Effects of the Synthetic Inertia from wind power on the total system inertia after a frequency disturbance

Abstract

The future power systems face several challenges; one of them is the use of high power converters that virtually decouple primary energy source from the AC power grid. An important consequence of this situation is their effect on total system inertia and the ability to overcome the system's frequency disturbances. The wind power industry has created a controller to enable inertial response on wind turbines generators: Synthetic Inertial. This paper evaluates the effects of the inertia emulation of wind turbines based on full-converters and their effect on total system inertia after frequency disturbances happen. The main contribution of this paper is to demonstrate (based on simulations)that during an under-frequency transients on future power systems, synthetic inertia does not completely avoid worse scenarios in terms of under-frequency load shedding. The extra power delivered from a wind turbine during frequency disturbances can increase "momentary" the total system inertia and substantially reduce the rate of change of frequency providing time for the active governors to respond. However, synthetic inertia might not completely avoid under-frequency load shedding.

Impact of Distributed Generation Grid Code Requirements on Islanding Detection in LV Networks

“…Usually, inertia emulation is implemented in modern wind turbines (WTs) and its impact on frequency stability is widely demonstrated [36][37][38]. In this work the synthetic inertia is supposed to be applied also to static generators connected to the LV distribution network (e.g., photovoltaic plants) in order to investigate its impact on frequency oscillations and islanding detection.…”

“…With reference to the most widely used models illustrated in [37,38], the additional active power ∆P SI is assessed starting from ∆ω (frequency deviation measured by a phase-locked loop, PLL) through a derivative block combined with a low-pass filter, as represented in Figure 6. Thus, the incremental active power is proportional to the frequency deviation derivative.…”

VSC-HVDC for Frequency Support (a review)

“…Supplementary control loops are used to release inertia from a wind turbine as proposed in [30] and [31]. Control of wind turbines for the purpose of frequency support is often achieved by releasing the kinetic energy by increasing the power output, which relies on operating in a de-loaded state, rather than maximum power point tracking to allow a power increase [29]. Coordinated control is required between the VSC and WPP to optimally provide frequency support.…”

“…The use of WPPs to provide frequency support has been extensively investigated in [29]- [31]. Supplementary control loops are used to release inertia from a wind turbine as proposed in [30] and [31].…”

Investigation on grid-scale BESS providing inertial response support

“…However, some of the electrical systems critical issues like system stability and power quality are regularly affected by this transformed infrastructure since most related control strategies are configured to work with conventional electricity generation. Furthermore, frequency stability is the most venerable and affected facet among other power system stability matters within this essential change [1]. Most existing frequency stability control methodologies such as secondary and tertiary are still effective to work in the present state of the system.…”