Active and reactive power coordinated secondary control based on control sensitivities in microgrid

In low-voltage level microgrids, the values of resistance and inductance of lines are very close. So the power control is no longer has the characteristic that active and reactive power can be tuned independently. If we still do so, overshoot and oscillation will appear. To solve this problem, this paper proposed a new active and reactive power coordinated control method in microgrid based on control sensitivities. Firstly, the formula of control sensitivities for secondary control is deduced according to the control modes of micro-sources. Then, a quadratic programming model to minimize the deviations of frequency and voltage is established based on the control sensitivities, and the adjustments of the secondary control of the microgrid are obtained by solving this quadratic programming model. Taking an actual islanded microgrid as an example for simulation, it is proved that the method proposed in this paper can improve the accuracy and stability of the secondary control in microgrid, by comparing with the secondary control that active and reactive power are tuned independently.