Siemens 7SA511 manual Impedance Fault Detection Test optional, Prerequisite Setting Addr LCD Text

7SA511 Line Protection Relay Acceptance Tests

6.Using a phase-to-phase input voltage, set the test voltage of the tested loop to approximately the rated voltage (VN SECOND at address 1104; factory preset is 100 V). Set the test current of both the phases to twice the setting value IPH> at address 1611 (factory preset is 0.20 IN) The phase relationship of the test voltage and test current is irrelevant.

7.Slowly decrease voltage until the fault detector picks up. Pickup occurs for both the tested phases when the test voltage goes below the set value of addresses 1614 and 1615 (factory preset is 80 V). With factory preset I/O configuration the following LEDs will light for the tested phases.

LED 2 and LED 3 for phase loop 1-2

￿LED 3 and LED 4 for phase loop 2-3 LED 2 and LED 4 for phase loop 1-3

If the voltage dependent branch is inclined, the expected pickup value of the voltage can be calculated according to the following formula, provided the test current is 2 times the setting value of Iph>:

⎡		Iph	>			⎤
Pickup value V = V(I >) + [V(I >>) − V(I >)] ⎢						⎥
		>>	- I
⎢ I	ph			ph	> ⎥
⎣						⎦

where:	V(I>) =	Vphe(I>) (address 1613) with phase-to-ground voltage
		Vphph(I>) (address 1615) with phase-to phase voltage
	V(I>>) =	Vphe(I>>) (address 1612) with phase-to-ground voltage
		Vphph(I>>) (address 1614) with phase-to phase input voltage
	Ip > =	setting at address 1611
	Iph >> =	setting at address 1601

3.9.3 Impedance Fault Detection Test (optional)

This test checks the operation of the optional impedance fault detection element. The relay model number must be 7SA511*-**A52-**** for this test to be applicable. Testing requires the use of a three-phase voltage source with clockwise rotation and a single-phase current source.

Prerequisite Setting

Addr.	LCD Text
7802	DIST.F.DET

Description

Select the type of fault detection system

Setting

IMPEDANCE ZONE

Test Procedure

Feed a test current of 2IN into the loop under test. If the test voltage will exceed the rated voltage when the threshold is reached, reduce the test current (minimum current Iph> at address 1621 must still be exceeded). Test current must be kept constant during this test.

July 27, 1995 3-19