Considerations about the Development of Protective Devices on the Increase Safety in Exploitation of the Electric Power Transformers
Journal Title: ANALELE UNIVERSITATII DIN CRAIOVA - Seria Inginerie electrica - Year 2013, Vol 37, Issue 37
Abstract
Installations and devices of the protection, mounted on transformer, are: oil conservator, gas relays, thermo-siphon filters, air filters, safety valves and thermal image (thermo-copy). Here are some contributions to the development of devices to increase safety in exploitation of power transformers such as gas protection on-line and relay protection for on-load-tap-changers. The constructive principles of gas Buchholz relay (patented in 1921) remained generally unchanged, as with all the past nearly 100 years. In the exploitation of electrical power transformers have been noticed, on the basis of statistics prepared in the USA since 1947, a number of inconveniences. In first place is erroneous operation of lifting-contacts with mercury, in terms of vibrations, as for example disconnection of power transformers through gas protection, in high voltage stations of Romania, at the 1977 earthquake. As a result, in practice showed various models: gas relays with magnetic contacts, gas relays with cups and resort, gas relays with bellows, electronic gas relays and others. These have a correspondent to the versions equipped with a single float that are used as protection for on-load-tap-changers. For this reason, we have studied and protection of on-load-tapchanger, that command disconnecting breakers of the transformer, when current speed of oil through pipe, from tank of the on-load-tap-changer to the oil conservator, exceeds a threshold value. Thus, the capacitor C2 (from the scheme of the gas protection on-line for power transformers), patented individually under the name Flag to flow velocity, meets all conditions in order to provide as protection for the on-loadtap- changer. Protections gas integration in SCADA (Supervisory Control and Data acquisitions) is the last issue addressed before final conclusions.
Authors and Affiliations
Tiberiu-Octavian Cujba
Keywords
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