CN221960233U - Test system for measuring DC magnetic bias current of AC transformer - Google Patents

Abstract

The utility model relates to a test system for measuring the DC bias current of an AC transformer, and belongs to the technical field of transformer test equipment. The technical scheme is: the high-voltage outlet terminals of the 1# test transformer (3) and the 2# test transformer (4) are connected in parallel and then connected to the regulating transformer (2); the three phases of the low-voltage outlet terminals of the 1# test transformer and the 2# test transformer are respectively connected in a triangle manner, and each phase of the low-voltage outlet terminals of the 1# test transformer and the 2# test transformer are connected in parallel; the DC power supply (5) is connected between the primary neutral points of the 1# test transformer and the 2# test transformer, and the data acquisition component is connected to the 1# test transformer. The beneficial effect of the utility model is that it can accurately measure the excitation current, no-load loss, noise, vibration and other parameters of the transformer under DC bias, thereby analyzing the vibration characteristics, temperature field and leakage magnetic field distribution characteristics of the transformer under DC bias, thereby obtaining the DC bias characteristics of the test transformer.

Description

A test system for measuring DC bias current of AC transformer

Technical Field

The utility model relates to a test system for measuring a direct current bias current of an alternating current transformer, belonging to the technical field of transformer test equipment.

Background Art

Judging from the current needs of the national power grid, the demand for large-capacity and high-voltage transformers is increasing day by day, especially the changes in ground potential caused by existing DC transmission, metallurgy and rail transportation, which form a DC circuit through the transmission lines and the grounding points of the windings of coil-type equipment, causing the transformer core magnetic density to saturate in half a cycle, resulting in DC bias in transformers and mutual inductors, causing problems such as increased noise, additional losses, increased vibration and local overheating of operating equipment, and increased grid harmonics and losses, which have an adverse impact on grid operation.

Although power transformers have a certain ability to withstand DC bias, they cannot be tested for this ability before leaving the factory. Untested power transformers will fail due to insufficient DC bias. Therefore, the AC transformer DC bias research project has positive significance for the safe operation of transformers and power grid security.

Utility Model Content

The utility model aims to provide a test system for measuring the DC bias current of an AC transformer. By placing a vibration sensor and a measuring induction coil on the oil tank wall and windings of the test transformer, the excitation current, no-load loss, noise, vibration and other parameters of the transformer under DC bias can be accurately measured, so as to analyze the vibration characteristics, temperature field and leakage magnetic field distribution characteristics of the transformer under DC bias, thereby obtaining the DC bias characteristics of the test transformer. The utility model has simple operation and strong practicality, and is of great significance for accurately designing and testing the technical parameters of the transformer under different DC bias conditions. It can verify, guide and improve the safe operation of transformer design and manufacturing, and effectively solves the above-mentioned problems existing in the background technology.

The technical scheme of the utility model is: a test system for measuring the DC bias current of an AC transformer, comprising a test power supply, a regulating transformer, a 1# test transformer, a 2# test transformer, a DC power supply, a data acquisition component and a test load, wherein the test power supply, the regulating transformer, the 1# test transformer, the 2# test transformer and the test load are connected in sequence, the high-voltage outlet terminals of the 1# test transformer and the 2# test transformer are connected in parallel and then connected to the regulating transformer; the three phases of the low-voltage outlet terminals of the 1# test transformer and the 2# test transformer are respectively connected in a triangle manner, and each phase of the low-voltage outlet terminals of the 1# test transformer and the 2# test transformer are connected in parallel; the DC power supply is connected between the primary-side neutral points of the 1# test transformer and the 2# test transformer, and the data acquisition component is connected to the 1# test transformer.

The data acquisition component comprises a power analyzer, a waveform recorder, a voltage transformer, a current transformer, a vibration and noise test system, a vibration sensor and a microphone. The power analyzer and the waveform recorder are connected to the 1# test transformer; the current transformer is arranged on the primary side connection and the secondary side triangle connection of the 1# test transformer, and the current transformer, the voltage transformer and the vibration and noise test system are connected in sequence; the vibration sensor is arranged on the longitudinal center line of the oil tank wall of the 1# test transformer, and the microphone is arranged around the 1# test transformer; the power analyzer and the waveform recorder are connected to the voltage transformer and the current transformer, and the vibration sensor and the microphone are connected to the vibration and noise test system.

