Fault Analysis Analysis of power system parametersresulting from a ground or line to line faultsomewhere in the system Simulator contains a tool for analyzingfaults in an automatic fashion Can perform single and three phase faults 2008 PowerWorld CorporationI13-1

Fault Analysis Fault types include:––––Single line to groundLine to lineDouble line to groundThree phase balanced The general fault analysis tool can beaccessed in run mode by: Tools ribbon tabÆFault Analysis 2008 PowerWorld CorporationI13-2

Setting the Fault Location Information about the fault location can be filled inmanually Alternatively, you can right-click on a bus or transmissionline on the oneline diagram, and select Fault from themenu to have the fault location fields automatically set– Selecting Fault for a bus will set the bus number field– Selecting Fault for a transmission line will set the from and tobus numbers, the circuit identifier, and the approximate linelocation as a percentage of the length of the line– Any of these fields can still be changed manually 2008 PowerWorld CorporationI13-3

Select Type of Fault Determines which calculations to perform– Line to ground: assumes phase A to ground– Line to line: assumes phase B to phase C– Line to line to ground: assumes phase B to phase C toground– Three phase balanced A non-zero impedance to ground can be defined onthe options tab, default is 0 (except for line to line) 2008 PowerWorld CorporationI13-4

Fault Dialog: DataSet type offaultCurrent throughthe faultDeviceslisted heredepend onbus or inline faultResults of analysis are displayedin the grids on these five pages 2008 PowerWorld CorporationI13-5

Sequence Data for Fault Analysis By default, sequence data for fault analysis is notstored with load flow data Sequence data can be loaded from the Optionspage– PowerWorld Auxiliary file (*.aux)– PTI Sequence Data file (*.seq) Sequence data can similarly be saved to the sametypes of external files; however, Simulator willstore sequence data with the load flow case(*.pwb) if you save the case after loading thesequence data 2008 PowerWorld CorporationI13-6

Sequence Data for Fault Analysis Sequence data is required for variousdevices:– Generators Internal sequence impedances Neutral to ground impedance– Transmission Lines Zero sequence impedance Zero sequence line shunt admittance 2008 PowerWorld CorporationI13-7

Sequence Data for Fault Analysis– Transformers Zero sequence impedance and line shunt admittance Phase shifts, entered as Phase in the load flow data Transformer grounding configuration, as acombination of Wye, Grounded Wye, and Deltaconnections– Loads Negative and zero sequence load, as an admittance Set on a bus-basis, with admittance given is totaladmittance for all loads at that bus 2008 PowerWorld CorporationI13-8

Sequence Data for Fault Analysis Transmission line mutual impedance– Zero sequence mutual impedance between partor all of two transmission lines– Displayed on Options tab Fault data for all devices (except mutualimpedances) can be entered on theInformation Dialogs 2008 PowerWorld CorporationI13-9

Fault Analysis: OptionsImpedance toground at the faultLoad and save sequence dataas a text fileMutualimpedancerecords 2008 PowerWorld CorporationI13-10

Fault Analysis Example Open B7FaultExample.pwb– No sequence data exists, so all fault analysis data fieldsare set to defaults Run the Fault Analysis tool from run mode by:Tools ribbon tab ÆFault Analysis From the Fault Options tab, select Load Data– Confirm replacing sequence data– Load B7FaultExample.aux 2008 PowerWorld CorporationI13-11

Fault Analysis Example Switch to the Fault Data tab, and select faultbus number 3 Leave as bus fault, single line to ground Click Calculate– The case will be solved first to make sure theanalysis will be valid– The fault analysis calculation is a linearizedcalculation about the operating point 2008 PowerWorld CorporationI13-12

Fault Analysis Example Results are displayed on the five tab sheets on theFault Data page– Per phase bus voltage magnitude (p.u.) and angle (deg.)– Per phase branch from and to bus current magnitude,with current direction at BOTH ends defined AWAYfrom the terminal bus– Per phase generator current magnitude and angle (deg.),with current direction defined OUT of the generator– Per phase load and switched shunt magnitude, withcurrent direction defined AWAY from the terminal bus 2008 PowerWorld CorporationI13-13

Fault Analysis Visualization ofResults Voltages and currents calculated duringFault Analysis can be visualized on aoneline diagram– In the Data Type Shown on Oneline box, selecta single phase or all phases– When Data Type Shown is changed to phase orphases, Simulator searches for and replaces thefollowing types of text fields on the onelinediagram: 2008 PowerWorld CorporationI13-14

Fault Analysis Visualization ofResults Bus voltage fields replaced with phase voltage magnitude(s) inp.u. Bus angle fields replaced with phase voltage angle(s) indegrees Branch MW or Amp fields replaced with phase currentmagnitude(s) in Amps or p.u., as specified Branch MVAR fields replaced with phase current angle(s) indegrees Generator MW fields replaced with phase current magnitude(s)in Amps or p.u., as specified Generator MVAR fields replaced with phase current angle(s)in degrees 2008 PowerWorld CorporationI13-15

Fault Analysis Visualization ofResultsOnly fieldsswitched tofault analysisresults willremain ononelineCurrents shownare magnitudeonly; wouldneed to includeangles todeterminedirection 2008 PowerWorld CorporationI13-16

Fault Analysis Visualization ofResults The phase of the fault data displayed on thediagram can be quickly toggled to adifferent phase by clicking on the dropdown arrow on the Fault Analysis toolbarbutton and choosing a new visualizationsetting 2008 PowerWorld CorporationI13-17

In-Line Faults Calculated based on a location given as apercentage distance from the From end ofthe line Inserts a temporary bus and line segmentsrepresenting the fault point of the line;reflected on the oneline diagram Calculations performed the same as a busfault at the temporary bus 2008 PowerWorld CorporationI13-18

Fault Analysis: Final Notes The fault analysis form can be closed while a faultis calculated without clearing the fault; the valueswill remain in memory until manually cleared orthe case is saved or closed A Double Line fault automatically uses a FaultImpedance of 999 j999 and ignores the FaultImpedance settings; use a Double Line to Groundfault to specify a desired Fault Impedance 2008 PowerWorld CorporationI13-19

Fault Analysis: Final Notes Before visualizing fault analysis currents inp.u., you may need to first change thenumber of decimal places for the branchand generator MW and MVAR fields Once Sequence Data is loaded from anexternal file, saving the case file will storethe sequence data with the *.pwb as well 2008 PowerWorld CorporationI13-20

Determines which calculations to perform - Line to ground: assumes phase A to ground - Line to line: assumes phase B to phase C - Line to line to ground: assumes phase B to phase C to ground - Three phase balanced A non-zero impedance to ground can be defined on the options tab, default is 0 (except for line to line)