The ASPEN Breaker Rating Module™ is an add-on module of the ASPEN OneLiner software. It streamlines the otherwise tedious work of checking the rating of circuit breakers against the short circuit currents they need to interrupt.
The program logic adheres to ANSI/IEEE standards (for both total- and symmetric-current rated breakers) and to IEC standards.
The Breaker Rating Module simulates faults with appropriate branch outages to find maximum short-circuit that flow through the breaker. It then computes the ANSI X/R ratio and adjusts the short-circuit current accordingly. Finally, it compares the currents to the rated capabilities of the breakers and reports the findings. Breakers with reclosing operations are checked with reduced ratings as required by the applicable standards.
The Breaker Rating Module utilizes a breaker connection model that is designed to work with traditional sequence networks in which circuit breakers connections are not modeled explicitly. The connection model associates each breaker with the bus where the breaker is located. It allows the user to specify two separate groups of network equipment for each breaker. These equipment groups are typically branches and generators protected by the breaker. In checking breaker rating, user can specify whether the rating should be compared with the total group current or the maximum current in each of these two groups. This connection model allows the program to accurately check breakers connected in various connection schemes currently in use in utility networks. Click here to download an IEEE paper on the connection model.
The output of the Breaker Rating Module is a easy-to-read text report showing the highest fault current as a percentage of the breaker rating. The report calls attention to those breakers that are operating at or near their short-circuit ratings and therefore warrants closer scrutiny by the protection engineers. Optionally user can select to create checking output in comma-delimited format that is suitable for processing by external programs such as Microsoft Excel.
