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Fault analysis

Fault analysis is an essential tool for the determination of short-circuit currents that result from different fault phenomena, the estimation of fault locations, the identification of under-rated equipment in electric power systems and the sizing of various system components including Distributed Generation components. 
Eaton's CYME power engineering software features a comprehensive fault analysis module to assist engineers in the assessment of the effects of short-circuit of varying severity on the overall system reliability. The Fault Analysis module offers various analyses and functionalities to help engineers carefully assess issues related to short-circuit. The knowledge of the magnitude of the short-circuit current that can be present at any point in an electric system is crucial to ensure system reliability. The abnormal current level produced by faults put an important stress on the electrical equipment, and if the latter are not properly rated, it could lead to equipment damage, personnel injuries and system downtime. 

Fault analysis module

Short-circuit calculations

Conventional short-circuit

The conventional short-circuit calculation is a robust calculation algorithm that does not follow any particular standard. It offers:

  • Sequence and phase-domain calculations
  • Computation of short-circuit current at all nodes, or computation of the effect of a fault applied at a given location
  • All fault types (LLL, LLL-G, LL, LL-G, L-G)
  • Sliding fault option
  • Impedance tolerance adjustments
  • Machine short-circuit contributions

IEC-60909 short-circuit

The IEC-60909 short-circuit calculation adheres to the international IEC-60909 guidelines and supports fault current calculations for three-phase radial or meshed AC networks.

  • Four types of fault current calculations: Initial short-circuit current, Maximum asymmetrical fault or peak current, Breaking fault current and Steady-state fault current
  • Standard-based or user-defined voltage factors
  • Impedance correction factors for transformer, generator, network feeders and power station units
  • Report of typical X/R ratios for generators, motors and network feeders

IEC-61363 short-circuit

Calculates short-circuit levels on three-phase radial AC electrical installations of ships and mobile and fixed offshore units. It calculates both AC and DC components of the current from fault inception to steady-state for three-phase symmetrical short-circuit condition.

  • Calculate the initial current (I’’k), the peak current (Ip), the breaking current (Ib) and the DC breaking current (Idc)
  • Time-domain plot to show the short-circuit current from fault inception point to steady-state

ANSI short-circuit

The ANSI short-circuit calculations adhere to the North American ANSI C37.5, ANSI C37.010, and ANSI C37.13 standards relevant to short-circuit studies of specific duty types.

  • Duty types studied include: time-delayed, contact parting, closing/latching
  • Low voltage circuit breaker rating assessment
  • Automatic selection of multipliers applied to motor sub-transient reactance as dictated by the standard

Series and simultaneous fault

Series fault

The Series fault analysis evaluates the effect of open circuits or asymmetrical line impedance conditions on the network, which usually causes a significant increase in the neutral current.

  • Single-phase open fault
  • Two-phase open fault
  • Asymmetrical impedances

Simultaneous fault

The Simultaneous fault analysis studies the impact of having faults at different locations simultaneously on the network.

  • Study the combination of both shunt and series faults
  • Assess the impact of faults occurring simultaneously at two or more network locations

Other analysis

Fault locator

The Fault Locator analysis takes the short-circuit recorded from a current measuring instrument to determine possible locations of the fault on the network.

Network Fault

The Network Fault option, integrated in the standard short-circuit analysis, performs a series of short-circuit analysis in batch mode and offers the possibility to generate detailed reports and summary reports on the entire network or at user-defined monitored locations.

Voltage sag

The Voltage sag analysis assesses the impact of a sudden reduction of voltage magnitude caused by network faults, or other disturbances such as motor starting or overloads.

  • Assert the validity of the clearing time of different protective devices through the determination of sag frequency and duration calculation
  • Determine the voltage dip caused by a disturbance

Equipment rating verification

The Equipment rating verification analysis evaluates devices to determine if they are properly sized to perform their intended functions as the stress on them increases along with the growing energy demand.

  • Determine, with the short-circuit analysis, if network devices can withstand fault currents as per ANSI or IEC requirements
  • Pinpoint, with the power flow analysis, if network devices are overloaded or suffered voltage violations during steady-state conditions

Result viewing

  • Reports and charts
    • Detailed reports in tabular format that can be exported to Microsoft Excel, XML or database format
    • Customizable report content
  • One-line diagram display
    • Color-coding to illustrate anomalies according to user-defined criteria
    • Customizable tags and tooltips at user-defined locations on the one-line diagram

Need product support?

CYME users portal:

P: 450-461-3655 or 800-361-3627 (Canada and US)


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