Micom P634 - Transformer Monitoring (Function Group TRMON)

3.34 Transformer Monitoring (Function Group TRMON)
Big transformers are usually fitted with one or more Buchholz relays.
A Buchholz relay detects gases that arise due to normal ageing processes of the
transformer insulation. After a sufficient amount of gas has accumulated, the
alarm contact is activated. This measurement principle has the effect that the
alarm is also activated if the filling level of the insulating oil sinks below the
mounting place of the Buchholz relay due to a leakage. Since in such a case the
filling level sinks quite rapidly, it is common to have a separate detection
hardware for this, which then issues an insulation alarm.
Additionally, a Buchholz relay monitors the rate of oil flow. In case of an inner
short-circuit fault gas arises from the fault location, and the gas pushes some
part of the insulating oil into the equalizing tank. The Buchholz relay reacts to
this by closing its release contact.
The number of such relays mounted at the transformer is dependent on the size
and construction details (e. g. 3-phase or three single-phase transformers, with or
without tap changers, etc.)
The P634 features dedicated input signals for determining the alarm and triping
signals of up to 3 Buchholz- / insulation monitoring relays. The P634 records
these input signals, issues them via the communication interfaces or converts
them to user-defined signals and / or trip commands.
It is recommended with respect to a safe transformer protection that a Buchholz
trip always directly opens the circuit breaker. This means that routing the
Buchholz trip to the P634 is advisable only for reporting purposes, or for
triggering a second, independent tripping system.
1: Yes
0: No
TRMON:
General enable USER
[ 018 040 ]
0
TRMON:
Insul. Alarm 1 EXT
[ 016 241 ]
TRMON:
Buchholz Alarm 1 EXT
[ 016 242 ]
TRMON:
Buchholz Trip 1 EXT
[ 016 243 ]
TRMON:
Insul. Alarm 2 EXT
[ 016 244 ]
TRMON:
Buchholz Alarm 2 EXT
[ 016 245 ]
TRMON:
Buchholz Trip 2 EXT
[ 016 246 ]
TRMON:
Insul. Alarm 3 EXT
[ 016 247 ]
TRMON:
Buchholz Alarm 3 EXT
[ 016 248 ]
TRMON:
Buchholz Trip 3 EXT
[ 016 249 ]
49Z8942A
TRMON:
Insulation Alarm 1
[ 016 250 ]
TRMON:
Buchholz Alarm 1
[ 016 251 ]
TRMON:
Buchholz Trip 1
[ 016 252 ]
TRMON:
Insulation Alarm 2
[ 016 253 ]
TRMON:
Buchholz Alarm 2
[ 016 254 ]
TRMON:
Buchholz Trip 2
[ 016 255 ]
TRMON:
Insulation Alarm 3
[ 018 007 ]
TRMON:
Buchholz Alarm 3
[ 018 016 ]
TRMON:
Buchholz Trip 3
[ 018 039 ]
c
1
Fig. 3-173: TRMON transformer monitoring: Enabling, disabling and signals.
P634
3 Operation
3-218 P634/EN M/R-42-A // P634‑311‑653