Method of power differential protection for distribution network containing inverter-interfaced distributed generator

• A positive-sequence power fault component differential protection method is proposed. • A weighted power vector is proposed, and a power differential criterion is formulated based on the phase difference between the weighted power factors of the power fault components at both ends. • Resolves the near-end fault blind zone (reduced to 5% of the line length) and maloperation under high DG penetration levels (up to 90%). • Simulations confirm robust performance under 5dB SNR measurement noise, transition resistances up to 300Ω, while remaining unaffected by CT saturation. The increasing penetration of inverter-interfaced distributed generators (DGs) has significantly altered the structure, power flow patterns, and operating modes of modern distribution networks. These changes have degraded the dependability of conventional single-ended protection schemes. To address this issue, this study proposes a power differential protection method. First, by considering the output characteristics of distributed generators with low-voltage ride-through (LVRT) controlling strategies, the magnitude and directional characteristics of the positive-sequence differential power components at both ends of the distribution line are examined. Next, a weighted power vector is introduced, and based on its phase difference with the power fault components at both ends, a power differential criterion is developed to resolve the difficulty of distinguishing between normal unbalanced current and fault current caused by DG branches. Finally, simulation results demonstrate that the method maintains reliable performance under a range of challenging conditions, including near‑end faults as close as 5% of the line length, transition resistances up to 300 Ω, current transformer (CT) saturation, DG penetration levels up to 90%, load variations, control strategies, measurement noise with an SNR of 5 dB and time desynchronization up to 20 ms.