CN110632513A - Generator stator slot anti-corona layer potential measuring device and measuring method - Google Patents
Generator stator slot anti-corona layer potential measuring device and measuring method Download PDFInfo
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- CN110632513A CN110632513A CN201910765671.XA CN201910765671A CN110632513A CN 110632513 A CN110632513 A CN 110632513A CN 201910765671 A CN201910765671 A CN 201910765671A CN 110632513 A CN110632513 A CN 110632513A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/0084—Arrangements for measuring currents or voltages or for indicating presence or sign thereof measuring voltage only
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
- G01R27/025—Measuring very high resistances, e.g. isolation resistances, i.e. megohm-meters
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
- G01R31/1227—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials
- G01R31/1263—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/34—Testing dynamo-electric machines
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- General Physics & Mathematics (AREA)
- Tests Of Circuit Breakers, Generators, And Electric Motors (AREA)
- Insulation, Fastening Of Motor, Generator Windings (AREA)
Abstract
The invention discloses a potential measuring device for an anti-corona layer of a stator slot part of a generator, which comprises a metal probe, an insulating rod, a flexible lead and a high internal resistance voltmeter probe, wherein one end of the metal probe is arranged in a bending way, the other end of the metal probe is connected with one end of the flexible lead inside the insulating rod, and the other end of the flexible lead is connected with the high internal resistance voltmeter probe. When the generator tests the potential of the stator slot anti-corona layer, the stator winding of the generator applies alternating-current power-frequency phase voltage, a tester wears soft-bottom insulating shoes to measure in a stator chamber, firstly, a high-internal-resistance voltmeter probe is inserted into the positive pole of a universal meter, the negative pole of the universal meter is grounded, then, a metal probe is contacted with the surface of a stator coil at a ventilation ditch, and the ground potential of each point is measured. The method is applied to potential measurement of the anti-corona layer of the stator slot part during overhaul of a steam turbine, a hydraulic generator and a phase modifier, and is simple, safe and easy to operate.
Description
Technical Field
The method is applied to potential measurement of the anti-corona layer of the stator slot part of the generator during the overhaul of the power plant.
Background
Potential measurement of the anti-corona layer of the slot part of the generator stator is widely applied to insulation detection of the anti-corona layer of the slot part of the stator bore during overhaul of the generator.
There are two cases of the problem of trench galvanic corrosion: the corona discharge between the main insulating layer and the corona-proof semiconductor layer is caused, namely internal corrosion; the other is caused by corona discharge between the anti-corona semiconductor layer and the stator core, namely external corrosion. The internal corrosion is caused by the air gap between the main insulation and the semi-conductive paint layer, so that the voltage to earth is distributed on two series capacitors with different epsilon formed by the main insulation and the air gap, and the air gap free discharge is caused to corrode. The external corrosion is caused by air ionization discharge between the semiconductor layer and the stator core due to the over-high potential of the slot corona-proof layer to the core.
The surface potential of the wire rod in the stator slot of the generator is too high, so that high-energy corona discharge is generated between the surface of the wire rod and the slot wall of the stator core. This discharge is distinguished from surface corona occurring at the ends of the stator bars and from internal ionization of the stator bars due to the strands coming out of the primary insulation. This high energy discharge severely damages the bar insulation and accelerates the aging of the insulation. In addition, the surface potential of the wire rod is too high, so that air in the gap is ionized to generate harmful gas, chemical reaction is caused, electrical corrosion is generated on the insulation of the wire rod, the insulation strength and the service life of the wire rod are seriously influenced, and even accidents are caused.
Potential measurement of the anti-corona layer of the slot part of the generator stator can find whether the insulation performance of the anti-corona layer is degraded or not in time, such as Chinese patent with publication number of CN207051394U and publication number of 2018, 2 and 27. Corona generated by the corona-proof layer for preventing the insulation from being damaged enables contact resistance on the surface of the winding bar to be larger and larger, and electric corrosion is generated after the area of the corona is continuously enlarged, so that main insulation of the winding bar is damaged, and the winding bar breakdown accident is caused in serious conditions.
Disclosure of Invention
The invention aims to overcome the defects in the prior art, and provides a generator stator slot corona prevention layer potential measuring device and a measuring method, which are convenient for safely, efficiently and accurately finding the insulation weak point of the corona prevention layer in time through test data.
