Operation Analysis Of REL511Back-up Distance Protection For Transformer

Power transformer is an important electrical power system equipment, especially330～500kV large transformer, which directly affect the operational status of the entire power network security and stability of the trunk. When a transformer fails, you need timely and accurate transformer removal of faults, so to protect the reliability of operation is directly related to the safe operation of the transformer. A large number of ABB’s REL511device used in the East China Power Grid, as a back-up distance of transformer protection. Actual operation of the device is often abnormal exit the operation, even false to export the accident leading to the transformer trip, resulting in a serious impact on the safe operation of the grid. It is necessary to the health of the device and defects hidden pooled analysis, and propose targeted to improve the design program. In order to study the current REL511protection devices operating conditions, the paper first configuration features of the large-scale transformer protection Background, detailed analysis of the main transformer has been the main protection, it also configure the backup distance protection. This article describes the REL511device characteristics, as well as the distance of the main transformer backup protection features. As in the dual-bus Connection mode, the voltage switching circuit is essential REL511devices collect voltage and voltage lockout circuit, transformer protection is different from the line intervals, generally not equipped with operative box, provided by the REL511protection device itself. This article draw on the research results of the secondary voltage switch circuit in the dual-bus Connection mode and the use of voltage REL511device to switch back to the road. This paper analyzes the East China Power Grid loss of pressure in different types of running REL511device locking manner, Found that the device due to the different stages of secondary voltage break blocking circuit design flaws, resulting in instability of the device running. During the analysis, combined with design features found in the actual operation of accident cases and different types of REL511devices, this article presents the targeted improvements and design practice has proven to be effective to avoid grid accidents.