Siemens siprotec 7SA522 User Manual

3 Mounting and Commissioning
414
7SA522 Manual
C53000-G1176-C155-3
If the measured values are not plausible, the connection must be checked and correct-
ed after the line has been isolated and the current transformer circuits have been
short-circuited. The measurements must then be repeated.
Phase Rotation The phase rotation must correspond to the configured phase rotation, in general a
clockwise phase rotation. If the system has a counterclockwise phase sequence, this
must have been considered when the power system data was set (address 
3+$6(6(4). If the phase rotation is incorrect, the alarm ´)DLO3K6HTµ (FNo
171) is generated. The measured value phase allocation must be checked and cor-
rected, if required, after the line has been isolated and current transformers have been
short-circuited. The measurement must then be repeated.
Voltage
Transformer
Miniature Circuit
Br e a k er ( V T m cb)
Open the miniature circuit breaker of the feeder voltage transformers. The measured
voltages in the operational measured values appear with a value close to zero (small
measured voltages are of no consequence).
Check in the spontaneous annunciations that the VT mcb trip was entered (message
´!)$,/)HHGHU97µ “ON” in the spontaneous annunciations). Beforehand it has to
be assured that the position of the VT mcb is connected to the device via a binary
input.
Close the VT mcb again: The above messages appear in the spontaneous messages
as “OFF”, i.e. ´!)$,/)HHGHU97µ “OFF”.
If one of the annunciations does not appear, check the connection and allocation of
these signals.
If the “ON” state and “OFF” state are swapped, the contact type (H–active or L–active)
must be checked and remedied.
If a busbar voltage is used (for voltage or synchronism check) and the assigned VT
mcb is connected to the device, the following function must also be checked:
If the VT mcb is open the message ´!)$,/%XV97µ “ON” appears, if it is closed the
message ´!)$,/%XV97µ “OFF” is displayed.
Switch off the protected power line.
3.3.8 Direction Check with Load Current
≥ 10 % of Load
Current
The correct connection of the current and voltage transformers is checked via the pro-
tected line using the load current. For this purpose, connect the line. The load current
the line carries must be at least 0.1 · I
N
. The load current should be in-phase or lagging
the voltage (resistive or resistive-inductive load). The direction of the load current must
be known. If there is a doubt, network or ring loops should be opened. The line
remains energized during the test.
The direction can be derived directly from the operational measured values. Initially
the correlation of the measured load direction with the actual direction of load flow is
checked. In this case the normal situation is assumed whereby the forward direction
(measuring direction) extends from the busbar towards the line (see the following Fig-
ure).
P positive, if active power flows into the line,
P negative, if active power flows towards the busbar,
Q positive, if reactive power flows into the line,

Siemens siprotec 7SA522 Specifications

General

Brand	Siemens
Model	siprotec 7SA522
Category	Protection Device
Language	English