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Operating parameters such as voltages, leakage, and ground fault currents are decisive for a correct and safe operation of low-voltage unearthed networks with diode rectifiers. The knowledge of the maximum possible values of these parameters is necessary for correct assessment of numerous hazards. So far, no simple methods for determining the highest levels of these parameters in AC/DC IT three-phase networks have been available. The paper presents a new approach to the evaluation of the variation ranges of diode rectifiers' voltages and currents with the help of Mathcad. [ABSTRACT FROM AUTHOR]

Operating parameters of electrical networks such as phase voltages, leakage and ground fault currents are decisive for safe operation of low-voltage unearthed networks with diode rectifiers. The knowledge of maximum possible values of network operating parameters is necessary for correct assessment of numerous hazards. So far no simple methods of determination of the highest levels of these parameters in AC/DC IT 3-phase networks have been available. The present paper reports a new approach to the evaluation of the variation ranges of the operating parameters of these systems using Mathcad. [ABSTRACT FROM AUTHOR]

This paper analyses the electrocution hazard in three-phase electrical networks that operate with the neutral point isolated from ground. The following cases are analyzed: short low-voltage electrical networks, long low-voltage electrical networks and highvoltage networks. In high voltage electrical networks, touching a phase is always dangerous even if the insulation resistances are considered to be infinitely high. The analyzed cases show that in three-phase electrical networks with ground-isolated neutral point, the value of the current which passes through the human body depends on its electrical resistance as well as on the insulation resistances of the phases to earth. [ABSTRACT FROM AUTHOR]