چكيده به لاتين
Abstract:
Series capacitive compensation is an economical way to increase the power transfer capability of the transmission lines. For example, a study performed by ABB Group reveals that increasing the power transfer capability of an existing transmission line from 1300 MW to 2000 MW using series compensation is 90% less than the cost of building a new transmission line.
However, a factor hindering the extensive use of series capacitive compensation is the potential risk of sub-synchronous resonance (SSR). SSR is an electric power system condition where the electric network exchanges energy with a turbine generator at one or more of the natural frequencies of the combined system below the synchronous frequency of the system. This phenomenon may cause severe damage in the turbine generator if is not prevented.
Therefore, this thesis deals with the SSR phenomena in a capacitive series compensated system. The IEEE First Benchmark Model, is considered as a case study. The small-signal stability analysis of the system is presented, and the eigenvalues of the system are obtained. Using both modal analysis and time-domain simulation, it is shown that the system is potentially unstable due to the first torsional mode.
Then, application and control of the gate-controlled series capacitor (GCSC) as a new series FACTS device for series compensation and sub-synchronous resonance (SSR) damping is presented. Also, GCSC is used in conjunction with fixed series capacitor to minimize the overall cost of compensation.
Furthermore, functionality of GCSC in fixing a bus voltage feeding a variable load is presented in this thesis. A comparison is also made in which the performance of GCSC and TCSC in a common system is considered.
In this thesis, Matlab/Simulink is used as a tool for modeling and design of control system, and PSCAD/EMTDC is used for time-domain simulations.
Keywords: Series capacitive compensation, gate-controlled series capacitor, sub- synchronous resonance
