the Manufacturing Method of Zinc Oxide Arrester

2025-04-26 12:09:43

Zinc oxide arresters are core equipment for lightning protection in power systems. Their core material is nonlinear ZnO resistive sheets, and they achieve high-efficiency surge absorption through precise processes. The following are its key production processes and technical points:

I. Material Selection and Formula Design

1. ZnO Resistor sheet raw material

- Main component: Zinc Oxide (ZnO, accounting for 90% to 95%), with the addition of metal oxides such as Bi?O?, CoO, and MnO? (accounting for 5% to 10%), to optimize nonlinear volt-ampere characteristics.

- Particle size control: The particle size of ZnO powder is ≤1μm to ensure the uniformity of sintering.

2. Additive functions

-Bi ?O? : Forms grain boundary layers and reduces leakage current (≤50μA).

-CoO /MnO? : Enhances energy absorption density (≥200J/cm3) and anti-aging performance.

Ii. Resistance Sheet Forming and Sintering

1. Dry pressing molding

Mold design: Circular sheet (diameter 30-80mm, thickness 5-20mm), pressure 100-300MPa.

- Pre-burning treatment: Degrease at 600℃ for 2 hours to remove the binder.

2. High-temperature sintering

Sintering curve: Hold at 1150℃ to 1350℃ for 4 to 8 hours, protected by nitrogen to prevent oxidation.

- Microstructure: ZnO grains (particle size 8-15μm) and grain boundary layers are formed to ensure a high nonlinearity coefficient (α≥30).

Iii. Assembly Process of Lightning Arresters

1. Stacking of resistor sheet groups

- Insulation design: Wrapped with silicone rubber sleeve or epoxy resin, with a withstand voltage of ≥100kV/mm.

- Parallel voltage equalization: When multiple pieces are connected in series, a voltage equalization ring is configured, and the voltage distribution deviation is ≤5%.

2. Sealing and encapsulation

- Inflation process: SF6 or dry air filling (pressure 0.3-0.5MPa) to enhance moisture resistance.

- Environmentally friendly alternative: C5-FK mixed gas (GWP < 10), in compliance with the EU F-Gas regulations.

Iv. Electrical Performance Testing and Verification

Key test items

Nominal discharge current test: Under an 8/20μs waveform, it can withstand three impacts of 10kA-40kA, with a residual voltage ratio of ≤2.5.

Leakage current detection: Under the continuous operating voltage (Uc), the total current is ≤1mA and the resistive current is ≤0.3mA.

- Power frequency withstand: No flashover or breakdown at 1.3 times the rated voltage (IEC 60099-4 standard).

2. Life assessment

- Accelerated aging test: In an environment of 85℃/85% humidity for 1000 hours, the parameter drift is less than 5%.

V. Environmental Protection and Intelligence Trends

Green manufacturing.

- Lead-free formula: Replace traditional lead-containing glass glazes and reduce heavy metal pollution.

- Recycling process: The metal recovery rate of used ZnO resistor sheets is over 95% (acid leaching - electrolysis method).

2. Intelligent lightning arrester

Built-in sensors: Real-time monitoring of temperature and leakage current, with data wirelessly transmitted to the SCADA system.

Digital twin: By predicting deterioration trends through simulation models, operation and maintenance costs can be reduced by 40%.

Conclusion

The manufacturing of zinc oxide arresters integrates materials science, electrical engineering and precision technology. Its core lies in optimizing the nonlinear characteristics and long-term stability of ZnO resistors. With the popularization of high-voltage direct current transmission and the grid connection of new energy, high energy density (≥300J/cm3) and intelligent monitoring will become the competitive focus of the next generation of products.