Abstract: The present invention provides a high-strength and high-heat-resistant bio-based polyamide composition, which consists of the following parts of materials by mass: 43.50-89.95% of bio-based polyamide resin slices; 10-50% of reinforcements; 0.01-2% of rare earth compounds; 0.01-1% of copper salt antioxidant combinations; 0.01-1% of free-radical scavengers; 0.01-0.5% of heat-conducting masterbatches; 0.01-1% of stabilizers; and 0-1% of dispersants. The advantage of the present invention is presented in that: the bio-based polyamide resin slice is prepared through a stepwise polycondensation process of pentanediamine and adipic acid, or through a stepwise polycondensation process of pentanediamine, adipic acid and terephthalic acid and the pentanediamine is prepared through fermentation of starch, so the prepared polyamide resin pertains to an environmentally-friendly engineering plastic.

Abstract: An exemplary two-step method for power system inertia online estimation is described. The first step is to accurately estimate the POI-level aggregated inertia. The second step is to calculate the system-level inertia constant by weighting all the POI-level aggregated inertia and to monitor the inertia spatial distribution. In one example embodiment, the PMU is installed at POI, the frequency spatial difference is considered, and the mechanical power is carefully treated.

Abstract: In this disclosure, the energy management problem of the D-IEGS with FFR is analyzed, so as to enhance the frequency stability of the main grid. The post-disturbance frequency response behaviors of both the main grid and the D-IEGS are precisely depicted, where the dead zones, limiting ranges and time constant of the governors are considered. The frequency regulation units of the D-IEGS include GTs and P2G units, whose impacts of providing frequency regulation service on the gas networks are quantified. Considering the time-scale similarity of the frequency dynamics and the dynamics of the GDN, the gas flow dynamics model is adopted. The frequency response dynamics of the GTs and P2G units, and the gas flow dynamics of the GDN, a variable-step difference scheme and a binary variable reduction method are devised.

Abstract: Online estimation of area-level inertia can be used for frequency stability control in low-inertia power systems. This disclosure provides an area-level inertia online estimation method considering inter-area equivalent frequency dynamics. The disclosed method only needs one phasor measurement unit placed at any bus within each area. The inter-area equivalent frequency dynamics model for the multi-area power system is developed, which is employed to estimate area-level inertia under the small disturbance situation. Then, the area-level inertia estimation model boils down to a nonlinear parameter identification problem. The other boundary conditions of the disclosed method are derived by parameter identifiability.

Abstract: A method for primary frequency regulation (PFR)reserve procurement of a renewable energy power system is provided. The renewable energy power system includes synchronous power sources and renewable energy sources, and the renewable energy sources participate in frequency regulation using virtual synchronous machine (VSM) control.

Abstract: A method implemented in a power grid including a DFIG wind turbine is provided. The method includes: assuming the DFIG wind turbine to be operated in a MPPT mode; generating a simplified transient model of the DFIG wind turbine, the simplified transient model including an equivalent circuit model, and an equivalent rotor motion model in a nonlinear form; linearizing the equivalent rotor motion model in the nonlinear form to be an equivalent rotor motion model in a linear form with respect to a steady-state operating point of the DFIG wind turbine; and determining a first contribution and a second contribution of the DFIG wind turbines to a post-disturbance frequency of the power grid, in a center of inertia (COI) frequency frame and in a frequency spatial variation frame, respectively, by incorporating the simplified transient model of the DFIG wind turbine into a frequency dynamics analysis.

Abstract: This disclosure provides a method to limit the post-disturbance node maximum RoCoF by optimizing UC decisions. The node initial RoCoF expressions under common disturbance types, including the load, the line switching, and the generator turbine disturbances, are derived. Then, the piecewise linear relationship between the node initial RoCoF and UC decision variables are obtained. To avoid numerical simulation of the node maximum RoCoF, two analytical constraints, i.e., the node initial RoCoF constraint and the COI maximum RoCoF constraint, are formulated in the UC model.

Abstract: This disclosure provides a method to limit the post-disturbance node maximum RoCoF by optimizing UC decisions. The node initial RoCoF expressions under common disturbance types, including the load, the line switching, and the generator turbine disturbances, are derived. Then, the piecewise linear relationship between the node initial RoCoF and UC decision variables are obtained. To avoid numerical simulation of the node maximum RoCoF, two analytical constraints, i.e., the node initial RoCoF constraint and the COI maximum RoCoF constraint, are formulated in the UC model.

Abstract: An exemplary two-step method for power system inertia online estimation is described. The first step is to accurately estimate the POI-level aggregated inertia. The second step is to calculate the system-level inertia constant by weighting all the POI-level aggregated inertia and to monitor the inertia spatial distribution. In one example embodiment, the PMU is installed at POI, the frequency spatial difference is considered, and the mechanical power is carefully treated.