Method, device and system for inhibiting low-frequency oscillation of power system

Abstract

The invention discloses a method, device and system for inhibiting the low-frequency oscillation of a power system. The method comprises the following steps: determining a system transfer function of an interconnected power system section of a variable-frequency transformer (VFT); determining parameters of a damping controller in accordance with the system transfer function; and using the VFT to inhibit the low-frequency oscillation of the power system based on the parameters of the damping controller. In the method, device and system for inhibiting the low-frequency oscillation of a power system, the control objective is definite, and the parameters of the damping controller can be adjusted in time by simply tracking the response of an analytic system to the turbulence without learning about the specific structure and parameters of the system or solving complicated power system equations. Thus, the invention achieves a favorable effect on inhibiting the low-frequency oscillation in the system, thereby being beneficial to promoting the security and stability of the power grid.

Description

technical field [0001] The invention mainly relates to the technical field of safe operation and control of electric power systems, in particular to a method, device and system for suppressing low-frequency oscillations of electric power systems. Background technique [0002] The interconnection of large power grids is the basic trend of the development of power grids in the world, and the interconnection of large power grids may cause low-frequency power oscillation problems. The oscillation frequency is generally between 0.1-2.0Hz. When the oscillation mode is weakly damped or even negatively damped, it will It may lead to grid instability and endanger the security of the grid. [0003] In the 1960s, power low-frequency oscillations occurred in the North American power system. Since the 1980s, with the increase in the proportion of large-scale unit rapid excitation systems and the large-scale interconnection of power grids in my country, low-frequency oscillations have al...

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Problems solved by technology

[0008] However, the above-mentioned measures have certain limitations to varying degrees.

The limitations of installing a power system stabilizer in the generator excitation system to suppress the low-frequency oscillation of the power system are: first, the number of generators in the power system is large and the distribution points are wide, and the workload of configuring a power system stabilizer for each unit is large; Second, in actual operation, some unit power system stabilizers may be out of operation without monitoring due to management or technical factors, affecting the damping effect; third, the parameter design of the power system stabilizer needs to be coordinated with each other and be consistent with the different wiring modes of the system. Adaptation can effectively suppress low-frequency oscillations. If there are major changes in system wiring and start-up methods, the original power system stabilizer may be limited in suppressing low-frequency oscillations.

[0009] Applying DC modulation function and FACTS equipment such as controllable series compensation and static var compensator for damping control, the limitation is firstly that the system needs to have corresponding equipment

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