Checking The Temperature Detection - Siemens 7SK80 Manual

Mounting and Commissioning
3.3 Commissioning
Figure 3-30
3.3.13

Checking the Temperature Detection

Temperature Detection via RTD Box
When connecting an RTD box to the RS485 interface, check the setting of the bus address at the protection
device as described in Section 3.2.
When connecting an RTD box to the Ethernet interface, you have to carry out the preparatory steps for com-
missioning first which are described in the operating instruction. Make sure that the IP address at the RTD box
corresponds to that at the protection device.
If the settings are correct, you can start checking the measured values and thresholds of the temperature.
If temperature sensors with 2-phase connection are used, you must first determine the line resistance for the
temperature detector being short-circuited. Proceed as described in the operating manual. Enter the resistance
value determined for the corresponding sensor at the RTD box (range: 0 to 50.6 Ω).
When using the preset 3-phase connection for the temperature detectors no further entry must be made.
Checking the Measured Temperature Values
Pt100 temperature sensors are standard for temperature detection via both the RTD box and the I/O 2 exten-
sion module. When using Ni100 or Ni120 temperature sensors, the device will convert the temperature dis-
played at the RTD box.
For checking the measured temperature values, the temperature detectors are replaced by adjustable resistors
(e.g. precision resistance decade) and the correct assignment of the resistance value and the displayed tem-
perature for 2 or 3 temperature values from the following table are verified.
344
Polarity testing for I , example with current transformers configured in a Holmgreen-connection
N
(VTs Wye-connected)
SIPROTEC, 7SK80, Manual
E50417-G1140-C344-A5, Release date 11.2012