A solar thermal power plant in principle works no differently than a conventional steam power plant. However, there is one important difference. No harm is done to the environment by burning coal, oil, natural gas or by splitting uranium to produce steam. It is produced solely by the energy that
Year: 2014
n GENERAL PROVISIONS: The exposed conductive parts are interconnected and earthed either altogether or in groups, or individually. Protection against indirect contact is ensured by RCD having a sensitivity I Dn to meet the condition: (1) 25 V in damp premises, work site installations and farm buildings. The choice of
Systems for insulation monitoring and help with first fault location have been developed and provide a significant reduction in the number of maintenance and repairs operations. The principle implemented consists in applying a low frequency or d.c. low voltage between the network to be monitored and earth using a suitable
n GENERAL PROVISIONS: The IT earthing system does not require the power supply to be automatically disconnected on occurrence of an insulation fault, referred to as the “first fault”. Indeed, we have seen that for this system the touch voltages which develop on occurrence of a first insulation fault are not dangerous
The different types of neutral point connection to earth are shown in table below. We can make a distinction between: The solidly (or directly) earthed neutral. The unearthed neutral, or high impedance-earthed neutral. Rresistance earthing. Reactance earthing. Petersen coil earthing.
In any medium or low voltage three-phase system there are three single-phase voltages which are measured between each phase and a common point called the “neutral point”. In balanced operating conditions these three voltages are phase shifted by 120° and have the value: U being the phase-to-phase voltage measured between
Solidly grounded systems are usually used in low voltage applications at 600 volts or less. In solidly grounded system, the neutral point is connected to earth. Solidly Neutral Grounding slightly reduces the problem of transient over voltages found on the ungrounded system and provided path for the ground fault current
In un-grounded system there is no internal connection between the conductors and earth. However, as system, a capacitive coupling exists between the system conductors and the adjacent grounded surfaces. Consequently, the “ungrounded system” is, in reality, a “capacitive grounded system” by virtue of the distributed capacitance. Under normal operating conditions,
There are many neutral grounding options available for both Low and Medium voltage power systems. The neutral points of transformers, generators and rotating machinery to the earth ground network provides a reference point of zero volts. This protective measure offers many advantages over an ungrounded system, like: · Reduced magnitude
There are many topologies of electric machines, which create various classifications. Traditionally, they were classified into two groups DC and AC. With the advent of new machine types, this classification becomes ill-suited. Figure 3 shows the proposed classification of electric machines in which the bold types are those that have
