Why Do Power Equipment Need Surge Arresters? Functions & Application Scenarios
In modern power systems, whether it’s a high-voltage transmission line or a residential distribution panel, surge arresters play a critical role. Lightning strikes and switching overvoltages can threaten equipment safety at any moment. So, why must power equipment install surge arresters? What are their core functions? This article will explain in detail.
1. Core Functions of Surge Arresters
A surge arrester, also known as a surge protective device, is primarily designed to safeguard electrical equipment from transient overvoltages. Its working principle is straightforward: under normal voltage, it presents a high impedance and barely conducts. Once a lightning or switching overvoltage occurs, it rapidly switches to low impedance, diverting the surge current to the ground, thereby limiting the voltage amplitude and protecting the equipment insulation.
Specifically, the functions of surge arresters include:
Limiting overvoltage amplitude: Prevents transient high voltages from breaking down equipment insulation.
Discharging lightning energy: Quickly directs lightning current into the ground to avoid equipment burnout.
Suppressing switching overvoltages: Surges generated by switching operations can be equally dangerous, and arresters effectively absorb them.
Extending equipment service life: Reduces insulation aging and minimizes failure rates.
Without proper surge arrester protection, critical equipment such as transformers, switchgear, and cable terminations are highly susceptible to damage from overvoltages, leading to power outages and even safety incidents.
2. Main Application Scenarios of Surge Arresters
Surge arresters are widely used across a variety of power system scenarios. The most common ones are listed below:
| Application Scenario | Protected Equipment | Typical Installation Location |
|---|---|---|
| Substations | Transformers, busbars, circuit breakers | Incoming line side, busbar side |
| Transmission Lines | Conductors, insulator strings | Tower-mounted or line terminations |
| Distribution Systems | Switchgear, cable branch boxes | Incoming and outgoing line ends |
| Industrial & Buildings | Distribution boards, precision equipment | Main distribution panels, terminal boxes |
| Renewable Energy Systems | Inverters, combiner boxes | PV/Wind grid connection points |
Especially in mountainous or high-lightning areas, line-type surge arresters can significantly reduce lightning-induced tripping rates. In new energy projects such as photovoltaic power stations and wind farms, appropriately rated surge arresters must be installed on both the AC and DC sides.
3. How to Choose the Right Surge Arrester?
Key technical parameters must be considered when selecting a surge arrester:
Rated Voltage: Must match the nominal system voltage.
Continuous Operating Voltage: Should be higher than the system’s maximum continuous operating voltage.
Nominal Discharge Current: Reflects the discharge capacity; choose according to the protection level.
Residual Voltage: The lower the better, indicating a superior protection level.
Energy Absorption Capability: Crucial for long-duration overvoltage events.
Take the industry-leading brand Wishpower as an example. Its metal oxide surge arresters utilize high-quality zinc oxide varistors, boasting excellent nonlinear voltage-current characteristics, low residual voltage, and high energy absorption capacity. They can meet the full range of needs from low-voltage distribution to ultra-high voltage substations. Wishpower surge arresters also undergo rigorous aging tests and sealing inspections, ensuring long-term stable operation even in harsh environmental conditions.
4. Installation and Maintenance Considerations
Proper installation and maintenance are essential to ensure surge arresters function effectively:
Arresters should be installed as close to the protected equipment as possible, minimizing lead lengths.
The grounding system must be reliable, with grounding resistance meeting the required specifications.
Specialized operating rods must be used for live-line installation, maintaining safe clearance distances.
Regularly inspect for external damage or contamination, and measure leakage current and insulation resistance.
Record the number of lightning discharge actions, and replace aged components in a timely manner.
Particularly before and after rainy seasons, inspections of surge arresters and their grounding devices should be enhanced.