Modeling of the work of the UFLS using the new component of the UFLS in the PSCAD/EMTDC software

The most severe consequences for the power system occur during system accidents with the occurrence of a large deficit in the generated active power and a deep decrease in frequency. To prevent and limit the frequency avalanche, a complex of automatic frequency reduction limitation (AFRL) is used, namely its main component is under frequency load shedding (UFLS). The UFLS device is one of the emergency control (EC) devices, which is not provided as a separate component in some of the leading computer systems. In this paper, it is developed a component that implements the functions of under frequency load shedding in the power system. The introduced study briefly discusses the modeling of UFLS processes in the PSCAD/EMTDC software and testing the operation of the component developed by the authors.

I. Introduction

When designing any power supply system, one has to take into account the possibility of damage and abnormal modes in the power plant. The functions of eliminating any kind of accidents and eliminating abnormal modes are performed by relay protection and automation. Properly selected and calculated protection and automation must comply with regulatory materials in terms of ensuring selectivity, speed and sensitivity.