Estimating Nigerian Power System Post Contingency Line Flows Using Power Distribution Factors

At the point of convergence of any power system AC load flow iterative method, the principal bus parameters necessary to compute the transmission line flows and losses are provided. The exactness and accuracy of the result depends largely on the iterative method and the iteration termination criteria and each operating condition requires a unique solution of the analysis. State estimation techniques are also viable alternatives to AC load flow techniques in estimating network bus parameters from a known state but the speed of estimation is comparatively similar to the AC counterpart. However, the justification for the use of DC load flow for quick estimation of transmission line flows as against the AC is that the resulting mismatch is negligible when used for contingency and security analyses. Estimates of transmission line active power flow can be made using linear distribution sensitivity factors whose result match those of DC load flow. These sensitivity factors Power Transfer Distribution Factors PTDF and Line Outage Distribution Factors LODF are calculated and stored for a network and remains valid if the network remains significantly unmodified. With these stored factor from an operating point, post contingency flows may be predicted on any line. In this work, the PTDF and LODF of the Nigerian 330kV of 41 bus were computed and stored from a base case, then post contingency flows were predicted for the 77 transmission lines of the network following contingency in the form of 140MW load shedding at bus 1, 50 generator output reduction at bus 2, 100MW generator output increment at bus 20 and 100MW generator output decrease at bus 25. The result shows that using sensitivity factors to estimate transmission line flow works as validated by the result from load DC load flow technique. Therefore, a quicker, linear and non-iterative method is validated in order to estimate transmission line flows from a known operating point with the slack bus responsible for active power exchanges. Emmanuel. A. Anazia | Onyedikachi N. Samuel` | Obroh O. Rebecca "Estimating Nigerian Power System Post Contingency Line Flows Using Power Distribution Factors" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-6 , October 2018, URL: http://www.ijtsrd.com/papers/ijtsrd18854.pdf