Models for Calculating Voltage Dip Caused by Induction Motor Starting.

The induction motor is the major power utilization component in a large industrial plant. A typical plant will have several dispersed motors operating at certain speeds and loadings while other motors are at a standstill. When a large motor is switched onto the distribution system, a disturbance is created which will impact the operation of running motors and other equipment electrically removed from the point of connection. For instance, a large motor started across-the-line will have an inrush current of from five to eight times its normal full-load value, and damage to the motor can result. Such magnitudes of current are caused by the lower machine impedance upon starting. For this condition, the terminal voltage will dip for other motors throughout the network. Because the torque is related to voltage squared, significant performance deterioration can occur at remote motor load locations.In an existing plant, a voltage dip study can isolate problem areas to be avoided when considering a new motor addition or can provide data necessary for design changes in the distribution system itself.This thesis investigates the voltage dip problem for an industrial plant where a single large induction motor is switched onto a stable multi-motor system. The study represents a chronological ordering of voltage snapshots for the entire motor-starting sequence and includes all motors in the system after connection of the large motor. Two computer programs were written on a microcomputer to simulate the simultaneous behavior of each motor bus at a specific instant in time. The Transient Stability model was used as a standard of reference for comparing the accuracy of the Steady-State model, thus allowing meaningful decisions relative to practical engineering applications to be made. The results presented tend to verify that the two models compare favorably with only minor exceptions; therefore, the Steady-State model is sufficient for most cases.

Level thesis:degree_level

Thesis

Year

1984

Author dc:creator

• Robison, Harold Jack

• Induction motor
• Voltage dip
• Computer programs
• Steady-State model

Repository record dc:identifier

https://digitalcommons.library.uab.edu/etd-collection/6973

OAI identifier oai:identifier

oai:digitalcommons.library.uab.edu:etd-collection-7965