1、 摘要 大型发变机组是现代电力系统最重要的组成部分之一，它造价昂贵，结构复杂，一旦故障，检修期长，给国民经济造成的直接和间接经济损失巨大。大型发变组保护的拒动和误动，均将产生严重后果，决不可掉以轻心，因此，必然对大型机组的可靠性、灵敏性、选择性和快速性提出了更高的要求。 由于大型发变组不可避免地存在一些故障及不正常运行方式的可能，迅速地切除或隔离故障点，是继电保护的主要任务。本文主要介绍了现代大型发电机一变压器继电保护的配置目的、原理，并系统地介绍了目前大型发变组保护配置的以下主保护及后备保护：发电机差动保 护、变压器差动保护、发电机定子匝间保护、发电机定子接地保护，发电机对称过负荷保护、发电
2、机负序过负荷保护，发电机失磁保护、发电机转子接地保护、发电机 (变压器 )过激磁保护、发电机逆功率保护等。通过对这些保护原理的分析，指出存在的问题，并提出相应的改进措施。同时，本论文还就一些存在争议的问题提出了自己的观点，并对发变组保护发展的趋势作了相应的探讨。 关键词： 主保护；后备保护；存在问题；发展趋势 Abstract Large-scale Generator-Transformer Unit Protection is one of the most important part of the modern electrical power system.Its costly an
3、d complex structured Once it fails， a long term examination and repair is needed It will bring huge economic losses directly and indirectly The incorrect or rejected tripping of Large-scale Generator Transformer Unit Protection will cause serious consequences Therefore， it put forward higher require
4、ments to the reliability , sensitivity, selectivity and speed of Large-scale Generator Transformer Unit Protection There are some inevitable faults and abnormal run mode with Large scale Generator Transformer， therefore， rapid removal or segregation point of failure is the main task of relay protect
5、ion This passage mainly introduces the purposes， principles of the modern Large-scale Generator-Transformer Unit Protection and introduces the following main protections and back-up protections： the generator differential protection， the transformer differential protection， the protection of inter-t
6、urn， the stator ground fault protection， the generator symmetry overload protection， the negative sequence overload protection， the generator excitation loss protection， the rotor earth-fault protection， the generator(or transformer)over excitation protection， the generator reverse power protection， etc. Meanwhile， the author put forward her point of view on some controversial issues The development trend of microcomputer protection is also discussed Keywords: Main Protection； Back-up Protection； Existent Problems； Development Trend
