3.1.5 Faulty phase identification with load encroachment for mhoFMPSPDISThe function is based of different principles to identify the fault type. The signals from thedifferent fault identification algorithms are combined in selection logic.The advanced parameters for faulty phase identification are chosen to the default settingvalues.1. Set IMaxLoad to 90 % of IBase 1000 AThe maximum load current for identification of three phase fault is calculated as:1 2 180 0 903 138.IMaxLoad . kA׳ =×GUID-0BF144D9-D5AC-490D-9CF5-2C67C4352ADA V1 EN (Equation 19)2. Set RLd to 70 ΩThe minimum apparent resistance during non-faulted conditions is calculated as:( )22 0 9 1380 8 85 7180minext ,max.VRLd . .P×£ × = = WGUID-AA7CA356-FAA7-4504-8BA0-C8ADDFC40C68-ANSI V1 EN (Equation 20)3. Set LdAngle to 30ºIt is normally considered that the apparent impedance during non-faulted conditionhas a phase angle in the range ± 30º.3.1.6 Calculating settings for scheme communication logic with deltabased blocking scheme signal transmit ZCPSCH (85)The communication logic is used to assure fast fault clearance for all faults along the line,that is also for faults outside the zone 1 reach of the distance protection. The logic for thecommunication schemes requires a communication link between the distance protectionon the two line ends. The communication link alternatives are:• Power line carrier (PLC)• Microwave link (radio)• Optic fibre linkThe following alternatives for communication scheme are possible:1MRK 506 334-UUS A Section 3REL650 setting examples57Application manual
