## How is transformer differential protection calculated?

Application Example on Transformer Differential Protection Calculation

1. E87 = Y.
2. W1CT = Y.
3. W2CT = Y.
4. CTR1 = 80.
5. CTR2 = 240.
6. MVA = 33.
7. ICOM = Y.
8. W1CTC = 0.

What are the protection used for transformer?

The protection of a transformer against the overloads is performed by a dedicated protection usually called thermal overload relay. This type of protection simulates the temperature of the transformer’s windings.

### What is transformer differential protection relay?

The differential relay actually compares between primary current and secondary current of power transformer, if any unbalance found in between primary and secondary currents the relay will actuate and inter trip both the primary and secondary circuit breaker of the transformer.

What are the types of differential protection?

Differential Protection Relay

• Current Differential Relay.
• Voltage Differential Relay.
• Biased or Percentage Differential Relay.
• Voltage Balance Differential Relay.

## What is overcurrent protection of transformer?

Transformer overcurrent protection is required to protect the primary windings from short circuits and overloads and the secondary windings from overloads.

What is biased differential protection?

What is the biased-differential protection. Biased-differential protection is an older design of protection than high impedance circulating current. It is widely applied to two-winding transformers except those connected to the lower distribution voltages.

### What is ppm in transformer oil?

PPM stands for Parts Per Million. It is used to measure the weight of moisture divided by the value of oil. The moisture content in oil lowers the insulating system dielectric strength that permits flashover to harm a transformer. For example, for mineral oil, a generally accepted maximum moisture content is 35 ppm.

How many earthing is required for a transformer protection?

There are minimum four earthings will be required for any transformer. 2 connections for its body earthing.

## What are disadvantages of differential protection?

Problems Encountered in Differential Protection of Transformer:

• Unmatched characteristics of CTs.
• Ratio change as a result of tapping.
• Magnetizing inrush current.

What is the principle of differential protection?

Principle of differential protection Differential protection is based on the fact that any fault within an electrical equipment would cause the current entering it, to be different, from the current leaving it.

### Which relay is used in transformer?

Buchholz relays
Buchholz relays have been applied on oil-filled power and distribution transformers at least since the 1940s. The relay is connected to the oil piping between the overhead conservator tank and the main oil tank of a transformer.

Which oil is used in a transformer?

Mineral oil
Mineral oil and Synthetic oil are the majorly used transformer oil. These are the petroleum products, like Naphthenic based transformer oil and Paraffinic based transformer oil. Naphthenic based transformer oils are known for their heat distribution, which is one of the main problems with transformer.

## What is differential protection?

Differential protection is a unit-type protection for a specified zone or piece of equipment.

What is differential protective relay?

Differential Protective Relay is a protective relay that functions on a percentage or phase angle or other quantitative difference of two currents.

### What is the protection of a transformer?

Overheating protection

• Overcurrent protection
• Differential Protection of Transformer
• Earth Fault Protection (Restricted)
• Buchholz (Gas Detection) Relay
• Over-fluxing protection
• What is transformer protection?

Transformer protection means protecting the transformer from internal as well as external faults. The protection scheme must automatically isolate it in case of faults within stipulated time. Since small distribution transformer is connected to the supply system through series fuse wire instead of breaker,…