Under-Frequency Load Shedding Strategies for Power Districts with Distributed Generation

The analysis of technical documents and regulatory legal acts regarding the use of under-frequency load shedding devices in power districts is presented in the paper. The approaches used by power grid companies in forming a consumers' list, included in the under-frequency load shedding schemes, are presented in the paper. The paper proves that the interconnection of distributed generation (DG) to the distribution grids or facilities of internal power supply grids leads to significant changes in schemes and operating conditions and may cause an incorrect operation of underfrequency load shedding devices in the island mode operation of the power district. The features of transient processes to be analyzed in modeling and simulating of electrical grid operation under development of the DG interconnection project, are revealed. The recommendations on the calculation of values and speed of response parameters of under-frequency load shedding of a power district are substantiated for various values of the active power gap. The recommendations for under-frequency load shedding devices' settings selection in order to provide reliable power supply to essential consumers in the island mode operation of the power district, are formulated.