Question

The load-flow solution is always assured in case of
1. Newton-Raphson method
2. Gauss-Seidel method
3. Fast Decoupled method
4. None of these methods guarantee

Answer 1

Correct Answer - Option 1 : Newton-Raphson method

Difference between the Gauss-Seidel method and Newton-Raphson method:

Gauss-Seidel Method	Newton Raphson Method
It requires a large number of iteration to reach convergence	It requires less number of iterations to reach convergence
The number of iterations required for convergence increases with the size of the system	The number of iterations required is independent of the size of the system
It has linear convergence characteristics	It has quadratic convergence characteristics
The Computation time per iteration is less	The Computation time per iteration is more
Less memory requirement	More memory requirement
More dependent on the selection of slack bus on the convergence	Less dependent on the selection of slack bus on the convergence
Unreliable convergent, less accurate, and used for a smaller system	Reliable convergent, more accurate, it can be used for larger power system

 

As accuracy is more Newton-Raphson method have assured load flow solution

• Load flow study determines the operating state of the system for a given loading.
• Load flow solves a set of simultaneous non-linear algebraic power equations for the two unknown variables (|V| and ∠δ) at each node in a system.
• The output of the load flow analysis is the voltage and phase angle, real and reactive power (both sides in each line), line losses, and slack bus power.
• Gauss seidel, Newton Raphson, and Fast decoupled load flow method are the different load flow methods.
• The fast decoupled load flow method gives an approximate load flow solution because it uses several assumptions. Accuracy depends on the power mismatch vector tolerance.

• The fast decoupled load flow method is an extension of the Newton-Raphson method formulated in polar coordinates with certain approximations, which results in a fast algorithm for load flow solution.

• The fast decoupled method requires a greater number of iterations than the Newton-Raphson method.