Subsynchronous resonance risk quantitative evaluation method based on electrical damping at modal frequency

Abstract

The invention discloses a subsynchronous resonance risk quantitative evaluation method based on electrical damping at modal frequency, and belongs to the field of power system modeling and stability analysis. The method comprises the following steps: firstly, establishing a corresponding network space model for an actual thermal power generating unit connected to a complex power grid system, obtaining a corresponding network parameter matrix through the network space model, and establishing a state space equation of the whole system by simultaneous establishment of the network parameter matrixand a researched generating unit state space equation; calculating an electrical damping value at the natural torsional vibration modal frequency of the shafting of the generator set, comparing the electrical damping value with mechanical damping, judging whether subsynchronous resonance characteristics exist or not by judging whether the sum of the mechanical damping and the electrical damping is positive or negative, and realizing batch processing of subsynchronous resonance risk quantitative evaluation of the generator set accessed to a complex large power grid. The risk degree is observedmore comprehensively in combination with time domain simulation, repeated use of test signals for obtaining an electrical damping curve is avoided, and the workload and time are reduced.

Description

technical field [0001] The invention belongs to the field of power system modeling and stability analysis, in particular to a quantitative evaluation method for subsynchronous resonance risk based on electrical damping at modal frequencies, and in particular to a subsynchronous method for thermal power units connected to complex AC power grids with series compensation Quantitative analysis method for resonance risk assessment. Background technique [0002] my country is rich in coal resources, but the geographical distribution is extremely uneven, showing the energy distribution characteristics of "more in the south and less in the north" and "less in the west and more in the east". Are concentrated in the southwest and other places. However, the economic center and power load center are distributed in the central and southeast coastal regions of my country, so the energy distribution and load present the characteristics of reverse distribution, which determines the basic pa...

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Problems solved by technology

At present, although there are solutions for sub-synchronous resonance caused by series compensation, they are basically in the system of single machine (small scale) and point-to-network directly sent by series compensation

In recent years, there have been more and more UHV lines in my country, and the system has become more and more complex. The series compensation sending system no longer presents a single point-to-network model. Therefore, when the system structure changes, the resonance frequency of the entire system There may be a large change, which has a great impact on the subsynchronous resonance caused by the series compensation, and the risk degree of the entire system cannot be fully analyzed only by empirical judgment. Even if the researchers evaluate the risk through time domain simulation, there are drawbacks , when there are tens of thousands of combinations of system operation modes, this will have a large workload, and it is difficult to simulate one by one. Therefore, a method for batch and quantitative processing of subsynchronous resonance risk assessment is needed

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