Subsynchronous damping control system and subsynchronous damping control method for generator terminals

Abstract

The invention discloses a design method of the subsynchronous damping control of a generator terminal. The subsynchronous damping control of the generator terminal is designed according to an upper controller, a lower controller and a primary device, wherein the upper controller implements the control strategy and information monitoring of subsynchronous resonance, the lower controller implements the large-current output of a control instruction through driving a power electronic power component, and the primary device contains the power electronic power component and a transformer for controlling a current to be compensated to the generator terminal; the upper controller carries out sampling, demodulating and filtering processing as well as independent proportional phase shift processing on a rotating-speed pulse signal so as to obtain a rotor-side modal controlled quantity, then, the modal controlled quantity is converted into a three-phase control current instruction according to an obtained electrical angle coordinate of the system, and the lower controller controls the power electronic power component to output a three-phase power current according to the received control current instruction; and the three-phase power current is injected into the generator terminal by a step-up transformer. By using the design method disclosed by the invention, a current is outputted at the generator terminal so as to carry out compensation according to an identified torsional vibration modal signal of a generator set, thereby improving the modal damping of the generator set.

Description

technical field [0001] The invention belongs to the technical field of power system stability and control, and in particular relates to a design method of a subsynchronous damping controller at the end of a generator, and provides a new solution for solving system subsynchronous oscillation. Background technique [0002] With the increasing demand for long-distance large-capacity transmission, especially large-scale coal power bases are far away from the load center, most of them adopt the long-distance plant-to-grid transmission mode. In order to improve the transmission capacity and system stability, more and more fixed series capacitors are used. Compensation (FSC), high-voltage direct current transmission (HVDC) and some high-speed control devices based on power electronics technology. However, these devices may induce subsynchronous resonance (SSR) or oscillation (SSO) problems under certain conditions. Slight SSR / SSO will reduce the life of turbogenerator shafting, an...

AI Technical Summary

Problems solved by technology

The respective control technology characteristics of these solutions determine some limitations in their practical application: (1) The traditional thyristor control used by SVC has relatively backward technology, poor harmonic characteristics, and a relatively large floor area, cost relatively high cost

However, this method is limited by the excitation capacity of the generator, and the suppression ability provided is limited

(3) The cost of the solution using the blocking filter is the highest, and the filtering characteristics are greatly affected by the primary components (inductance, capacitance), and the inductance and capacitance are greatly affected by environmental factors such as temperature, so the maintenance cost of the equipment after operation very high

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