CN111123050B - Transformer partial discharge test device for transformer and GIS in GIL connection mode - Google Patents
Transformer partial discharge test device for transformer and GIS in GIL connection mode Download PDFInfo
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- CN111123050B CN111123050B CN201911420866.7A CN201911420866A CN111123050B CN 111123050 B CN111123050 B CN 111123050B CN 201911420866 A CN201911420866 A CN 201911420866A CN 111123050 B CN111123050 B CN 111123050B
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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
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Abstract
The invention discloses a transformer partial discharge test device for a transformer and a GIS in a GIL connection mode, and belongs to the technical field of electrical preventive tests of large transformers. The structure steps are simple, and the field implementation is easy. The device comprises a non-partial-discharge variable frequency power supply G, a non-partial-discharge excitation transformer T, a non-partial-discharge compensation reactor L, a non-corona alternating-current voltage divider V, a tested transformer T1, a coupling impedance Z1, a GIL bus and GIS equipment; the input end of the non-partial discharge variable frequency power supply G is connected to a 380V three-phase power supply, the output end of the non-partial discharge variable frequency power supply G is connected to a low-voltage winding of a non-partial discharge excitation transformer T, and the high voltage of the non-partial discharge excitation transformer T is connected to a phase A and a phase C of a low-voltage winding of a tested transformer T1; the phase A and the phase C of the low-voltage winding of the tested transformer T1 are respectively connected with one ends of two compensation reactors L without partial discharge, and the other ends of the two compensation reactors L without partial discharge are grounded.
Description
Technical Field
The invention relates to the technical field of electrical preventive tests of large transformers, in particular to a partial discharge test device of a transformer, wherein the transformer is connected with a GIS in a GIL mode.
Background
Generally, in outdoor transformer substations of 220 kV and 500kV voltage classes, the connection between the main transformer and the GIS (gas insulated switchgear) is usually in an overhead manner, and with the requirements of environmental friendliness and conservation of land resources, the connection in a GIL (gas insulated bus) manner is more and more widespread for the large-scale popularization and application of GIS (gas insulated switchgear) equipment. Usually, the GIS equipment sleeve and the transformer sleeve adopt an overhead connection mode, and when a preventive test is carried out, the connection between the transformer and an overhead conductor is removed, so that an obvious disconnection point exists between the GIS equipment and the transformer, and various types of equipment are convenient and simple to overhaul and test. The transformer adopting the GIL connection mode adopts an oil-SF 6 sleeve, is connected with GIS equipment through a GIL pipe bus, and has no exposed conductor and lead, so that no obvious disconnection point exists, various overhauling and tests of the equipment become complicated, and much inconvenience is caused. For a preventive test for connecting a transformer and GIS equipment by using a GIL, a partial discharge test and a GIS alternating current withstand voltage test are required to be respectively carried out on the transformer due to the non-uniform test standards during a special test. However, the steps and procedures of the preparation work before the test are relatively complicated: 1. recovering SF6 gas in a gas chamber connecting the transformer bushing and the GIL; 2. removing the flexible connection between the transformer bushing and the GIL; 3. installing a voltage-sharing ring (or a voltage-sharing ball) at the fracture where the flexible connection is removed; 4. sealing and vacuumizing the air chamber; 5. filling SF6 gas into the gas chamber to a rated pressure; 6. and (5) after standing for 24h, detecting the water content of the gas in the gas chamber SF6, and testing after the gas is qualified. After the test is finished, the soft connection between the transformer bushing and the GIL is recovered through the steps. The whole process is labor-consuming and time-consuming, and a plurality of professional work types and mechanical equipment are required to be completed in a coordinated mode, so that the difficulty of organization, coordination and management work is greatly improved. Therefore, the transformer preventive partial discharge test which is suitable for the transformer and the GIS in the GIL connection mode and is time-saving and labor-saving and capable of greatly reducing the working difficulty is very necessary.
Disclosure of Invention
The invention aims to overcome the defects of the transformer preventive partial discharge test of the existing 200 kV and 500kV voltage class transformer and GIS in a GIL connection mode, adopts the transformer partial discharge test device which has the advantages that the transformer side isolating switch in the GIS equipment is disconnected, the transformer side grounding switch is disconnected, the transformer switch side grounding switch is connected, the transformer switch is disconnected, the transformer and the GIL tube bus carry out the partial discharge test together, the structure steps are simple, and the field implementation is easy.
