Measurement and modelling of earthing impedance in ships (DC-30MHz)

Consequence of disturbance due to fault of earthing of on-board systems are not always clear. Second, the military EMC standards are outdated and the rationale behind these standards lacks. Therefore, research into rationale of standards and directives related to system earthing on board is necessary; in addition, develop appropriate on-board earthing models and appropriate method to measure on-board ship earthing impedance is necessary. There are two objectives of the project. From industrial point of view, this focusses on: how to measure and install earthing on board of ships. While scientific objective is how to develop a measurement method from which the DC resistance and HF impedance (up to several MHz) can be measured and finally build a general model which represents the on-board ship earthing. A test set up of measuring earthing impedance regarding to well-defined environment is built in order to get high reproducibly. In addition, for the measurement impedance from DC to 30 MHz, two approaches are done: first, in the company, current supply and voltage meter, LCR meter and spectrum analyser is used to measure DC, low frequency (20Hz to 100 kHz) and high frequency (100 kHz to 30MHz) separately. The loop areas, cross section of wire and length influence on the impedance are studied. In the university, current supply, voltage meter, and impedance analyser are chosen to measure ten groups of wire which one point earthing and multiply earthing are studied. Finally, a general model using curve fitting method and based on ten groups of measurement is built which can be used to further analysis.electrical power processingElectrical Power EngineeringElectrical Engineering, Mathematics and Computer Scienc