为了更准确地监测电力系统的运行状况，提出了一种应用于电力变压器局部放电（partial discharge，PD）检测的分立式多点检测方案。该方案基于光纤外差式干涉原理，传感系统由4个传感头构成，以实现多点检测和局部放电声源的定位。通过优化设计传感头的结构提高了传感器的灵敏度，同时传感器紧凑型的封装方式使其能够安装在电力变压器内部，提高检测结果的准确度。实验结果表明，该传感方案的单通道分辨率可达4 mrad，同时对构造的三相电力变压器模型进行了实验演示和分析，在对150 kHz局部放电超声多通道测量时，可实现声源定位的分辨率为 1 cm。由于该方案结构小巧、分辨率高及成本低廉，其在电力系统安全检测中有着巨大的应用潜力。

In order to monitor the working condition of the power system more accurately, a discrete multi-point detection scheme applied to partial discharge (PD) detection of power transformers was proposed. Based on the heterodyne interference principle of optical fiber, the sensing system was composed of four sensing heads to realize multi-point detection and partial discharge source localization. The sensitivity of the sensor was improved by optimizing the structure of the sensor head. At the same time, the compact package of the sensor enabled it to be installed in the power transformer, which improved the accuracy of the detection results. The experimental results show that the single-channel resolution of the proposed sensing scheme can reach 4 mrad. The constructed three-phase power transformer model is experimentally demonstrated and analyzed, and the resolution of sound source localization can be 1 cm when the 150 kHz PD ultrasonic multi-channel measurement is carried out. Because of its compact structure, high resolution and low cost, the proposed scheme has great application potential in security detection of power system.