New Substation Voltage And Reactive Power Control System

The development of substation integrated automation, power network dispatching automation and regional voltage and reactive power optimal control put forward higher and higher demands to the voltage and reactive power integrated control system (VQC) in substation. In order to optimize the voltage and reactive power control and improve the level of substation integrated automation, this thesis is specialized in the application of voltage and reactive power control in substation and carries on research to novel VQC device on the basis of MCVQ-1 device.Firstly, the thesis briefly reviews the history of voltage and reactive power control technology, focusing on the defects of the equipment in use. Then, with the theoretical analysis and the discussion on voltage and the characteristic of power system as well as the basic principle of voltage and reactive power control, the thesis makes a research on the character of voltage and reactive power control and interprets the controlling regularity of substation. In addition, with the consideration of the changes of transformer taps and the combined influence of capacitor groups and reactive power and voltage, it have work regulate based on fuzzy border voltage criterion apply the new-type control device the thesis makes adjustment suggestion to the different operating-zones of voltage and reactive power. It analyzed the influence of harmony and parallel capacitor and proposed measures of preventing the harmony to be amplified in substation from the VQC device.With the improvement of the computer technology, communication technology, substation automation and dispatching automation level, regional voltage and reactive power optimal control already become possible. Two means of realizing voltage and reactive power optimal control are compared, then, integrated to the require of the regional power network voltage and reactive poweroptimal control and substation automation system, the paper discussed the communication content between the dispatcher and the VQC terminal and proposed the communication content and data structure and communication protocol was made. The communication function has been realized on MCVQ-1 and work well.Finally, this paper proposed to develop AVR+DSP new-type voltage and reactive power control device on the basis of MCVQ-1 and provided the concrete design plan of software and hardware. AVR as the principal CPU undertake the control task of system to fulfill the control of circuit outside and man-machine interface, deal with the interrupt outside, finish the communication with the center computer. DSP (digital signal processor) as the subordinate CPU undertake data gathering and processing. System adopt AC sample to receive the high-accuracy measurement result. It can measure the real-time voltage, current, active power, reactive power, power factor and content of harmonious wave of the power network, monitor the position of taps of transformer and the state of protection equipments. Through adjusting advanced control strategy based on fuzzy theory to adjust shunt capacitor and transformer, it can suppress the wave of system voltage effectively, keep qualified voltage, balanced reactive power and fixed power factor, meanwhile, it can ensure minimum operation times of transformer taps and shunt capacitor switch. Through the measurement of harmonic, it can estimate if the harmonic will be amplified after puting into capacitor in advance, thereby suppress the amplifing of harmonic effectively and guarantee the security of the capacitor groups; It has strong and reliable communication function and cooperate with the optimal software in the dispatcher center to realize regional power network voltage and reactive power optimal control effectively.