Selection Essentials: Six Key Parameters
When selecting a lightning arrester, consider six parameters: voltage class, continuous operating voltage, residual voltage (protection level), nominal discharge current, type, and discharge capacity.
Industry experts advise checking against this parameter list: voltage class (e.g., 10kV/35kV systems), continuous operating voltage (Uc matching), residual voltage (protection level ≤ equipment withstand voltage), nominal discharge current (e.g., 20kA), type (Zinc Oxide/MOA is the mainstream choice; Silicon Carbide is obsolete), and discharge capacity (explosion-proof capability).
Residual voltage and discharge capacity are critical factors in selection.
The Six Parameters
- Voltage Class: System voltage (10kV/35kV/110kV) to match the power grid;
- Continuous Operating Voltage: Uc (Continuous Operating Voltage) must match the system to prevent false operation;
- Residual Voltage Protection: Residual voltage (protection level) ≤ equipment insulation withstand voltage for reliable protection;
- Nominal Discharge Current: 20kA/10kA (rating), selected based on the lightning hazard level;
- Type Selection: Zinc Oxide (MOA) is the mainstream choice; Silicon Carbide is obsolete;
choose MOA; - Discharge Capacity: High-current discharge capability (explosion-proof/resistant to thermal breakdown) is critical for safety.
Selection Highlights
First, verify residual voltage.
Ensure residual voltage (protection level) ≤ equipment withstand voltage to guarantee protection.
Second, prioritize discharge capacity.
High discharge capacity (ensuring no explosion under high current) is crucial for safety.
Third, opt for the mainstream choice.
Zinc Oxide Arresters (MOA) are the industry standard due to their superior performance and are the preferred choice for selection.
Fourth, verification via testing.
Type testing (per GB/T 11032) and verification of discharge capacity and residual voltage confirm compliance.
Pitfalls to Avoid
First, “excessive residual voltage.”
Excessive residual voltage risks equipment breakdown; verify the protection level.
Second, “insufficient discharge capacity.”
Insufficient capacity risks explosive failure;
select a higher discharge capacity rating.
Third, “obsolete products.” Silicon carbide (SiC) arresters are obsolete;
select Metal Oxide Arresters (MOA) instead.
Trends and Reminders
Arresters are moving toward “smart” technology, featuring trends such as online monitoring (e.g., leakage current monitoring) and application at higher voltage levels (e.g., UHV MOAs).
For those selecting equipment, the recommendation is to “verify six key parameters, check residual voltage, and prioritize MOAs.”
Accurate selection ensures reliable lightning protection.
