The term ground has a very important and specific meaning in the context of electric circuits: it is an electrically neutral place, meaning that it has zero voltage or potential, which moreover can absorb excesses of either positive or negative charge and disperse them so as to remain neutral regardless of what might be electrically connected to it. The literal ground outdoors has this ability because the Earth as a whole acts as a vast reservoir of charge and is electrically neutral, and because most soils are sufficiently conductive to allow charge to move away from any local accumulation. The term earth is synonymous with ground, especially in British usage. A circuit “ground” is constructed simply by creating a pathway for charge into the earth. In the home, this is often done by attaching a wire to metal water pipes. In power systems, ground wires, capable of carrying large currents if necessary, are specifically dug into the earth.
Auto Transformer Tap Changing: Working Principle, Switching Sequence and Applications Auto transformer tap changing is a practical method of adjusting transformer output voltage without unnecessarily interrupting the electrical supply. In power transmission and distribution networks, the load does not remain constant throughout the day. As load current changes, voltage drops across transformers, cables, feeders, and transmission lines also change. A tap-changing arrangement compensates for these variations by modifying the effective number of turns in the transformer winding. A reactor-type on-load tap changer uses a center-tapped reactor, selector switches, and a bypass or short-circuiting switch to transfer the load from one tap to the next. The reactor limits the circulating current during the transition, allowing the tap position to change while the transformer continues supplying the connected load. This article explains the auto transformer tap-changing working principle , switch...
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