随着电力系统的发展，电网的容量，电压等级不断提高，大型高压变压器作为电能传送的枢纽，它的安全运行与否，直接关系到电力系统能否连续稳定地工作。特别是由于大型变压器结构复杂、造价昂贵，一旦发生严重故障而损坏，将给维修工作带来很大困难，造成经济上的重大损失。微机继电保护系统作为一种能反映电力系统故障和不正常状态、及时动作于断路器跳闸或发出信号的自动化设备能自动、迅速和有选择地切除故障组件，使系统免遭损坏。因此对于研制开发性能优良的变压器微机保护装置具有十分重要的现实意义。

本论文在现有的变压器主、后备保护原理和配置方案的研究基础上，设计了一种保护配置方案；利用谐波比率差动、瓦斯保护配以电流保护、过负荷保护等，形成了变压器保护的综合方案；该方案具有较高的速动性、灵敏性、可靠性、抗干扰等性能。论文介绍了装置的硬件结构和软件设计，硬件上采用基于高性能的ARM系列AT91M55800A芯片作为硬件平台，软件上采用模块化编程的方法，该设计方案可以更好的满足设计要求。

关键字：变压器保护，微机保护，AT91M55800A

-With the development of power systems, power grid capacity and voltage level are rising.large-scale high-voltage transformer is the power transmission hub, and its safe operation is directly related to the continuous and stable electric power systems which could work or not. In particular, a large transformer structure as complex and expensive machine is damaged, maintenance work will bring much difficulty, causing economic losses. Computer Relay Protection System can reflect the power system as a fault and not normal, timely acting in the circuit breaker or automatically sending signal.it is the device that could automatically, quickly and selectively remove fault component and prevent the system from damage. Therefore, it is of great practical significance for excellent structure of the developed transformer protection

The paper designed a protection configuration on the basis of the research program in the current transformers, protection principle and configuration. It forms a com