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A grounding transformer. A grounding transformer or earthing transformer is a type of auxiliary transformer used in three-phase electric power systems to provide a ground path to either an ungrounded wye or a delta-connected system. [1] [2] Grounding transformers are part of an earthing system of the network.
The ground shield of S, along with the ground wire ("third wire") P in the components' power cord and the building's utility ground wiring G form a ground loop. One of the best ways to prevent such a ground loop is to insert an isolation transformer in the signal cable S, as shown. The transformer breaks the conductive path between the ground ...
Any Δ-Y (delta-wye) connected transformer may be used for the purpose. A nine winding transformer (a "zig zag" transformer) may be used to balance the phase currents of a delta connected source with an unbalanced load. Low-resistance grounding systems use a neutral grounding resistor (NGR) to limit the fault current to 25 A or greater.
A conventional six-winding, grounding transformer or zigzag bank, [1] with the same winding and core quantity as a conventional three-phase transformer, can also be used in zigzag winding connection. In all cases the first coil on each zigzag winding core is connected contrariwise to the second coil on the next core.
An earthing system (UK and IEC) or grounding system (US) connects specific parts of an electric power system with the ground, typically the equipment's conductive surface, for safety and functional purposes. [1] The choice of earthing system can affect the safety and electromagnetic compatibility of the installation.
A transformer supplying a three-wire distribution system has a single-phase input (primary) winding. The output (secondary) winding has a center tap connected to a grounded neutral. As shown in Fig. 1, either end to center has half the voltage of end-to-end. Fig. 2 illustrates the phasor diagram
Parallel operations: All the transformers should have same phase rotation, vector group, tap setting & polarity of the winding. Ground fault Relay: A Dd transformer does not have neutral. To restrict the ground faults in such systems, we may use a zigzag wound transformer to create a neutral along with the ground fault relay.
While transformers are usually used to step up or step down the voltages, isolation transformers with a 1:1 ratio are used mostly in safety applications while keeping the voltage the same. If two electronic systems have a common ground, they are not galvanically isolated. The common ground might not normally and intentionally have connection to ...