A DC power mutual aid method for an AC system with multi-circuit UHV DC feed-in

Abstract

The present invention proposes a DC power mutual aid method for an AC system fed by multi-circuit UHV direct current for the scenario of multi-circuit ultra-high voltage direct current feeding into an AC power grid. The present invention constructs the constraint model of the sending and receiving AC systems through the Thevenin equivalent parameters of the sending and receiving AC systems and the equivalent PQ node parameters of the sending and receiving AC sides obtained from the quasi-steady-state mathematical model; Under the constraint conditions, optimize and solve the maximum value of the active power fed into each DC line, and correct the adjustable capacity of the DC line according to the current DC operating state and the equivalent inertia of the AC system at the sending end of the DC line, and calculate the DC line accordingly. The frequency current reference droop coefficient and adjusts the DC current reference value of the DC link. The invention gives full play to the mutual benefit of power between multiple feed-in DCs, enhances the power support capability, and improves the stability and robustness of the AC system at the receiving end.

Description

technical field [0001] The invention belongs to the field of active power control strategy of a multi-area AC-DC power grid interconnection system, and in particular relates to a DC power mutual aid method for an AC system fed by multi-circuit UHV DC. Background technique [0002] With the continuous operation of my country's UHV DC transmission projects and the construction of large-scale power bases in the west, "West-to-East Power Transmission" has become the current power transmission pattern in my country. At the same time, because my country's load centers are concentrated in the southeast coastal area, a large number of existing and planned DC lines are fed into relevant areas. Taking Jiangsu, the load center of East China, as an example, there are currently three UHV DC feed-in projects of "±800kV Ximeng-Taizhou", "±800kV Jinping-Sunan" and "±800kV Jinbei-Taizhou" , the planned Baihetan hydropower transmission in the future will also adopt the UHV DC project. Due t...

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Problems solved by technology

[0006] Aiming at the impact of the large disturbance of the receiving-end grid on the safe and stable operation of the receiving-end AC system of the multi-regional AC-DC grid interconnection system, and overcoming the large unbalanced active power problems caused by DC blocking and part of the generator set off-grid, a method for DC power mutual aid method for AC system with multi-circuit UHV DC feed-in

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