No abstract

A realistic simulation of fault arc is required in proper design of transmission system equipment such as fault locators. Usually, in the travelling wave-based fault location algorithms, the effect of the arc of the fault is neglected. The influence of fault arc characteristics on the accuracy of fault locator which is based on the travelling wave theorem, is studied in this paper. Proposed algorithm uses samples taken from two terminals and shows that it is possible to calculate the accurate location of fault by measuring voltage transients caused by the fault. The travelling wave-based algorithm does not use the line parameters. Therefore, the accuracy of algorithm is not affected by aging, change of climate and temperature, which change wave speed. In addition, the effect of fault conditions such as arcing fault resistance, fault inception angle and fault distance are studied on the accuracy of the proposed algorithm. Simulations carried out by SimPowerSystem toolbox of MATLAB software confirm that mentioned parameters do not affect the accuracy of the method.

No abstract

As one of the most important ancillary services, reactive power production plays a crucial rule in power system operation, reliability and security. Because of the opportunity costs in providing reactive power, producers are under great pressure to provide VAr support. In this paper, a new challenge on the reactive capability curves (RCC) of the synchronous generator is discussed. The RCC is a graphical representation of the reactive and active power produced by the generators under various operating conditions, as specified by the cold gas pressure and temperature inside the generators as well as the power factor. These curves define the normal limits of operation without exceeding thermal limitations. The generator manufactures provide the determined RCC, However, in the real world RCC is changed over time and aging of the generators. This paper discusses about some reasons, which lead to the variations, and the importance of re-evaluation of RCC.