Question

Ten thyristors are used in a string to withstand a de voltage of Vs = 15 kV. The maximum leakage current and recovery charge differences of thyristors are 10 mA and 150µC, respectively. Each thyristor has a voltage sharing resistance of R = 56 kΩ and capacitance of C1 = 0.5 µF. Determine the

1. Maximum steady-state voltage sharing, V_DS(max);
2. Steady-state voltage derating factor;
3. Maximum transient voltage sharing, V_DT(max); and
4. Transient voltage derating factor

Answer 1

Answer -

   Given,

n_s = 10

V_s = 15 kV

(i) The maximum steady-state voltage sharing is,

     

     

  

(ii) The steady-state derating factor is,

     

  

   DRF = 25.15%

(iii) The maximum transient voltage sharing is,

  

  

     

(iv) The transient voltage derating factor is,

  

  

DRF = 15.25%