Photovoltaic injection power estimation method based on variable voltage sensitivity matrix

The operation of PVs has a significant impact on the safe and economic operation of the distribution networks. Nevertheless, there are many cases where the distribution system operators cannot obtain the accurate operation information of PVs. To solve the above problems, this paper proposes a PV injection power estimation method based on the variable voltage sensitivity matrix. First, the voltage sensitivity matrix is constructed. Second, all the node voltage magnitudes are obtained indirectly through distribution network state estimation owing to the limited number of voltage measurements. Then, combine the estimated voltages with the voltage sensitivity matrix to realize the estimation of PV injection power. Finally, the validity of the proposed method is verified in CIGRE distribution network, IEEE 34-node and IEEE 123-node distribution systems. The results show that PV on-grid state and output can be effectively identified in several different scenarios: PV continuous change, PV injection power plunge, and PV injection power plunge during continuous change. Furthermore, the performance of the proposed method is unaffected by the on/off-grid action of the impact load. The average error of PV injection power estimation results is less than 4 %, which has strong adaptability to operating conditions and good estimation accuracy.