Transient Stability Response of Hydro- Wind Based of Power system Network ( case study on KOKA, Awash- II &amp; Adama- I Power Plants
Creators: name: Keraj Alemu  Debela
Publisher: name: National Academic Digital Repository of Ethiopia
Year: 2020
Subjects: Power System Planning, Power System Stability, Power System Security, Transient Stability, Critical Clearing Time.

description: Power system planning and operation can maintain optimum system performance. Such method is<br> categorized under the study of power system stability. The major obstacle in system stability is<br> characterized by improper dumping of the oscillatory transient and rotor angle variation between<br> the generation units in the system. A system reliability is a broad concept comprising power system<br> security and power system adequacy. Power system security is a vast area containing system<br> stability as one of its constituent. A stable power system network, containing multi machine system<br> is the one having the rotor angle is within the stable margin and the speed of one machine in<br> relation to the other one is in synchronism throughout its operation. Both transient and steady state<br> power system stability of an identical multi machine system has been studied by different<br> researchers. This thesis focuses on the transient stability response of a hybrid generation system<br> contained network. Due to the hybrid nature of the generation system, the modeling of the<br> generator follows a different mathematical modeling than its identical counterpart. The main aim<br> of transient stability study is to find the fault clearing time in order to set the threshold value of<br> different switch gear equipment. The speed, dependability, sensitivity and selectivity of the<br> protective device in relation to the studied critical clearing time determine whether the fault<br> sustains or be cleared from the system. The purpose of the study is to maintain the power system<br> generators to be stable when they are failing under transient disturbance in the interconnected<br> network operation. For the sake of understanding, an existing practical network is chosen for case<br> study. A network containing three generating units in which one of it is from wind plant and the<br> other two are the usual hydro based generation unit of the country, Ethiopia. The wind based<br> generation unit is the Adama-I wind plant and the other two are Koka and Awash II hydro plants.<br> After mathematically modeling all the three systems, ETAP and MATLAB software are used to<br> see the response of a transient system disturbance in the network. The ETAP software used to find<br> the load flow response of the system and MATLAB software is used to see the exact transient<br> response of the network during disturbances. The system is checked for disturbances at different<br> transmission line for different critical clearing time and the response of the system angle, speed<br> and power has been studied. From the result, the system shows that 0.1 second and 0.19 second<br> were the marginal transiently stabile of the IEEE case and the interconnected 14-bus system of<br> Ethiopian network configuration respectively. When the protective devices of fault clearing time<br> is advanced from this threshold value, the fault was sustaining and a blackout will happen in the interconnected system. From the simulation, at 0.11 second and 0.2 second the beginning of the transiently instability is shown in clear manner and beyond this marginal time it’s never return to stability region. Hence, for analysis of system stability during transient disturbance the critical<br> fault clearing time plays a vital role.