ABSTRACT
Electric utilities usually conduct some system studies for the purpose of reactive power planning. Digital computers are the most versatile and can be used to solve all the earlier-mentioned problems, although in particular cases and depending on the facilities available, other methods can be more advantageous and economical. The first step in solving the problems using either digital or analog computers is to obtain the mathematical model of the system described by linear or nonlinear differential equations, algebraic equations, and other relationships involving limiters. In analog computers the problem is solved continuously in a parallel manner. The analog computer consists of electronic integrators, amplifiers, summers, multipliers, and switches, which are interconnected in a manner providing a solution to the set of describing system equations. In analog computers one will meet with very small and very large coefficients in the scaled equations, making the computer setup very inaccurate.
