When two-point-ground fault happened in secondary circuit of the potential transformer， and at the same time a single-phase ground fault happened in the primary system， if the zero sequence current directional protection misjudged， the phase difference between the zero sequence voltage and the fault phase voltage is small. But in normal condition this difference is large. Based on this phenomenon， a real-time identification method is proposed to identify the two-point-ground fault in secondary circuit of the potential transformer（“two-point-ground” for short）. Under“two-point-ground” situation， according to the characteristics of additional voltage components influence on each single phase voltage， a new zero sequence direction algorithm with healthy phase voltage instead of zero sequence voltage is put forward. Then the real-time identification method and the new zero sequence direction algorithm of“two-point-ground” is combined together to form a new zero sequence direction element， which is not affected by“two-point-ground”. This protective element can effectively avoid malfunction of pilot zero sequence direction protection. And the validity of above method is proved through the analysis of recorded field data.