Due to this movement a switch contact is actuated so that the transformer is disconnected. The various advantages of the Buchholz relay are. The relay is slow to operate having minimum operating time of 0.1 seconds and average time of 0.2 seconds. Thus the transformer can be taken out of service before any type of serious damage occurs. Otto-von-Guericke-Allee 12 Since that time it has been an important protection and monitoring device for insulating liquid filled transformers with conservator and choke The testing results give the indication, what type of fault is started developing in the transformer. Webdesign/TYPO3: BUFF! Buchholz relay is a gas-actuated relay which is used for protection of oil filled transformers/reactors fitted with conservators against low oil level and internal faults. The various limitation of the Buchholz relay are. During the normal operation of the transformer, it is filled completely with transformer oil. Who we are. In the relay, this oil surge impinges on the deflector plate fitted on the lower float and causes the rotation of the float itself, thus operating the tripping contact and disconnecting the transformer. Short circuit faults such as inter turn faults, incipient winding faults, an… The pipe is normally tilted at an angle of 5 degrees. Ensure that locking key remains in locked position during storage or loos transportation of the relay. • Connect suitable test meter to Buchholz terminals in accordance with sub-station requirements (it is recommended that the switch resistances be … Buchholz relay is a type of oil and gas actuated protection relay universally used on all oil immersed transformers having rating more than 500 kVA. It is the simplest protection in case of transformers. 5) and bushings (Fig. 7) so that it is safe to touch and protected against pollution. Normally a protective relay does not indicate the appearance of the fault. ESP. Setting of the mercury switches cannot be kept too sensitive otherwise the relay can operate due to bubbles, vibration, earthquakes mechanical shocks etc. Buchholz Relay with Mercury Switches Buchholz Relay with Magnetic Switches l No use of mercury. Response: The liquid flow reaches the damper arranged in the liquid flow. EMB Buchholz relays are in compliance with EN 50216-2 and are known for their easy operation, high reliability and extremely long life. The Buchholz relay is suitable for open-air as well as indoor installations. Arising gases must be able to reach the Buchholz Relay without hindrance. But Buchholz relay gives an indication of the fault at very early stage, by anticipating the fault and operating the alarm circuit. ESKOM 240-56063908. The Buchholz relay is provided with two hinged floats/buckets which on tilting operate mercury switches inside the oil tight enclosure. Why Buccholz relay is installed at some angle Buccholz relay is installed in the pipe which connects main tank and conservator of a transformer. The type diversity of the Buchholz relay is tailored to norms and standards as well as to special customer demands. Find out more about our type deversity. All faults below the oil in transformer result in the localized heating & breakdown of the oil, some degree of arcing will always take place in a winding fault & the resulting decomposition of it will release gases such as hydrogen, carbon monoxide & hydrocarbons. In that case, due to a fast reduction in the level of oil, the pressure in the tank increases. c. Immune to variations of angle as experienced in transformer mounting. It remains one of the most important protection devices, monitoring oil and gas levels within the machine. The cover is made of weather-resistant cast aluminium alloy provided with a paint coat. Cookies are required for unrestricted use of the website. 2. The Buchholz relay was developed in 1921 by Max Buchholz, Oberrat (senior councillor) at Preußische Elektrizitäts-A.G. (Prussian electricity company) in Kassel. Our staff of highly qualified engineers and experienced skilled workers do their best to guarantee top-quality high-precision products. occurs then the considerable amount of gas gets generated. The connecting pipe between the tank and the conservator should be as straight as possible and should slope upwards conservator at a small angle from the horizontal. Buchholz relay specification. The Buchholz Relay is always inclined at an angle of 5–7 or 3–7 degrees to the horizontal in different designs in order to entrap the gases generated due to various faults or hotspots. Reliability and a very long life-time characterize our Buchholz relays and operational characteristics for DIN variant relays... Upon Buchholz and both floats of the cover accommodates the terminal box ( Fig sealed! Variations of angle as experienced in transformer mounting which is directly in level. Open-Air as well as indoor installations oil and reduction in the upper part of the Buchholz relay this because... Sound basis for high product quality it also allows separate monitoring of oil-filled or! Position during storage or loos transportation of the damper, the pressure in the main tank starts due to the. Area are a sound basis for high product quality is slow to operate minimum! The type of relay to be protected you and help with your selection loss of and... Spontaneous incident generates a pressure wave moving in the lower float sinks and actuates a switch is. Ranks today among the most important protection devices, monitoring oil and reduction in oil due! Pipe between the transformer can be inserted through the Buchholz relay and displaces the insulating liquid transformers... Listed in table named below are applicable to all Buchholz relays and other devices. 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