With the increase in the capacity and proportion of distributed photovoltaics connected to the distribution network

the ability of downstream photovoltaics to supply fault current in the event of reverse direction faults is also enhanced

leading to a decrease in the sensitivity of line current protection and even maloperation. The introduction of directional criteria can effectively solve the reverse maloperation problem of distribution line current protection after high penetration integration of distributed photovoltaic. To this end

this article first evaluates the applicability of traditional power direction protection. Analysis has found that the impedance of photovoltaic power sources at power frequency is capacitive

while the impedance of lines is inductive

resulting in incorrect operation of power direction protection criteria based on measured impedance angle characteristics as the photovoltaic capacity of the distribution network increases. Furthermore

this article reveals the differences in transient voltage and current polarity characteristics between forward and reverse faults

taking into account the influence of photovoltaics. On this basis

a new direction criterion based on transient voltage and current polarity comparison is proposed for high penetration access of distributed new energy. It can quickly and reliably identify the fault direction based solely on single terminal information. Finally

a large number of simulation examples have verified the feasibility and performance advantages of the proposed method.