Operation feasible zone evaluation method for high-capacity photovoltaic inverter system connected to power grid

The invention provides an operation feasible zone evaluation method for a high-capacity photovoltaic inverter system connected to a power grid. The operation feasible zone evaluation method is characterized by comprising the following steps that impedance per unit value of the power grid which the photovoltaic inverter system is connected to is calculated with photovoltaic system rated capacity and power grid connecting point voltage serving as reference values and used as a quantitative index for measuring the strength of the power grid; according to a given controller stability margin constraint, an operation feasible zone boundary expressed through the impedance per unit value of the power grid is derived; on the basis of a flow equation of the power grid which the photovoltaic inverter system is connected to, the relation between solutions of the flow equation and the impedance of the power grid is created, an operation feasible zone boundary which meets a corresponding constraint and is expressed through the impedance per unit value of the power grid is derived according to the given access point voltage regulation constraint, and therefore the operating state of the high-capacity photovoltaic inverter system connected to the power grid can be determined. The operation feasible zone evaluation method for the high-capacity photovoltaic inverter system connected to the power grid has the advantages of being clear, scientific and reasonable in evaluation system, simple in process and the like.