The test load is a reactor group formed by three single-phase shunt reactors connected in star shape.

The beneficial effects of the utility model are as follows: by placing vibration sensors and measuring induction coils on the oil tank wall and windings of the test transformer, the excitation current, no-load loss, noise, vibration and other parameters of the transformer under DC bias can be accurately measured, so as to analyze the vibration characteristics, temperature field and leakage magnetic field distribution characteristics of the transformer under DC bias, thereby obtaining the DC bias characteristics of the test transformer. The utility model has simple operation and strong practicality, and is of great significance for accurately designing and testing the technical parameters of the transformer under different DC bias conditions, and can verify, guide and improve the safe operation of transformer design and manufacturing.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a no-load test circuit diagram of the utility model;

FIG2 is a load test circuit diagram of the utility model;

In the figure: test power supply 1, regulating transformer 2, 1# test transformer 3, 2# test transformer 4, DC power supply 5, power analyzer 6, waveform recorder 7, voltage transformer 8, current transformer 9, vibration and noise test system 10, vibration sensor 11, microphone 12.

DETAILED DESCRIPTION

The technical solution of the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments, which are preferred embodiments of the utility model. It should be understood that the described embodiments are only part of the embodiments of the utility model, not all of the embodiments; it should be noted that the embodiments and features in the embodiments of the utility model can be combined with each other without conflict. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

A test system for measuring the DC bias current of an AC transformer comprises a test power supply 1, a regulating transformer 2, a 1# test transformer 3, a 2# test transformer 4, a DC power supply 5, a data acquisition component and a test load. The test power supply 1, the regulating transformer 2, the 1# test transformer 3, the 2# test transformer 4 and the test load are connected in sequence. The high-voltage outlet terminals of the 1# test transformer 3 and the 2# test transformer 4 are connected in parallel and then connected to the regulating transformer 2; the three phases of the low-voltage outlet terminals of the 1# test transformer 3 and the 2# test transformer 4 are respectively connected in a triangle manner, and each phase of the low-voltage outlet terminals of the 1# test transformer 3 and the 2# test transformer 4 are connected in parallel; the DC power supply 5 is connected between the primary-side neutral points of the 1# test transformer 3 and the 2# test transformer 4, and the data acquisition component is connected to the 1# test transformer 3.

The data acquisition component includes a power analyzer 6, a waveform recorder 7, a voltage transformer 8, a current transformer 9, a vibration and noise test system 10, a vibration sensor 11 and a microphone 12. The power analyzer 6 and the waveform recorder 7 are connected to the 1# test transformer 3; the current transformer 9 is arranged on the primary side connection and the secondary side triangle connection of the 1# test transformer 3, and the current transformer 9, the voltage transformer 8 and the vibration and noise test system 10 are connected in sequence; the vibration sensor 11 is arranged on the longitudinal center line of the oil tank wall of the 1# test transformer 3, and the microphone 12 is arranged around the 1# test transformer 3; the power analyzer 6 and the waveform recorder 7 are connected to the voltage transformer 8 and the current transformer 9, and the vibration sensor 11 and the microphone 12 are connected to the vibration and noise test system 10.

The test load is a reactor group formed by three single-phase shunt reactors connected in star shape.

Noise test steps: Draw a noise test circle at a distance of 0.3 meters outside the transformer outline, mark test points on the test circle at intervals of 1 meter, and use microphone 12 to measure the noise values of no-load, no-load bias, load, and load DC bias conditions. The test transformer is small, and a total of 4 microphones are set, one at the center of each of the four sides of the transformer.

The DC power supply 5 is a DC current generator. Since it is located on the neutral point connection line of two test transformers with the same performance, the circulating current on the line is very small and the DC power supply can tolerate it. Therefore, the DC source has no protection device and directly participates in the test.

