Safety
Safety instructions
Make sure that any person installing, taking into operation
and operating the Buchholz Relay:
• Is technically qualified and competent.
• Fully comply with these assembling instructions.
Improper operations or misuse could cause danger to:
• life and limb.
• to the equipment and other assets of the operator.
• to the equipment proper function.
Opening of the device will void your warranty.
Safety instructions in this manual are shown in three diffe-
rent forms to emphasize important information.
WARNING
This information indicates particular danger to life and health.
Disregarding such a warning can lead to serious or fatal injury.
CAUTION
This information indicates particular danger to equipment or
other property of the user. Serious or fatal injury cannot be
excluded.
This notes give important or specific information concerning the
equipment or as to work with the equipment.
Safety notes on the equipment operation
Electrical installation is subject to the relevant national
safety rules.
It is mandatory to connect the grounding cable because of
safety reason.
CAUTION
Installation, electrical connection and fitting the device may only
be performed by qualified personnel and only in accordance
with this instruction manual.
It is the responsibility of the user to ensure that the device is
used for specified application only.
For safety reasons, please avoid any unauthorized and improper
usage.
WARNING
All relevant fire protection regulations must be strictly followed.
4
NOTE
Product description
The Buchholz Relay is used to protect the transformer
when a malfunction occurs (high eddy current, local
overheating or partial discharges) inside the main tank.
WARNING
It is important to observe the limit values indicated on
the nameplate and in the operating instruction before
commissioning the device.
The generation of gas in an oil filled transformer is a clear
indication of a problem. The gas may be a result of the
following:
• Decomposition/degradation either of solid or liquid
insulation inside the transformer due to overheating, or
arcing.
• From external environment through bad pipeline sealing.
• From the oil itself due to unsatisfactory de-gassing
operations prior filling transformer main tank.
The Buchholz relay is placed in the pipework between the
transformer and its conservator and it is filled with oil du-
ring normal transformer operation. When gas is generated
in the transformer it rises towards the conservator and
collects in the upper chamber of the relay.
The oil level drops and the top float triggers alarm switch.
Gas shall not freely pass from the relay body and escape
into the pipework before the alarm contact has operated.
Moreover this relay operates in case of abnormal oil flow
from the transformer tank to the conservator. If it happens
the flow vent moves the support of magnets that switches
the trip reeds.
Installation
Assembly
CAUTION
The operating and installation requirements described in this
manual must be strictly followed. If not, the device can be
damaged or a malfunction may occur.
Buchholz Relay (A/1) is installed in the pipe (Fig.A/2)
between the transformer tank (Fig.A/3) and the oil
conservator (Fig.A/4). Make sure that the pipe and the BR
Buchholz Relay have the same nominal diameters.
The red arrow on the cover at the top of the relay should
always point towards the oil conservator.
The Buchholz relay must initially be full of oil which means
that the minimum oil level of the conservator must be
higher than the discharge valve on the top of the relay.
BUCHHOLZ RELAYS