The article deals with partial discharge modeling based on gas inclusion (defect) in high-voltage electrical insulation on board ship. For modeling a sample of insulating material used in ship high-voltage equipment , has been taken. A sample of the insulating material is described by means of three capacitors. Based on the calculated capacitance values, a replacement circuit was constructed, and then a scheme for modeling partial discharges in Matlab / Simulink program was designed. While simulating the most common voltage values applied in ship high-voltage systems have been used. The gas inclusion (defect) of a cylindrical shape, located in the middle of the insulating material, has been taken as reference. Simulation of partial discharges is performed for three gas inclusion versions differing in size. The graphs show partial discharges for which the voltage across the capacitances and the apparent charges for each defect and voltage are calculated using a formula. Dependences of the apparent charge on the area of the defect in the insulation and on the amplitude of the partial discharges are presented for different voltages. Based on these graphs, conclusions are drawn regarding the dependence of partial discharges on the supply voltage and the size of the defect within the insulating material. Spectral analysis of the simulated signals corresponding to the defects considered by the fast Fourier transform method is made and the frequency distribution of the signal depending on its amplitude is presented diagrammatically. Found values of the apparent charge allow to calculate the average value of the current, which makes it possible to estimate the intensity of partial discharges and technical condition of electrical insulation. Another problem with constant monitoring of partial discharges in high-voltage powerequipment is,separating useful signal (partial discharges) from the noise component. This issue needs further detailed study.
The computer modeling of changes in the shape and amplitude of a high-frequency signal at its propagation in the ship high-voltage cables is considered in the paper. The computer simulation was carried out on the basis of the real parameters of the ship high-voltage electric power system of gas carrier vessel Corcovado LNG. On the basis of the ship's technical documentation, it was concluded that the overwhelming number of the electricity receivers are connected to high-voltage switchboards using cables of 60 meters long. Only cargo pumps for liquid natural gas have a cable length of 200 meters. Thus, the computer simulation of a high-frequency signal propagation is performed in the ship high-voltage cables of 60 and 200 meters long. A theoretical description of change in the shape and the amplitude of a high-frequency signal at its propagation is presented using mathematical equations. The simulation is produced in Matlab/Simulink program. The cables of 60 and 200 meters long are described by means of a quadripole (RLCG section). The cable parameters and other simulation parameters are set in the program dialog window. Based on the obtained simulation results, the additional mathematical calculations were performed to obtain the attenuation coefficient and the propagation constantan. The graphs show the dependence of the change in the shape and the amplitude of the high-frequency signal on its frequency, taking into account the influence of the cable length. As a result, on the basis of the computer simulation, it was concluded that a partial discharge with a frequency of 30 MHz can be successfully measured in the high-voltage cable of 60 m long and a partial discharge with the frequency of 10 MHz can be measured in the high-voltage cable of 200 m long.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.