Neutral point potential variation from the low voltage distribution electricity grids

In low voltage distribution electricity grids is important to examine how to protect against hazardous voltages and currents that can occur with insulation degradation. It was found that the treatment of neutral defect is important in those regimes, the present paper aim to analyze the networks with isolated neutral. Describing phenomena circuitry directly affected by faulty depend on the network parameters C_iz, C_p and R which are variable in time. Touch voltage and electric currents of earthing in case of failure constitutes selection criteria for the protection system. This is chosen depending on the size of the neutral displacement voltage, fault current and how is the variation of these parameters over time. It is also shows the calculation of the total leakage current, variation of the neutral point and its consequences. The phenomena occurring in the network are identical in the powered equipment ones, they directly influencing the security of the personnel and also of the facilities. The paper also presents how to determine the equations that allow the geometric place plotting of curves for different voltages and network parameters. It is analyzed and the situation when the earthing is done by human body, which passes an electric current whose value, depends directly on resistance R_h of the body. As a conclusion it is found that the leakage current values in the networks with isolated neutral are lower compared to the values that appear in the case of networks with neutral connected directly to the ground, resulting that networks with isolated neutral can be used better in the hazardous environments.