| With the improvement of industrial level, customers become stricter with the power quality. The reactive load, especially the impulsive reactive load, not only increases power loss, but also deteriorates the power quality of customers seriously, so immediate reactive power compensation is a powerful means of optimizing power flow on transmission networks as well as enhancing power quality.Conventional reactive compensator has a long responsive time constant and bad regulative quality. Its compensative capacity is also restricted by the capacity of itself. Based on the electronic inverted technology, STATCOM can be faster and more effective to compensate the reactive power in power system, in which GTO and IGBT are be used. Because the compensative capacity is not restricted by the capacity of itself, it has a better regulative quality.The circuit diagram and work principle as well as its applications are introduced in detail in this paper. Two control strategies of STATCOM are discussed which includes direct-current control and indirect-current control. The harmonic elimination technologies of STATCOM are discussed, which can be achieved by improving circuit configuration and optimizing pulses-generating modes.According to different control strategies, we model two emulate system architectures. The regulative quality and dynamic quality of STATCOM are analyzed from the waveforms of some electric variables.Three-level technology and multi-inverter technology are applied in the main circuit. The control part of STATCOM makes use of two pieces of CPU which are used for central controller and pulses generator. The main functions of central controller include data sampling, A/D converting, data processing and user interface. According to the data provided by the central controller, pulse generator will produce the pulse sequence to trigger the inverters. At the same time, pulse generator protects the power system when the variables exceed certain values. |
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