Online monitoring of lightning arrester leakage current

Online monitoring of lightning arrester leakage current

1. System background

Zinc oxide lightning arrester is the main device used in power systems to limit lightning overvoltage and operational overvoltage, and to protect power equipment from overvoltage damage. It is widely used in overvoltage protection devices in power systems, and its technical level has a significant impact on the safety and reliability of the power grid. Although the manufacturing process and detection technology of zinc oxide lightning arresters have been greatly improved and enhanced, many faults and accidents still occur in the actual operation process.

Once the zinc oxide lightning arrester fails to shut down in a timely manner due to potential faults, it can lead to explosion accidents, causing power system accidents and posing a serious threat to the safe operation of the power system.

The traditional detection method for zinc oxide surge arresters in the power system usually adopts preventive testing, which is usually carried out on an annual basis, and the surge arresters are taken out of operation and subjected to power outage detection. From an economic perspective, due to the large number of lightning arresters, each inspection requires a significant investment of manpower and resources, as well as power outages, which can cause significant direct or indirect economic losses. From a technical perspective, due to the significant differences between preventive testing and the actual operating conditions, environment, and influencing factors of the equipment, and the need to conduct preventive testing regularly according to the plan, it is difficult to accurately detect and judge the defects or failures of lightning arresters in a timely manner. As an important component of ensuring the safe operation of the power system, zinc oxide lightning arresters urgently require an online monitoring technology and device that can timely and accurately reflect their working conditions.

A passive wireless lightning arrester online monitor for transmission lines based on electric field energy provides power to electronic circuits. The monitoring device is equipped with analog testing circuits for lightning arrester full current and harmonic current, microcontrollers, A/D conversion circuits, and wireless communication modules. The leakage current, harmonic current, and discharge frequency of the lightning arrester are wirelessly transmitted to a data receiver.

2. Power supply principle

Unlike lightning arresters in substations, transmission line lightning arresters work on high-voltage transmission lines without power supply conditions, and monitoring equipment cannot work. Even if built-in batteries are installed, they can only work briefly and cannot operate for a long time. This product overcomes the shortcomings of traditional monitors by converting electric field energy into electrical energy to achieve power supply. Its power supply principle is shown in Figure 1.

3. Measurement parameters

Ø Total leakage current;

Harmonic current (3rd, 5th, 7th, 9th);

Ø Number of lightning discharges;

Ø Temperature;

4. Technical features

No need for power supply or built-in battery, convert electric field energy into electrical energy;

Wireless transmission;

Simple structure and easy installation;

5. Main monitoring parameters

6. Installation rendering

Online monitoring of lightning arrester leakage current