The technical scheme adopted by the invention for solving the problems is as follows: the utility model provides a generator stator slot part prevents dizzy layer potential measuring device, characterized by, includes metal probe, insulating rod, flexible conductor and high internal resistance voltmeter probe, the crooked setting of one end of metal probe, the other end of metal probe and the one end of flexible conductor are at the internal connection of insulating rod, the other end and the high internal resistance voltmeter probe of flexible conductor are connected.
The method for measuring the potential of the corona-proof layer of the stator slot part of the generator is characterized in that when the generator tests the potential of the corona-proof layer of the stator slot part, an alternating-current power-frequency phase voltage is applied to a stator winding of the generator, a tester wears soft-bottom insulation shoes to measure the potential in a stator chamber, firstly, a probe of a high-internal-resistance voltmeter is inserted into an anode of a universal meter, a cathode of the universal meter is grounded, then, a metal probe is contacted with the surface of a stator coil at a ventilation groove to measure the ground potential of each point, each groove measurement is carried out on a steam turbine generator, a phase modulator and a small-sized hydraulic generator, a common hydraulic generator samples and measures according to a proportion, each groove is divided into 3-5 sections during measurement, the measurement is.
Furthermore, during measurement, the metal probe is tightly attached to the anti-corona layer on the surface of the wire rod, and after the rapid measurement, the voltage value is directly read through a universal meter.
Further, it should be noted that all grounds are good, measurements are performed under the condition that the generator is filled with water, water flow is normal, and water quality is qualified.
Furthermore, the potential measuring device of the anti-corona layer of the stator slot part of the generator is suitable for the stator winding of the generator when rated alternating-current phase voltage is applied.
Further, the potential measuring device for the slot anti-corona layer of the stator of the generator is suitable for measuring the potential of the surface of the anti-corona layer of the upper and lower wire bars of the generator according to the requirements of the upper and lower wire bars of the generator, and meets the requirement of DL/T596 'requirement specification of preventive test specification of electrical equipment' which is not more than 10V.
Furthermore, when the measured data exceeds the standard or is larger than the standard, the measured data is processed in time and retested again until the measured data is qualified.
Compared with the prior art, the invention has the following advantages and effects: the method is applied to potential measurement of the anti-corona layer of the stator slot part during overhaul of a steam turbine, a hydraulic generator and a phase modifier, and is simple, safe and easy to operate.
Drawings
FIG. 1 is a schematic wiring diagram of a potential measurement test of a slot part of a generator stator according to an embodiment of the invention.
FIG. 2 is a schematic structural diagram of a device for measuring the potential of the anti-corona layer of the slot part of the generator stator according to the embodiment of the invention.
FIG. 3 is a diagram of measuring the potential of the slot corona shielding layer of the generator according to the embodiment of the present invention.
In the figure: the device comprises a metal probe 1, an insulating rod 2, a flexible conductor 3, a high internal resistance voltmeter probe 4, an upper layer stator winding bar 5, a lower layer stator winding bar 6 and a universal meter 7.
Detailed Description
The present invention will be described in further detail below by way of examples with reference to the accompanying drawings, which are illustrative of the present invention and are not to be construed as limiting the present invention.
Referring to fig. 1 to 3, the generator stator slot corona prevention layer potential measuring device in this embodiment includes a metal probe 1, an insulating rod 2, a flexible conductor 3, and a high internal resistance voltmeter probe 4, wherein one end of the metal probe 1 is bent, the other end of the metal probe 1 is connected with one end of the flexible conductor 3 inside the insulating rod 2, and the other end of the flexible conductor 3 is connected with the high internal resistance voltmeter probe 4.
The length of the exposed part of the metal probe 1 is about 30cm, the tip has an oblique angle of about 30 degrees, the metal probe is wound on the flexible lead 3, the length of the silica gel insulating rod 2 is about 20 cm, the length of the flexible lead 3 is about 30cm, the high internal resistance voltmeter probe 4 at the tail part of the flexible lead 3 can be inserted into the anode of the high internal resistance multimeter 7, and the cathode of the multimeter 7 is grounded during measurement.
