Proposing New UFLS Schemes to Model the Iran Grid management Co. (IGMC) Constraints Considering Three Main Aspects: Load Shedding, Frequency and Geographical Distribution

In this paper, we have proposed some under-frequency load shedding (UFLS) schemes for implementation in the Khorasan Network. In this regard, we have suggested a new relation to determine the number of substations required for load shedding at each frequency step, using which, the guideline of IGMC is well observed for the UFLS schemes. In the analysis of the proposed schemes, after reviewing the required constraints, their features have been analyzed in terms of three basic aspects: 1.The amount of load shedding at each frequency step; 2.The frequency response and its stability after disturbance (generator or tie-line outage or sudden load increase); 3.The geographical distribution of substations in each scheme; The Khorasan grid was modeled in the DigSilent Power Factory software with all the actual information of loads and power plants as well as the required dynamic parameters to analyze the frequency of the system in the contingency. The results of this study will be highly effective and useful in the quantitative evaluation of UFLS and selecting the optimal schemes.