Relay protection configuration and setting method for high-voltage power distribution system of ferroalloy electric furnace

Abstract

The invention discloses a relay protection configuration and setting method for a high-voltage power distribution system of a ferroalloy electric furnace. The method comprises overload protection, instantaneous current quick-break protection and low-voltage locking overcurrent protection, wherein the instantaneous current quick-break protection serves as main protection, and is set to be effectivewhen a short-circuit fault occurs in the transformer; the low-voltage locking overcurrent protection serves as backup protection of the instantaneous quick-break protection and is set to be effectivewhen a small-current grounding fault of the transformer occurs; and inverse time limit overload protection has an inverse time limit characteristic, is used as backup protection of the instantaneousquick-break protection and the low-voltage blocking overcurrent protection, is matched with an operation curve of the ferroalloy electric furnace transformer by utilizing an inverse proportion relation between time and current, and does not act during normal production. Each kind of protection can be used as backup protection of the next kind of protection, especially in an ungrounded system withthe high voltage side being a neutral point or places away from an electric power system. Although the fault current is small, the applied low-voltage locking overcurrent protection and the inverse time limit overload protection can be effective.

Description

technical field [0001] The invention relates to the technical field of energy generation, supply and distribution, and in particular to a relay protection configuration and setting method for a high-voltage power distribution system of a ferroalloy electric furnace. Background technique [0002] The ferroalloy electric furnace transformer is a kind of submerged arc furnace transformer. Because its load characteristics are similar to those of the electric arc furnace transformer, the relay protection function of its electrical system is one of the most important technical indicators to ensure the safety and stable operation of the equipment, especially the overload Protect. At present, the main setting calculation methods are as follows: [0003] "Iron and Steel Enterprise Electric Power Design Manual" Volume 1 P706, the protection and setting calculation of the ferroalloy furnace transformer should be set according to the requirements of Table 1. [0004] Table 1 Setting c...

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Problems solved by technology

[0007] At present, before the ferroalloy electric furnace is put into operation, there are no national unified standards and regulations for the relay protection setting of the microcomputer, so that the configuration scheme and setting of the relay protection remain on the traditional relay scheme, and the protection scheme is too simple. There are two schemes of "quick break" and "definite time" protection, which cannot meet the operation of modern large-scale submerged arc furnace equipment, especially in places where the high voltage side is a neutral point ungrounded system or is far away from the power system. Due to the small fault current, according to The configuration setting method in Table 1 cannot meet the action requirements and cannot quickly remove the fault

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