Abstract
Inverter-interfaced distributed generators (IIDGs) have been widely applied due to their control flexibility. The stability problems of IIDGs under large signal disturbances, such as large load variations and feeder faults, will cause serious impacts on the system. The virtual synchronous generator (VSG) control is an effective scheme for IIDGs to increase transient stability. However, the existing linearized stability models of IIDGs are limited to small disturbances. Hence, this paper proposes a Lyapunov approach based on non-linearized models to assess the large signal stability of VSG-IIDG. The electrostatic machine model is introduced to establish the equivalent nonlinear model. On the basis of Popov’s theory, a Lyapunov function is derived to calculate the transient stability domain. The stability mechanism is revealed by depicting the stability domain using the locus of the angle and the angular frequency. Large signal stability of the VSG-IIDG is quantified according to the boundary of the stability domain. Effects and sensitivity analysis of the key parameters including the cable impedance, the load power, and the virtual inertia on the stability of the VSG-IIDG are also presented. The simulations are performed in PSCAD/EMTDC and the results demonstrate the proposed large signal stability assessment method.
Highlights
Inverter-interfaced distributed generators (IIDGs) feature in flexible control and quick response uses in different application scenarios
Large signal stability of the virtual synchronous generator (VSG)-IIDG is quantified according to the boundary of the stability domain
This paper focuses on large signal stability assessment of the VSG-IIDG
Summary
Inverter-interfaced distributed generators (IIDGs) feature in flexible control and quick response uses in different application scenarios. Reference [19] investigated how transient energy of VSG-IIDG would be stored and released during disturbances using a Lyapunov function These studies address little on the assessment of large signal stability. The Lyapunov function in [20] was not applicable to the stability assessment of the VSG-IIDG, but it provided reference values for the large signal stability study of the VSG-IIDG. The contributions of the paper are threefold: (1) A nonlinear mathematical model of the VSG-IIDG is established by applying the equivalent model of an electrostatic machine This nonlinear model combining both the electrical parts and control signals can be an analytical tool for the study of large signal stability (2). Popov’s theory, a Lyapunov function is derived and the stability domain of IIDG is determined This Lyapunov-based method has a distinct computational advantage.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have