Xianliang Teng

Real-time dispatching and coordinated control of large capacity wind power integration

Currently, conventional energy generators implement Automatic Generation Control (AGC) to regulate active power disturbance of power system attribute to wind power fluctuation after large capacity wind power integrated into grid. As an auxiliary means, wind farm would follow wind power schedule, adjust output plan in short-term and adopt emergency control in order to reduce the effect of wind power fluctuation on system stability and security. The performance of power system Peak load regulation and frequency control is increasingly affect by wind powers ‘peak-valley reversal’ and high ramp rate, especially in high wind power penetration area. Therefore, it is necessary to improve and optimize power system active power dispatching strategy and AGC strategy to advance system admitting wind power ability. This article analyzes influence after large capacity wind power integrating on system active power dispatching and control first. Then, a real-time dispatching strategy is proposed which contains regulation volume distribution strategy and active power balancing model to resolve deviation of wind power output from wind power prediction in order to satisfy system real-time active power regulation requirement in operation. In the meantime, dispatching centre should properly utilize system regulation resource and acquire forecast information of wind power fluctuation in certain period of the future to reduce AGC adjusting pressure in regulating system unbalance between load and generation. Real-time dispatching Furthermore, coordinated control strategy between real-time dispatching of AGC is proposed to solve real-time dispatching order conflict to AGC order in operation and AGC regulation volume insufficiency. The approach and strategy are serving wind power reasonable integration and secure and stable operation of power system.

Solution of Active Power Dispatch and Control for Interconnected Power Grids with Large-Scale Wind Power Integration

As large-scale wind power has been and will be integrated into power grid, traditional Active Power Dispatch and Control (APDC) system has encountered new challenges. In this paper, the active power dispatch mode of interconnected power grids which is suitable for the large-scale integration of wind power is analyzed firstly. Secondly, it is pointed out that traditional decentralized balance control mode of active power in provincial power grids would not withstand the impact of the large-scale wind power fluctuation. Then, a centralized control mode is proposed in the paper to reallocate all of the generation resources in a wider power grid. Thirdly, the characteristics of the proposed centralized control mode are analyzed from the following aspects: ways of active power balance, mainbodies of active power control, methods of resource allocation, inter-provincial power exchange, security constraints, and data communications. Finally, considering present dispatch system and technical basis in China, a solution is proposed for the active power control for China interconnected power grids. The aim of the proposed solution is to achieve the centralized control mode, and the hierarchical coordination control mode is the transition between present system and the final system.

Research on real-time control strategy of tie-lines in UHV interconnected power grid

Researches on UHV power transmission have been carried out more than forty years. It aims to improve the transmitting capability of power grid and realize the long-distance large power transmission and system interconnection. In China, the successful commissioning of UHV pilot projects makes it possible to optimally dispose electric power resources on a large scale, to effectively control the short-circuit current in the areas of high electric density, and to solve the dynamic stability problem in long chained power grid. On the background of UHV networking, the system frequency will be more stable, but even micro fluctuation of system frequency can cause the power flow of UHV tie-line to be changed. Started from instructing the relationship between active power of tie-line and system frequency, this paper researches on the primary cause of why tie-line flow changes and analyzes the principle how it changes. Then new control strategies for tie-line flow control on the background of UHV networking are especially presented, which provides some reference to Three-Hua synchronous UHV power grid, which connects North China, East China and Central China grids.

The control strategies and assessment methods for transmission interface power flow based on hierarchical and divisional dispatch mode

Due to the rapid development of China power source construction, the generation and load in regional power grids are gradually imbalanced, which highlights the contradiction between power source and network distribution and causes the security constraints problems. The paper first presents a divisional control modeling method which significantly reduces the complexity of the flow control. Then, an automatic hierarchical interface control strategy is proposed based on the divisional dispatch mode, which achieves the multi-target and hydro-thermal coordination. In addition, the paper also designs a series of indexes which used to evaluate the control performance for transmission interface control. These indexes provide a basis for decision making on real-time power control. The proposed control strategies and assessment methods have been put into operation in actual power grids. The results are proved to be feasible and effective.

A multi-objective coordinated control method for AGC

By dividing the global area into several control areas, a multi-objective coordinated AGC control method is introduced in this paper. The main control areas objective is the ACE of global area. The sub-areas maintain the power flow of transmission lines among areas at scheduled interchange and cooperate with the main area in emergency. AGC system based on the addressed method can realize multi-objective coordinated control conveniently. The proposed method has been implemented in several provincial power grids in China and proved efficient.