Critical Condition Detector of the Insulators Using Leakage Current Analysis

Insulators are one of the most important high voltage equipment used in transmission lines, distribution lines, and substations. Therefore, accurate and precise performance of insulators leads to increase power quality and grid reliability which are the most important concerns of the power companies and researchers of this field. Main reasons of changing the electrical behavior of the insulators and their incomplete performance are pollution and humidity of the environment. Pollution also reduces the efficiency of the insulators and increases the possibility of flashover occurrence which consequently results in transmission line outage. Therefore, forecasting the flashover and detecting the critical conditions are very important. This paper proposes a novel method for critical condition detection and consequently preventing from flashover in porcelain and glass insulators by employing leakage current analysis. A device is also designed and built for critical condition detection and flashover prediction by using harmonic components of the leakage current and the defined index (R3/5). This warning device is able to analyze and describe the main characteristics of the leakage current of polluted insulators (both single-insulator and insulator-chain forms). The index which is defined here is the ratio of the third order harmonic component of the leakage current to its fifth order component. Index (R3/5) in critical condition are higher than 40% for porcelain and glass insulators. This detector enables operators to have a better planning for optimal utilization of high voltage equipment. Experimental results have verified the validation of the defined index and proper function of the device.

کلیدواژه ها:

Flashover Detector ، Harmonic Components ، Index ، Insulator