Causes of Transformer Failure

Causes of Transformer Failure:

 Causes of Transformer Failure

➢ Over Heating:

1. Over load

2. Poor cooling

3. Core heating due to eddy current.

➢ Mechanical forces:

1. Mechanical force due flow of through fault currents.(3Ф, Ф-Ф, 1Ф)

1. Transportation

2. Earthquake, storm etc.

➢ Insulation Failure:

3. Aging

4. Lack of maintenance

5. Manufacturing defect.

GENERATOR PROTECTION

 

GENERATOR PROTECTION:

 The generator protection system design should take into account the types of faults and abnormal operating conditions that could be present at the generating plant and provide means for detecting and acting upon these conditions. The protection system design will depend on the size of the generating unit.

These fault types and disturbance conditions are classified as:

 Overload protection, and Overcurrent (short-circuit) problems

 Stator electrical faults

 Rotor electrical faults

 Failure of prime mover (mechanical problems)

 Failure of the field circuit

Hence we must protect the generator against the effect of these faults and abnormalities using the following protection schemes:

 Overload protection, and Overcurrent protection

 Overvoltage and undervoltage protection

 Overexcitation

 Unbalanced loading (Currents ) –sequence relay

 Loss of Excitation

 Loss of synchronism

 Phase Faults

 Earth Faults

 Abnormal Frequencies

 Motoring

 Overspeeding

 Excessive vibration

 Internal faults,

 Stator and rotor thermal protection, and

 Field ground.