Research On The Several Key Technology Of Distribution Static Synchronous Compensator

Electrical energy plays an important role in the economic development and industrial production. With the increasing shortage of energy, power saving and power quality management have been put on the agenda. Distribution Static Synchronous Compensator (DSTATCOM) is a shunt FACTS device. Compared with traditional reactive power compensator SVC which based on reactors and switched capacitor, it has significant advantages in controllability and response speed, and has been used widely.The basic working principle of the DSTATCOM is studied and its mathematical model is established in this paper. The direct current control and indirect current control are compared in this paper. In order to improve the response speed and control accuracy of DSTATCOM, this paper adopts the direct current control method. The PID control theory of neuron and voltage space vector is adopted in the direct current control to further improve the self-adapting control performance of the device and compensate the shortage of high switching frequency.DSTATCOM can regulate the reactive power continuously and has good dynamic performance. Thyristor switched capacitor (TSC) has large capacity and low cost. Combining the advantages of them, this paper builds a low-cost large-capacity dynamic reactive power compensation device(Hybrid Var Compensator, HVC).Based on its equivalent circuit and the compensation mechanism, this paper proposes an expert cooperative hybrid control technology based on the reasoning and judgement of experts and Instantaneous power balance voltage control,which makes good coordination between continuous subsystem DSTATCOM and discrete subsystem TSC to realize the low-cost, high-speed, continuous reactive power compensation,save energy of the low voltage distribution network and improve the power quality.Based on the basic theory above, experimental device which uses DSP TMS320F28335 as the controller is built in the laboratory. The system's hardware structure diagram is given in this paper. The inverter design, parameters design of DC capacitors and heat sink design are also given in this paper. At last, software structure diagram and the program flow chart of computer software and lower computer software are given in this paper. DSTATCOM designed in this paper has been used successfully in the laboratory. The results prove that the achievement of this paper is effective and practical.