CN110441688A - Hydraulic generator rotor winding dynamic turn-to-turn short circuit detection device and detection method - Google Patents

Abstract

Hydraulic generator rotor winding dynamic turn-to-turn short circuit detection device and detection method.Traditional detection method is that the AC impedance of the measurement rotor magnetic pole in rotor static state can not then detect data exception to judge failure magnetic pole number, but this method shorted-turn fault dynamic for rotor magnetic pole.Its composition of the invention includes: iron core bracket (5), partition (6), big axis (9), key phase block (10) and key phase (11), one group of screw rod (1) is fixed on iron core bracket, stator core (4) are fixed on screw rod, 3 sections are divided by the partition from bottom to up on stator core, circle detection winding (3) is wound on the silicon steel sheet ventilation hole of the stator core in each section, it connects between two adjacent rings detection winding, every circle detection winding bypasses the silicon steel sheet (2) of multi-layer stator iron core.The present invention is used for the detection of hydraulic generator rotor winding dynamic shorted-turn fault.

Description

Dynamic turn-to-turn short-circuit detection device and detection method for hydro-generator rotor winding

Technical field:

The invention relates to a dynamic inter-turn short-circuit detection device and a detection method for rotor windings of a hydroelectric generator.

Background technique:

When an inter-turn short-circuit fault occurs in the rotor pole of a hydro-generator, the traditional detection method is to measure the AC impedance value of the rotor pole when the rotor is static (that is, in a static state), so as to judge the faulty pole number, but this method is only applicable to hydroelectric power generation For the static turn-to-turn short circuit of the rotor magnetic pole, the abnormal data cannot be detected for the dynamic turn-to-turn short circuit of the rotor magnetic pole.

Invention content:

The purpose of the present invention is to solve the problem that the current detection method is only applicable to the static turn-to-turn short-circuit of the rotor magnetic pole of the hydro-generator, and cannot detect abnormal data for the dynamic turn-to-turn short-circuit of the rotor magnetic pole, and to provide a method that can accurately determine A dynamic turn-to-turn short-circuit detection device and detection method for a hydraulic generator rotor winding with a faulty magnetic pole number.

Above-mentioned purpose realizes by following technical scheme:

A dynamic turn-to-turn short-circuit detection device for a rotor winding of a hydro-generator, which consists of: an iron core support, a partition, a large shaft, a key phase block, and a key phase sensor. A group of screws are fixed on the iron core support, and the The stator core is fixed on the screw, and the stator core is divided into 3 sections from bottom to top by the partition plate, and is wound on the silicon steel sheet ventilation hole of the stator core in each section. There is one circle of detection winding, and the detection windings of two adjacent circles are connected in series, and the detection winding of each circle winds around the silicon steel sheets of the stator iron core of multiple layers.

In the dynamic turn-to-turn short-circuit detection device for the rotor winding of the hydro-generator, the detection winding goes around 4-5 layers of silicon steel sheets of the stator core for each turn.

A detection method of a dynamic inter-turn short circuit detection device for a hydroelectric generator rotor winding, the method comprising the following steps:

(1) Install detection coils in the ventilation holes of the stator core. The detection coils use single-core insulated flexible wires. The detection coils are respectively installed in three sections and connected in series. The layers of silicon steel sheets of the stator core surrounded by them are 4 layers; the detection coils The more layers of the iron core surrounded, the greater the magnitude of the induced potential; the detection coil should form a closed winding; the distance between the detection coil and the rotor surface should be kept;

(2) Install the key phase sensor on the end cover of the oil basin on the water guide of the waterwheel chamber of the unit, and paste the key phase block at the corresponding position of the major shaft of the unit. The installation orientation of the key phase block should be directly facing the magnetic pole center of the rotor;

(3) Connect the signals of the detection coil and the key phase sensor to the power waveform recorder and analyzer. After the unit starts to idle, gradually increase the excitation current of the rotor winding from 0. The applied excitation current shall not be greater than the rated no-load excitation current of the rotor winding , and use 10% of the rated voltage as the gradient to step up the voltage in batches, and stay for 5-10 minutes at each voltage gradient, and record the waveform after the waveform data is stable. Use the power waveform record analyzer to record and analyze the induced potential of the detection winding at each gradient. According to the comparison of the characteristic peak amplitudes of the waveforms, it is judged whether there is a certain peak amplitude that is obviously smaller than other peak amplitudes. If there is A peak with a significantly smaller amplitude indicates that there is an inter-turn short circuit in the magnetic pole generating the peak, which leads to a decrease in the electromagnetic force there. After the wave peak with small amplitude is determined, the key phase signal can be used for positioning, so as to accurately determine which magnetic pole of the rotor has an inter-turn short circuit fault.

