CN201576074U - UHV Transformer No Partial Discharge Variable Frequency Resonance Test Device - Google Patents

Abstract

UHV transformer without partial discharge variable frequency resonance test device, the three-phase AC power supply is connected to the variable frequency power supply, the output of the variable frequency power supply is connected to the low voltage end of the excitation transformer, the high voltage end of the excitation transformer is connected to a parallel compensation reactor, parallel compensation reactor, and a voltage divider It is connected in parallel with the low-voltage end of the test product (i.e. UHV transformer). Both the high-voltage head end and the iron core tail end are connected to the detection impedance input end, the detection impedance grounding end is connected to the ground, and the detection impedance output end is connected to the partial discharge tester. The test of the utility model is not limited by the balance measurement method and the unbalance measurement method, and the partial discharge interference of the system is less than 10pC.

Description

UHV Transformer No Partial Discharge Variable Frequency Resonance Test Device

technical field

The utility model relates to the technical field of field testing of high-voltage equipment, in particular to a non-partial discharge variable-frequency resonance test device suitable for transformers of UHV and lower voltage levels.

Background technique

When performing high-voltage on-site insulation tests on electrical equipment, parallel or series resonance is often used to provide the high voltage required for the test. At present, when conducting partial discharge tests on UHV transformers, manufacturers, Hubei Electric Power Research Institute and Shanxi Electric Power Research Institute all use generators to change the excitation to adjust the frequency. In order to meet the resonance conditions, many reactors need to be connected in series and parallel, and The generator capacity requirements are relatively high, the equipment organization is cumbersome, the wiring is complicated, the floor area is large, and the interference is increased. In the partial discharge field test of transformers with a voltage level of 500kV and below, although there are two ways to pressurize the frequency conversion source and the generator set, it is generally believed that the frequency conversion source has poor reliability, large PD interference, and low efficiency. With the development of electronic technology, the variable frequency source device adopts the triode parallel amplification method to realize frequency conversion adjustment easily, and its reliability can be guaranteed. At the same time, the efficiency is greatly improved under the condition of pure resistive load.

Contents of the invention

The purpose of this utility model is to overcome the deficiencies in the existing on-site UHV equipment test technology, and provide a non-partial discharge frequency conversion resonance test device suitable for UHV transformers, which makes the on-site wiring simple, reliable in use, and has little partial discharge interference. The measurement is accurate and meets the requirements of the UHV field partial discharge test.

The technical scheme of the utility model is: UHV transformer without partial discharge frequency conversion resonance test device, including frequency conversion power supply, excitation transformer, parallel compensation reactor, voltage divider, test product (i.e. UHV transformer), iron core, detection impedance and Partial discharge tester, the three-phase AC power supply is connected to the variable frequency power supply, the output of the variable frequency power supply is connected to the low voltage end of the excitation transformer, the high voltage end of the excitation transformer is connected to the parallel compensation reactor, the parallel compensation reactor, the voltage divider and the low voltage end of the test product In parallel connection, the high-voltage end of the excitation transformer, the end of the parallel compensation reactor, the low-voltage end of the test product, the iron core, and the high-voltage end are all grounded, and the low-voltage head end, high-voltage head end, and iron core end of the test product are all connected to the detection impedance input The detection impedance grounding terminals are all grounded, and the detection impedance output terminals are all connected to the partial discharge tester.

Compared with the prior art, the utility model has the advantages of:

(1) The frequency conversion power supply adopted in the utility model adopts the triode parallel amplification method, and a special chip generates a standard sine wave voltage with a frequency in the range of 4-1MHz and a voltage adjustable in the range of 0-350V, which effectively reduces the power supply side's resistance to partial discharge. The interference of the test improves the efficiency; at the same time, the optical fiber isolation method is used for control and measurement, which effectively ensures that the device works stably when the tested product breaks down or other faults occur. It overcomes the shortcomings of low reliability, low efficiency, and large interference that were generally believed to be in the past.

(2) The parallel compensation reactor of the utility model adopts an air-core reactor, which is small in size and reduces the occupied area, and has pressure equalizing flanges at its upper and lower ends, and the reactance value is fixed.

(3) The utility model aims at the defects of the existing on-site insulation test scheme, especially the insufficiency of the on-site test method for UHV power equipment. , a practical frequency conversion resonance test device with simple operation. It can meet the partial discharge test requirements of all high-voltage power equipment such as power transformers, cables, bushings, GIS, transformers, etc., and is not limited by balanced measurement methods and unbalanced measurement methods. The partial discharge interference of the device is less than 10pC. It has extremely high use value and economic value.