In the embodiment, the method for measuring the potential of the anti-corona layer of the stator slot part of the generator comprises the following steps that when the generator tests the potential of the anti-corona layer of the stator slot part, an alternating-current power-frequency phase voltage is applied to a stator winding of the generator, a tester wears soft-bottom insulating shoes to measure the potential in a stator chamber, firstly, a high-internal-resistance voltmeter probe 4 is inserted into the positive electrode of a universal meter 7, the negative electrode of the universal meter 7 is grounded, then, a metal probe 1 is contacted with the surface of a stator coil at a ventilation groove to measure the ground potential of each point, each groove measurement is carried out on a turbo generator, a phase modulator and a small-sized hydraulic generator, a general hydraulic generator samples and measures according to the proportion, each groove is divided into 3-5 sections during measurement, the measurement is.
During measurement, the metal probe 1 is tightly attached to the anti-corona layer on the surface of the bar, and after rapid measurement, a voltage value is directly read through the universal meter 7. All grounding is good, the measurement is carried out under the condition that the generator is filled with water, the water flow is normal, and the water quality is qualified.
The method for measuring and testing the slot potential of the stator winding of the generator in a certain factory is briefly described below.
The known parameters are:
(1) the generator model is QFSN-300-2-20, the rated capacity is 330 MW, the rated power is 300000 kW, the cooling mode is water hydrogen, the rated voltage is 20kV, and the rated current is 10190A. The total measurement is 360 measuring points of 60 bars.
(2) The main test equipment comprises: the series resonance complete test equipment comprises a megameter special for an HV-T type water internal cooling generator, a high internal resistance multimeter and two metal probes.
The test is carried out under the test condition, and the main steps are as follows:
(1) the generator is in a maintenance state, and the end covers on the two sides of the steam excitation are opened.
(2) Before the test, all the temperature measuring elements in the generator need to be grounded in a short circuit mode, and the secondary terminal of the CT at the outlet of the generator is grounded in a short circuit mode, so that the damage during pressurization is prevented.
(3) The test is carried out under the condition that the stator coil is filled with water, the conductivity of the inner cooling water is not more than 1.0 mu s/cm, and the flow is normal.
(4) The tester grounds the rotor winding and the bearing, grounds the closed bus, and connects the generator water collecting pipe into the instrument for shielding.
(5) The test should be carried out after the generator has been shut down and the hydrogen has been completely removed.
(6) And checking whether the insulation resistance of the stator winding of the generator is qualified.
(7) An alternating current rated phase voltage (11.5 kV) is relatively applied to the stator winding, and a digital multimeter is used for measuring the ground potential of the anti-corona layer of the slot part of the stator winding, wherein the requirement is not more than 10V.
(8) And fully discharging the high-voltage lead before removing the wiring after the test is finished, and discharging when the tin foil paper is removed.
The test results were as follows:
the surface potential is less than 80% of 5V;
the total surface potential is less than 15% of 1V;
the surface potential is 5% between 5V and 10V.
And (3) measuring results: the maximum value was 9.8V and all point measurements were less than 10V. Some of them, which were close to 10V, were further subjected to a stopper-added semiconductor insulating plate treatment, and all were 6V or less when measured after the treatment.
In a stator chamber of the generator, a high internal resistance alternating current voltmeter is used for measuring the surface-to-ground potential of upper and lower wire rods of the stator in a radial ventilation channel of the generator. According to the requirements of DL/T596 preventive test regulations for electrical equipment, the earth potential of the anti-corona layer on the surface of the groove part of each line bar is not more than 10V.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be able to cover the technical scope of the present invention and the equivalent alternatives or modifications according to the technical solution and the inventive concept of the present invention within the technical scope of the present invention.
Claims (4)
1. The utility model provides a generator stator slot portion prevents dizzy layer potential measuring device, characterized by, includes metal probe (1), insulating rod (2), flexible conductor (3) and high internal resistance voltmeter probe (4), the crooked setting of one end of metal probe (1), the other end of metal probe (1) and the one end of flexible conductor (3) are at the internal connection of insulating rod (2), the other end and the high internal resistance voltmeter probe (4) of flexible conductor (3) are connected.
2. A generator stator slot portion corona-preventing layer potential measuring method using the generator stator slot portion corona-preventing layer potential measuring device of claim 1, it is characterized in that when the generator tests the potential of the stator slot corona-proof layer, the stator winding of the generator applies alternating current power frequency phase voltage, a tester wears soft-bottom insulating shoes to measure in a stator bore, firstly, a high internal resistance voltmeter probe (4) is inserted into the anode of a universal meter (7), the cathode of the universal meter (7) is grounded, then a metal probe (1) is contacted with the surface of the stator coil at the ventilation groove, the earth potential of each point is measured, for the turbo generator, the phase modifier and the small-sized hydraulic generator, each groove is measured, the general hydraulic generator samples and measures according to the proportion, each groove is divided into 3-5 sections during measurement, the length of each groove depends on the length of a stator core, and an upper layer stator winding bar (5) and a lower layer stator winding bar (6) are respectively measured.
