Analysis of Transient Recovery Voltage at the Terminals of Breakers Using Current-Limiting Reactors

Resumo

Current-limiting reactors (CLR) are known to have a significant effect on transition processes during short circuits (SC) leading to excesses beyond the permissible values of the transient recovery voltage (TRV) at the terminals of breakers for short-circuit currents, which in turn can lead to failure of the breakers. It is shown that the traditional (generally accepted) method for calculating transient recovery voltages based on using a circuit with the reactor replaced by lumped parameters is not suitable for magnetized CLR, and in the case of uncontrolled CLR can yield erroneous results. It is argued that there is a need to account for the distribution of the winding parameters of current-limiting reactors in calculations of the TRV at the contacts of breakers as they interrupt short circuits and relevant analytic expressions are derived.