In this ever changing digital age, every moment of power stability is crucial. With excellent technical strength and reliable quality, surge protectors provide a full range of security for equipment, and become a solid protective barrier in the power system.
Ⅰ. What is the Working Principle of a Surge Protector？
The surge protector primarily consists of two key components: Metal Oxide Varistor (MOV) and Gas Discharge Tube (GDT). These elements work together to suppress surge voltages and protect electrical devices from damage.
MOV is the core component of a surge protector and is made from a metal oxide material with nonlinear properties. For example, in a household electrical system, when a lightning strike causes a sudden voltage increase, the MOV quickly switches from a high resistance state to a low resistance state, allowing surge current to flow through, thus limiting the voltage to a safe level and protecting household appliances.
The GDT, made of two metal electrodes and insulating gas, activates when the voltage exceeds the breakdown voltage of the gas. In the case of a high voltage surge, the gas inside the GDT becomes ionized and forms a conductive arc between the electrodes. This arc can carry a large current, effectively diverting the surge and preventing further voltage increase, thus ensuring the stability of industrial equipment or photovoltaic systems.
The working principle of a surge protector can be broken down into four steps:
Sensing: The surge protector detects voltage changes in the circuit. When it senses that the voltage has reached a certain threshold, the MOV quickly responds and enters a low resistance state.
Absorption: Once the MOV is in the low resistance state, a large amount of current flows through it, absorbing the surge energy. Simultaneously, the GDT breaks down and forms an arc, further limiting the voltage rise.
Limiting: The surge protector limits the voltage and current in the circuit through the combined action of the MOV and GDT. Together, they ensure that the voltage and current are kept within a safe range.
Recovery: Once the surge is over, the MOV and GDT return to their original states. The MOV reverts to a high resistance state, and the arc in the GDT extinguishes. Throughout this process, neither MOV nor GDT suffers irreversible damage, making them reusable.
The combined operation of the MOV and GDT effectively suppresses surge voltages and protects the circuit from potential harm.
Ⅱ. What is the Maximum Current Throughput of a Surge Protector?
Maximum Discharge Current (Imax) is one of the most important parameters for evaluating the performance of a surge protector. It refers to the maximum value of current that the surge protector can withstand in a single surge event, usually measured in kiloamperes (kA). The exact value depends on the type and specification of the surge protector.
– For residential surge protectors, the maximum discharge current typically ranges from 20kA to 40kA. This capacity is sufficient to handle most voltage surges caused by lightning strikes or grid operations.
– Industrial surge protectors face more complex surge environments. Their maximum discharge current typically needs to range from 40kA to 100kA, allowing them to effectively manage high surge currents generated by equipment such as motors or welding machines.
Ⅲ. How Fast is the Response Time of a Surge Protector?
The response time of a surge protector is another crucial performance indicator. It refers to the time taken from detecting an overvoltage to the moment it starts diverting the current. This time is typically measured in nanoseconds (ns) or microseconds (μs).
Good surge protectors typically have extremely fast response times, being able to respond and divert current quickly within a few nanoseconds to tens of nanoseconds. This speed ensures that the surge protector can effectively contain the overvoltage within acceptable limits, before it can cause damage to electronic equipment. For particularly sensitive or critical electronic equipment, such as communications equipment, the response time of a surge protector needs to be at the subnanosecond level, to ensure stable protection under extreme conditions.
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