| With the rapid development of renewable energy, integration and consumption of wind power has become serious issues in China. With the implement of western develop-ment strategy, a large number of traditional industries, especially the high ener-gy-consuming in-dustries (such as electrolytic aluminium), are moved from the eastern coastal regions to the western regions that are rich in energy sources. This can be benefit for the economic devel-opment while greatly stimulating the electricity demand of those regions. Recently, our country has introduced a large number of policies to encourage the construction of local power grids to realize the local accommodation of wind power. However, considering the economy factors, many regional grids operate on isolated mode and are not connected to the bulk power system. Due to the small inertia of this kind of isolated power systems, the fre-quency control is a main problem. With more and more obvious increase of wind power penetration, the local accommodation of renewable energy sources such as wind power is seriously confined.This paper discusses the way to maintain the frequency stability in the isolated power system. The participation method of energy-intensive load in frequency regulation in iso-lated power system with high-level wind power penetration is proposed. What’s more, an industrial application method is proposed to apply this control method into industrial appli-cation. The research achievements of this paper have theoretical and engineering application value for the frequency stability control of isolated power systems and local accommodation of wind power. The specific research works are as follows:Firstly, this paper study the load characteristics of the electrolytic aluminum, analyzes the possibility for the electrolytic aluminium load to participate in the frequency adjustment of the isolated power grid. Combined with the field test data, this paper built the electrical model of the electrolytic aluminum. Based on this electrical model, a WAMS-based control method of electrolytic aluminum is proposed. Based on this, in view of the frequency con-trol difficulty of isolated power grid with high energy-consumption industries, a control method to rapidly adjuste the active power of electrolytic aluminium loads is proposed based on the DC voltage regulation. With the help of the WAMS, the power disturbance can be identified online and be set as the control target for the active power of electrolytic alu-minium loads. In this way, the electrolytic aluminium loads can be regulated effectively to participate in the frequency control of the isolated power system.Secondly, a frequency control method for the isolated power system based on the load-damping control is proposed. The load-damping control method of voltage-sensitive load is studied. Through measuring the frequency deviation online and adding it to the gen-erator excitation control, the voltage-sensitive load can present equivalent load-damping characteristics, which makes it possible to successively adjust the active power of the elec-trolytic aluminium loads to solve the isolated grid frequency stability problems when the wind power fluctuates. Through the online optimization of the load-damping coefficient of the electrolytic aluminium load, in order to minimize the cost while main-taining the system stability, as well as reducing the control overshoot during the transient process, a two-stage time-varying load-damping control method is presented. It can effectively improve the tran-sient frequency response characteristics.Thirdly, the platform architecture of hardware-in-loop based on RTDS is designed in this paper. It contains the uplink and downlink devices of the real-time control and the WAMS control center in the closed-loop constructure. The way of hardware devices’access to the simulation platform is described based on the input-output relationship of the hard-wares. With the help of the hardware-in-loop platform, the control delay of WAMS is tested, which can reflect the actual scene in a large extent. So the control delay of WAMS and the output characteristic of the controlled devices are fully considered.Lastly, the industrial applying method for the high energy-consuming load to partici-pate in the frequency control of the isolated power system is proposed. The overall frame-work of the control system based on WAMS is proposed, the closed-loop control function has been extended to WAMS. The interface modification method for the control devices and controlled objects is present, which can make the output range of the NCU cover the objec-tive adjusting range. The proposed control strategy is applied into practical field test site system to verify the validity of the control strategy in the actual operation. |
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