براي بهبود پايداري سيستمهاي قدرت SPS استفاده از حفاظت شبكه اي

Special Protection Schemes (SPS) for Improvement of Power System Stability

Special protection schemes are those schemes and related devices used in order to reduce the impact of Voltage and Transient instability. Dynamic instability and at last but not least transmission line, substation or power plant outages on power system. Till 1990 only the local control devices were the major equipment that protect the system against disturbances, but since then the idea of protection schemes that combined the logical operation of various protection and control equipment under frequency and under-voltage load schedding devices, transformer tap changer. Generator AVR and governor, etc. in a region came to operation to increase the reliability of power system in large scale disturbances. In this paper first the various kinds of SPS will be introduced and categorized and then by reviewing the impact of various disturbances in power system, the proper protection scheme for each case will be presented.