Protection algorithm for power distribution network containing distributed power supply

A protection algorithm for a power distribution network containing a distributed power supply is disclosed. The algorithm introduces circuit infeed current and shunt compensation coefficients, compensates a fault current generated by the distributed power supply, and through calculation of integrated impedance of a system, based on the current actual operation mode and fault status of the power distribution network, a protection set value is changed self-adaptively so that a protection device can meet the requirements of selectivity, mobility, reliability and sensitivity. As for the compensation coefficient introduced in the invention, the connection position of the distributed power supply is considered, when the protection occurs at the upstream of distributed power supply, the circuit shunt compensation coefficient compensates the reducing part of a flowing protection current due to the connection of the distributed power supply, and thus the problem of possible protection failure is avoided. When the protection occurs at the downstream of the distributed power supply, the circuit infeed current compensation coefficient compensates the increased current due to the connection of the distributed power supply, and thus the problem of possible protection maloperation is avoided. When no distributed power supply is connected, the compensation coefficient is 1, and the original protection coordination is unchanged.