ACS

Protection Coordination

Overview

Protection Coordination (PCN) provides the system operation engineer and dispatcher a tool to review, edit or analyze the protective device settings. The protective devices include relays, reclosing relays and fuses. PCN presents to the dispatcher the actual “time-current” curves of protective devices along the feeder for graphical analysis and manipulation based on known fault currents.


The Protection Coordination (PCN) function supports the following capabilities:


  • Graphically present time-current curves of protective devices, such as circuit breaker relays, automatic reclosing relays, and fuses.
  • Determine the appropriate parameter settings of protective devices based on known fault currents.

user defined protective device library can be imported to PCN that includes relevant time-current curves and parameters and can be edited or modified through PCN.


Detailed features of the PCN function are available as follows:


  • User selection of the devices to be studied from SCA one-line diagrams that are defined in the device library. If the selected device type (or model) does not exist in the library, it will be highlighted, so that the user can add this new device into the library through the library edit function.
  • Automatically display up to 10 time-current curves for the selected device on a log-log scale.
  • Addition or deletion of individual time-current curves on the log-log display.
  • User addition or deletion of phase-to-ground, phase-to-phase, or three-phase fault current lines on the log-log display by entering fault current values either manually or obtained from SCA.
  • User adjustment of the parameter settings of individual devices, and automatic re-display of the corresponding time-current curves on the log-log display.
  • User selection of alternative protective devices from the device library.
  • Save PCN cases for any of the selected devices with up to 10 time-current curves and associated parameters.
  • Capabilities for printer output and video hard copy of the study results.

In addition, the fault current lines can also be modeled decaying with time by specifying proper time constants.