CN205608139U - Change of current becomes partial discharge test device - Google Patents

Abstract

The embodiment of the utility model discloses a converter partial discharge test device, which adopts the structure of a double variable frequency power supply and a double excitation transformer, that is, the variable frequency power supply includes a first variable frequency power supply and a second variable frequency power supply connected through a parallel control line, and the parallel control line controls The first variable frequency power supply and the second variable frequency power supply output alternating current with synchronous phase and consistent frequency. The output synchronous voltage and current are scalar superimposed in the test circuit. required high voltage and high current. The utility model provides a converter transformer partial discharge test device, which can reduce its volume and reduce its cost while satisfying large capacity and high voltage, and provides convenience for on-site partial discharge test. In addition, by adjusting the wiring of the test circuit, two test methods can be realized, namely, the symmetrical pressurization method of double frequency conversion power supply for delta-connected converter partial discharge test and the unilateral pressurization method of double frequency conversion power supply for star-connected converter partial discharge test.

Description

A converter partial discharge test device

technical field

The utility model relates to the technical field of high-voltage testing, in particular to a converter transformer partial discharge testing device.

Background technique

High-voltage DC transmission is a high-power, long-distance DC transmission method. It takes advantage of the advantages of stable DC without inductance and synchronization. It has the characteristics of low operating loss, low line cost, and narrow line corridors. Therefore, it is especially suitable for long-distance , Large-capacity power transmission. At present, there are large-scale direct current transmission projects under construction in my country, including the ±1100 kV UHV DC project in Xinjiang and Anhui.

As an indispensable equipment in HVDC transmission project, the converter transformer connects the converter valve with the AC system (the winding connected between the converter transformer and the AC system is called the converter network side winding, and the converter network side winding has The two outlets are respectively designated as the head end of the winding on the converter grid side and the tail end of the winding on the converter grid side; the winding connected between the converter transformer and the converter valve is called the converter valve side winding, and the converter valve side The winding has two outlets, which are respectively designated as the first end of the converter valve side winding and the end of the converter valve side winding), to realize the transmission of electric energy from the AC system to the converter or from the converter to the AC system. The operating state directly affects the safety and stability of the HVDC transmission system. Therefore, to ensure the long-term and reliable operation of the HVDC transmission system, it is essential to conduct partial discharge tests on the converter transformer.

Compared with the traditional AC transformer, the converter transformer has a large capacity and complex structure, and the power capacity and output voltage of the traditional partial discharge test device are difficult to meet the partial discharge test requirements of the converter transformer. In the prior art, a larger-capacity variable-frequency power supply and a higher-voltage-level excitation transformer are used to increase the power supply capacity and output voltage. However, the test cost is increased, and at the same time, the partial discharge test device is too large. During the partial discharge test, it affects the transportation of the partial discharge test device and the selection of the test site.

Therefore, an economical and portable converter transformer partial discharge test device with large power supply capacity, high output voltage is urgently needed.

Utility model content

The embodiment of the utility model provides a partial discharge test device for a converter transformer to solve the problem that the partial discharge test device for a converter transformer in the prior art has a large power supply capacity, a high output voltage, and is economical and portable.

In order to solve the above technical problems, the embodiment of the utility model discloses the following technical solutions:

A converter transformer partial discharge test device, including a variable frequency power supply and an excitation transformer, the input end of the variable frequency power supply is used to connect three-phase alternating current, the output end of the variable frequency power supply is electrically connected to the input end of the excitation transformer, and the frequency conversion power supply output frequency-controllable alternating current, and transmit it to the excitation transformer;

The variable frequency power supply is a double variable frequency power supply, specifically, the variable frequency power supply includes a first variable frequency power supply and a second variable frequency power supply, the first variable frequency power supply and the second variable frequency power supply are connected through a parallel control line, and through the parallel connection The control line controls the first variable frequency power supply and the second variable frequency power supply to output alternating current with phase synchronization and consistent frequency;

The output end of the excitation transformer is connected to a parallel circuit, and the excitation transformer converts the alternating current output by the variable frequency power supply into high voltage alternating current;

The parallel circuit includes a parallel voltage dividing branch and a compensation branch;

The converter transformer partial discharge test device also includes a partial discharge meter, which is used to detect the partial discharge value of the converter transformer to be tested.

Preferably, the excitation transformer includes a first excitation transformer and a second excitation transformer, and the first excitation transformer is connected to the second excitation transformer in reverse polarity; the parallel circuit includes a first parallel circuit and a second parallel circuit ;

The input terminal of the first variable frequency power supply is used to connect three-phase alternating current, the output terminal of the first variable frequency power supply is electrically connected to the low voltage side of the first excitation transformer, and the polarity terminal of the high voltage side of the first excitation transformer It is used to connect the first end of the winding of the converter valve side to be tested, and the non-polar end of the high voltage side of the first excitation transformer is grounded; the first end of the first parallel circuit is used to connect the side of the converter valve side to be tested The head end of the winding, the tail end of the first parallel circuit is grounded;

The input end of the second variable frequency power supply is used to connect to three-phase alternating current, the output end of the second variable frequency power supply is electrically connected to the low voltage side of the second excitation transformer, and the high voltage side of the second excitation transformer is non-polar end is used to connect the tail end of the winding of the converter valve side to be tested, and the polarity end of the high-voltage side of the second excitation transformer is grounded; the head end of the second parallel circuit is used to connect the side of the converter valve side to be tested The tail end of the winding, the tail end of the second parallel circuit is grounded;

The converter transformer partial discharge test device also includes a grid side voltage dividing capacitor, the first end of the grid side voltage dividing capacitor is used to connect the head end of the grid side winding of the converter transformer to be tested, and the first end of the grid side voltage dividing capacitor The tail end of the end is grounded;

The partial discharge meter is used to detect the partial discharge value of the converter to be tested.

