A quantitative approach and simplified generic transient motor startup power models for microgrids security assessment

Microgrid security can be significantly influenced by the design and operation of large electrical equipment (e.g., motors and chillers). During the startup period of large motors, the peak inrush current poses a substantial risk to microgrid security. Increasing the microgrid capacity is the common method to decrease the surge impact on microgrid security, which leads to huge investment. Quantification of motor startup performance is very valuable for assessing the security of microgrids. In this study, a quantitative approach is proposed to assess the security of microgrids dynamic load of power consumers. Two simplified generic transient models are developed based on the ANOVA (analysis of variance) method to quantify chiller motor startup performance including inrush current and startup time. The microgrid blackout risk and system wear potential can be effectively quantified using the proposed quantitative approach and models. The quantitative approach and the utilization of the simplified generic transient startup power models are tested and verified using a hotel microgrid on a remote island. Results show that the approach and models can be used to assess microgrid security. The systematic analysis recommends that the capacity of a single motor/chiller should be limited to 8% of microgrid capacity. The outputs of this work can effectively quantify the system security and system wear potential in the real application of the microgrid design and chiller size determination.