Siyang Liao

An Isolated Industrial Power System Driven by Wind-Coal Power for Aluminum Productions: A Case Study of Frequency Control

Summary form only given. Due to the uneven geographical distribution between load and wind power, currently it is difficult to integrate the large-scale wind power into the State Grid in China. There are significant wind curtailments for wind farms due to system restrictions. This paper proposes a new way of utilizing wind power, i.e. in-situ consumption, as an alternative to the costly development of long-distance transmission of large-scale wind power. Electrolytic aluminum load, which is one of the most typical high energy consuming loads, is employed to absorb the excess wind power in western China. An actual isolated industrial power system for aluminum production driven by wind power and coal-fired power is described. The penetration level of wind power in the isolated power system is up to 48.8%. The power imbalance between generation and load demand caused by wind power fluctuation or the tripping of coal-fired generators can dramatically impact the frequency stability of the isolated power system, which is of small inertia. An on-line identification method of power imbalance based on Wide Area Measurement System (WAMS) is presented. According to the characteristics of the electrolytic aluminum load, a system frequency control method by regulating the bus voltages of aluminum loads to eliminate the power imbalance is introduced. The simulation is done in Real Time Digital Simulator (RTDS) and the results verify the validity of the proposed frequency control method.

Load-Damping Characteristic Control Method in an Isolated Power System With Industrial Voltage-Sensitive Load

Load-damping characteristic models the load response to the frequency deviation, which has important impact on system frequency response. The load-damping coefficient is normally considered as a constant, obtained from operational experiences in large-scale power systems or from detailed load models in isolated power systems. An industrial isolated power system for aluminum production driven by coal-fired power and large scale wind power is studied in this paper. Since the electrolytic aluminum load is driven by direct current, it is one type of voltage-sensitive load and does not respond to the frequency deviation. This paper proposes a load-damping characteristic control method for such isolated industrial power system with voltage-sensitive load. To decrease the maximum frequency deviation during transient process, a time-varying load-damping coefficient control scheme is presented. Simulation is done on real-time digital simulator (RTDS) and the results verify the effectiveness of the proposed control method.

An industrial verification of frequency regulation by electrolytic aluminum in an isolated power system

Efficient utilization of large-scale wind power is crucial to make the power industry economical and environment friendly. One way to consume wind power is through constructing isolated power systems with wind power supplying high energy consumption industries directly. However, one key issue, which limits the isolated power system for industry-wide application is to maintain the system frequency in an allowable range. To address this problem, a load-response control scheme for this kind of isolated power systems is presented and verified from the field tests in this paper. The testing results demonstrate that the electrolytic aluminum load reveals a good frequency regulation capability. Therefore, using frequency regulation capability from electrolytic aluminum provides an opportunity to fully utilize large-scale wind power in an isolated power system with high energy consumption loads.

An isolated industrial power system driven by wind-coal power for aluminum productions: A case study of frequency control

Due to the uneven geographical distribution between load and wind power, currently it is difficult to integrate the large-scale wind power into the State Grid in China. There are significant wind curtailments for wind farms due to system restrictions. This paper proposes a new way of utilizing wind power, i.e., in-situ consumption, as an alternative to the costly development of long-distance transmission of large-scale wind power. Electrolytic aluminum load, which is one of the most typical high energy consuming loads, is employed to absorb the excess wind power in western China. An actual isolated industrial power system for aluminum production driven by wind power and coal-fired power is described. The penetration level of wind power in the isolated power system is up to 48.8%. The power imbalance between generation and load demand caused by wind power fluctuation or the tripping of coal-fired generators can dramatically impact the frequency stability of the isolated power system, which is of small inertia. An online identification method of power imbalance based on Wide Area Measurement System (WAMS) is presented. According to the characteristics of the electrolytic aluminum load, a system frequency control method by regulating the bus voltages of aluminum loads to eliminate the power imbalance is introduced. The simulation is done in Real Time Digital Simulator (RTDS) and the results verify the validity of the proposed frequency control method.