Evaluation method and system for short-term voltage stability of power grid

Abstract

The invention provides an evaluation method and system for short-term voltage stability of a power grid. When a power grid operation state monitored in real time by a power grid relay breaks down, a monitoring bus voltage, a load bus current and a real-time relative power angle detected in real time by PMU measurement of the power grid are substituted into a real-time power grid parameter identification equation which is built in advance, and calculation is carried out to obtain load margin; if the load margin is larger than a preset short-term voltage stability value, a voltage of the power grid is in a stable state, otherwise, the voltage of the power grid is in a breakdown state; and the PMU measurement achieves rapid evaluation and margin calculation of the short-term voltage stabilityof the power grid, and enhances on-line monitoring of a short-term voltage stability point by the power grid.

Description

technical field [0001] The invention relates to the technical field of power system security and control, in particular to a method and system for short-term voltage stability evaluation of a power grid. Background technique [0002] Day-ahead early-warning evaluation of power grid operation mode is one of the important daily tasks in the field of power system production. However, day-ahead early-warning evaluation only through power grid simulation calculation often assumes that there is no comprehensive abnormal disturbance caused by rotating equipment such as generators or induction motor loads in the power grid. The early-warning evaluation of the grid operation mode, which takes into account the abnormal disturbance probability of historical grid nodes, can effectively reduce the risk of grid operation to a certain extent. [0003] With the continuous progress of modern power generation technology, the unit capacity of the unit is increasing. With the increasing adopti...

AI Technical Summary

Problems solved by technology

More and more large-scale centralized access to the transmission network is adopted, which makes the impact of wind power on the power grid continue to increase, and the ability to withstand shocks is limited

On the one hand, when the terminal voltage is too low, the unit will actively cut off for its own safety, which will cause the system to suddenly lose power and cause system instability; on the other hand, if the output is too high, the voltage safety margin of the grid may be reduced, which is easy lead to voltage collapse

[0004] The existing technology adopts the medium and long-term voltage stability assessment method, and the online calculation period is long, which causes the grid voltage to fluctuate, which cannot be detected in time, leading to the collapse of the grid

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