Energy Stability Control For Synchronous Generator Excitation And STATCOM

“Global Energy Internet Strategic thoughts” is put forward in China’s thirteenth five-year national development plan and UHV AC and DC transmission lines are constructed so that energy could be transmitted cleanly and efficiently. With the power system interconnection and the use of many new equipment, the efficiency of power generation and transmission is improved,but the complexity of the power system is increased at the same time, which allows the power system stability issues more prominent. Therefore, the generator excitation and STATCOM get more and more attention as a measure to improve the stability of the power system. Appling the Lyapunov’ direct method, energy stability control is presented to deal with both stability and voltage regulation for generator excitation and STATCOM to get the voltage stability and the improvement of the system’s stability. The main content are as follows:(1) From the engineering practice, terminal voltage, rotor speed and active power of the generator and the voltage at the bus of STATCOM are chosen as control objectives in order to force them to get punishment with the energy attenuation of Lyapunov function and make them satisfy the design and practical requirements.(2) The energy stability control is presented for STATCOM’s current source mathematical model for the case in which STATCOM is at the midpoint of the grid. However, the STATCOM’s current source mathematical model is so ideal that the STATCM’s third-order mathematical model is established and energy stability controls are presented for the case in which STATCOM is in the high voltage bus outlet side. In order to avoid the case that the controls are weak robustness with system parameters, energy stability robust controls are presented with d-axis and q-axis currents introduced which are represented by a measureable amount of local.(3) A Single Machine Infinite System(SMIB) model is built on the Simulink environment of MATLAB with STATCOM. With imported disturbance situations and three-phase short circuit fault situation, simulations and discussions are pointed for coordinate control for the generator excitation and STATCOM. Simulations show that the control objectives can track their expectations accurately and the static and dynamic characteristics of system are enhanced. And energy stability robust controls are robust for system parameters with removal of fault situations.