Buchholz Relay Protection - Ansi Code 63 - Iskra FPC 200 User Manual

Functionality
Buchholz relay protection – ANSI code 63
2.5.6.1 Description
Buchholz relay protection is external protection that
mechanically controls oil level and oil flow in certain
power transformers. Protection consists of two
instances one dedicated to Leak and pressure switch
and second to Float switch. Float switch indicates slow
air build up in Buchholz cylinder, usually indicating
minor discharge fault in transformer. While Leak and
pressure switch detects forceful oil flow usually
indicating major short-circuit related fault in
transformer.
2.5.6.1.1 Setting parameters
Parameter
Enabled
Operate mode
Trip delay
Pickup delay
Drop-out delay
Pickup block
Table 48 Buchholz function parameters.
2.5.6.1.2 Associated digital inputs
Digital input
Buchholz 1
Buchholz 2
Table 49 Digital inputs associated with the protection.
2.5.6.1.3 Counters
Name
Pickup
Trip
Table 50: Counters presented in buchholz protection.
58
Range
No
Yes
Off
On
0,00 ... 1,00 ... 300,00 s
0 ... 5 ... 1000 ms
0,00 ... 0,20 ... 60,00 s
None
Variable 1
Variable 2
Variable 3
Variable 4
Description
External trigger of Buchholz relay 1 protection.
External trigger of Buchholz relay 2 protection.
Description
Total consecutive number of pickup signals.
Consecutive number of trip signals.
Float switch
Leak and
preassure switch
Figure 2.35 Schematic of Buchholz relay operation.
It is recommended that pressure switch
immediately trips CB while float switch
indicates fault that needs to be treated as
soon as possible to prevent further damage
to transformer.
Description
Enabling protection function.
Enabling protection function separately for each group level.
Delay of trip signal.
Time stabilization of fault detection. As a filter of short disturbances on
measuring circuits. Time before protection starts.
Time stabilization of pickup signal. Time when the monitored value is
outside the operating range, but the protection does not stop yet.
Source of blocking signal.
USER MANUAL FPC 200 - 3/2017