A Survey on Damping Low Frequency Oscillation Based on Coordination Strategy of Static Synchronized Compensator Modulation

In order to suppress the low frequency oscillation effectively in AC-DC paralleling transmission, a strategy based on sliding mode control theory is proposed to coordinate supplementary control between HVDC and STATCOM. Firstly, the mathematical model of multi-machine AC-DC parallel transmission system, including HVDC and STATCOM, is established through COI (center of inertia) method. To stabilize the COI angular velocity deviation between areas, the unified damping control strategy based on sliding mode variable structure theory is designed. And then, COI angular velocity deviation and relative gain array are taken as the objective functions, which are obtained from the supplementary control of HVDC and STATCOM on the STATCOM voltage controller. The purpose is to coordinate and allocate the participation weights of HVDC and STATCOM damping control. The coordination strategy guarantees the stability of voltage and realizes the optimal effect of damping control. Finally, the simulations of 4-generator 2-area model in PSCAD have verified the control strategy. © 2017, The editorial office of Transaction of China Electrotechnical Society. All right reserved.