A generator rotor insulation on-line monitoring grounding locating method and device

Abstract

The invention discloses a generator rotor insulation on-line monitoring grounding locating method and device, which pertains to the generator rotor grounding monitoring protection technology and is object to provided a method and device capable of rapid judging the grounding positions. The method calculates the relative locating value alpha according to the resistor switch sampling method, figures out beta[i] (beta ) and gamma [i] based on the rotor winding structural parameters, and accurately judge the physical position of faults by analysis. The device includes a microcomputer, a rotor voltage measuring circuit and a resistance network, wherein, the resistance network (4) is connected to the large axis (1-3) through a non-excited conversion circuit (5) and a switched voltage measuring circuit (8), a voltage injecting signal circuit (13) is connected between windings cathode (1-2 ) and the non-excited conversion circuit (5), the non-excited conversion circuit (5) and the photoelectric isolation switch (3) are connected to the microcomputer (6), and the rotor voltage measuring circuit (2) and the switched voltage measuring circuit (8) are connected to the microcomputer (6) through an A / D conversion buffer circuit (7).

Description

Technical field: [0001] The invention relates to an on-line monitoring grounding location method, in particular to a method for on-line monitoring the insulation condition of a generator rotor and diagnosing the grounding position of the generator rotor; the invention also relates to a device for realizing the method. Background technique: [0002] The generator rotor is an important part of the generator. It is usually composed of a large shaft and a winding arranged on the large shaft and insulated from it. Since the winding and the large shaft must be insulated, the insulation of the winding will directly affect the quality of the winding. It is related to the safe and normal operation of the generator, and the rapid diagnosis of the ground fault point can directly improve the economic benefit of the generator. At present, the following problems exist in the protection and monitoring of the generator rotor grounding: [0003] 1) In the prior art, the resistance network d...

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Problems solved by technology

Its application is used as two-point grounding protection, and it is not used as a grounding position judgment. Even if it is used as a grounding position judgment, it cannot automatically give the specific physical location of the ground fault point and insulation deterioration point, such as a certain number of magnetic poles grounded, or If a certain coil is grounded or a certain connection of them is grounded, the on-site maintenance personnel must spend a lot of time to check the data and calculate, which directly affects the economic benefits of the power plant

[0004] 2) Since the rotor grounding alarm signal is issued only when the insulation resistance drops below tens of kilohms, it is impossible to monitor and warn the insulation state before the ground fault occurs, and the failure cannot be avoided, and the state-of-the-art maintenance cannot be achieved

[0005] 3) Since there is no function of memorizing the location of the fault, if the ground fault disappears when the machine is shut down, it cannot be repaired because the fault point cannot be found

[0006] 4) Although some one-point grounding protection devices can display the insulation resistance value, the range of the resistance value is too narrow, usually only about 0-100 kΩ, and there are defects such as low monitoring accuracy and dead zone in the action, which cannot meet the online monitoring Require

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