Motor load transient process calculation method suitable for electromagnetic transient simulation

Abstract

The invention relates to the technical field of power grid transient simulation calculation and specifically relates to a motor load transient process calculation method suitable for electromagnetic transient simulation. The method can quickly calculate load transient characteristics of an induction motor under symmetrical and asymmetrical fault voltage sag of a power system, and is characterizedby (1) firstly, solving a first-order mechanical transient equation of a rotor to obtain changes in speed and slip of the rotor after disturbance; (2) solving a transient potential differential equation in the form of a rotor phasor to obtain change in transient potential; and (3) obtaining current and power response of the motor after the disturbance. Compared with PSCAD/EMTDC electromagnetic transient simulation results, the result of the calculation method verifies effectiveness of the algorithm; and compared with PSD/BPA electromechanical transient simulation results, the result of the calculation method shows the advantages of the algorithm under asymmetric voltage sag. An analytical method explicitly gives computation expressions of mechanical and electrical parameters of the induction motor after the disturbance; and in addition to being used to quickly evaluate mutual influence of the induction motor and the voltage sag, the method can also be used in stability analysis of thepower system.

Description

technical field [0001] The invention relates to the technical field of power grid transient simulation calculation, and more particularly, relates to a calculation method for a motor load transient process suitable for electromagnetic transient simulation. Background technique [0002] With the implementation and deepening of the "West to East Power Transmission" strategy, my country has formed a typical receiving end system structure in load centers such as the "Yangtze River Delta" and "Pearl River Delta". The load of the receiving end system is heavy, and the load ratio of the induction motor is high. During the power grid failure and recovery process, the induction motor often absorbs a large amount of transient power due to the decrease of electromagnetic torque and the increase of slip, which makes it difficult to recover the transient voltage of the system. Various studies have shown the importance of the interaction between the transient characteristics of the motor ...

AI Technical Summary

Problems solved by technology

The advantage of the two is that the results are authentic and credible, but in order to reveal the influence of a certain factor, multiple experiments or simulations are required. In addition to being tedious and time-consuming, it is beyond their ability to analyze and explain the phenomena of experiments and simulations.

The analytical method needs to rely on circuit and motor analysis theory to explicitly solve the interaction between the transient response of the motor and the system voltage. All operating and state variables; only constant torque mechanical loads can be considered, which will also lead to pessimistic results of voltage stability analysis

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