Emergency control method and system based on branch transient power transmission capacity

Abstract

The invention provides an emergency control method and system based on branch transient power transmission capacity. According to the method and the system, the amplitude and the phase of node voltages at two ends of a branch which are easy to measure are used as information sources, a branch transient power transmission capability BTTC quantitative evaluation index is constructed, and whether anemergency control measure is taken or not is judged according to the BTTC index of the branch with the minimum BTTC index in an interconnected power grid. According to the method and the system, a wide-area measurement technology and a high-speed communication technology are fully utilized, a response-based power system wide-area safety and stability control system is constructed, real-time decision and real-time control are realized, whether transient stability exists or not can be precisely judged, and the stability level is rapidly and quantitatively evaluated; the method and the system donot depend on off-line or on-line simulation calculation, do not need to anticipate an operation mode and a fault set, are not limited to local information, can effectively avoid the risk of failure of safety and stability control measures, ensure safe and stable operation of a power system and prevent large-area power failure.

Description

technical field [0001] The present invention relates to the field of power control, and more specifically, to an emergency control method and system based on branch transient power transmission capacity. Background technique [0002] In recent years, with the continuous increase of the grid-connected capacity of new energy power sources and the large-scale trans-regional transmission and reception of UHV DC, my country's power grid has formed a new DC hybrid transmission pattern. Transient stability characteristics have undergone profound changes. In the traditional AC power grid, the impact range of transient energy induced by system disturbance is small, and the existing prevention and control system can effectively deal with it; in the UHV AC-DC hybrid power grid, system disturbance and even normal equipment operation may cause large-capacity multi-circuit DC commutation The failure or blockage will lead to a chain reaction of the AC and DC system, resulting in a huge tra...

AI Technical Summary

Problems solved by technology

Based on the related method of unit disturbance information, the calculation of the trajectory of the center of inertia of the fleet requires the information of the entire network unit, the required amount of information is large, the measurement and communication requirements are high, and some information such as the mechanical power of the unit is difficult to measure, and the validity of the determination of stability depends on the accuracy of the grouping. sexual issues

In addition, it is difficult to track the migration of weak sections or critical branches due to the blanking of network state changes of random group swings Dynamically optimized emergency control

The transient stability discrimination and control method based on network disturbance information is currently difficult to apply to the actual power grid

For example, the integral calculation in the branch transient potential energy method requires the steady-state power flow of the branch after the fault, so the method is only suitable for offline analysis with predetermined faults, and it is difficult to use this method for complex disturbance scenarios where the cascading fault path is difficult to predict Stability discrimination and emergency control; the method based on the drop characteristics of a single electrical quantity of the bus voltage is difficult to effectively distinguish the two stable forms of power angle stability and voltage stability; the newly proposed method of judging stability based on the active peak characteristics of the AC branch has too Conservative and other issues

Images