A Fault Identification Method for Turn-to-turn Short Circuit of Stator Winding of Offshore Doubly-fed Electric Machine
A technology for inter-turn short-circuit faults and stator windings, which is applied in the direction of motor generator testing, electrical measurement, and electrical variable measurement. It can solve the problems of large outage losses, difficult maintenance, and high maintenance costs, so as to reduce economic losses and improve Accuracy and the effect of improving the service life
Active Publication Date: 2019-02-22
SHANGHAI UNIVERSITY OF ELECTRIC POWER
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In addition, once an offshore wind turbine fails, its maintenance is difficult, long maintenance time, high maintenance costs, and large outage losses, etc. Therefore, it is urgent to find electrical defects of offshore wind turbines early to avoid catastrophic accidents caused by deterioration of faults happened
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[0046] The principle of the existing Park's vector method, when the ideal three-phase current i A , i B , i C After 3s / 2s transformation to get i α i β , because the ideal three-phase current only contains positive sequence components, the following formula is obtained:
[0047]
[0048] From formula (1), it can be seen that when i α is the abscissa, i β is the ordinate, and its trajectory is a regular circle under ideal conditions; and when the three-phase current is in a non-ideal condition, the three-phase current contains not only positive sequence components but also negative sequence components, and the x-axis is the Park's vector The coordinate axis where the minor axis of the circle is located, y is the coordinate axis where the major axis of the Park's vector circle is located, and i is obtained x i y for:
[0049]
[0050] From formula (2), it can be obtained that Park’s vector trajectory is elliptical under non-ideal working conditions, and I in formul...
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The invention relates to a fault identification method for inter-turn short circuit of stator windings in doubly-fed motor at sea. The method comprises the following steps of: obtaining three-phase voltage and three-phase current of the stator of the doubly-fed motor whose fault has yet to be recognized; calculating the three-phase voltage and three-phase current of the stator through a modified Park's vector method to obtain the 2 times fundamental frequency component amplitude I2p caused by the inter-turn short circuit fault of the stator windings; and determining whether the 2 times fundamental frequency component amplitude I2p caused by the inter-turn short circuit fault of the stator windings reaches the fault pre-warning value or not. If so, the doubly-fed motor whose fault has yet to be recognized at sea is confirmed to have an inter-turn short circuit fault. Compared with the prior art, the identification method of the invention has robustness to the motor stator voltage imbalance and load variation, and the discrimination is both accurate and strong.
Description
technical field [0001] The invention relates to a fault identification method for a marine doubly-fed motor, in particular to a method for identifying a short-circuit fault between turns of a stator winding of a marine doubly-fed motor. Background technique [0002] In recent years, my country has introduced a series of policies and measures to encourage the development of offshore wind power. With the successful completion and grid connection of many offshore wind power projects, my country's offshore wind power industry chain has been initially established. In the national "13th Five-Year" energy plan, deep water, far sea, and large-scale offshore wind farms have become an important trend in the development of offshore wind power in my country; in the double-fed wind power generation system, the inverter only flows through the slip power, which has a small investment loss , high power generation efficiency, and convenient harmonic absorption, etc., make the doubly-fed wind ...
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IPC IPC(8): G01R31/34G01R31/02
CPCG01R31/34G01R31/50
Inventor 魏书荣张路符杨王健米阳
Owner SHANGHAI UNIVERSITY OF ELECTRIC POWER