Ensure that the maximum continuous current in an IED does not exceed four timesits rated value, if the measurement of the operating characteristics runs underconstant voltage conditions.To verify the mho characteristic, at least two points should be tested.In the following, three test points are proposed. The mho characteristic always goesthrough the origin, which automatically gives a fourth point for the characteristic.13.4.2 High speed distance protection zones, quadrilateral andmho characteristic ZMFPDIS GUID-DF1650F4-EC3E-402B-BE26-EF2EF1034237 v6Prepare the IED for verification of settings outlined in section "Requirements" andsection "Preparing for test" in this chapter.Measure operating characteristics during constant current conditions. Keep themeasured current as close as possible to its rated value or lower. But make sure it ishigher than the set minimum operating current.Ensure that the maximum continuous current to the IED does not exceed four timesits rated value, if the measurement of the operating characteristics runs underconstant voltage conditions.The test procedure has to take into consideration that the shaped load encroachmentcharacteristic is active. It is therefore necessary to check the setting. To verify thesettings with the shaped load encroachment characteristic the test should be carriedout according to figures 42 and 43 and tables 19 and 20. In cases where the loadencroachment characteristic is activated tests according to the adjusted figuresshould be carried out.To verify the settings for the operating points according to the following fault typesshould be tested:• One phase-to-phase fault• One phase-to-earth faultThe shape of the operating characteristic depends on the values of the settingparameters.The figures illustrating the characteristic for the distance protectionfunction can be used for settings with and without loadencroachment. The solid lines designate the diagram applicablewhen the load current compensation is active. The solid line and alltest points except 13 are valid for this case.When the load current compensation is inactive, the dotted linesand test point 13 are valid. Test points 5, 6, and 7 are not valid forthis measurement.Section 13 1MRK 502 073-UEN ATesting functionality by secondary injection136 Generator protection REG670 2.2 IEC and Injection equipment REX060, REX061, REX062Commissioning manual
