Alternating-current and direct-current interconnected power grid Thevenin equivalent parameter online calculation method

Abstract

The invention discloses an alternating-current and direct-current interconnected power grid Thevenin equivalent parameter online calculation method. The method includes the steps that equivalent impedance or equivalent current source processing is conducted on a direct-current power transmission unit in an alternating-current and direct-current interconnected power grid according to PMU measurement values to obtain a primary correction admittance matrix; equivalent impedance processing is conducted on the load of current state load nodes in the alternating-current and direct-current interconnected power grid to obtain a secondary correction admittance matrix after equivalent impedance processing; load impedance at the current state load node in the alternating-current and direct-current interconnected power grid is cut off, and a node admittance matrix for open-circuit voltage is calculated according to the secondary correction admittance matrix; according to the node admittance matrix for open-circuit voltage and node state information of all nodes in the current state, a node voltage equation for open-circuit voltage is calculated; Thevenin equivalent impedance is calculated, and accordingly all Thevenin equivalent parameters of researched load nodes in the alternating-current and direct-current interconnected power grid can be obtained.

Description

technical field [0001] The invention belongs to the field of electric power industry, and in particular relates to an online calculation method for Thevenin equivalent parameters of an AC-DC interconnected power grid. Background technique [0002] As a complex cyber-physical system, the power system’s stable operation is inseparable from state monitoring and control. Situational awareness enables power grid operators to understand the current power grid operating status and accurately predict possible future situations in order to take effective actions. Significantly improve the safety and economy of power system operation. One of the key reasons for the blackout in the United States and Canada on August 14, 2003 was the lack of situational awareness or insufficient situational awareness. Therefore, improving situational awareness is an important technical means to accurately and effectively grasp the security of the power grid. Organizations such as the Institute of Techn...

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Problems solved by technology

[0006] However, the existing Thevenin equivalent parameter identification methods do not judge the stability of nodes with large random fluctuations in the AC-DC interconnection grid, and the research objects of the existing Thevenin equivalent parameter identification methods are all pure AC networks, and have not studied the AC-DC interconnection. The processing method of the DC transmission branch when the Thevenin parameter identification of the AC side node in the system, so the existing method cannot be directly applied to the AC-DC interconnection grid

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