Example

The test power supply 1 uses a generator set with a capacity of 7500kVA/voltage of 10500V, the regulating transformer 2 uses a model YDJ-2000 kVA/2500V test transformer, the 1# test transformer 3 and the 2# test transformer 4 use a model S-150/11/1 three-phase five-column transformer, and the test loads are connected in sequence. The DC power supply 5 uses an AN531500-30 programmable DC power supply, which is connected between the primary side neutral points of the 1# test transformer 3 and the 2# test transformer 4. The data acquisition component is connected to the test transformer, and the test load is a reactor group formed by three single-phase shunt reactors connected in star shape.

In the data acquisition component, the vibration sensor 11 uses the acceleration sensor of model YA23F. Eight vibration sensors 11 are arranged on the side wall of the oil tank and the center line of the upper cover of the 1# test transformer 3 in sequence through the magnetic base. The vibration sensor 11 collects the vibration signal of the test transformer through the vibration and noise test system 10. The microphone 12 collects the sound signal, and the voltage signal converted from the sound signal is collected through the vibration and noise test system 10 and converted into the sound pressure data of the test transformer. Multiple current transformers 9 are installed on the primary side wiring and secondary side triangle wiring of the 1# test transformer 3, and three current transformers 9 are used for load current measurement; the voltage transformer 8 is a standard voltage transformer of model HJ12-25, which is installed at the primary side line end of the 1# test transformer 3 to measure the high-voltage side voltage of 11kV. The voltage and current data signals enter the waveform recorder 7 and the power analyzer 6. The power analyzer 6 displays the short-term voltage and current waveforms, and displays the voltage, current and power data, and realizes recording. The waveform recorder 7 collects long-term data and waveforms.

The specific test process includes four working conditions: the test system tests no-load conditions, no-load bias conditions, load conditions, and load plus DC bias conditions, and tests parameters such as voltage, current, waveform, vibration and noise.

No-load test steps: power analyzer 6, waveform recorder 7, vibration and noise test system 10 and other test equipment are turned on and started on site, test power supply 1 is started, regulating transformer 2 is adjusted, and the three-phase voltage/current fed to 1# test transformer 3 and 2# test transformer 4 are respectively A phase: 6.35725V, B phase: 6.38622V, C phase: 6.35488V, three-phase average (3P4W) 6.35345V; A phase: 0.20147A, B phase: 0.154704A, C phase: 0.192068A, three-phase average (3P4W) 0.182748A; power analyzer 6 records the test power indication, waveform recorder 7 records the waveform of no-load working condition, and vibration and noise test system 10 records the vibration acceleration, displacement data and sound pressure data under this working condition. Data can be collected from seconds to minutes as needed.

No-load bias test step 1: maintain the input voltage/current of 1# test transformer 3 and 2# test transformer 4, phase A: 6.34982V, phase B: 6.35239V, phase C: 6.34785V, three-phase average (3P4W) 6.35002V; phase A: 0.42517A, phase B: 0.32906A, phase C: 0.42509A, three-phase average (3P4W) 0.39161A, start DC power supply 5, input current 0.63A; power analyzer 6 records the test power indication, waveform recorder 7 records the waveform of the test condition, and vibration and noise test system 10 records the vibration acceleration, displacement, and sound pressure data under the working condition. Test step 2: Maintain the input voltage/current of 1# test transformer 3 and 2# test transformer 4, phase A: 6.35251V, phase B: 6.36001V, phase C: 6.35169V, three-phase average (3P4W) 6.35474V; phase A: 0.80358A, phase B: 0.61603A, phase C: 0.80396A, three-phase average (3P4W) 0.74119A; start the DC power supply 5, input current 1.26A; the power analyzer 6 records the test power indication, the waveform recorder 7 records the waveform of the test condition, and the vibration and noise test system 10 records the vibration acceleration, displacement, and sound pressure data under the working condition. Test step 3: Maintain the input voltage/current of 1# test transformer 3 and 2# test transformer 4, phase A: 6.34083V, phase B: 6.35719V, phase C: 6.34189V, three-phase average (3P4W) 6.34664V; phase A: 1.54225A, phase B: 1.17071A, phase C: 1.55765A, three-phase average (3P4W) 1.42353A, start the DC power supply 5, and input current 2.52A in sequence; at the same time, the power analyzer 6 records the test power indication, the waveform recorder 7 records the waveform of the test condition, and the vibration and noise test system 10 records the vibration acceleration, displacement, and sound pressure data under the working condition. Test steps 4-6: Maintain the input voltage/current of 1# test transformer 3 and 2# test transformer 4, start the DC power supply 5, and input DC currents of 3.78A, 5.06, and 6.35A in sequence; at the same time, the power analyzer 6 records the test power indication, the waveform recorder 7 records the waveform of the test condition, and the vibration and noise test system 10 records the vibration acceleration, displacement, and sound pressure data under the working condition.

