A Method for Evaluating Ultra-low Frequency Oscillation Stability of Multi-machine Power System

An electromechanical system, stability technology, applied in the direction of reducing/preventing power oscillation, circuit devices, AC network circuits, etc.

CN107658892BActive Publication Date: 2018-08-28YUNNAN POWER GRID
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2018-08-28

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Abstract

The invention relates to a method for estimating the ultralow frequency oscillation stability of a multi-machine power system, and belongs to the technical field of power grid safety. The method comprises the steps: building a unified frequency model comprising a main generator set of a system; carrying out the frequency sweeping of a target generator set prime motor-speed regulator transfer function at an ultralow frequency (0.05-0.1Hz), and obtaining the ultralow frequency domain characteristics of each generator set in a plane s; and estimating the impact on the ultralow frequency oscillation stability of the system from the target generator set through analyzing the attributes of the ultralow frequency domain characteristics of the target generator set prime motor-speed regulator transfer function. According to the invention, the method is clear in principle, can be used for the estimation of the ultralow frequency oscillation stability of the multi-machine power system and enablesthe operation of the system to be stable.
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Description

technical field

[0001] The invention belongs to the technical field of power grid security, and relates to a small disturbance stability evaluation method, in particular to a multi-machine power system ultra-low frequency oscillation stability evaluation method. Background technique

[0002] Low-frequency oscillation affects the safe and stable operation of the power system for a long time, which is mainly caused by the rapid action of the excitation system and the weak connection between regional power grids. By constructing DC transmission lines to interconnect regional grids asynchronously, the grid structure can be enhanced to mitigate the effects of low frequency oscillations. However, after the asynchronous connection between Yunnan Power Grid and the main grid of China Southern Power Grid in 2016, a long-term, ultra-low frequency frequency oscillation phenomenon appeared in Yunnan Power Grid, that is, ultra-low frequency oscillation. The frequency of ultra-low freque...

Examples

specific Embodiment

[0047] (1) Statistics of unit data and power flow calculation results of Yunnan Power Grid in the 2017 winter power grid of China Southern Power Grid. According to the steps mentioned above, a unified frequency model was established in Matlab / Simulink software.

[0048] The establishment of the above-mentioned unified frequency model follows the following steps:

[0049] 1) The thermal power output in the method data is 3977.2MW, and the hydropower output is 32559MW.

[0050] 2) For thermal power units, the typical unit type is GS (including GS-type governor module and TB-type steam turbine module). For hydroelectric units, the typical unit types are GH (the GH model itself contains the governor and prime mover) and GM (including the GM type governor module, the GA type servo module and the hydro turbine detailed model module). The total output of GS-type units is 3977.2MW, the total output of GH-type units is 7717MW, and the total output of GM-type units is 24842MW.

[005...