Method of protecting buses from short circuits

Abstract

The invention relates to electrical engineering, specifically relay protection technology, and can be used as a method for protecting busbars from short circuits in the main circuit of a power plant. The technical result consists of preventing the shutdown of units during a short circuit on the busbar in the event of a failure of the busbar protection measuring element, thereby preventing the power plant from going dark. This is achieved by additionally constantly measuring the voltage U1 at the output of the busbar protection measuring element and the voltage Uвш at the output of the “Off” position relay of four busbar switches, measuring the voltage U2 at the output of the main protection of each of the four lines and Uвл at the output of the “Off” position relay of every two switches of each line, and the voltage U5 at the output of the “Off” position relay of every two switches of each block, voltage U3 and U4 of each of the main and backup protections of the four units and then compare U1 with Ureference1 and U2 with Ureference2, U3 with Ureference3, U4 with Ureference4, U5 with Ureference5, where Ureference1, Ureference2, Ureference3, Ureference4, Ureference5 are specified reference values, and if U1< Ureference1, U2 < Ureference2, U3< Ureference3 and for all four units U4 ≥Ureference4 or U5>Ureference5, or for three units U4 ≥Ureference4 and for the fourth U4< Ureference4 or U5>Ureference5 or for two units U4 ≥Ureference4 and for the other two U4< Ureference4 or U5>Ureference5 or for one U4 ≥Ureference4 or U5>Ureference5, then they start counting down the time, then after counting down the time t = tВО + tоткл + △t (where tВО is the response time of the output bus protection element, tоткл is the time required to turn off the bus switches, △t is the reserve time) they send a signal to turn off all the bus switches, and in the event that any block or line or any bus switch is in the off state during a short circuit on the bus bars, Then, instead of the missing voltages (U2, U3, or U4), the signal voltage from the corresponding "Off" position relays is used. The economic result: the power plant will operate at full capacity without any shortfall in energy output.