The technical problem is solved by the following technical scheme:
the transformer partial discharge test device with the transformer and the GIS in a GIL connection mode comprises a non-partial discharge variable frequency power supply G, a non-partial discharge excitation transformer T, a non-partial discharge compensation reactor L, a non-corona alternating-current voltage divider V, a tested transformer T1, a coupling impedance Z1, a GIL bus and GIS equipment;
the input end of the partial discharge-free variable frequency power supply G is connected to a 380V three-phase power supply, the output end of the partial discharge-free variable frequency power supply G is connected to a low-voltage winding of a partial discharge-free excitation transformer T, and the high voltage of the partial discharge-free excitation transformer T is connected to a phase A and a phase C of a low-voltage winding of a tested transformer T1; the phase A and the phase C of the low-voltage winding of the tested transformer T1 are respectively connected with one end of two compensation reactors L without partial discharge, and the other ends of the two compensation reactors L without partial discharge are grounded;
One end of the coupling impedance Z1 is connected to the A-phase output end of the tested transformer T1; the other end of the coupling impedance Z1 is grounded, and the neutral point N of the high-voltage winding is grounded; passing a non-corona AC voltage divider V on the low-voltage side of the tested transformer T1;
the GIS equipment comprises a DS1 disconnecting switch, an ES1 grounding switch, an ES2 grounding switch, a CB breaker switch, an ES3 grounding switch, a DS2 disconnecting switch, a DS3 disconnecting switch, an IM bus and an IIM bus; one end of a DS1 disconnecting switch is connected to a tested transformer T1 through a GIL bus, one end of a DS1 disconnecting switch is also connected to the grounding end through an ES1 grounding switch, and the other end of a DS1 disconnecting switch is connected to one end of a CB breaker switch; the other end of the DS1 isolating switch is also connected to the grounding end through an ES2 grounding switch; the other end of the CB breaker switch is connected with one end of a DS2 disconnecting switch, and the other end of the DS2 disconnecting switch is connected with the IM bus; the other end of the CB breaker switch is also connected with one end of a DS3 isolating switch, and the other end of the DS3 isolating switch is connected with the IIM bus; the other end of the CB breaker switch is also connected to ground through an ES3 ground switch.
Preferably, a non-partial discharge variable frequency power supply G is adopted as a test power supply, the test power supply of the non-partial discharge variable frequency power supply G is connected to a low-voltage winding of a non-partial discharge excitation transformer T, the high-voltage side of the non-partial discharge excitation transformer T is connected to a phase A and a phase C of a low-voltage winding of a tested transformer T1, pressurization is carried out, a non-partial discharge compensation reactor L is used for proper compensation, the main capacitor of a sleeve of the high-voltage side phase A of the tested transformer T1 is used as a coupling capacitor, and a signal is extracted from the end screen of the sleeve and is measured by a partial discharge instrument through a coupling impedance Z1.
Preferably, the neutral point N of the high-voltage winding of the transformer T1 under test is grounded, the test voltage is monitored by the corona-free ac voltage divider V on the low-voltage side of the transformer T1 under test, and the high-voltage side test voltage is converted by the transformation ratio.
Preferably, the partial discharge test of the transformer under test is realized by monitoring the partial discharge amount with a partial discharge tester after the test voltage rises to a predetermined test voltage at a constant speed, and measuring the partial discharge amount continuously within a predetermined test time.
Preferably, in the partial discharge test, the ES1 grounding switch in the GIS equipment is in an open state, the DS1 disconnecting switch is also in an open state, the ES2 grounding switch is in a closed state, and the CB breaker switch is in an open state; therefore, the high-voltage side of the tested transformer T1 can be induced to generate test voltage meeting test requirements, and the safety and the influence of other parts of GIS equipment can be guaranteed.
The invention can achieve the following effects:
according to the invention, the transformer side disconnecting switch, the transformer side grounding switch, the transformer switch side grounding switch and the transformer switch in the GIS equipment are switched off, and the transformer and the GIL tube bus perform a partial discharge test together.
Drawings
Fig. 1 is a schematic diagram of an electrical primary main wiring of a transformer-GIS device according to an embodiment of the present invention.
Fig. 2 is a schematic diagram of a state of a transformer-GIS device in a partial discharge test of a transformer according to an embodiment of the present invention.
Fig. 3 is a schematic diagram of a wiring diagram for a partial discharge test of a transformer according to an embodiment of the present invention.
The system comprises a non-partial discharge variable frequency power supply G, a non-partial discharge exciting transformer T, a non-partial discharge compensating reactor L, a non-corona alternating-current voltage divider V, a tested transformer T1 and a coupling impedance Z1.
