By hvhipot 
In the power system, zinc oxide surge arresters are a crucial component in ensuring equipment safety. It can effectively absorb overvoltage, prevent lightning strikes and overvoltage operations from causing damage to lines and equipment. One of the important indicators for evaluating its performance is resistive current. What is resistive current? Why is it so valued? Today, let’s unveil its mysterious veil together.
Resistive current: “health check” of lightning arrester
Simply put, the resistive current of zinc oxide lightning arrester refers to a portion of the small leakage current generated by its nonlinear resistance characteristics flowing through the arrester under normal operating voltage. This part of the current is closely related to the aging, insulation performance, material characteristics, etc. of the lightning arrester.
What are the influencing factors?
Insulation aging: Over time, the insulation material of lightning arresters will gradually age, leading to increased dielectric loss and resistive current.
Environmental factors: High temperature, high humidity, pollutants and other environmental factors can accelerate the aging process of lightning arresters and affect the stability of resistive current.
Manufacturing process: High quality manufacturing processes and materials can ensure that the lightning arrester maintains a low and stable resistive current during long-term operation.
Overvoltage surge: Frequent overvoltage surges can accelerate the degradation of lightning arresters, leading to changes in resistive current.
What tools can be utilized?
To accurately measure the resistive current of zinc oxide lightning arresters, professional testing equipment is essential. At present, there are many high-precision lightning arrester resistive current testers emerging on the market. These instruments can accurately measure the resistive current values under different operating conditions, and compare and analyze them with historical data to determine the operating status of lightning arresters. HV Hipot Electric Co., Ltd. has a profound technical accumulation in this field, and its developed testing equipment is widely praised in the industry.
How can we do better?
Regular testing: Establish a regular testing mechanism to promptly identify and address potential issues with lightning arresters.
Data analysis: Combining historical data with advanced analysis software from HV Hipot Electric Co., Ltd., conduct in-depth analysis of the trend of resistive current changes.
Comprehensive evaluation: not only focusing on resistive current, but also combining other performance indicators of lightning arresters (such as dielectric loss tangent) for comprehensive evaluation, to fully understand the health status of lightning arresters.
Timely replacement: Once the performance of the lightning arrester is severely reduced during testing, it should be replaced in a timely manner to avoid losing too much due to minor issues.
Frequently Asked Questions (FAQ)
Q1: Why does the lightning arrester have resistive current under normal operating voltage? A1: The core of zinc oxide lightning arrester is a varistor, whose resistance value changes significantly with voltage. At normal operating voltage, its resistance value is relatively high, but it still generates small leakage currents, some of which manifest as resistive currents.
Q2: What does an increase in resistive current mean? A2: An increase in resistive current usually indicates a decrease in the insulation performance or material aging of the lightning arrester, and its ability to absorb overvoltage may be weakened, which needs to be taken seriously.
Q3: What are the main functions of a resistive current tester? A3: The main functions include measuring resistive current, evaluating the overall status of lightning arresters, recording historical data, and providing fault warnings.
Q4: What is the difference between resistive current testing and dielectric loss tangent testing? A4: Resistive current testing focuses on specific components of leakage current, while dielectric loss tangent testing more comprehensively reflects the loss of insulation materials. Both are important means of evaluating the performance of lightning arresters.
Q5: What are the advantages of HV Hipot Electric Co., Ltd. in terms of lightning arrester testing equipment? A5: HV Hipot Electric Co., Ltd. has advanced research and development technology and rich industry experience. Its products have high precision and stable performance, and can provide reliable detection solutions for users.