Reactive power coordinated control at the gateway between provincial and regional power grids

It is the key problem in automatic voltage control of large-scale power grids to quantitatively assess the reactive power regulation capability of provincial power grid to determine the control range of reactive power between provincial and regional power grids. Based on the concept of layered decoupling, firstly the definition of average coordination power factor limits (ACPFL) is given to evaluate the reactive power limit of provincial power grid, and the optimized mathematical model of ACPFL is solved to obtain the correlation curve between ACPFL and load level transmitted from provincial power grid to subordinate power networks; then according to the differences among loads of 500kV substations, the approximate linearization calculation of limit value of the upstream gateway coordinated power factor is performed, and taking it as the constraint a calculation model and fast estimation method for the limit value of downstream gateway coordinated power factor are established to implement dynamic setting of parameters of AVC system; finally a method to implement the AVC system based reactive power coordinated control at the gateway between provincial and regional power grids is given. Simulation results of applying the proposed method to a certain regional power grid in Guangdong power grid show that the proposed method is favorable for energy-saving and loss-reduction, improving voltage quality, enhancing security margin of voltage and reactive power in provincial power grid and bringing the potential of area substation capacity into play.