Star - Sequence-of-Operation


Protective Device Sequence-of-Operation

Star Sequence-of-Operation (SQOP) software evaluates, verifies, and confirms the operation and selectivity of the protective devices for various types of faults for any location directly from the one-line diagram and via normalized Time Current Characteristic Curve (TCC) views.
Protective device sequence of operation software
Sequence-of-Operation provides a system-wide solution for an accurate and realistic operating time and state of protective devices, such as relay, fuse, circuit breaker, trip devices, contactor, etc.

The operation time is calculated for each protective device based on its settings, time current characteristic, and interlocks for a specified fault location and type.

Star - Sequence-of-Operation Key Features

  • Graphically drag & drop faults on the one-line diagram
  • Coordination via one-line diagram
  • View device operation sequence graphically
  • Device failure & backup operation
  • Detailed relay actions (27, 49, 50, 51, 51V, 59, 67, 79, 87)
  • Current summation
  • Normalized (shifted) Time Current Characteristic Curves
  • Phase & Ground faults (symmetrical & asymmetrical)
  • Flashing protective device via the one-line diagram
  • Sequence of event viewer
Sequence-of-Operation Module

Star - Sequence-of-Operation Capabilities

  • Evaluate the operating time & state of protective devices
  • Phase & ground faults insertion
  • Display fault currents on the one-line diagram
  • Illustrate system wide coordination
  • Tabulate operating times via an event viewer
  • Automatically calculate & display the fault current contributions
  • Graphical animation of protective device operation
  • Switch between automated or slider mode of operation  
  • Sequential display of operated devices
  • Globally view post fault actions & associated operating time via a tabulated event viewer
  • Customizable report
  • Option to ignore Maintenance Switch in Sequence of Operation

Normalized Time Current Characteristic Curve

Normalized / Shifted TCC mode is an analysis feature in Star TCC View which is based on Sequence-of-Operation calculation.

This analysis mode provides a graphical view of the operation times of protective devices based on their corresponding settings and characteristics for specified fault location and type.

Normalized TCC mode graphically displays the Time Current Characteristic Curves of protective devices in relation to one and another for a given fault.
Shifted Time Current Curves


Sequence of Event Viewer

The Sequence-of-Operation of protective devices are automatically calculated and listed in an Event Viewer, which is dynamically linked with the one-line diagram. This one-step concept utilizes the intelligent one-line diagram and performs a complete set of actions to determine the operation of all protective devices. The internal shifting (normalizing) of each Time Current Characteristic Curve is based on the individual fault contribution level.


Protection & Selectivity in Industrial Facilities

Protection & Selectivity in Industrial Facilities

PETRONAS RAPID project is the largest oil & gas refinery and petrochemical plant in Malaysia which is powered by a 1200MW utilities plant and connected to a 275kV Grid supply. The integrated ETAP model for the RAPID complex reached up to 5000 buses that consist of various distribution voltages from 400V up to 275kV. Protection Coordination evaluation study for the RAPID complex was performed using “PD Sequence-of-Operation” to identify abnormal relay behavior, which may not be observed in the conventional TCC curve. When simulating earth fault at 275kV system, there is sympathetic relay operation at all 275kV healthy feeders due to circulating earth fault current. The circulating earth fault current is more than 1pu, which will potentially cause a broader outage to the RAPID complex. Further analysis has been performed by the author and academician experts to ascertain the root cause of the circulating earth fault current. This presentation will discuss the root cause of sympathetic relay operation during 275kV earth fault simulations and the recommended solutions to mitigate the sympathetic operation. This will help engineering design firms and plant operators clearly understand the protection relay behavior during faults by utilizing ETAP special features.


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