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. They let three-phase (delta connected) systems accommodate phase-to-neutral loads by providing a return path for current to a neutral.
Grounding transformers are typically used to:
Provide a relatively low-impedance path to ground, thereby maintaining the system neutral at or near ground potential.[3]
Limit the magnitude of transient overvoltages when restriking ground faults occur.
Provide a source of ground fault current during line-to-ground faults.
Permit the connection of phase-to-neutral loads when desired.[2]
Grounding transformers most commonly incorporate a single winding transformer with a zigzag winding configuration, but may also be created with a delta-wye transformer.[2][4] Neutral grounding transformers are very common on generators in power plants and wind farms.[2] Neutral grounding transformers are sometimes applied on high-voltage (sub-transmission) systems, such as at 33 kV, where the circuit would otherwise not have a ground; for example, if a system is fed by a delta-connected transformer. The grounding point of the transformer may be connected through a resistor or arc suppression coil to limit the fault current on the system in the event of a line-to-ground fault. [5]
^"Grounding Transformer" (PDF). Swedish Neutral.
^ abcdDickinson, Mike (August 19, 2011). "Grounding Transformers". Pacific Crest Transformers. Retrieved September 4, 2017.
A groundingtransformer or earthing transformer is a type of auxiliary transformer used in three-phase electric power systems to provide a ground path...
It is used as a groundingtransformer, creating a missing neutral connection from an ungrounded 3-phase system to permit the grounding of that neutral...
return path for current to a neutral. Groundingtransformers most commonly incorporate a single winding transformer with a zigzag winding configuration...
Canadian Electrical Code, the feed from the distribution transformer uses a combined neutral and grounding conductor, but within the structure separate neutral...
a system neutral is also used for grounding (earthing) of equipment and structures. Current carried on a grounding conductor can result in objectionable...
transformer called a zig zag is used to provide grounding on three-phase systems that otherwise have no connection to ground. A zig-zag transformer provides...
to reduce the noise from transformers, improve appearance, or protect switchgear from extreme climate or pollution. A grounding (earthing) system must be...
strict separation of the transformer center from the negative pole (otherwise short-circuit currents will flow) or a possible grounding of the negative pole...
such as a mobile phone charger, is connected to the mains through a transformer of one type or another, and there is no direct electrical connection...
frequency range. SFRA is a comparative method, meaning an evaluation of the transformer condition is done by comparing an actual set of SFRA results to reference...
includes the design of circuit breakers, transformers, disconnect and grounding switches, instrument transformers, circuit switches, surge arresters, and...
Continuity tests have uses which include testing components, ensuring proper grounding of equipment, and reverse engineering circuit boards. A continuity test...
charges is greater and the two objects feel a force of attraction. Careful grounding of part of an object can permanently add or remove electrons, leaving...
overcurrent protection of the converter transformers, isolating switches, grounding switches, and instrument transformers for control, measurement and protection...
metering, control, and protection equipment. For industrial applications, a transformer and switchgear line-up may be combined in one housing, called a unitized...
of the transformer, and the effect is enhanced in some high-quality cables that have an outer layer of mu-metal. Because of this 1:1 transformer, the aforementioned...
power cables, grounding networks, and motors for tracking and pumping fluids, as well as in the main generator and high voltage transformers. Typically,...
as shown in figure 5. With transformers the sending and receiving circuitry can be entirely unbalanced with the transformer providing the balancing. Active...
electric energy (AC or DC) to operate their core parts (electric motors, transformers, lighting, rechargeable batteries, control electronics). They can be...
fifth linear element after the resistor, capacitor, inductor and ideal transformer. Unlike the four conventional elements, the gyrator is non-reciprocal...
problems in its first few years of operation, with numerous converter transformer failures and one serious converter fire, although reliability is now...
circumstances. The neutral is connected to the center tap of the power company transformer of a split-phase system, or the center of the wye connection of a polyphase...