Research On Aspects For Real-time Voltage Stability Monitory And Control Of Power System

As complicated huge nonlinear dynamic system, the stability of power system has been always one of the key issues that electric industry puts great emphasize on. Along with the continuously occurrence of voltage stability accidents featuring the voltage collapse phenomenon, voltage stability issue has become a hot topic of the stability research. Power system of China is now at the threshold of transforming towards direction featuring huge network, giant generator, large capacity and long transmission distance, meanwhile, development of power market is very fast now and in the near future. Both big changes pose great challenge for conserving stability of power system. Under such circumstances, establishment of comprehensive voltage stability monitory and control system to prevent voltage collapse is of great significance in reality.As the fast development of the scale of power system, the off-line calculation mode is gradually unable to meet the ever-increasing demand in stability monitory and control. Recent years, electrical engineers have been dedicated in developing on-line voltage stability monitory and control system. Based on study of theories and practice on modern on-line voltage stability monitory and control system, from the viewpoint of the engineering reality, this thesis brings forward two drawbacks that exist in current voltage stability monitory and control system, and raises relative resolving schedules. The algorithms are realized with the Visual C++ tool, and data of a real power system are used to rectify the made programs. The work of this thesis can be generalized as the following two parts:1. Catering to the fact that angle stability constraints are unconsidered in forming control method in a monitory and control system, in order to fully coordinate the performance of voltage stability and angle stability in stability control, this thesis raises the idea to embed an angle stability test module into on-line voltage stability monitory and control system. The function of this arrangement is to test the angle stability state of power system under voltage stability strengthening measure, which is produced by certain voltage control module. Therefore, as the voltage capacity is improved, the angle stability can be kept as well, so that the overall stability state may be better assured.2. The aim of the second task of this thesis is to improve the efficiency of the program of CPFLOW (Continuation Power Flow). The CPFLOW method is one of indispensable parts of voltage stability analysis system, which may calculate the critical point through tracing down nose curve, and also may provide useful operative information for recognizing weak buses and guiding reactive compensation. However, solving a CPFLOW is time-consuming process, efficiency of which is directly linked to overall performance of on-line voltage monitory and control system. To overcome the speed bottleneck, this thesis develops the CPFLOW algorithm employing advanced sparse matrix techniques, and also summarized certain treatment in realizing details of the algorithm. This thesis also made comparison between proposed program and former one without considering sparse, the result of which illustrates the priority in performance of the new program: with fine precision, the proposed program remarkably shortens the solving time.Both of the two main tasks of this thesis are realized with the Visual C++ tool, and simulations are carried out based on practical operative data from a provincial network of Southeast, which verify practicability and reliability of the programs. The transient stability test module has already served as a functional module in a voltage stability monitory and control system in a provincial network of Southeast.