| Due to the adjustment of energy structure of real demand and the production of energy west to east in our country's actual situation,we must develop west-east power transmission and the large power grid interconnection system.In large capacity over a long distance transmission line with series compensation capacitor devices can reduce the circuit reactance,in turn,improve the system static stability limit and transmission capacity,the resulting sub-synchronous oscillation(SSO)problem is bound to become a problem cannot be neglected when the safety of power grid..Visible detailed studies subsynchronous oscillation of related mechanism,analysis method,the damping control measures and examples of engineering application to maintain the stability of power system and the subsynchronous oscillation suppression system has a very high application value.Under such background,this paper aimed at subsynchronous oscillation related problem and its power system strategy are studied,the main content of the study are as follows:(1)This paper analyzes the test signal method related principle and the method of implementation.First analysis of the electrical power system damping and the calculation method of mechanical damping,and then use it to judge the stability of the system of subsynchronous oscillation;Second the first standard tests based on power system subsynchronous resonance model verify the validity of the test signal method,mainly using time domain simulation curve comparing with the results and combined with the analysis of the test signal analysis;Finally based on the standard model of infinite system operation condition analysis,given the subsynchronous oscillation in power system is a set of suitable for the analysis of the test signal method application solutions.(2)This paper proposes a damping controller of UPFC to suppress the sub-synchronous oscillation.It analyzes the mathematical mechanism of the SSR of the power grid with UPFC Based on the single machine infinite bus system this paper proposes an improved model considering the transient characteristics of UPFC.Through mathematical simulation model and the simulation results can find there is no guarantee that the damping is positiveonly by UPFC and fixed series compensation capacitance,then the system exists the risk of subsynchronous oscillation.In this paper,with thehelp of additional damping control of UPFChas reached to improve the system damping effect.Then design the damping controller and give the parameters setting scheme.Finally through the first standard testing system of frequency domain and time domain simulation verify the effectiveness of the additional controller.(3)This paper analyzes the project using the field data and the additional damping controller to suppress subsynchronous oscillation problem.Analysis of subsynchronousoscillation problems of site engineering,combined with the test data for analysis.First of all from the hardware device on the analysis of subsynchronous oscillation inhibition effect,and then the test data and graphics combination with the engineering analysis.Goal is to solve the subsynchronous oscillation problems of engineering.Finally based on the electromagnetic transient simulation model and the actual NanJing system engineering data analysis,the engineering to improve system damping,inhibit the feasibility of subsynchronous oscillation problem. |
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