... .easy maintenance and mobile YBM, YBP series of prefabricated substation is the compacted sets of power distribution equipment combined by the high-voltage ... 250,315,400,500,630,800,10003No-load tap changer ±2*2.5%4Vector group Yn115Rated insulation levelLightning impulse withstand voltage ( ... degree IP349Cooling method Oil immersed: ONAN ANY QUESTION FEEL FREE CONTACT US! WE WILL DO OUR BEST FOR YOU!