Method for measuring rotate speed of synchronous generator based on circulation method

Abstract

The present invention provides a measurement method based on the rotation vector algorithm, which is used for measuring the rotating speed of the synchronous generator. The three-phase phase voltage and the three-phase phase current at the motor terminal are sampled; and the velocity of the phase angle changes of the transient potential vector of the generator which rotates synchronously with the rotating shaft of the generator can be calculated, so as to acquire the rotating speed of the generator. In order to prevent the interference in the calculation process, the invention adopts the positive sequence components of the three-phase phase voltage and the three-phase phase current to perform the calculation. The invention has the advantages of simple calculation, high accuracy, large measuring range and easy operation, and is prevented from being influenced by the interference.

Description

technical field [0001] The invention belongs to the technical field of electrical engineering, and in particular relates to a method for measuring the rotational speed of a synchronous generator. Background technique [0002] Power System Stabilizer (PSS), such as the PSS-2A model, introduces generator active power (Pe), machine terminal voltage (U t ) and generator speed (ω) are used as input control quantities. Pe and U t It is the electrical quantity of the generator, which can be easily measured directly by electrical measurement method, while ω is a mechanical quantity, which is generally measured by mechanical measurement method, which is more difficult and less accurate than the electrical quantity. [0003] At present, there are two main types of measurement methods for rotational speed in power systems: one is to use non-electrical sensors to achieve measurement. A common practice is to set a mechanical measuring point or a speed measuring gear on the rotor shaft...

AI Technical Summary

Problems solved by technology

A common practice is to set a mechanical measuring point or a speed measuring gear on the rotor shaft, or install a photoelectric, brush or electromagnetic device around the rotor, the latter accepts the pulse signal generated by the former or other quantities related to the rotor position or speed, Furthermore, the measurement of the rotational speed is realized through a certain transformation (hereinafter referred to as the pulse method). The pulse method often requires different degrees of modification of the generator body, the process is complicated, and the use of non-electrical sensors requires the use of more complex signals. Processing and error compensation technology to remove structural errors caused by machining errors, signal transmission delays, shaft torsional vibrations, etc.

[0004] The other is the pure electrical method. The general method is: calculate the power angle of the generator according to the active and reactive power of the generator and some unit parameters, and then differentiate the power angle to obtain the generator speed. This method is stable in the system. The generator speed can be accurately calculated when it is in the state, but since the active power and reactive power of the generator are determined by the power grid, when the system is disturbed, it will change a lot, resulting in a big change in the calculated power angle. Differentiation will magnify the error

In the electrical law, the generator terminal voltage frequency signal is also used to replace the generator speed signal. The measurement of frequency is electrical measurement, which saves the trouble of mechanical installation, but the interference and noise transmitted through the power grid must be specially treated (usually with filtering) The generator) can work normally, and when the power system fails, the frequency of the terminal voltage may jump, which will have a large difference with the generator speed, which will affect the control effect of the controller

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