4
Safety Product description
Installation
Safety instructions
Make sure that any person installing, taking into operation
and operating the electronic Buchholz relay:
• Is technically qualied and competent.
• Fully complies 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.
Safety instructions in this manual are shown in three diffe-
rent forms to emphasize important information.
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.
This information indicates particular danger to life and health.
Disregarding such a warning can lead to serious or fatal injury.
It is important to observe the limit values indicated on
the nameplate and in the operating instruction before
commissioning the device.
All relevant fire protection regulations must be strictly followed.
This information indicates particular danger to equipment and/
or other property of the user. Serious or fatal injury cannot be
excluded.
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.
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.
These notes give important or specific information concerning the
equipment or as to work with the equipment.
WARNING
WARNING
WARNING
CAUTION
CAUTION
CAUTION
NOTE
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.
The Buchholz relay is located in the pipework between the
transformer and its conservator and it is lled 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 oat triggers alarm switch.
Gas shall not freely pass from the relay body and escape
into the pipework before the alarm contact has operated.
The double ow vanes ensure the detection of two thre-
sholds of oil ow speed. In particular, an alarm and a trip
signal are independently generated at two different values
of oil ow (e.g. alarm at 1.5m/s and trip at 3m/s).
The standard electro-mechanical features, an electronic
transducer and a dedicated PCB allow you to constantly
monitor the gas accumulation in the Buchholz relay by
4-20mA analog output or MODBUS RTU protocol.
Assembly
Electronic Buchholz Relay eBR (A/1) is installed in the
pipe (A/2) between the transformer tank (A/3) and the oil
conservator (A/4). Make sure that the pipe and the eBR
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 eBR 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 (5/C).
The recommended angle of inclination of the eBR pi-
pework should be between 0 to 5 degrees. The pipe from
the transformer to the eBR must exit the transformer at
the highest point, it must be straight and the recommen-
ded length to the relay should be 10 times the internal
diameter of the pipe (L1). The distance between the eBR
and the conservator should be at least 3 times the internal
diameter of the pipe (L2).
ELECTRONIC BUCHHOLZ RELAYS eBR
