Changing The Transformation Ratios Of The Transformer On The Device - Siemens 6MD85 Manual

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Figure 3-100
If you have already set the settings in the secondary view by including the new transformation ratio of the
transformer in the calculation, then answer the question with No. In this case, the protection settings in the
secondary view remain unchanged. DIGSI 5 recalculates the settings (threshold values) of the primary view. In
the example, the primary threshold value is then 300 A (1.5 A * 1000 A/5 A = 300 A).
In the example, the current-transformer ratio changes from 1000 A/1 A to 1000 A/5 A. The following table
summarizes the pickup values that DIGSI 5 will recalculate in the setting view. The new values (in bold)
depend on the answer of your query (see
Threshold value secondary (active setting view)
Threshold value primary (covered setting view)
3.9.3

Changing the Transformation Ratios of the Transformer on the Device

The device is preset to the secondary value at the time of delivery. Only secondary values can be set directly
on the device.
If you change transformer data directly on the device, it is not followed by a query, like in DIGSI 5 (see
Figure 3-99). Instead, the device assumes that all settings remain unchanged in the secondary view.
NOTE
i
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If the device works with IEC 61850 protocol, you change the transformer data only via DIGSI 5 and not
directly on the device. If you change the transformer data directly on the device, the IEC 61850 configura-
tion of the measurement and metered values can be faulty.
SIPROTEC 5, High-Voltage Bay Controller, Manual
C53000-G5040-C015-9, Edition 11.2017
Automatically Recalculated Secondary Values After Changes in the Transformer Data
Figure
3.9 General Notes for Setting the Threshold Value of Protection Functions
3-99).
System Functions
Reply to the Question
Yes No
7.5 A 1.5 A
1500 A 300 A
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