Method for analyzing load characteristics of induction motor under constant mechanical power

Abstract

The invention relates to a method for analyzing the load characteristics of an induction motor under constant mechanical power and belongs to the power system load modeling field. The method of the invention includes the following steps that: the slip rate of the induction motor under that the constant mechanical power is calculated; the relational expression of active power and reactive power absorbed by the induction motor is obtained according to a relation between the slip rate and frequency and voltage; the partial derivative of a stator-side frequency is obtained according to the obtained active power and reactive power, the partial derivative is multiplied by the ratio of an initial frequency to initial power, so that a frequency characteristic coefficient expression is obtained; and the partial derivative of a power supply voltage is obtained according to the obtained active power and reactive power, and the partial derivative is multiplied by the ratio of an initial voltage tothe initial power, so that a voltage characteristic coefficient expression can be obtained. With the method of the invention adopted, a complicated calculation process can be simplified, calculationtime and workload can be decreased, and relatively simple relations among the active power, the reactive power, the slip rate, the frequency and the voltage can be obtained.

Description

technical field [0001] The invention relates to a load characteristic analysis method of an induction motor with constant mechanical power, which belongs to the field of power system load modeling. Background technique [0002] With the gradual development and improvement of my country's "West-East Electricity Transmission, North-South Interconnection, and National Networking" strategic project, it has become an inevitable development trend to realize asynchronous interconnection among provincial power grids. Asynchronous interconnection can effectively reduce short-circuit capacity, eliminate reactive power problems, and improve the reliability of stable system operation. However, the feed-in of the DC system makes the system operation mode complicated, and the commutation failure of the DC system is likely to cause DC blocking faults. In some microgrid systems or small islands, if a fault occurs or there is a special impact load, the frequency characteristics and voltage c...

AI Technical Summary

Problems solved by technology

Load modeling is a very complex problem: the load of the power system is composed of many different electrical equipment, and there are many types; the load composition and load quantity change with time; there is a lack of accurate data on the load composition; Many loads are nonlinear

The accuracy of the model will directly affect the simulation results and the decision-making scheme based on it. An inappropriate load model will make the calculation results inconsistent with the actual situation, thereby posing potential dangers to the system or causing unnecessary waste.

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