Method for acquiring control input signal of subsynchronous oscillation suppression and control device

Abstract

The invention relates to a method for acquiring a control input signal of a subsynchronous oscillation suppression and control device. In the method, a three-phase AC bus voltage Vabc(t) of an access point of the subsynchronous oscillation suppression and control device serves as an input voltage signal which is converted into two phases of orthogonal static coordinate signals Valpha(t) and Vbeta(t) by Clarke conversion, and a phase error signal Pherr is output after the two phases of orthogonal static coordinate signals pass through a digital phase closed loop link; and a generator set shafting torsional vibration mode signal is separated from the phase error signal by a filtering link as the control input signal of the subsynchronous oscillation suppression and control device. In the method, the bus AC voltage of the access point of the subsynchronous oscillation suppression and control device is adopted as a source signal, and the generator set shafting torsional vibration mode signal is obtained by digital phase locked loop and digital processing technologies, and the reliable control input signal can be provided in situ for a device; and the method is relatively lower in cost and easy to implement.

Description

technical field [0001] The invention belongs to the field of electric power systems, and in particular relates to a method for acquiring a control input signal of a subsynchronous oscillation suppression and protection device. Background technique [0002] Subsynchronous oscillation is a transient process in which the power grid and the steam turbine exchange energy at one or several frequencies lower than the power frequency. The energy exchange of this oscillation may be weakly damped or negatively damped. If it is negatively damped, it is unstable. At present, my country's thermal power bases generally adopt the point-to-grid transmission mode, and the transmission distance is generally long. In order to improve the stability limit of the line and increase the transmission capacity, series compensation transmission technology and high-voltage direct current transmission technology are adopted. The application of series compensation technology and high-voltage direct curre...

AI Technical Summary

Problems solved by technology

If suppression measures are taken for each unit near the machine end, the project cost is high and the control is complicated. Therefore, it is necessary to adopt various suppression and protection measures on the grid side to solve the problem of subsynchronous oscillation of multiple units in thermal power bases.

The rotor speed measurement signal of the unit is a reliable input signal for the subsynchronous oscillation suppression and protection device near the machine end, but for the subsynchronous oscillation suppression and protection device on the grid side with a certain distance from the unit, if the unit rotor speed signal is used as the input signal, it may Faced with the problem: the shafting speed signals of multiple units need to be transmitted to the suppression and protection device through a communication channel at a certain distance, the project cost is high and the reliability of the project is reduced due to many intermediate links

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