Transformer Protection & Transformer Protection Circuits(1)

 

Transformer Protection & Transformer Protection Circuits(1)

 

Large transformers have oil or zigzagging temperature detection devices, which measure oil or winding temperature; commonly, there are two ways of measurement, one is stated warm-spot size and 2nd is called top-oil measurement, the under photograph suggests a typical thermometer with a temperature control container from Steinhausen used to degree the temperature of a liquid insulated conservative form of transformer.

The box has a dial gauge that shows the temperature of the transformer (that is, the black needle), and the pink needle suggests the alarm set point. If the black needle surpasses the crimson needle, the tool will activate an alarm.

If we appearance down, we can see four arrows via which we can configure the tool to act as an alarm or experience, or they can be used to start or stop pumps or cooling lovers.

As you could see inside the image, the thermometer is established on the top of the transformer tank above the core and the winding; it's so done because the highest temperature is going to be on the center of the tank because of the middle and the windings. This temperature is known as the top oil temperature. This temperature offers us an estimate of the Hot-spot Temperature of the transformer middle. Present-day fiber optic cables are used within the low voltage winding to appropriately measure the temperature of the transformer. That is how overheating protection is implemented.

Overcurrent Protection in Transformer

The overcurrent safety device is one of the earliest developed safety structures accessible; the graded overcurrent machine was advanced to protect against overcurrent situations. Energy distributors make use of this technique to discover faults with the assist of the IDMT relays. This is, the relays having:

Inverse function, and

Minimum time of operation.

The abilities of the IDMT relay are restricted. These varieties of relays need to be set 150% to 2 hundred% of the max rated cutting-edge. Otherwise, the relays will function for emergency overload conditions. Therefore, those relays provide minor protection for faults in the transformer cistern.

Differential Defense of Transformers

The Percentage Biased Current Discrepancy Protection is used to protect energy transformers, and it is one of the most commonplace transformer protection schemes that offer first-rate basic safety. These types of protection are used for transformers of rating exceeding 2 MVA.

A modifier is a famous person linked on one aspect, and a delta linked the opposite aspect. The CTs on the famous person facet is delta-related, and those at the delta-connected aspect are superstar-linked. The impartial of both the transformers remain grounded.

The transformer has two coils, one the operating coil and the alternative is the restraining coil. As the name suggests, the restraining-coil is used to supply the restraining force, and the working-coil is used to produce the running pressure. The restraining-coil is hooked up with the secondary winding of the modern-day transformers, and the running coil is hooked up in among the equipotential point of the CT.

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