ASPEN OneLiner™ is a PC-based short circuit and relay coordination program for relay engineers. OneLiner is a productivity tool. It relieves the engineer from the tedious and time-consuming tasks of leafing through stacks of printouts and plotting and re-plotting relay curves and one-line diagrams. OneLiner works very quickly under the control of the engineer. The engineer can change the relay settings and network configuration and see the results of the change immediately.

ASPEN OneLiner is the leading short circuit and relay coordination program with a 46% market share, according to an independent survey of 87 utilities in 24 countries (55 in the US, 12 in Europe, 3 in Latin America, 7 in Asia Pacific, 5 in the Middle East and Africa, and 5 in Canada) by Newton-Evans Research Co., Inc. in 2009.


The following are some highlights of OneLiner:

  • Native Microsoft Windows program.
  • Easy-to-use interactive graphics interface under Windows Vista, 7, 8 and 10.
  • Accurate modeling of 2- and 3-winding transformers,phase shifters, lines, switch, series capacitors (with and without nonlinear MOV elements), generators, loads, shunts, dc lines, and zero-sequence mutual coupling.
  • Modeling of current-limited generators for wind and solar plants.  Modeling of VSC converter.
  • Detailed modeling of fuses, reclosers, and overcurrent relays. Comes with an extensive relay library that can be edited by the user.
  • Detailed modeling of distance relays using make- and model-specific parameters and operating logic.
  • Modeling of over- and under-voltage protection relays.
  • Modeling of line differential protection schemes.
  • Modeling of relays' communication assisted protection schemes.
  • Built-in short circuit program that simulates all classical fault types (bus faults, and close-in, line-end, line-out and intermediate faults), as well as simultaneous faults (arbitrary collections of classical faults, plus phase-open and bus-to-bus faults).
  • Unlimited system size with modest memory requirement.
  • Lightning fast solution speed.  Parallel processing on muti-core computers.
  • Tools for PRC compliance: PRC-023-3, PRC-025-1, PRC-026 and PRC-027.
  • Advanced analysis tools: stepped-event analysis, boundary equivalence, voltage sag analysis, fault location, arc flash analysis, and more.
  • Graphical display of post-fault solution and relay operating time on the one-line diagram and the phasor diagram.
  • Automatic checking of overcurrent and distance relay coordination, plus automatic checking of overcurrent relays' pickup and instantaneous settings.
  • Automatic plotting of overcurrent and distance relay characteristics on the screen, as well as fault-based time-distance diagrams for all relay types.
  • User-defined distance-relay methods using DLLs written in C++.
  • High-quality printed outputs on a large variety of printers and plotters.
  • Built-in boundary equivalence program.
  • Generates relay end-to-end test files in Doble, COMTRADE and other formats.
  • Data importing facilities for short circuit data in ANAFAS, ANAREDE, GE, PTI (PSS/E and PSS/U) and other formats.
  • Data exporting in PTI PSS/E raw and sequence data format, GE PSLF and Short Circuit formats, ANAFAS data format, and AREADE data format.
  • Two-way data exchange with ASPEN Relay Database.  Ability to download relay settings from Doble/ENOSERV PowerBase.
  • Built-in scripting language using the BASIC programming language.