Power system transient stability analysis using matlab software
The electric market liberalization increases its importance, as economical pressure and intensified transactions tend to operate electric power systems much closer to their security limits than ever before. The trend to merge existing systems into much larger entities and to monitor them in shorter and shorter time horizons creates more difficulties. This holds true for analysis aspects and even more for control, in as much as, today; control actions must cope with considerably more stringent market requirements than in the past. The difficulties increase further when it comes to transient stability phenomena. This thesis has discussed some theory related to transient stability such as the swing equation, transfer reactance, power angle curve and equal area criterion. In this thesis two possible methods of transient stability have been discussed and they are step by step solution for swing curve and equal area criterion. Some MATLAB programs have been developed to study the transient stability cases by using these two methods. For first method, the transient studies are conducted in two cases. For case 1, the fault cleared at time t 0.2 second and the second case 2 where the fault cleared at time t =0.4 second. For second method of equal area criterion has three case studies. All the input are same accept for sudden increase in power generator which for case 3 is 0.9 p.u, case 4 is 1.099 p.u and case 5 is 1.1 p.u. Lastly for case 6 and 7 the application of equal area criterion to three phase fault were investigate the fault at the sending end of the line and fault at some distance away from the sending end. These programs are helpful in determining critical power angle, critical clearing times for circuit breaker, voltage level of systems and transfer capability between systems. Thus, a better relay setting can be proposed.