ICT-Supported Scenario-Aware Adaptive Setting Method for Line Current Protection in Distribution Networks with High Proportion of Distributed Generation
Abstract
INTRODUCTION: With the large-scale integration of distributed generators (DGs), distribution networks are gradually evolving into multi-source power supply systems. Although high-penetration DG integration improves system operational flexibility and power supply reliability, it changes fault current distribution characteristics and weakens the adaptability of conventional fixed-setting overcurrent protection. Under high DG penetration, wide-range DG output fluctuations and load demand variations may lead to protection miscoordination, maloperation, or failure to operate.
Objectives
To address these challenges, this paper aims to develop an ICT-supported scenario-aware adaptive setting method for overcurrent protection in distribution networks with high DG penetration, so as to improve the adaptability, sensitivity, and reliability of line current protection under varying operating conditions.
Methods
The proposed method classifies operating states into typical scenarios according to load demand, DG output, and network topology. Refined protection settings are calculated offline for each scenario by considering the infeed and outfeed effects of DGs. Meanwhile, an information and communication technology (ICT) architecture composed of distribution terminals, intelligent electronic devices, communication networks, and edge computing units is introduced to collect real-time DG output, feeder current, switch status, and topology information. Based on these data, online operating scenario identification and adaptive switching of protection settings are realized.
Results
Simulation results show that the proposed method can adapt to different operating scenarios, including a low-load scenario with zero DG output, a high-load scenario, and a high-DG-output scenario with a load of 8 MW. For a fault at point k1, when the system switches from Scenario 1 to Scenario 3, the fault current measured by QF2 decreases to 1.93 kA, which is lower than the original Stage II protection setting of 1.98 kA under Scenario 1 and may lead to protection failure. After applying the proposed method, the Stage II setting of QF2 is adjusted to 1.39 kA, while the protection sensitivity coefficient remains greater than 1.3. In addition, when the load increases from 5 MW to 10 MW, the Stage III setting of QF21 is adjusted from 0.11 kA to 0.23 kA, thereby avoiding the risk of maloperation under heavy-load conditions.
Conclusion
The proposed ICT-supported scenario-aware adaptive setting method can effectively respond to changes in DG output, load demand, and network topology. By enabling scenario-based setting calculation and online adaptive switching, the method improves the adaptability and reliability of overcurrent protection in active distribution networks with high DG penetration.