Calculation method for penetration level of inverter-based DG (distributed generation)

Abstract

The invention relates to a calculation method for penetration level of an inverter-based DG (distributed generation). According to the method, three operation states are firstly defined; when drop degree of grid-connection-point voltage is different on the condition of breakdown, the IBDG (inverter-based distributed generation) with a low-voltage-ride-through capability has three operation states which are respectively defined as a constant power state, an intermediate state and a constant current state; the IBDG is equivalent to a voltage-controlled current source; when three-phase short-circuit faults are caused in the downstream area of the IBDG and at tail end of each circuit of adjacent feeders, an expression of the relationship between system potential and the grid-connection-point voltage is acquired according to an equivalent circuit diagram and a nodal method of analysis; an approximate calculation formula of a short-circuit current flowing through the circuits is acquired through neglect of a phase angle difference between the IBDG grid-connection-point voltage and the system potential; the penetration level of the IBDG is then calculated. By the calculation method, the accurate penetration level, capable of meeting requirements on selectively and sensitivity, of the IBDG can be acquired.

Description

Technical field [0001] The invention belongs to the field of power system distribution network protection and control, and relates to an inverter-type DG admission capacity calculation method taking into account the current protection setting principle of the distribution network. Background technique [0002] Distributed generation (DG) is a new type of electric energy, including photovoltaic power generation system, wind power generation system, micro gas turbine power generation system, small hydropower and so on. Distributed power generation technology has a series of advantages such as environmental protection and economy, and can well meet people's requirements for power safety, stability and economic environmental protection. It has attracted widespread attention and has been gradually promoted and developed. [0003] Most of the traditional medium and low voltage distribution networks are radial networks that supply power to loads in one direction. The protection doe...

AI Technical Summary

Problems solved by technology

The access of DG changes the fault current distribution of the distribution network and the basic conditions of the original protection configuration of the distribution network. The original three-stage current protection may malfunction or refuse to operate

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