Research On Leveraging The Flexibility Of Industrial Loads For Power System Frequency Operation

The integration of large-scale renewable energy has caused tremendous pressure on the operation and control of power systems.Exploring large-scale and rapid adjustment of resources to improve the flexibility of power systems is an urgent problem to be solved in the process of power system transformation.Energy-intensive industrial loads have a large potential for thermal energy storage,and leveraging the flexibility of energy-intensive industrial loads is of great significance for improving power system flexibility.This paper studies the characteristics and control methods of energy-intensive industrial loads and its application in power systems frequency regulation.Based on the energy-intensive industrial loads production process,theveral direct load control methods are proposed for regulating the industrial loads.And the effectiveness of the dynamic adjustment characteristics of energy-intensive industrial loads is verified by field test.A primary frequency feedback control method for islolated industrial power grid based on load control is proposed for the safe operation of the islolaged industrial power grid.A secdondary frequency regulation based on load control is proposed for smoothing the fluctuations of tie-line between grid connected industrial power grid and utility power grid.Besides a hierarchical framework of industrial loads for participating frequency regulation ancillary services is proposed in this paper.In summarize,this paper leverage the flexbility of energy-intensive industrial loads for constucting a new mode of power system control which enhances the flexibility of the power system.The main work and innovations of this paper are as follows:(1)The power characteristics of energy-intensive industrial load is established and two control methods are proposed and verified by field tests.The effectiveness of high energy-consuming equivalent energy storage regulation technology.(2)A primary frequency control strategy for isolated energy-intensive industrial power grid is proposed.A energy-intensive industrial load controller based on system frequency feedback is proposed for the isolated power grid which realizes the automatic feedback control of the system frequency with a high energy-consuming industrial load.On this basis,considering the complex operating environment of the actual power grid,a closed-loop control system based on wide-area information is developed,which realizes the safe operation of the isolated power grid.The closed-loop control system is verified by the field test.The test results prove that the isolated industrial power grid can maintain frequency stable with the help of the closed-loop control system.(3)A secondary frequency modulation control strategy for grid-connected energy-intensive power grid based on load control is proposed.Aiming at the grid-connected energy-intensive industrial power grid,a model predictive control is proposed to coordinate the thermal power unit secondary frequency and load control which realizes the control of the power of the grid-connected energy-intensive industrial power grid.Renewable energy power fluctuations in grid-connected energy-intensive industrial grids.On this basis,a explicit model predictive controller based on offline calculation is proposed,which improves the calculation rate of model prediction control without affecting the adjustment effect of the model predictive controller.(4)A new hierarchical framework to coordinate the demand responsive industrial loads with thermal power plants in an industrial park for secondary frequency control is proposed in this paper.In the proposed framework,demand responsive loads and generating resources are coordinated for optimal dispatch in two-time scales: 1)the regulation reserve of the industrial park is optimally scheduled in a day-ahead manner.The stochastic regulation signal is replaced by the specific extremely trajectories.2)a model predictive control strategy is proposed to dispatch the industry park in real time with an objective to maximize the revenue.Various scenarios are simulated to study the performance of the proposed approach to enable industry parks to provide ancillary service into the power market.The proposed strategy is demonstrated to be capable of maintaining the economic and secure operation of the industrial park while satisfying performance requirements from the real world regulation market.