Study on the influence of low temperature FOCT state parameters

Fiber-optic current transformer (FOCT) is widely used in DC power transmission and transformation system of power grid. Power grid users pay attention not only to its measured output value, but also to its state quantity. They expect to find equipment failure in advance by monitoring the internal state parameters of optical path and reduce the risk of abnormal shutdown. This work mainly analyzes the modulation and demodulation process of FOCT based on PZT modulation, and extracts the condition monitoring parameters for fault diagnosis. And the influence of typical low-temperature fault process on outdoor modulation circuit devices is analyzed, and the data of performance deterioration process of modulation tank is collected through accelerated aging test, which explains the influence of performance deterioration of low-temperature devices on state parameters.