1. The protection does not affect the normal operation of equipment to be protected ;

 

2. when the shock wave generated by lightning , using protective devices should have a low impedance , the impact of current directly into the ground without causing a dangerous impact on the ground potential difference ;

 

3. Surge protective device should be a higher ability to withstand impact energy , and a standard grounding system.

 

According to IEC1312-1 ~ 3 norms for the protection of your device inverter system will need to protect space is divided into different lightning protection zones (LPZ), part of the space under each different LEMP ( lightning flashes electromagnetic pulse ) the severity and the actual situation to establish their respective level of protection and rational use of the appropriate SPD.

 

4. Power System: According to the statistics show that 80% of lightning is penetrated through the power line network equipment , to protect electronic equipment, they need to be set before power input power mine , so you can from along the mains circuit hit the lightning overvoltage advance vent into the earth .

 

 

The characteristics of the distribution system for the drive , which can be divided into three zones were to be mine to consider . As mentioned above may bring a single-stage lightning current is too large due to lightning discharge caused by residual pressure after excessive or inadequate protective equipment damage caused . So use multi-level power system protection, to prevent the operation from direct lightning surge overvoltage invasion levels .

 

1. Class I surge protection- lightning zone LPZOA-LPZ1

 

Press the "Lightning design specifications," Chapter VI : Section 6.4.7 requires each line should not be less than the nominal discharge current 15KA. Meanwhile , according to " Building Lightning Protection Design Code " Chapter VI: IV, paragraph 6.4.7 and IEC " lightning electromagnetic pulse protection, " the third part ; surge protection requirements , surge protectors can be tens of thousands of volt lightning induced over voltage limit to 4KV less.

 

In summary shall 380V low voltage distribution Boso distribution cabinet installation nominal flow capacity 25KA of 10/350μS waveform ( or 100KA of 8/20μS waveform switching ) AOTEM AT PORT/4P-B100 modular power surge protection, all electrical equipment used throughout the first level power protection.

 

2. Class II surge protection - lightning protection zone LPZ1-LPZ2 area :

 

Building power distribution box were installed 8/20μS waveform Flow capacity 20KA ~ 40KA of AT T385/4P-C40 phase power SPD.

 

3. Class III surge protection - lightning protection zone LPZ0-LPZ3 :

 

According to IEC 61312-3 Protection against lightning electromagnetic impulse Part III: surge protector , as requested in LPZ2-LPZ3 District SPD Flow capacity (8/20μS): ≥ 10KA. When the inverter power distribution box were installed 8/20μS waveform Flow capacity 20KA ~ 40KA of AT T385/4P-C20 phase power SPD.

 

4. Surge protective device connecting wires should be short and straight , surge protective device connecting wires should not be greater than 0.5m, 0.5m should be appropriate when the length is greater than the diameter bold . When surge protective device 1 ~ surge protective device 2 line distance of less than 10m, SPD2 ~ SPD3 line distance of less than 5m, surge protective device 3 ~ surge protective device 4 line distance of less than 5m , should be installed between the two SPD decoupling devices. To prevent short circuit caused by aging surge protective device , surge protective device requires overcurrent protection devices should be installed on the line , should be used in a deterioration of display capabilities surge protective device.

 

5. The grounding system

 

5.1 The first is a surge arrester discharge current of the discharge channel , but also a equipotential connector. All arrester lightning protection principle is the moment to ensure that equipment , land , buildings and ancillary equipment is formed between equipotential body , thus avoiding over-voltage damage , one of the most critical is the grounding system.

 

5.2 ideal grounding means ( including the lead from air terminals to ground ) there is no resistance , when the lightning , the lightning current regardless of how big the grounding device of any point on the earth electric potential difference is zero , so that the device and the absolute safe. However, such a grounding device does not actually exist. So grounding resistance should be as small as possible , based on " computer room grounding norms" as well as other relevant national lightning protection standards to ask , room grounding resistance should be less than 4 ohms , and take joint ground approach.

 

5.3 General use of large steel joint ground landlord . Big landlord cut steel , welding leads to the ground , according to the norms connecting wire lightning , lightning ground wire should be short and straight , not more than 0.5m.

 

 

( 1 ) arrester installed , you should check that all wiring is properly installed , and then run the test to see if the system and the device is working properly , without exceptions , if any , should be checked in until the entire system are functioning correctly .

 

( 2 ) a year before the thunderstorm season grounding system should be inspected and maintained. Major Check connections are tight contact is good , ground deflectors rust, whether the ground near the ground without exception , when necessary checks underground shelter dug ground corroded part , if you find the problem promptly.

 

( 3 ) grounding resistance of grounding grid measurements should be conducted annually .

 

( 4 ) a year before the thunderstorm season deal with the operation of the arrester to conduct a test , thunderstorm season to enhance the appearance of the inspection, such as detecting abnormal should timely manner.