With the development of the science technology , the capacity of generator unit keeps increasing , devices with large power load are becoming more and more , the impact of their make - and - break at electric meshwork is very visible 隨著科學技術的發展,發電機組的單機容量不斷增加,大功率負荷設備也越來越多,他們的投切對電網的影響越來越明顯。