The principle of surge protectors, the working principle of surge protectors

Overvoltage protection type leakage circuit breaker is used for overvoltage protection.

Surge protection device is an indispensable device in lightning protection of electronic equipment, and it was often called in the past.

"Surge arrester" or "overvoltage protector" is abbreviated as SPDThe function of the surge protector is to limit the instantaneous overvoltage that enters the power line and signal transmission line within the voltage range that the equipment or system can bear, or discharge the strong lightning current into the ground to protect the protected equipment or system from damage caused by impact.

The type and construction of a surge protector varies depending on the application, but it should contain at least one nonlinear voltage limiting element. The basic components used for surge protectors are: discharge gap, gas discharge tube, varistor, suppression diode and choke coil.

The function of a surge protective device is to protect the protected equipment or system from damage caused by shock.

Surge protector is also called surge protector, in the circuit protection solution, lightning surge protection is a key point of protection that electronic engineers pay special attention to, surge is also called surge, as the name suggests is the instantaneous overvoltage beyond the normal working voltage, surge protector, also known as lightning protector, is an electronic device that provides safety protection for various electronic equipment, instrumentation and communication lines. When the electrical circuit or communication line suddenly generates a spike current or voltage due to external interference, the surge protector can turn on and shunt in a very short time, so as to avoid the damage of the surge to other equipment in the circuit, in essence, the surge is a violent pulse that occurs in only a few millionths of a second.

Surge protectors(Surge protector), also known as surge arrester, abbreviated (SPD) is suitable for AC 50 60Hz, rated voltage to 380V in the power supply system (or communication system), indirect lightning and direct lightning impact or other instantaneous overvoltage surge protection, suitable for family housing, tertiary industry and industrial surge protection requirements, with relative phase, relative, relative centerline, sensitive mode centerline to ground and its combination and other protection modes.

The role of surge protectors

Lightning discharges may occur between or within clouds, or between clouds to the ground; In addition, the internal surge caused by the use of many large-capacity electrical equipment has become the focus of attention on the power supply system (China low-voltage power supply system standard: AC 50Hz 220 380V) and electrical equipment, as well as the protection of lightning protection and surge.

A lightning discharge between clouds and the ground consists of one or more separate lightning bolts, each of which carries a number of currents of high amplitude and of short duration. A typical lightning discharge will consist of two or three lightning bolts, with about one-twentieth of a second between each lightning bolt. Most lightning currents land in the range of 10,000 to 100,000 amperes, and their duration is generally less than 100 microseconds.

The use of large-capacity equipment and inverter equipment in the power supply system is causing an increasingly serious internal surge problem. We attribute this to the effects of transient overvoltages (TVS). Any electrical device has a permissible range of power supply voltage.

Sometimes even a narrow overvoltage impulse can cause power or total damage to the equipment. Transient overvoltage (TVS) destruction is just that. Especially for some sensitive microelectronic devices, sometimes a small surge shock can cause fatal damage.

Surge protective device principle

1.Switching type: It works on the principle that when there is no transient overvoltage, it appears to be high impedance, but once it responds to the lightning transient overvoltage, its impedance suddenly changes to a low value, allowing lightning current to pass through.

When used as such devices, the devices are: discharge gap, gas discharge tube, thyristor transistor, etc.

2.Pressure limiting. Type:

Its working principle is that it is high obstruction when there is no transient overvoltage, but its impedance decreases continuously with the increase of surge current and voltage, and its current-voltage characteristics are strongly nonlinear. The devices used as such devices are: zinc oxide, varistors, three-phase power surge protectors, suppression diodes, avalanche diodes, etc.

3.Split or choke.

Shunt type: Connected in parallel with the protected equipment, it presents a low impedance to lightning pulses and a high impedance to a bridge at normal operating frequency.

Choke type: In series with the protected equipment, it presents a high impedance to lightning pulses and a low impedance to normal operating frequencies.

The devices used as such devices are: choke coils, high-pass filters, low-pass filters, 1 4-wavelength short-circuits, etc.

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Its main function is to control the instantaneous overcurrent and voltage that suddenly rushes into the wire circuit and signal transmission line within the range that the equipment can bear, or to introduce a strong lightning current into the ground to ensure that the equipment or system can work safely and stably without damage caused by impact.

What are the features of a surge protector?

1. The protection flow rate is large, the residual pressure is relatively low, and it can respond quickly.

2. The use of arc extinguishing technology can prevent fires.

3. Use temperature control protection circuit, and set up thermal protection inside.

4. Equipped with power status indication, which can display the working status of the protector.

5. The structure is relatively rigorous, and the performance is stable and reliable.

Wiring method of surge protective device:

1. Wiring of surge protector in single-phase system: single-phase three-wire, upper two-hole L port fire wire, N port grounding wire, and lower PE port grounding wire.

2. The wiring of the surge protector in the TT system: three-phase four-wire, the upper three L ports are connected to three live wires, the lower N port is connected to the PEN wire, and the PE grounding wire on the right side.

3. The wiring of the surge protector in the TN-C system: three leakage phase detection and four wires, the upper three L ports are connected to three live wires, and the lower PE port is connected to the PEN wire.

4. The wiring of the surge protector in the TN-S system: three-phase five-wire, the upper three L ports are connected to three live wires, the N port on the right is connected to the zero line, and the PE port is connected to the ground digging line.