Beneficial effect:

1. The stator core of the present invention is divided into 3 sections from bottom to top by partitions, and a circle of detection winding is wound on the ventilation hole of the silicon steel sheet in each section, and the detection windings of the adjacent two circles are connected in series, each The detection winding described in the circle bypasses the silicon steel sheets of the stator core described in the 4-5 layers, which can increase the amplitude of the induced potential and ensure the accuracy of the detection results.

The invention adopts the dynamic detection coil waveform method, and innovatively installs the detection winding on the stator core of the hydroelectric generator set. When the rotor rotates at the rated speed, an appropriate excitation current is applied to the rotor winding, and each magnetic pole will detect the winding here. The induced electromotive force is generated on the ground, and the amplitude of the induced electromotive force is proportional to the effective number of turns of the corresponding magnetic pole. By analyzing the amplitude and distortion of the induced electromotive force waveform and locating the key phase signal, the faulty magnetic pole number can be accurately determined.

The detection method of the invention can improve the rapidity and accuracy of fault finding, and can lock the fault magnetic pole in the shortest time, thereby formulating a maintenance plan to quickly deal with faults and minimize power loss.

The key phase block of the invention should face a certain magnetic pole of the rotor, which can facilitate faulty magnetic pole positioning during waveform analysis.

Description of drawings:

Accompanying drawing 1 is a structural representation of the present invention;

Accompanying drawing 2 is the schematic diagram of dynamic detection coil waveform method;

Accompanying drawing 3 is detection coil waveform method waveform diagram;

In the figure: 1. screw; 2. silicon steel sheet; 3. detection winding; 4. stator core; 5. core support; 6. partition; 7. connecting wire; 8. rotor; key phase block; 11, key phase sensor.

Detailed ways:

Example 1:

A dynamic turn-to-turn short-circuit detection device for a rotor winding of a hydroelectric generator, which consists of: an iron core support 5, a partition plate 6, a large shaft 9, a key phase block 10 and a key phase sensor 11, and the iron core support is fixed on the There is a group of screw rods 1, on which the stator core 4 is fixed, and the stator core is divided into 3 sections from bottom to top by the partition plate, and the stator core in each section A circle of detection winding 3 is wound on the ventilation hole of the silicon steel sheet, and the detection windings of two adjacent turns are connected in series, and the detection winding of each circle bypasses the silicon steel sheets 2 of the stator core in multiple layers.

Example 2:

According to the dynamic turn-to-turn short-circuit detection device for the rotor winding of a hydro-generator described in Embodiment 1, each turn of the detection winding bypasses 4-5 layers of silicon steel sheets of the stator core.

Example 3:

A detection method of a dynamic inter-turn short circuit detection device for a hydroelectric generator rotor winding, the method comprising the following steps:

1) Install detection coils in the ventilation holes of the stator core. The detection coils use single-core insulated flexible wires. The detection coils are respectively installed in three sections and connected in series. The more layers of the iron core, the greater the magnitude of the induced potential; the detection coil should form a closed winding; the distance between the detection coil and the rotor surface should be kept;

(2) Install the key phase sensor on the end cover of the oil basin on the water guide of the waterwheel chamber of the unit, and paste the key phase block at the corresponding position of the major shaft of the unit. The installation orientation of the key phase block should be directly facing the magnetic pole center of the rotor;

(3) Connect the signals of the detection coil and the key phase sensor to the power waveform recorder and analyzer. After the unit starts to idle, gradually increase the excitation current of the rotor winding from 0. The applied excitation current shall not be greater than the rated no-load excitation current of the rotor winding , and use 10% of the rated voltage as the gradient to step up the voltage in batches, and stay for 5-10 minutes at each voltage gradient, and record the waveform after the waveform data is stable. Use the power waveform record analyzer to record and analyze the induced potential of the detection winding at each gradient. According to the comparison of the characteristic peak amplitudes of the waveforms, it is judged whether there is a certain peak amplitude that is obviously smaller than other peak amplitudes. If there is A peak with a significantly smaller amplitude indicates that there is an inter-turn short circuit in the magnetic pole generating the peak, which leads to a decrease in the electromagnetic force there. After the wave peak with small amplitude is determined, the key phase signal can be used for positioning, so as to accurately determine which magnetic pole of the rotor has an inter-turn short circuit fault.

