Siemens 7SA511 manual Determination of the Fault Loop for Grounded Systems, LCD Text Description

7SA511 Line Protection RelayProgramming the Relay

5.10.7 Determination of the Fault Loop for Grounded Systems (1700)

In phase-selective fault detection systems, the currents and voltages of the fault loop are decisive when calculating the distance to fault. The settings under address block 1700 are applicable for systems with a solidly grounded neutral. Skip this section if the system neutral is ungrounded, (i.e., isolated or compensated).

Table 5-16 lists the presettings and setting options for determination of the fault loop for grounded systems (1700). Compare these presettings to the information on the completed worksheets and determine which settings you need to change to match your operating environment. When you have changed all of the necessary settings, follow the procedure described in section 5.3.4 to save the new settings.

Prerequisite Settings:

Addr.	LCD Text
1102	SYSTEMSTAR
7801	DIST. PROT.

Description

System neutral condition

Distance protection function

Setting

SOLIDLY EARTHED

EXIST

Table 5-16.Settings for Determination of the Fault Loop for Grounded Systems

Addr.

1701

LCD Text

Ue>

Description

Displacement voltage detection for ground fault detection

Preset

20 V

Options/Range

2•- 100 V

1703

1704

1705

2PH-E FLTS

3PH FAULTS

1PH FAULTS

Fault loop measurement controls for double ground faults

Fault loop measurement controls to be used for 3-phase faults

Select the fault loop measurement controls to be used for single- phase faults

PHASE-PHASE LOOP

E/F CONTROL

PHASE-EARTH

LEADING PH-E LAGGING PH-E

￿PH-PH ONLY PH-E ONLY

PHASE-PHASE

5.10.8 Determination of the Fault Loop for Ungrounded Systems (1800) (Optional)

In phase-selective fault detection systems, the currents and voltages of the fault loop are decisive when calculating the distance to fault. The settings under address block 1800 are applicable for networks with an isolated or compensated neutral. Skip this section if the system neutral is grounded.

Table 5-17 lists the presettings and setting options for determination of the fault loop for ungrounded systems (1800). Compare these presettings to the information on the completed worksheets and determine which settings you need to change to match your operating environment. When you have changed all of the necessary settings, follow the procedure described in section 5.3.4 to save the new settings.

Prerequisite Settings:

Addr.	LCD Text
1102	SYSTEMSTAR
7801	DIST. PROT.

Description

System neutral condition

Distance protection function

Setting

￿COMPENSATED ISOLATED

EXIST

5-32 July 27, 1995