ABB ETL600, Instruction Manual

Page: 154 / 382

ABB Switzerland Ltd
1KHW001489-EN ETL600
According to Table 5-2, the value for v
D2A
lies in the range between 1
and 3. For v
D2A
= 1, the PE-power of the sum of all APLC signals and
DPLC signals are equal., For v
D2A
= 3, the PE-power of the sum of all
APLC signals is 12 dB below RF-PEP, while the PE-power of the
DPLC signal is 2.5 dB below RF PEP.
5.2.13. Weight of the NSD600 guard signal
When a DPLC is configured, it can take a considerable amount of the
available RF power as explained in 5.2.12. When teleprotection
commands are transmitted, the MOD600 signal and other
disconnectable signals are switched off, so that more power can be
given to the teleprotection. This is called boosting, refer to section 0.
The additional power improves the dependability of teleprotection.
However, there are limits to this technique: The teleprotection guard
signal, which is transmitted when the teleprotection is inactive i.e.
during the quiescent state, doesn’t profit from boosting. On the
contrary: When a strong MOD600 signal is present, the level of the
guard signal is reduced. To improve this situation, the NSD600 guard
signal – which always has a weight of at least 0.5 corresponding to a
system level of -6 dBm0 – gets a higher weight so that its RMS power
is at most 18 dB below the PE power of the boosted NSD600
command signal.
When the ETL600 pilot acts as NSD600 guard, it obtains the weight of
the NSD600 guard signal, else the ETL600 pilot has the standard
weight of 0.5.
5.2.14. Internal teleprotection devices NSD600
Regarding internal teleprotection equipment (TPE), the following cases
can be distinguished:
1. No
internal TPE,
2. One NSD600 (called “TPE1” or NSD600#1),
3. Two NSD600 (called “TPE1” or NSD600#1 and “TPE2” or
NSD600#2).
Each internal TPE operates in one of the channels APLC1, APLC2 or
DPLC. The association to the channels is fixed. Thus, operation of
TPE2 is only possible if ETL600 is configured for at least two
channels. The following cases are possible:
5-10 November 2005 Configuration and Set-up