The waveform diagram of the test results of the dynamic detection coil waveform method is shown in Figure 3. It can be seen from the analysis waveform that in each cycle (10 magnetic poles alternately produce 10 peaks) there is one peak amplitude that is significantly smaller than the other nine peak amplitudes. , with a difference of about 14% in amplitude. Combined with the positional relationship of the detection coil, the key phase block and the key phase sensor, and using the key phase signal to locate, it is confirmed that the magnetic pole No. 6 is the one that causes the small induced potential amplitude.

After confirming that the No. 6 magnetic pole is faulty, immediately formulate a repair plan. Under the premise of not lifting out the rotor, complete a system repair work such as the removal of the No. 6 magnetic pole and the installation of a new magnetic pole in the machine pit, and then start the machine to the rated speed for zero-start boost. In the test, pressurize to 100% rated voltage, and the vibration swing value of the unit meets the requirements of the specification.

During the operation of the hydro-generator set, there may be a short-circuit fault between the turns of the rotor magnetic pole. When the excitation current or vibration amplitude of the generator increases significantly and the reason is unknown, the short-circuit fault between the turns of the rotor winding should be diagnosed. The static turn-to-turn short circuit of the rotor winding is relatively easy to detect. Through the static AC impedance test, the symmetry of the rotor poles can be used to determine which pole has a turn-to-turn short circuit. However, the dynamic turn-to-turn short circuit of the rotor pole is unstable. The rotating speed of the rotor changes, and when the machine is shut down for static electrical tests, all test results are normal, which brings great difficulties to fault finding, and even makes the fault finding work deadlocked. The dynamic AC impedance test method and the dynamic detection coil waveform method can improve the speed and accuracy of fault finding, and can lock the fault magnetic pole in the shortest time, so as to formulate a maintenance plan to quickly deal with faults and minimize power loss.

Claims (3)

1. a kind of hydraulic generator rotor winding dynamic turn-to-turn short circuit detection device, composition includes: iron core bracket, partition, big Axis, key phase block and key phase, it is characterized in that: one group of screw rod is fixed on the iron core bracket, it is solid on the screw rod Surely there is stator core, 3 sections are divided by the partition from bottom to up on the stator core, described in each section Stator core silicon steel sheet ventilation hole on be wound with circle detection winding, connect between detection winding described in two adjacent rings, Detection winding described in every circle bypasses the silicon steel sheet of stator core described in multilayer.

2. hydraulic generator rotor winding dynamic turn-to-turn short circuit detection device according to claim 1, it is characterized in that: every circle Described detects winding around the silicon steel sheet of stator core described in 4-5 layers.

3. a kind of detection method of hydraulic generator rotor winding dynamic turn-to-turn short circuit detection device claimed in claims 1-2, It is characterized in that: this method comprises the following steps:

(1) search coil is installed in stator core ventilation hole, search coil uses single insulated flexible cord, and search coil is installed respectively In 3 section series wirings, the number of plies of the stator iron core silicon steel sheet surrounded is 4 layers；The iron core number of plies that search coil surrounds is got over More, then the amplitude of induced potential is bigger；Search coil should form the winding of closure；Search coil and rotor surface should keep away from From；

(2) basin end that oils is led in unit water wheel chamber water and cover installation key phase, and viscous in the corresponding position of the big axis of unit Key phase block is pasted, the installation position of key phase block answers the pole center of face rotor；

(3) signal of search coil and key phase being connected to electricity waveform recording and analyzing instrument, unit is switched on to idle running, from 0 starts to step up rotor windings exciting current, and the exciting current of application is not greater than the rated no-load excitation electricity of rotor windings Stream, and boost in batches using 10% voltage rating as gradient, each voltage gradient stops 5-10 minutes, stablizes to Wave data Recording records afterwards.The induced potential that winding is detected when by electricity waveform recording and analyzing instrument to each gradient carries out waveform recording point Analysis compares according to the characteristic wave peak amplitude size of waveform, judges whether there is some wave crest amplitude obviously than other wave crest amplitudes Less than normal, if there is the obvious wave crest less than normal of amplitude, then illustrating to generate the magnetic pole of the wave crest, there are Inter-turn Short Circuit Phenomenons, to lead Electromagnetic force at this is caused to reduce.It after determining amplitude wave crest less than normal, i.e., is positioned using key signal, to accurately determine to turn There are shorted-turn faults for which sub magnetic pole.