Recent Patents on Electrical & Electronic Engineering - Volume 19, Issue 1, 2026

Introducing pilot protection in active distribution networks containing PV can improve the reliability and selectivity of protection. However, the basic communication facilities of the existing distribution network make it difficult to meet the requirements of data synchronization, and the PV T-connection to the network leads to sudden changes in the impedance angle.

Therefore, pilot protection of a negative sequence and additional network considering PV is proposed. The scheme is based on the feature that the PV model only outputs positive sequence components after a fault. For asymmetrical faults, the negative sequence impedance detected at both ends of the protection is utilized to construct a comparative negative sequence impedance protection criterion. For symmetrical faults, the voltage characteristics of the faulty additional network are utilized to construct a protection criterion.

The protection method requires less data information, low dependence on communication, and can quickly identify asymmetric faults occurring in the area. The operation results have high reliability and simple calculation; additional criteria can effectively avoid the impact of load current changes on the protection, can effectively withstand different transition resistance access conditions, and different penetration rates of photovoltaic power access. This study has two limitations: (1) The model considers only PV; (2) The proposed protection scheme applies only to local circuits.

Finally, an actual distribution network model with PV is constructed in PSCAD to verify the effectiveness and reliability of the protection method.

The protection method is selective and reliable and is not affected by high penetration rate and PV fault characteristics.