2 Functions
44
7SA522 Manual
C53000-G1176-C155-3
setting values which depend on this distance unit. They have to be re-entered into their
corresponding valid addresses.
Mode of Earth Im-
pedance (Residual)
Compensation
Matching of the earth to line impedance is an essential prerequisite for the accurate
measurement of the fault distance (distance protection, fault locator) during earth
faults. In address )RUPDW== the format for entering the residual compen-
sation is determined. It is possible to either use the ratio 5(5/;(;/ or to enter
the complex earth (residual) impedance factor .. The actual setting of the earth (re-
sidual) impedance factors is done in the power system data 2 (refer to Section 2.1.5).
Operating Time of
the Circuit Breaker
The circuit breaker closing time 7&%FORVH at address is required if the device
is to close also under asynchronous system conditions, no matter whether for manual
closing, for automatic reclosing after three-pole tripping, or both. The device will then
calculate the time for the close command such that the voltages are phase-synchro-
nous the instant the breaker poles make contact.
Trip Signal Dura-
tion
In address the minimum trip command time 70LQ75,3&0' is set. This setting
applies to all protective functions that initiate tripping. It also determines the length of
the trip pulse when a circuit breaker trip test is initiated via the device. This setting is
only possible via DIGSI
®
at "Additional Settings".
In address the maximum close command duration 70D[&/26(&0' is set. This
applies to all close commands issued by the device. It also determines the length of
the close command pulse when a circuit breaker test cycle is issued via the device. It
must be set long enough to ensure that the circuit breaker has securely closed. There
is no risk in setting this time too long, as the close command will in any event be ter-
minated following a new trip command from a protection function. This setting is only
possible via DIGSI
®
at "Additional Settings".
Circuit Breaker Test 7SA522 allows a circuit breaker test during operation by means of a tripping and a
closing command entered on the front panel or via DIGSI
®
. The duration of the trip
command is set as explained above. Address 7&%WHVWGHDG determines the
duration from the end of the trip command until the start of the close command for this
test. It should not be less than 0.1s.
2.1.3.2 Settings
Addresses which have an appended "A" can only be changed with DIGSI, under Ad-
ditional Settings.
Addr. Parameter Setting Options Default Setting Comments
201 CT Starpoint towards Line
towards Busbar
towards Line CT Starpoint
203 Unom PRIMARY 1.0 .. 1200.0 kV 400.0 kV Rated Primary Voltage
204 Unom SECONDARY 80 .. 125 V 100 V Rated Secondary Voltage (L-L)
205 CT PRIMARY 10 .. 5000 A 1000 A CT Rated Primary Current
206 CT SECONDARY 1A
5A
1A CT Rated Secondary Current
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