Detailed Description
The invention is further described with reference to the following figures and examples.
Example, a partial discharge test device of a transformer, in which the transformer is connected to a GIS device in a GIL manner, is shown in fig. 1 to 3,
the device comprises a non-partial-discharge variable frequency power supply G, a non-partial-discharge excitation transformer T, a non-partial-discharge compensation reactor L, a non-corona alternating-current voltage divider V, a tested transformer T1, a coupling impedance Z1, a GIL bus and GIS equipment;
the input end of the non-partial discharge variable frequency power supply G is connected to a 380V three-phase power supply, the output end of the non-partial discharge variable frequency power supply G is connected to a low-voltage winding of a non-partial discharge excitation transformer T, and the high voltage of the non-partial discharge excitation transformer T is connected to a phase A and a phase C of a low-voltage winding of a tested transformer T1; the phase A and the phase C of the low-voltage winding of the tested transformer T1 are respectively connected with one end of two compensation reactors L without partial discharge, and the other ends of the two compensation reactors L without partial discharge are grounded;
One end of the coupling impedance Z1 is connected to the A-phase output end of the tested transformer T1; the other end of the coupling impedance Z1 is grounded, and the neutral point N of the high-voltage winding is grounded; passing a non-corona alternating-current voltage divider V on the low-voltage side of the tested transformer T1;
the GIS equipment comprises a DS1 disconnecting switch, an ES1 grounding switch, an ES2 grounding switch, a CB breaker switch, an ES3 grounding switch, a DS2 disconnecting switch, a DS3 disconnecting switch, an IM bus and an IIM bus; one end of a DS1 disconnecting switch is connected to a tested transformer T1 through a GIL bus, one end of a DS1 disconnecting switch is also connected to the grounding end through an ES1 grounding switch, and the other end of the DS1 disconnecting switch is connected to one end of a CB breaker switch; the other end of the DS1 isolating switch is also connected to the grounding end through an ES2 grounding switch; the other end of the CB breaker switch is connected with one end of a DS2 disconnecting switch, and the other end of the DS2 disconnecting switch is connected with the IM bus; the other end of the CB breaker switch is also connected with one end of a DS3 isolating switch, and the other end of the DS3 isolating switch is connected with the IIM bus; the other end of the CB breaker switch is also connected to the grounding end through an ES3 grounding switch;
during the partial discharge test, an ES1 grounding switch in GIS equipment is required to be in an off state, a DS1 disconnecting switch is also required to be in an off state, an ES2 grounding switch is required to be in a closing state, and a CB breaker switch is required to be in an off state;
Adopting a non-partial discharge variable frequency power supply G as a test power supply, connecting the test power supply of the non-partial discharge variable frequency power supply G to a low-voltage winding of a non-partial discharge excitation transformer T, connecting the high-voltage side of the non-partial discharge excitation transformer T to a phase A and a phase C of a low-voltage winding of a tested transformer T1, pressurizing, using a non-partial discharge compensation reactor L for proper compensation, using a main capacitor of a high-voltage side phase A sleeve of the tested transformer T1 as a coupling capacitor, and extracting a signal from the end screen of the sleeve to be measured by a partial discharge instrument through a coupling impedance Z1 (taking a transformer phase partial discharge test as an example);
the neutral point N of the high-voltage winding of the tested transformer T1 is grounded, the test voltage is monitored through the non-corona AC voltage divider V on the low-voltage side of the tested transformer T1, and the test voltage on the high-voltage side is converted according to the transformation ratio.
After the test voltage rises to the specified test voltage at a constant speed, the partial discharge amount is monitored by the partial discharge tester, and the partial discharge amount is measured uninterruptedly in the specified test time, so that the partial discharge test of the tested transformer is realized.
The method comprises the steps that a transformer side isolating switch in the GIS equipment is disconnected, a transformer side grounding switch is disconnected, a transformer switch side grounding switch is connected, a transformer switch is disconnected, and the transformer and a GIL (gate in line) tube bus part are subjected to a partial discharge test (the test standard of the GIL tube bus is higher than that of the transformer). The transformer partial discharge test device is simple in structural steps, easy to implement on site and suitable for transformer preventive partial discharge tests with transformers and GIS in a GIL connection mode.
The embodiments of the present invention have been described above with reference to the accompanying drawings, but the implementation is not limited to the above-described embodiments, and those skilled in the art can make various changes or modifications within the scope of the appended claims.
