reliable and effective earthing system for low-voltage installations. The main objective of this work is to develop a computer-aided and easy-to-use template which could be useful for industry practitioners in Malaysia who are responsible with earthing system design. A simple auto calculation software template was developed using Microsoft Excel spreadsheet. The template was tested by a consulting company in order to meet their industry needs. The developed template provides a technically acceptable computer simulation and yet a low-cost solution to the complex issue of effective design of earthing systems for low-voltage installations.

scholarly journals The Short-Circuit Protections in Hybrid Systems with Low-Power Synchronous Generators

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 160
Author(s):  
Bartosz Rozegnał ◽  
Paweł Albrechtowicz ◽  
Dominik Mamcarz ◽  
Natalia Radwan-Pragłowska ◽  
Artur Cebula
Keyword(s):  
Single Phase ◽  
Low Voltage ◽  
Short Circuit ◽  
Circuit Breaker ◽  
Synchronous Generator ◽  
Synchronous Generators ◽  
Electrical Systems ◽  
Protection Devices ◽  
Short Circuits ◽  
Damage Type

Single-phase short-circuits are most often faults in electrical systems. The analysis of this damage type is taken for backup power supply systems, from small power synchronous generators. For these hybrid installations, there is a need for standard protection devices, such as fuses or miniature circuit breaker (MCB) analysis. Experimental research mentioned that a typical protective apparatus in low-voltage installations, working correctly during supplying from the grid, does not guarantee fast off-switching, while short-circuits occur during supplication from the backup generator set. The analysis of single-phase short-circuits is executed both for current waveform character (including sub-transient and transient states) and the carried energy, to show the problems with the fuses and MCB usage, to protect circuits in installations fed in a hybrid way (from the grid and synchronous generator set).

State Measurement System for Control of Soft Actuator Made by Prestressed Super Elastic Alloy

2014 ◽  
Author(s):  
Yuya Suzuki ◽  
Atsushi Sakuma ◽  
Taichi Nozawa
Keyword(s):  
Measurement System ◽  
Low Voltage ◽  
Electric Resistivity ◽  
Soft Actuator ◽  
Electrical Systems ◽  
Heating And Cooling ◽  
Linear Behavior ◽  
State Measurement ◽  
Non Linear ◽  
Temperature Strain

Super elastic alloy (SEA) has the characteristic of two-way deformation by heating and cooling under prestressed condition. The characteristic makes it possible to realize an actuator of flexible, compact, and quiet. Therefore, SEA can be applied to such robots for medical, assist, welfare, automatic door, and so on. However, there are many difficulties in its control as actuator because SEA shows strong non-linear behavior on its deformation process. In this study, the measurement system of state quantities on the non-linear characteristics of SEA is constructed to control the deformation of it as practical actuator. Here, the actuator made by SEA is heated by electric current. And then, electrical systems are also developed to measure the state quantities of temperature, strain and electric resistivity of SEA during the Joule heating for its mechatronical control. In addition, the measurement of the electric resistivity on the process of heating and cooling is performed by applying pulse voltage for perform stable and accurate measurement even at a low voltage is applied.

scholarly journals An Alternate Representation of the Vector of Apparent Power and Unbalanced Power in Three-Phase Electrical Systems

2020 ◽  
Vol 10 (11) ◽  
pp. 3756
Author(s):  
Pedro A. Blasco ◽  
Rafael Montoya-Mira ◽  
José M. Diez ◽  
Rafael Montoya
Keyword(s):  
Nonlinear Systems ◽  
Distribution Systems ◽  
Low Voltage ◽  
Practical Case ◽  
Voltage Distribution ◽  
Efficient System ◽  
Electrical Systems ◽  
Three Phase ◽  
Unbalanced Loads ◽  
Wire System

Low-voltage distribution systems are typically unbalanced. These inefficiencies cause unbalanced powers that can significantly increase the apparent power of the system. Analysing and measuring these inefficient powers appropriately allows us to compensate for them and obtain a more efficient system. Correcting the imbalance at some nodes can worsen the rest of the system; therefore, it is essential that all nodes are analysed such that action can be taken when necessary. In most studies, the unbalanced power is measured from the modulus. Other more recent studies have proposed phasor expressions of unbalanced powers; however, in both cases, these are not enough to address the compensation of unbalanced powers in systems with unbalanced voltages. In this work, a different representation of the vector expressions for analysis of the unbalanced powers and the apparent powers of the three-phase linear systems is proposed. Additionally, these vector expressions are extended to nonlinear systems to quantify the harmonic apparent powers. These expressions have been formulated from the power of Buchholz and are valid for systems with unbalanced voltages and currents. To help understand the use of the proposed formulation, a practical case of a three-phase four-wire system with unbalanced loads and voltages is demonstrated.

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