Influence of Neutral Grounding Mode on the Safety Limit of Lightning Arrester Ground Potential Rise in Station 10 kV system
With the increase of grid capacity and the development of new power systems, the neutral grounding mode of the 10 kV station system has changed. The ground potential rise (UGPR) safety limit of the arrester's tolerance under the neutral ungrounded system may lead to safety accidents of the arrester under other grounding modes. The electromagnetic transient program ATP-draw can be used to build the model of UGPR counterattack arrester under different neutral grounding modes. By checking the energy absorbed by the arrester under the action of UGPR, the influence of neutral grounding mode on the safety limit of the arrester's tolerance to UGPR is obtained as follows: Under the neutral un-grounded system, the UGPR safety limit of the arrester is 10～23 kV, which decreases with the increase of the line capacitance to the ground. Under the neutral grounding via arc suppression coil system, UGPR oscillates in the series cir-cuit of the arc suppression coil and the line's capacitance to the ground, resulting in a lower safety limit of the arrester to withstand UGPR. The safety limit is mainly determined by the out-of-resonance degree and damping rate, and the typical value is 8～9.5 kV. Under the neutral grounding via resistance system, most of the UGPR is coupled to the high voltage bus, so that the safety limit of the arrester to withstand UGPR is higher, which decreases with the increase of the line capaci-tance to the ground and the neutral resistance. The typical value of the high resistance grounding condition is greater than 15 kV, and the typical value of the low resistance grounding condition is greater than 25 kV.
ground potential risesafety limitarresterneutral grounding modesbackflashstation power system
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