Are surge protectors and lightning arresters the same thing? Where are they suitable for use?
1. Lightning arrester
As common components in electrical equipment, both lightning arresters and surge protectors have the function of preventing overvoltage, especially lightning overvoltage. However, there are still many differences between the two in application. Today we will introduce the specific differences between these two types of products.
1. Lightning arrester
Overvoltage limiter. When overvoltage occurs, the voltage between the two terminals of the arrester does not exceed the specified value, which protects the electrical equipment from overvoltage damage; after the overvoltage occurs, the system can quickly return to normal state.
2. Valve plate
A resistor with nonlinear volt-ampere characteristics exhibits low resistance during overvoltage. Thereby limiting the voltage on the arrester, and showing high resistance under normal power frequency voltage, it can limit the current through the arrester.
3. Rated voltage of arrester
It is the effective value of the maximum allowable power frequency voltage applied between the terminals of the arrester. The arrester designed according to this voltage can work correctly under the transient overvoltage determined in the specified operating load experiment. It is an important parameter indicating the operating characteristics of the arrester. But it is not equal to the system rated voltage.
4. Residual voltage of arrester
The maximum voltage value between the terminals of the arrester when the discharge current passes through it.
KHY-JM overvoltage online monitor from lightning arrester manufacturer
5. Lightning impulse current
An inrush current with an 8/20 waveform. Due to equipment adjustment limitations, the measured value of apparent Boqian time is 7~9us, and the median wave tail time is 18~20us.
6. Operating impulse current
The apparent wave front time is greater than 30us but less than 100us, and the wave tail at half peak time is like an impulse current that is twice the apparent wave front time.
7. Square wave impulse current
A shock wave that rapidly rises to a maximum value, remains roughly constant for a specified period of time, and then quickly drops to zero.
8. Steep wave impulse current
It has an inrush current with an apparent wavefront time of 1us.
9. Inrush current tolerance (impulse current forcing capacity)
Under the specified waveform (square wave, lightning and line discharge, etc.), the ability of the nonlinear resistor to withstand the flow of current is expressed by the amplitude and number of currents.
10. Action load test
It is used to determine the ability of the arrester to operate reliably and repeatedly under specified conditions. The experiment that simulates lightning overvoltage action is called lightning impulse action load test. The experiment that simulates the operation overvoltage action is called the operation impact action load test.
11. Protection range of lightning arrester
The maximum allowable length between the arrester and the protected equipment is the maximum allowable length. Within this range, the overvoltage on the protected equipment does not exceed the specified value.
12. Continuous current of arrester
The current flowing through the arrester at continuous operating voltage, expressed as peak or effective value.
13. Continuous operating voltage of arrester
The effective value of the power frequency voltage allowed to be permanently applied to the arrester terminals during operation.
14. Arrester power frequency reference voltage
The maximum peak value of the power frequency voltage on the arrester measured under the power frequency reference current is divided by 2
15. DC reference current of arrester
The tributary reference current of the arrester is a certain current value near the inflection point of its volt-ampere characteristic curve. The value is related to the material and size of the resistor, and its value is about 1~20mA.
16. Voltage ratio of non-linear resistor
The ratio of the residual voltage (peak value) of the nonlinear resistor at the nominal current to its reference voltage (peak value).
17. Pressure release level
The ability of an arrester to withstand internal fault currents. Under the specified short-circuit current, porcelain with a pressure relief device arrester will not explode (that is, the fragments will not fly out of the specified range during the explosion). The pressure relief current level is expressed in terms of the effective value of power frequency current.
18. Pollution tolerance
The pollution resistance performance of the arrester is mainly related to its overall structure, the creepage distance of the outer surface of the arrester and the shape of the shed. The contamination on the surface of this set will not only cause surface flashover, but also cause uneven voltage distribution along the resistor sheet. Causes local overheating of the resistor and leads to damage. Regular cleaning and application of house paint can also improve the anti-fouling ability of the arrester.
Lightning arrester manufacturer
2. The difference between surge protector and lightning arrester
1. Application fields can be divided into voltage levels.
The rated voltage of the arrester ranges from ﹤3kV to 1000kV, low voltage 0.28kV, 0.5kV.
The rated voltage of the surge protector is ≦1.2kV, 380, 220~10V~5V.
2. Different protection objects
Lightning arresters protect electrical equipment, while SPD surge protectors generally protect secondary signal circuits or terminal power supply circuits such as electronic instruments.
3. Different insulation levels or voltage resistance levels
The withstand voltage levels of electrical equipment and electronic equipment are not of the same order of magnitude. The residual voltage of the overvoltage protection device should match the withstand voltage level of the protected object.
4. Different installation locations
Lightning arresters are generally installed on the primary system to prevent the direct intrusion of lightning waves and protect overhead lines and electrical equipment; while SPD surge protectors are mostly installed on secondary systems, which are supplementary measures after the arrester eliminates the direct intrusion of lightning waves, or when the arrester does not completely eliminate lightning waves; therefore, lightning arresters are mostly installed at the incoming line; SPDs are mostly installed at the end outlet or signal loop.
5. Different flow capacities
Because the main function of a lightning arrester is to prevent lightning overvoltage, its relative current capacity is large; for electronic equipment, its insulation level is much smaller than that of general electrical equipment, so SPD is needed to protect lightning overvoltage and operating overvoltage, but its current capacity is generally not large. (SPD is generally at the end and will not be directly connected to overhead lines. After the current limiting effect of the upper level, the lightning current has been limited to a lower value. In this way, the SPD with a small current capacity can fully play a protective role. The current value is not important, but the residual voltage is important.)
6. Surge protectors are suitable for fine protection of low-voltage power supply systems.
Since the power supply surge protector is far away from the front-end surge protector, the line is prone to oscillation overvoltage or other overvoltage induction. Fine power surge protection suitable for terminal equipment. When used in conjunction with a front-stage surge protector, the protection effect is better.
7. Different materials
The main material of lightning arresters is mostly zinc oxide (a type of metal oxide varistor), while the main material of surge protectors is different according to the surge resistance level and graded protection (IEC61312), and the design is much more sophisticated than ordinary lightning protectors.
8. Technically speaking, lightning arresters cannot reach the level of surge protectors in terms of response time, voltage limiting effect, comprehensive protection effect, and anti-aging characteristics.
9. Other insulation levels and focus on parameters are also quite different.
3. From the perspective of nominal discharge current
The indicator discharge current In of the arrester ranges from 1.5kV, 2.5kV, 5kV, 10kV, and 20kV. The nominal lightning current is 8/20us, and the nominal discharge current of the surge protector is from 5kA, 10kA, 0.5kA, 20kA, 30, 20, and 120kV.
4. There is a big difference in test standards and requirements.
Since the arrester is connected to the electrical primary system, it must have sufficient external insulation performance and the appearance size is relatively large. Since the surge protector is connected to low voltage, the size can be made very small. For example, in terms of appearance volume, the arrester is mainly made of silicone rubber, ceramics, and iron cans. It is large in size and heavy. The surge protector is made of a small amount of silicone, an epoxy package, a plastic shell, metal and ceramics, and metal and plastic.
5. Place of use
Lightning arresters are mainly used in power stations, lines, distribution stations, power generation, capacitors, motors, transformers, neutral points, steelmaking, and railways.
Surge protectors are mainly used in low-voltage power distribution, cabinets, low-voltage electrical appliances, communications, signals, machine stations, and machine rooms.
