Subsynchronous damping control system for effectively inhibiting subsynchronous resonance and oscillation

Abstract

The invention discloses a subsynchronous damping control system for effectively inhibiting subsynchronous resonance and oscillation, belonging to the technical field of stableness and control of the electrical power systems. The system comprises a rotary speed checking pre-processor, a combined mode filter, a combined proportion phase shifter, a mode control signal synthesizer, a subsynchronous compensating current command calculator, a current beat controller and a DC / AC convertor. The invention inhibits shafting torsional vibration by injecting subsynchronous / supersynchronous current complementary with machine set shafting modal frequency, and can simultaneously inhibit multiple torsional vibration modals, so that the invention has comprehensive function, can solve the multi-modal subsynchronous resonance and oscillation problems of the electrical power system, improves the supersynchronous stability of the system and lowers shafting torsional vibration fatigue loss of a high-rating generator.

Description

technical field [0001] The invention relates to the technical field of power system stability and control, in particular to a subsynchronous damping control system for effectively suppressing subsynchronous resonance and oscillation. Background technique [0002] At present, the demand for long-distance large-capacity power transmission continues to rise, especially because large coal power bases are far away from the load center, most of them adopt the long-distance plant-to-grid power transmission mode. In order to improve the transmission capacity and system stability during long-distance large-capacity transmission, more and more fixed series capacitor compensation (FSC, Fixed Series Compensation), high voltage direct current transmission (HVDC, High Voltage Direct Current Transmission) and some power electronics based Technology high-speed control device. However, these devices may cause subsynchronous resonance (SSR, Subsynchronous Resonance) or subsynchronous oscilla...

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Problems solved by technology

To damp the shaft system oscillation, an additional control signal is required for subsynchronous damping control; when the additional control uses the generator speed as the feedback signal, the controller structure is mostly simple proportional-integral (PI, Proportional-Integral) or transfer function , the design of control parameters is difficult to take into account multiple modal control effects and adapt to changes in operating modes, and the robustness is poor, resulting in poor actual control effects; when the bus voltage or current is used as the feedback signal, control strategies such as nonlinear optimization are used It can only roughly meet the requirements of damping torque in the important torsional vibration frequency range, without designing different control channels and parameters for specific torsional vibration modes, and performing decoupling control, it is difficult to simultaneously optimize and suppress multiple torsional vibration modes State effect;

[0006] (2) The subsynchronous damping control is only used as an additional control loop of the conventional voltage control. The static synchronous compensator is still based on power frequency reactive power control, and the concept and control logic of subsynchronous current dynamic compensation are not introduced in the mechanism. Play its main function of inhibiting SSR / SSO;

[0007] (3) The interaction between the sub-synchronous control logic and the DC side voltage (or current) of the converter and its influence on the control effect are not considered

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