3. The generator stator slot part corona-proof layer potential measuring method as claimed in claim 2, wherein a metal probe (1) is tightly attached to the corona-proof layer on the surface of the bar during measurement, and after rapid measurement, a universal meter (7) is used for directly reading a voltage value.
4. The method for measuring the potential of the anti-corona layer of the slot part of the stator of the generator as claimed in claim 2, wherein the measurement is carried out under the condition that the generator is supplied with water, and the water flow is normal and the water quality is qualified.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910765671.XA CN110632513A (en) | 2019-08-19 | 2019-08-19 | Generator stator slot anti-corona layer potential measuring device and measuring method |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201910765671.XA CN110632513A (en) | 2019-08-19 | 2019-08-19 | Generator stator slot anti-corona layer potential measuring device and measuring method |
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| CN110632513A true CN110632513A (en) | 2019-12-31 |
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| CN201910765671.XA Pending CN110632513A (en) | 2019-08-19 | 2019-08-19 | Generator stator slot anti-corona layer potential measuring device and measuring method |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116718915A (en) * | 2023-08-10 | 2023-09-08 | 西门子电机(中国)有限公司 | Motor notch electric field intensity detection method and device, electronic equipment and storage medium |
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|---|---|---|---|---|
| CN2686194Y (en) * | 2004-01-14 | 2005-03-16 | 东方电机股份有限公司 | Power generator stator winding in-slot bar fixing apparatus |
| CN204008807U (en) * | 2014-07-14 | 2014-12-10 | 葛洲坝集团机电建设有限公司 | A kind of generator unit stator slot for winding current potential detector |
| CN204203414U (en) * | 2014-11-25 | 2015-03-11 | 邢台钢铁有限责任公司 | A kind of rotor winding insulation measurement mechanism |
| CN204925215U (en) * | 2015-07-30 | 2015-12-30 | 龙源（北京）风电工程技术有限公司 | On line measurement device of generator shaft voltage among measurement wind turbine generator system |
| CN206292284U (en) * | 2016-11-02 | 2017-06-30 | 中广核核电运营有限公司 | Generator amature shaft-voltage measurement part |
| CN108548953A (en) * | 2018-06-13 | 2018-09-18 | 中国长江电力股份有限公司 | A kind of turbine generator stator bar slot potential measurement method and device |
| CN208984744U (en) * | 2018-08-24 | 2019-06-14 | 华电电力科学研究院有限公司 | A kind of modified generator stator winding Surface potential measurement instrument |
-
2019
- 2019-08-19 CN CN201910765671.XA patent/CN110632513A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2686194Y (en) * | 2004-01-14 | 2005-03-16 | 东方电机股份有限公司 | Power generator stator winding in-slot bar fixing apparatus |
| CN204008807U (en) * | 2014-07-14 | 2014-12-10 | 葛洲坝集团机电建设有限公司 | A kind of generator unit stator slot for winding current potential detector |
| CN204203414U (en) * | 2014-11-25 | 2015-03-11 | 邢台钢铁有限责任公司 | A kind of rotor winding insulation measurement mechanism |
| CN204925215U (en) * | 2015-07-30 | 2015-12-30 | 龙源（北京）风电工程技术有限公司 | On line measurement device of generator shaft voltage among measurement wind turbine generator system |
| CN206292284U (en) * | 2016-11-02 | 2017-06-30 | 中广核核电运营有限公司 | Generator amature shaft-voltage measurement part |
| CN108548953A (en) * | 2018-06-13 | 2018-09-18 | 中国长江电力股份有限公司 | A kind of turbine generator stator bar slot potential measurement method and device |
| CN208984744U (en) * | 2018-08-24 | 2019-06-14 | 华电电力科学研究院有限公司 | A kind of modified generator stator winding Surface potential measurement instrument |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116718915A (en) * | 2023-08-10 | 2023-09-08 | 西门子电机(中国)有限公司 | Motor notch electric field intensity detection method and device, electronic equipment and storage medium |
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Application publication date: 20191231 |