Description of drawings

Fig. 1 is the structural representation of the utility model

Fig. 2 is a schematic structural diagram of an embodiment when the test product in the device of the present invention is a DC UHV transformer.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the utility model is described in further detail.

Notes in Figures 1 and 2: 1-Variable frequency power supply, 1.1-Transformer network side head end, 1.2-Transformer network side tail end, 2-Excitation transformer, 2.1-Transformer valve side head end, 2.2-Transformer valve side tail end, 3-shunt compensating reactor, 4-voltage divider, 5-test product, 6-detection impedance, 7-partial discharge tester.

As shown in Figure 1, a partial discharge-free variable frequency resonance test device suitable for UHV and below voltage level transformers, including variable frequency power supply 1, excitation transformer 2, shunt compensation reactor 3, voltage divider 4, test product 5, Detect impedance 6 and partial discharge tester 7 . The connection relationship is: the three-phase AC power supply is connected to the variable frequency power supply 1, the output of the variable frequency power supply 1 is connected to the low voltage end of the excitation transformer 2, the high voltage end of the excitation transformer 2 is connected to the parallel compensation reactor 3, the parallel compensation reactor 3, and the voltage divider 4 is connected in parallel with the low-voltage end of sample 5, the high-voltage tail end of excitation transformer 2, the tail end of parallel compensation reactor 3 and the low-voltage tail end, iron core, and high-voltage end of sample 5 are all grounded, and the low-voltage head end and high-voltage head end of sample 5 are all grounded Both the ends of the iron core and the iron core are connected to the input terminals of the detection impedance 6, the ground terminals of the detection impedance 6 are all connected to the ground, and the output terminals of the detection impedance 6 are connected to the partial discharge tester 7.

The working principle is further described in conjunction with FIG. 2 of the embodiment. The three-phase 380V AC power supply through the 630A air switch is sent to the frequency conversion power supply 1, and the frequency conversion power supply 1 has a dedicated chip to generate a standard sine wave voltage with a frequency in the range of 4-1MHz and an adjustable voltage within 0-350V, which is sent to the excitation transformer 2. The transformation ratio of the excitation transformer 2 is 380V/180kV, and the output voltage is applied to two 6.5H shunt compensating reactors 3 and both ends of the valve side of the sample 5, and the variable frequency power supply is controlled through optical fiber communication, and the frequency is adjusted under a small output voltage. Make the resonant circuit in the parallel resonance state, adjust the voltage output, monitor the high voltage value through the voltage divider 4, make the valve side of the test product 5 reach the specified test assessment voltage, and the test product 5 grid side simultaneously reach the test assessment voltage 1.1U _m (113.0kV ), 1.3U _m (133.6kV) and 1.5U _m (154.2kV); the detection impedance 6 connected to the valve side, the grid side, and the iron core clamp and the partial discharge detector 7 connected to it realize the direct detection of partial discharge For measurement, the partial discharge signal is amplified by the detection impedance and then sent to the partial discharge tester. The partial discharge tester internally digitally filters the signal and then directly measures it.

The utility model test device is small in size, light in weight, high in efficiency, simple in wiring, high in reliability, small in external interference, and simple in operation. It is a practical frequency conversion resonance test device and brings great convenience to field test work. Anyone skilled in the art can realize the utility model.

Claims (1)

1. extra-high voltage transformer no partial discharge frequency conversion resonance experiment device, comprise variable-frequency power sources, exciting transformer, the shunt compensation reactor, voltage divider, test product, iron core, detect the impedance drawn game and put the discharge test instrument, it is characterized in that: three-phase alternating-current supply inserts variable-frequency power sources, the low pressure end of exciting transformer is received in variable-frequency power sources output, the high pressure termination shunt compensation reactor of exciting transformer, the shunt compensation reactor, voltage divider and the parallel connection of test product low pressure end, exciting transformer high pressure tail end, shunt compensation reactor tail end and test product low pressure tail end, iron core, the equal ground connection of high pressure tail end, test product low pressure head end, high pressure head end and iron core tail end all insert and detect the impedance input end, detect the equal ground connection of impedance earth end, detect the impedance output terminal and all insert instrument for measuring partial discharge.

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