Smart load management of water injection systems in offshore oil and gas platforms integrating wind power

Abstract

Abstract:The high pollution coming from the use of gas turbines in oil and gas (O&G) platforms is calling for more sustainable solutions. One of those is to use wind turbines (WT) to supply power to the water injection systems (WIS) of offshore O&G installations and explore the potential of smart energy management in providing more efficient and green solutions to the O&G sector. The effect of WT integration into the local power system and the coordination with the local gas turbines, need to be carefully analysed since the natural intermittency of the wind resource can jeopardize the stability and efficiency of the offshore grid. In general, the existence of flexible loads interfaced by variable speed drives (VSD), such as water injection systems, can help overcome some of the challenges related to wind intermittency and local rotor angle stability: suitable control of such non-essential loads and load segregation can be implemented to reduce the effect of wind power fluctuations, balance power generation and consumption and contribute to maintaining the optimal efficiency of the gas turbine adjusting its loading conditions. The basic assumption is that the WIS can follow the generation available from the wind turbines. The assumption is reasonable since WISs do not require a fixed injection rate. This work will investigate the system dynamics in the event of short-term wind-induced power fluctuations, analysing the evolution of electrical variables, such as active power and generator rotor speed/frequency, under different operating conditions, to specifically evaluate the possible arise of low-frequency oscillations. The impact of an adequate WIS load control to counteract wind variations and increase the system damping is also further explored. Moreover, in order to prevent the event of critical rotor oscillations in the gas turbine and other directly-connected rotating machines due to the WT dynamics, an algorithm for system damping estimation is proposed and its performance studied in the selected test cases.

Integration of Distributed Energy Resources into Offshore and Subsea Grids

“…Finally, possible stability risks due to electro-mechanical oscillations are addressed in [132] and load management is proposed as a mitigation measure.…”

Smart Load Management with Energy Storage for Power Quality Enhancement in Wind-Powered Oil and Gas Applications

“…On top of that, stochastic variations are added on the generation side when wind power is integrated. This raises concerns not only about insufficient amount of inertia, but also excessive frequency and voltage variations during operation that might negatively affect the electrical power quality and the GT operation [9,10]. Hence, during the design phase of a wind-powered OOGP, it is important not only to meet the power balance between generation and loads, but also consider system dynamics that may affect voltage and frequency in the electrical grid.…”

“…Within this context, the present work investigates power quality issues in an OOGPs operating in islanded mode where the wind turbine is rated at 36% of the GT nominal power. It is an extension of [10], which combines the previously proposed smart load management strategy with an ESS to mitigate the effects of wind variability. For that, the detailed dynamic model presented in this previous work is used as benchmark, extended to include an ESS, and then compared to the proposed simplified dynamic model in Section 4.…”

“…This paper is organized in the following manner: Section 2 introduces the case study and highlights the main additions compared to the previous contribution [10]; Section 3 presents the negative effects that power fluctuations have on the frequency and voltage of the studied HES in a time scale of seconds. It also demonstrates how those can be counteracted by an ESS providing inertial and voltage support; Section 4 introduces the simplified model of the HES, explains why it is necessary, and compares its results with the detailed model developed with MATLAB/Simulink using the Simscape Electrical library; finally, Section 5 presents a discussion of the obtained results and recommendations for further work.…”

“…Specifically, they are: a floating wind turbine with its associated AC/AC converter and transformer (T 1 ); the transmission line cable; fixed loads; a GT with its associated synchronous generator (SG) and transformer (T 2 ); flexible loads; and an ESS with its associated AC/DC converter. An extensive description of this model without the ESS is provided in [10], and a summary of the system parameters required for modeling is available in Table A1.…”