Load test steps: The load test conditions are that, based on the no-load test, the secondary sides of the 1# test transformer 3 and the 2# test transformer 4 are connected in parallel and connected together to the parallel reactor group of the test load. Start the test power supply 1, adjust the regulating transformer 2, and the 1# test transformer 3 and the 2# test transformer 4 reach the rated voltage. The power analyzer 6 records the test power reading, the waveform recorder 7 records the waveform of the load condition, and the vibration and noise test system 10 records the vibration acceleration, displacement, and sound pressure data under the condition.

The steps of load plus DC bias test are as follows: keep the rated voltage of 1# test transformer 3 and 2# test transformer 4 unchanged, start the DC power supply 5, and input current 0A, 0.63A, 1.26A, 2.52A, 3.78A, 5.06A, and 6.35A in sequence. After stabilization, the power analyzer 6 records the test power indication, the waveform recorder 7 records the waveform of the load condition, and the vibration and noise test system 10 records the vibration acceleration, displacement, and sound pressure data under the working condition.

The utility model has the advantages of simple operation and strong practicability, and solves the problem of DC bias current tolerance for transformer manufacturing companies and on-site test personnel. It is of great significance for accurately designing and testing the technical parameters of transformers under different DC bias conditions, and has the ability to verify, guide and improve the safe operation of transformer design and manufacturing.

Claims (3)

1. A test system for measuring the DC bias current of an AC transformer, characterized in that it comprises a test power supply (1), a regulating transformer (2), a No. 1 test transformer (3), a No. 2 test transformer (4), a DC power supply (5), a data acquisition component and a test load, wherein the test power supply (1), the regulating transformer (2), the No. 1 test transformer (3), the No. 2 test transformer (4) and the test load are connected in sequence, the No. 1 test transformer (3) and the No. 2 test transformer (4) high-voltage outlet terminals are connected in parallel and then connected to the regulating transformer (2); the No. 1 test transformer (3) and the No. 2 test transformer (4) low-voltage outlet terminals of the three phases are respectively connected in a triangle manner, and each phase of the No. 1 test transformer (3) and the No. 2 test transformer (4) low-voltage outlet terminals are connected in parallel; the DC power supply (5) is connected between the primary neutral points of the No. 1 test transformer (3) and the No. 2 test transformer (4), and the data acquisition component is connected to the No. 1 test transformer (3). 2. A test system for measuring the DC bias current of an AC transformer according to claim 1, characterized in that: the data acquisition component comprises a power analyzer (6), a waveform recorder (7), a voltage transformer (8), a current transformer (9), a vibration and noise test system (10), a vibration sensor (11) and a microphone (12), the power analyzer (6) and the waveform recorder (7) are connected to the No. 1 test transformer (3); the current transformer (9) is arranged on the primary side connection and the secondary side delta connection of the No. 1 test transformer (3), and the current transformer (9), the voltage transformer (8) and the vibration and noise test system (10) are connected in sequence; the vibration sensor (11) is arranged on the longitudinal center line of the oil tank wall of the No. 1 test transformer (3), and the microphone (12) is arranged around the No. 1 test transformer (3); the power analyzer (6) and the waveform recorder (7) are connected to the voltage transformer (8) and the current transformer (9), and the vibration sensor (11) and the microphone (12) are connected to the vibration and noise test system (10). 3. A test system for measuring the DC bias current of an AC transformer according to claim 1, characterized in that the test load is a reactor group formed by three single-phase shunt reactors connected in a star shape.