A voltage stability judging method for flexible HVDC connected power network is presented

Abstract

The invention provides a voltage stability judging method for a flexible direct current connected t power network, and belongs to the technical field of power network planning and operation of a powersystem. The method firstly makes the flexible DC work under the control mode of constant active power and reactive power, records the active power and reactive power fed into the AC power network bythe flexible DC, and measures the voltage amplitude and phase of the AC bus connected to the flexible DC. According to the measured results, the critical short-circuit ratio and short-circuit ratio ofthe system are calculated respectively after the FDC is connected to the power network. the relative magnitude of critical short-circuit ratio and short-circuit ratio is compared, if the short-circuit ratio is greater than the critical short-circuit ratio, the static voltage of the system will be stable after the FDC is connected to the power network, and the system will run stably in this state.The invention can judge whether the system can run stably under the control mode of the fixed active power and the reactive power of the flexible direct current after the flexible direct current is connected to the power grid, and can provide a reference basis for the planning and construction and the operation control of the transmission system containing the flexible direct current.

Description

technical field [0001] The invention proposes a method for judging voltage stability of a flexible direct current connected to a power grid, which belongs to the technical field of power grid planning and operation of a power system. Background technique [0002] Grid commutation converter high-voltage direct current transmission (traditional direct current) has become an important way for my country's "west-to-east power transmission" and asynchronous interconnection of large power grids by virtue of its advantages in long-distance, large capacity, and regional interconnection. However, its stable operation requires The AC power grid at the receiving end with a certain strength provides voltage support, and whether it can operate stably at the rated state in the constant power cut-off angle mode is limited by the short-circuit ratio of the system. The voltage source converter type high-voltage DC transmission (flexible DC) has developed rapidly in recent years due to its adv...

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