Comparison of the TRANSFORMER PROTECTOR and Pressure Relief Valve (PRV)
    Performances    [4].
   

   
    

 

Article Name:- Pressure Relief Valve efficiency calculations by comparison to the SERGI TRANSFORMER PROTECTOR during transformer short-circuit, ref. ffTPodpa

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    Most transformers that explode are equipped with a PRV. SERGI conducted a dynamic mechanical study and discovered that
    the PRV is not designed to react to very fast events since:

  • The spring inertia delays their response time and opening, 5 milliseconds

  • The evacuation section does not exceed 15% of the maximum nominal section when the PRV is half opened, which leads to an additional delay of 5 milliseconds

  • The U-shaped evacuation creates energy losses and reduces sharply the evacuation speed




2-D Pressure Relief Valve fluid flow image, 60% opened

     Computations showed that:

  • The TP prevented transformer tank explosion for all pressure gradients ranges up to 930 bar/second (13,500 psi/second)

  • The PRV cannot avoid transformer tank explosion as soon as pressure gradients reach 25 bar/sec (360 psi/sec) while during short circuits they can reach 5,000 bar/second (72,500 psi/second)

 



Comparison of pressure evolution between TP and PRV for a small pressure gradient 60 bar/sec (870 psi/sec)


TP OPERATION

 

During a transformer short circuit, the TRANSFORMER PROTECTOR is activated within milliseconds by the first dynamic pressure peak of the shock  wave, avoiding transformer explosions before static pressure increases.


 

The MTH Model

Comparison with the PRV

Power Plant Transformers

Pressure Wave Propagation Modelling

MTH model and Transformer reliability

Transformer Protector Tests

Results