An Adaptive Under Frequency Load Shedding For Frequency Stabilization of Power Systems Considering Voltage and System Inertia Changes

چکیده مقاله

Keeping the network frequency close to the nominal value is one of the most important criteria of the power network. When the stability of the frequency is disturbed due to the inequality of production and consumption of the network, severe damage is done to the network equipment such as turbines and motors. The under frequency load shedding plan is one of the most important protection plans in the power system, which is responsible for keeping the frequency within the permitted range during severe power shortages. The main problem of conventional load shedding schemes is the estimation of the active power deficit, which due to not taking into account the voltage dependence of the loads and the correct value of the inertia constant, the estimation of the power deficit faces uncertainty, which causes significant effects on the results and even the collapse of the system. In this article, a load-shedding plan is proposed, assuming that all production resources and loads are placed on one bus, it suggests a voltage-frequency index; Due to which the active power deficit of the system is well estimated and by updating the inertia constant in the unloading stages, the appropriate amount of load is cut off from the system. In order to show the efficiency of the proposed design, 4 scenarios for IEEE 39-bus system have been implemented in DigSILENT software. The simulation results confirm the proper and stable performance of the proposed design.