Photonics and Instrumentation Laboratory, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-901, Brazil.
Sensors (Basel). 2022 Jul 4;22(13):5034. doi: 10.3390/s22135034.
The leakage current (LC) caused by the surface contamination of insulators, together with environmental variables, is one of the most basic online monitoring parameters for insulator status. However, the impact of weather conditions such as temperature, air humidity, and dew point on the LC has not been deeply studied until now. In this paper, based on meteorological data obtained online and LC obtained with an optical fiber sensor, installed in 500-kV insulator strings of a transmission line, the impact of weather conditions was studied. Results indicate that the LCs follow a specific pattern, according to weather conditions. The system has been continuously monitoring LC, humidity, temperature, and dew point uninterrupted for three years, sending the acquired data to a web page; therefore, it has been demonstrated to be robust, reliable, and repetitive. The sensor features the broadband response and acquisition capabilities of partial discharge pulses in high-voltage insulators, allowing the detection of high-frequency pulses. When comparing the LC measured in this work with those from other works, our measurements are substantially higher; this is due to the type of pollution found in this specific situation, which includes iron oxide powder, producing a conductive layer over the insulator surface that, unlike sea salt, does not depend on humidity to conduct an LC. One of the conclusions reached in this work is that partial discharge surges are caused when the local temperature reaches the dew point and not simply from the presence of high humidity, as stated in many works dealing with LCs. The monitored LC can be used as an indicative parameter of a possible flashover, enabling the proper planning of insulator predictive maintenance, either by jet-washing the surface or even changing the insulators when they are damaged.
绝缘子表面污染引起的泄漏电流（LC）以及环境变量是绝缘子状态的最基本在线监测参数之一。然而，直到现在，温度、空气湿度和露点等天气条件对 LC 的影响还没有得到深入研究。在本文中，基于从在线获得的气象数据和通过光纤传感器获得的 LC，对天气条件的影响进行了研究。结果表明，LC 根据天气条件呈现出特定的模式。该系统已经连续三年不间断地监测 LC、湿度、温度和露点，并将采集到的数据发送到网页；因此，它被证明是强大的、可靠的和可重复的。传感器具有宽带响应和采集能力，能够检测到高压绝缘子中的局部放电脉冲。当将本文中测量的 LC 与其他工作中的 LC 进行比较时，我们的测量值要高得多；这是由于在这种特殊情况下发现的污染类型，包括氧化铁粉末，在绝缘子表面形成导电层，与海盐不同，它不需要湿度就能进行 LC。这项工作的结论之一是，局部放电浪涌是在局部温度达到露点时产生的，而不仅仅是由于存在高湿度，这与许多处理 LC 的工作中的说法不同。监测到的 LC 可以用作可能闪络的指示参数，从而可以合理地计划绝缘子预知性维护，要么通过喷射清洗表面，要么在绝缘子损坏时更换。
