摘要
110kV变压器低压侧近区出现短路故障后,变压器绕组会承受较大电流,多次短路电流冲击会对变压器造成较大损坏。本文介绍了一种变压器近区短路电流在线监测设备的设计方案,设备采用四引线法测量三相电流,设计了以CPLD为核心的量程自动适应电路,解决了信号变化范围大,采样精度低的问题。以TMS320F2812和LPC2220作为嵌入式微处理器,双处理器之间由双口RAM处理数据交互,提高了设备的数据处理能力和可扩展性。设备能实时采集正常运行状态以及短路故障状态下的电流,通过FFT计算出电流特征值,并存储短路故障波形,该设备的应用为检修时对变压器进行状态评估,提供了真实可靠的依据。
When a short-circuit fault occurs on the secondary side of 110kV transformer, a large current may flow through transformer windings. Under the repeated shorts the transformer would be damaged. To solve this problem, an on line monitoring equipment is introduced in the paper to detect the three phase short-circuit current using the four-wire method. An auto-range measuring circuit based on CPLD is designed to solve the problem of wide signal range and low sampling accuracy. To enhance data processing capability and system scalability, TMS320F2812 and LPC2220 are employed as embedded microprocessors, and a dual-port RAM is used to perform data interaction. The equipment can collect real-time current data both in normal operation and in fault states. Using the acquisition data, the characteristic values can be calculated with FFT, and the waveform of short-circuit current can be stored. Application of the monitoring equipment provides a real and reliable basis for evaluation of the transformer during the maintenance of the power grid.
出处
《电测与仪表》
北大核心
2013年第12期91-95,共5页
Electrical Measurement & Instrumentation
