Yu Zhihong

Online decision-making and emergency control method based on super-real-time simulation

Based on Super-Real-Time Simulation (SRTS), a novel online decision-making and emergency control method of power system is proposed, including two control modes: online pre-decision-making control and real-time control. In this paper, online pre-decision is made by the SRTS and parallel trajectory sensitivity calculation, and real-time decision is made by pure SRTS. A combination of these two decision-making modes is proposed to improve strategy matching degree and to avoid strategy mismatch problem due to changes of operating condition. Finally, an online decision-making and control system is developed based on the proposed method, and closed-loop testing is carried out based on digital real-time simulator to verify the efficiency of the system.

Quantitative evaluation for influence factors of calculation deviations of schedule power flow for large power grid

With the increase of the scale of the power grid and the improvement of the intelligence degree, the rationality and accuracy of the schedule power flow (the schedule) are becoming more and more serious. In this paper, by analyzing the relationship between input and output in the process of power flow calculation, the five main factors influencing the line active power deviation and the main cause of node voltage deviation are obtained. Furthermore, the influence of these factors on the line active power and node voltage are analyzed and the corresponding contribution indexes are calculated with the flexible use of sensitivity analysis and power flow distribution factors. The analysis and synthesis of these indexes lead to a set of methods for quantitative evaluation of the schedule, which can realize the rapid evaluation of the calculation precision. The rationality and practicability of this method are verified by the sample application, based on the schedule data from Central China State Grid.

Research on active power control analysis method of transmission interfaces for online TTC calculation

Total Transfer Capability(TTC) play an important role on anlysis and control of power system stability. This paper proposes an method about active power control strategy analysis of transmission interfaces, which identifies the most sensitive generator for transmission interfaces and decides control strategy of transmission interfaces active power automatically. It can improve accuracy of online TTC which dependent on off-line simulation knowledge, also could not automatically adapt the real-time operation mode of power system. In this paper, a varible of integrative sensitivity of transmission interfaces is defined for reflecting the control effect of different generator for total power of transmission interface. Based on this varible, the method can calculate the adjustment margin and priority of generator in power network, and search adjustable electric equipments for controlling transmission interfaces power, and provide control strategy for transmission interfaces active power. Finally the simulation analysis of actual exapmle verifies the effectiveness of the method.

Operation rule extracting based on time series association analysis in transient stability study

A robust operation rule extracting algorithm is proposed based on adaptive time series association analysis here. It is applied to extract association knowledge among the accumulating massive operation data. A data model describing the system state and topological structure before/after fault happening is built up at first. The initial abstract features are independent of the scale of a power system. A recursive principal component analysis method is employed to yield the reduced-size feature space. The extract features are then fed into the associative analysis. For considering temporal constraint, the generated associative rules not only reflect the relationship between power system operating condition and transient stability, but also reveal some valuable information about operating characteristics. Simulation results on on IEEE 39-bus test system demonstrate the feasibility and efficiency of the proposed method.