Claims (1)
1. The transformer partial discharge test device with the transformer and the GIS in a GIL connection mode is characterized by comprising a non-partial discharge variable frequency power supply G, a non-partial discharge excitation transformer T, a non-partial discharge compensation reactor L, a non-corona alternating current voltage divider V, a tested transformer T1, a coupling impedance Z1, a GIL bus and GIS equipment;
the input end of the non-partial discharge variable frequency power supply G is connected to a 380V three-phase power supply, the output end of the non-partial discharge variable frequency power supply G is connected to a low-voltage winding of a non-partial discharge excitation transformer T, and the high voltage of the non-partial discharge excitation transformer T is connected to a phase A and a phase C of a low-voltage winding of a tested transformer T1; the phase A and the phase C of the low-voltage winding of the tested transformer T1 are respectively connected with one end of two compensation reactors L without partial discharge, and the other ends of the two compensation reactors L without partial discharge are grounded;
one end of the coupling impedance Z1 is connected to the A-phase output end of the tested transformer T1; the other end of the coupling impedance Z1 is grounded, and the neutral point N of the high-voltage winding is grounded; passing a non-corona alternating-current voltage divider V on the low-voltage side of the tested transformer T1;
The GIS equipment comprises a DS1 disconnecting switch, an ES1 grounding switch, an ES2 grounding switch, a CB breaker switch, an ES3 grounding switch, a DS2 disconnecting switch, a DS3 disconnecting switch, an IM bus and an IIM bus; one end of a DS1 disconnecting switch is connected to a tested transformer T1 through a GIL bus, one end of a DS1 disconnecting switch is also connected to the grounding end through an ES1 grounding switch, and the other end of a DS1 disconnecting switch is connected to one end of a CB breaker switch; the other end of the DS1 isolating switch is also connected to the grounding end through an ES2 grounding switch; the other end of the CB breaker switch is connected with one end of a DS2 disconnecting switch, and the other end of the DS2 disconnecting switch is connected with the IM bus; the other end of the CB breaker switch is also connected with one end of a DS3 isolating switch, and the other end of the DS3 isolating switch is connected with the IIM bus; the other end of the CB breaker switch is also connected to the grounding end through an ES3 grounding switch;
adopting a non-partial discharge variable frequency power supply G as a test power supply, connecting the test power supply of the non-partial discharge variable frequency power supply G to a low-voltage winding of a non-partial discharge excitation transformer T, connecting the high-voltage side of the non-partial discharge excitation transformer T to a phase A and a phase C of a low-voltage winding of a tested transformer T1, pressurizing, using a non-partial discharge compensation reactor L for proper compensation, using a main capacitor of a sleeve of the phase A at the high-voltage side of the tested transformer T1 as a coupling capacitor, and extracting a signal from the end screen of the sleeve to a partial discharge instrument through a coupling impedance Z1 for measurement;
The neutral point N of the high-voltage winding of the tested transformer T1 is grounded, the test voltage is monitored through a non-corona alternating-current voltage divider V on the low-voltage side of the tested transformer T1, and the test voltage on the high-voltage side is converted according to the transformation ratio;
after the test voltage rises to the specified test voltage at a constant speed, monitoring the local discharge amount through a local discharge tester, and uninterruptedly measuring the local discharge amount within the specified test time, thereby realizing the local discharge test of the tested transformer;
during the partial discharge test, an ES1 grounding switch in GIS equipment is required to be in an off state, a DS1 disconnecting switch is also required to be in an off state, an ES2 grounding switch is required to be in a closing state, and a CB breaker switch is required to be in an off state; therefore, the high-voltage side of the tested transformer T1 can induce test voltage meeting test requirements, and other parts of GIS equipment can be ensured to be safe and not affected;
the method has the advantages that the transformer side isolating switch in the GIS equipment is disconnected, the transformer side grounding switch is disconnected, the transformer switch side grounding switch is connected, the transformer switch is disconnected, the transformer and the GIL tube bus are used for carrying out the partial discharge test, the structure steps are simple, and the field implementation is easy.
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CN111913080A (en) * | 2020-07-06 | 2020-11-10 | 西安热工研究院有限公司 | Partial discharge test method for GIL connection mode transformer |
CN112798999A (en) * | 2021-03-18 | 2021-05-14 | 国网山西省电力公司电力科学研究院 | Square wave calibration circuit and method for partial discharge test of transformer with oil-gas casing structure |
CN112782545A (en) * | 2021-03-18 | 2021-05-11 | 西安热工研究院有限公司 | Method for testing partial discharge of generator |
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