Adaptive UFLS for Controlling a 0.4 KV Load in the Event of Emergency Power Shortages in a Micropower System with a Mini-Hydroelectric Power Station

Annotation. The imbalance between generated power and load demand is a major factor leading to frequency instability in power systems, especially in isolated micropower systems. In order to maintain the frequency of the micropower systems within permissible limits during power deficit emergencies, this work presents adaptive automatic frequency shedding (UFLS) at the level of 0.4 kV. The proposed method for controlling a load at a voltage of 0.4 kV is based on a probabilistic method for determining the time of load shedding when the frequency decreases and takes into account the prioritization and planning of the operation of smart household appliances. The functionality of the proposed load management system was tested through simulation in the Power Systems Computer Aided Design (PSCAD) environment, representing a micro-power system with a mini-hydropower plant (mini-HPP) that had to operate autonomously due to power deficit. An emergency scenario is presented with simulation of both traditional UFLS and the proposed adaptive UFLS. The simulation results confirm the effectiveness of the proposed adaptive UFLS in ensuring frequency stability in the micropower systems. Furthermore, adaptive UFLS allows for the preservation of up to 15% of consumer load. The need for improving load prioritization and planning in 0.4 kV intelligent networks to ensure selective disconnection with minimal disruption to power consumers is identified. Research on the operation modes of micropower systems with mini-HPP is an important and relevant task for the Republic of Tajikistan, where the development of such power systems is of high importance.