Study On Substation Secondary System Lighting Surge Protection

China is a frequent lightning country, lightning has been the threat to the safe and stableoperation of the power system. Accidents caused by the invasion of lightning surge tosecondary equipment happened all the time. By far, lightning protection measures of primarysystem have developed very perfect. The secondary system mainly consists of low-voltageelectrical equipment, and may easily experience malfunction and damage due to its low voltagewithstand level under Lightning over-voltage surges. With the proposed of Smart Grid, therewill be more new applications of information technology equipment in the integrated automaticsubstation, so we should put towards a high request on lightning protection measures.Correctly installed surge protective devices are the most effective lightning protectivemeasures for secondary equipment. Cascade coordination of the surge protective devices is acore issue of the secondary system protection. Up to now, There is no surge protectionstandards for substation secondary system, the effective protection of the surge protectordistance, multi-level coordination in the substation secondary lightning protection engineeringalso need to study.This thesis analyzes the reasons for the formation of lightning, the building lightningprotection partition, and analysis of the main ways of substation secondary system oflightning damage mechanism of secondary equipment and lightning invasion theory. Usingtraveling wave reflection and refraction theory to analysis the effective protection distance ofsurge protective devices. Establish the simulation model of multi-stage surge protectiondevices. Change the distance between the surge protection devices, the distance between thesurge protective device and the protected equipment, and the characterization of the load tostudy the protective effect, study conclusion: the maximum voltage value across the loaddepends mainly on the load characteristics and the cable length between the second stage SPDand the load, to achieve the overvoltage protection of device can only shorten the cable lengthbetween the second stage SPD and device; Addition to the capacitive load, the cable lengthbetween two SPD doesn’t affect the maximum voltage value across resistive and inductiveload. For capacitive load, the cable length between two SPD shouldn’t be less than30meters;Configuring SPD should first consider the nature of the load, according to the relationshipbetween the load and the cable select the installation location of the SPD. This thesis analyzesthe lack of power system lightning protection at present. Because high-frequency componentsof Lightning transient over voltage waveform exist, the thesis analyses and simulates thelightning protection effect of varistor and low-pass filter circuit, the results showed choose asuitable inductor and capacitor values can be reduced lightning wave steepness, reducing the output voltage value. For the hazards of the high-frequency component of lightning transientvoltage waveform, Design Multi-stage surge protection device with a low pass filter circuitfor power system, After ATP simulation to the load-side voltage limit at a lower level, meetsinternational standards, and give recommendations for the selection and layout of the surgeprotective devices to improve the level of power system lightning protection.