Module 3 : Sequence Components and Fault Analysis
Lecture 10 : Sequence Components
  Review Questions
1. What are sequence components?
2. Derive the sequence transformation matrix using 'c' phase as reference phasor.
3. Show that sequence transformation is linear.
4. If Zs is the self impedance and Zm mutual impedance of a transmission line, show that Z0 = Zs + 2Zm and Z1 and
  Z2 = ZS - Zm.
5. Derive the equation for fault current in (a) L-L fault with fault impedance Zf. (b) L-L-G fault.
6. If we do not want to lose information during a transformation 'f' from domain say A to B, then it is required that 'f' should
  be invertible. In addition, to simplify analysis, we prefer linear transformations. List out some other transformations that
  you have come across in electrical engineering.
7. Clarke's transformation with 'a' phase as reference phasor is defined as follows:
 
  Show that the transformation matrix is invertible. Hence, define the inverse transformation from Clarke's components to phase components.
8. Using Clarke's transformation show that
  1) for a - g fault
      
      
  2) b - c - g fault
      
  3) b - c fault
        
  4) 3 - phase fault
      
9. Suppose that in an DSP implementation of relay, we have to choose between the sequence transformation and Clarke's
  transformation suggest your choice and justify it from computational requirement and ability to correctly detect a fault.
   
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