Functions
2.17 Additional Functions
SIPROTEC, 7SD610, Manual
C53000-G1176-C145-6, Release date 02.2011
250
2.17.4 Measurement During Operation
2.17.4.1 Function Description
A series of measured values and the values derived from them are available for on-site retrieval or for data
transfer.
A precondition for the correct display of primary and percentage values is the complete and correct entry of the
nominal values of the instrument transformers and the power system as well as the transformation ratio of the
current and voltage transformers in the earth paths.
Display of measured values
Operational measured values and metered values are determined in the background by the processor system.
They can be called up on the front of the device, read out via the operator interface using a PC with DIGSI, or
transferred to a control centre via the system interface.
Table 2-11 shows a survey of the measured values of the local device. Depending on the version ordered, the
connection of the device, and the configured protection functions, only a part of the measured operating values
listed is available.
Phase-to-earth voltages can only be measured if the phase-to-earth voltage inputs are connected. The dis-
placement voltage 3U
0
is e-n-voltage multiplied by v3 — if U
en
is connected — or calculated from the phase-
to-earth voltages 3U
0
=|U
L1
+U
L2
+U
L3
|. All three voltage inputs must be phase-earth connected for this.
Both devices connected via the protection interface form a joint frequency value (constellation frequency). This
value is displayed as the operational measured value „Frequency“. It allows to display a frequency even in
devices in which local frequency measurement is not possible. The constellation frequency is also used by the
differential protection for synchronizing the measured values. Locally operating functions always use the locally
measured frequency.
If the device is in „Log out device“ ON mode, in differential protection test mode or if there is no protection data
interface connection, the locally measured frequency is displayed.
For the thermal overload protection, the calculated overtemperatures are indicated in relation to the trip over-
temperature. Overload measured values can appear only if the overload protection was configured Enabled.
The power and operating values upon delivery are set such that power in line direction is positive. Active com-
ponents in line direction and inductive reactive components in line direction are also positive. The same applies
for the power factor cosϕ.
It is occasionally desired to define the power drawn from the line (e.g. as seen from the consumer) positively.
Using parameter 1107 P,Q sign the signs for these components can be inverted.
The computation of the operational measured values is also executed during an existent system fault in inter-
vals of approx. 0.5s.
To Next Page
Loading...
Need help?
General