Method for measuring wind driven generator air gap through eddy current sensors

Abstract

The invention discloses a method for measuring a wind driven generator air gap through eddy current sensors, and belongs to the field of measuring. At least four radial eddy current sensors are arranged on the surface of a generator stator, one axial eddy current sensor is arranged on the generator stator in the axial direction, and a key-phase sensor is arranged on the part, at the radial position of a rotating shaft of a generator, on a machine body or a rack; the signal output ends of the radial eddy current sensors, the signal output end of the axial eddy current sensor and the signal output end of the key-phase sensor are correspondingly connected with the signal input ends of a wind power state monitoring and collecting device respectively; the wind power state monitoring and collecting device reads and processes the sampling result and uploads the processed result to a database of a server through an Ethernet port, a workstation in a local area network or a remote workstation can have access to the database in the server, real-time air gap data of the wind driven generator are checked in real time, and different working modes or working patterns of the wind power state monitoring and collecting device can be controlled to be switched through air gap monitoring system software.

Description

technical field [0001] The invention belongs to the field of measurement, in particular to a real-time on-line monitoring method for the air gap of a wind power generator. Background technique [0002] The air gap between the generator stator and rotor (hereinafter referred to as the air gap) is an important electromagnetic parameter, which has a direct impact on other parameters, operating performance and technical and economic indicators of the motor; the uniformity of the air gap of the generator in operation The stability will directly affect the stability of electrical characteristics and mechanical properties. [0003] In order to ensure the safe operation of large generators and prevent sudden accidents, some countries and relevant departments have proposed to establish a set of special generator air gap monitoring system to monitor the air gap when the unit is put into trial operation and after it is officially put into production. Repeated measurements provide a se...

AI Technical Summary

Problems solved by technology

[0016] 1), the measurement accuracy is not high: the full range can only guarantee the measurement accuracy of 3%;

[0017] 2) The temperature performance is not good: the working range is only from 0°C to 125°C, and the measured value changes greatly due to temperature changes;

[0018] 3), the influence of parasitic capacitance is great:

[0019] The initial capacitance of the capacitive sensor is very small, and the lead cable capacitance of the sensor (the length is usually 1 to 2 meters, the lead cable capacitance of the wire can reach 800pF), the stray capacitance of the measurement circuit, and the structure of the sensor plate and its surrounding conductors. The "parasitic capacitance" such as the capacitor's capacitance is large, which reduces the sensitivity of the sensor on the one hand; on the other hand, these capacitances (such as cable capacitance) often change randomly, which will make the sensor work unstable and affect the measurement accuracy.

Although some of them can be eliminated by improving the installation and connection method by selecting shielded cables, there are still certain effects;

[0020] 4) Larger volume and detection surface area:

[0022] 5) The installation method leads to many unsafe factors:

[0023] The air gap sensor VM3.1 mentioned above is installed by pasting, and the installation area is relatively large. Due to the strength and life of the pasting glue, the cleanliness and material of the pasted materials are different, which will affect the life of the installation and use, and there are many unsafe factors;

[0024] 6), the price is very expensive:

[0025] The market price of the existing air gap sensor is not less than 100,000 yuan / set; according to the standard of 5 sets of sensors generally installed in a wind turbine, the price of the entire air gap monitoring system only for the sensors used is no less than 50 yuan 10,000 yuan; and a new large-scale wind turbine (installed capacity of 3MW) put into the market has an overall unit price of only more than 15 million yuan (calculated at a quotation of 5,000 yuan / KW); it can be seen that the air gap monitoring system is only The one-time purchase cost of the sensors used already accounts for more than 3% of the total product cost. Compared with the one-time purchase cost of the entire unit, the one-time purchase cost of the used sensors is very expensive

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