Modeling of Electrical Systems for Uninterrupted Operation of Drives in Case of Short-Term Distortions in the Supply Networks

Abstract

The article considers the problem of increasing the stability of an electrical system with running synchronous and asynchronous electric motors, which are electrically connected through an intra-factory network and for which the operating modes affect the stability of the entire load. A method is proposed for studying electrical systems with an electric motor load to assess the effect of short-term power supply interruptions (voltage dips) in supply networks on the dynamic stability of synchronous and asynchronous drives. The influence of considering operating synchronous and asynchronous electric motors on transient processes and levels of residual voltages of sections was studied. It was found that to ensure the stability of the drives, to avoid shutdowns in case of various types of short circuits, it is desirable to use an automatic reserve input with a response time of less than 12 ms. A device for the instantaneous activation of a reserve is proposed, providing a response time of 9 ms and a total switching time to a reserve input within 17 ÷ 65 ms. The results of experiments and calculations according to the author’s developed programs are presented, confirming the possibility of the uninterrupted operation of technical electric systems consumers. The requirements for such automation devices are determined.

Keywords

• automatic reserve power supply activation
• dynamic stability
• short circuits
• short-term power supply interruptions
• critical duration of power supply interruption
• formulation of nonlinear model for calculating residual stresses