ALLEVIATION OF VOL-TAGE LIMIT VIOLATION USING LOCAL. OPTIMIZATION

Abstract

And God said-'let there;he light and there was light'in' the dark world.-God saw Lhat:!the light was good and he - separated the light from darkness. But . only is since' - Thomas- Edison mankind is taking care- o€.. ihis, heavenly.' ,job religious'ly:, and. 'a'' vigor of :a stickler. Any product is marked by its cost(economy)',reliability,and of course quality. So is with Power;- System•.One 'of the main responsibility of power system planner is to 'design the system with an eye on and econom Even today operator maintain reliable performance using their past experience and on the spot assessment of network conditions. But today as the power network are becoming titanic and more involved, the increased number of possible operating r`{ scenarios can lead to exigencies beyond the ken of the operator.Power system operation become more complex under emergency conditions due to scheduled or random events.These conditions may be of voltage limit violations or overloading of the circuits. This tudy is directed' towards:alleviation of voltage limit violati - ns, the method developed the techn i_gtie of 'Local solution' using Gauss Siedel, is caxfied out for few.buses: in the vicinity of the outage line, and a mathematical mode], is developed for this selecticii of buses for local solution. n The solution so obtainedis..improyed,by using the Jacobian at the base case and improving the right hand side (RHS) vector for outaged line admittance. This adjustment on the RHS is incorporated by injecting the suitable power sources at the terminal buses to the outaged line, and is .called as Source Compensation. An acceleration factor is used to expedite .the process of convergence. In the literature available, many methods have been developed which are normally of the form of optimally load flow, using. optimization techniques. All these methods are. quite complicated and consume more time from computational point of. view, especially for large systems.An emergency condition warrants a quick decision, on the part of the operator without caring much for the optimality of the operating point. Here a direct and efficient method has been developed for.. alleviation of voltage limit violation. In this method the concept of local optimization is extended and a direct method is developed to obtain emergency adjustment to VAR control variables to alleviate the voltage limit violation. A few buses in the vicinity of the. buses suffering with voltage limit violation are processed for the local optimization and 'Conjugate Gradient' technique is used for optimization. This method fficiently, the sparsity of.• matrices to educe the computational effort and memory requirement.