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OPTIMISATION OF 330KV NIGERIA ELECTRIC POWER SYSTEM BY PRIMAL-DUAL INTERIOR-POINT TECHNIQUE: IMPROVED PERFORMANCE ON SELECTED POWER STATIONS.
Dr. C. I. Obinwa*
The paper developed an optimization technique that is applied in 330 kV and other Extra High Voltage Networks. The Technique solves load flows which are non-linear with both equality and inequality constraints at the same time thereby saving time and saving the system from encountering problems due to delays in faults clearing. The existing solves one constraints after the other and has more than six (6) iterations before converging, while the developed method has few iterations and often converges after first iteration. The developed technique guarantees higher system power generation and consequently, larger loading with high system stability. With these advantages over the other methods the technique is realised by applying the non-negative Primal Variables ,“S” and “z” into the problem formulation to transform the Inequality constraint part to Equality constraints and subsequently apply another non-negative Dual Variables, “” and “v” together with Lagrange multiplier “?” to solve optimisation. Optimisation is solved by incorporating, Barrier Parameter “” which ensures feasible point(s) exist(s) within the feasible region (INTERIOR POINT), Damping Factor or Step length parameter “?”, Step Size ?Y, in conjunction with Safety Factor “” (which improves convergence and keeps the non-negative variables strictly positive) are used for updating variables (Y1=Y0+??Y0). If initialised variables fail convergence test, iteration starts with the updated variables. The problem formulation is done economically through minimisation of cost of power generation; min C(PG)= ?+?PG+?PG2, g(x)=0, stands for conventional power flow equation and other www.wjert.org 473 equality constraints, which is represented as; PGPDloss=0 and h £ h(x) £ ?, stands for operating limits on the system, which is represented as PGmin £ PG) £PGmax. The numerical algorithms of the method runs; Step Zero (Initialisation), Step One (Compute Newton Direction ?Y), Step Two (Update Variables), Step Three (Test for Convergence). Studies with results and analysis of improved performance by using PD-IP technique on the 330KV Bus of seven selected Power Stations namely; Shiroro, Afam, Geregu, Delta, Kainji and Jebba Power Stations of Nigeria where table 4 shows that percentage improvement to the existing methods. Therefore, this method ensures and guarantees high system stability.[Full Text Article]