Preferably, the output terminals of the first variable frequency power supply and the second variable frequency power supply are connected to the low voltage side of the first excitation transformer at the same time, and the polarity terminal of the high voltage side of the first excitation transformer is connected to the first parallel circuit The head end of the first excitation transformer is connected, the high-voltage side non-polar end of the first excitation transformer is connected to the tail end of the first parallel circuit, and the head end of the first parallel circuit is used to connect the converter valve to be tested The head end of the side winding, the tail end of the first parallel circuit is grounded;

The converter transformer partial discharge test device also includes a grid side voltage dividing capacitor, the head end of the grid side voltage dividing capacitor is used to connect the head end of the converter transformer grid side winding to be tested, and the grid side voltage dividing capacitor The tail end of the ground;

The partial discharge meter is used to detect the partial discharge value of the converter to be tested.

Preferably, a detection impedance is provided in the partial discharge meter, and the partial discharge value of the converter to be tested is detected through the detection impedance.

Preferably, a voltmeter is provided in the voltage dividing branch, and the voltmeter is used to measure the voltage value of the test circuit. It can be seen from the above technical solutions that a converter partial discharge test device provided by the embodiment of the utility model adopts a double frequency conversion power supply structure, that is, one large-capacity frequency conversion power supply is replaced by two small-capacity frequency conversion power supplies, and the two are connected through a parallel control line. Only a small-capacity variable frequency power supply, and the parallel control line can control the two variable frequency power supplies to output synchronous voltage to the test circuit, and the synchronous voltage is scalar superimposed in the test circuit to provide the high voltage and high current required for the partial discharge test for the converter to be tested . At the same time, compared with a large-capacity variable-frequency power supply, two small-capacity variable-frequency power supplies have a smaller volume and a more suitable price, so the volume of the converter transformer partial discharge test device is greatly reduced, and its test cost is reduced.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art In other words, other drawings can also be obtained from these drawings under the premise of not paying creative work.

Fig. 1 is a schematic structural diagram of a converter transformer partial discharge test device provided by an embodiment of the present invention;

Fig. 2 is a circuit diagram of a parallel resonant circuit;

Fig. 3 is a circuit diagram of a symmetrical pressurization mode of a double-frequency conversion power supply for a corner-connected converter partial discharge test provided by an embodiment of the utility model;

Fig. 4 is a circuit diagram of a single-side pressurization mode of a star-connected converter transformer partial discharge test provided by the embodiment of the utility model;

The symbols in Figure 1-4 are expressed as: P-variable frequency power supply, P1-first variable frequency power supply, P2-second variable frequency power supply, T-excitation transformer, T1-first excitation transformer, T2-second excitation transformer, R- Parallel circuit, R1-first parallel circuit, R2-second parallel circuit, C1-first voltage dividing capacitor, C2-second voltage dividing capacitor, C3-third voltage dividing capacitor, C4-fourth voltage dividing capacitor, C5 -The fifth voltage dividing capacitor, C6-the sixth voltage dividing capacitor, L1-the first compensation reactor, L2-the second compensation reactor, L3-the third compensation reactor, V1-the first voltmeter, V2-the second Voltmeter, V3-the third voltmeter, M-partial discharge instrument, Zm-detection impedance, G-converter to be tested, Gv1-the first end of the valve side winding of the converter to be tested, Gv2-converter to be tested end of the side winding, Ge1 - the beginning of the grid side winding, Ge2 - the end of the grid side winding, C ₀ - the equivalent capacitance of the converter to be tested, L ₀ - the compensation inductance.

detailed description

In order to enable those skilled in the art to better understand the technical solution in the utility model, the technical solution in the utility model embodiment will be clearly and completely described below in conjunction with the accompanying drawings in the utility model embodiment. Obviously, The described embodiments are only some of the embodiments of the present utility model, but not all of them. Based on the embodiments of the present utility model, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present utility model.

In order to solve the problem that the large-capacity, high-output voltage converter partial discharge test device in the prior art is too large and inconvenient to carry when performing on-site partial discharge tests, the utility model provides a converter converter partial discharge test device using The double frequency conversion power supply structure is to replace one large-capacity variable-frequency power supply in the existing converter transformer partial discharge test device with two smaller-capacity variable-frequency power supplies. Compared with a large-capacity variable-frequency power supply, two small-capacity variable-frequency power supplies have a smaller volume and a more suitable price, so the volume of the converter transformer partial discharge test device can be greatly reduced and the test cost can be reduced. At the same time, two small-capacity variable frequency power supplies are controlled to output synchronous voltages through parallel control lines, and the output synchronous voltages are scalar superimposed in the circuit to provide the high voltage and high current required for the discharge test for the converter to be tested.

Fig. 1 is a schematic structural diagram of a converter transformer partial discharge test device provided by the embodiment of the utility model. As shown in Fig. 1, the input terminal of the variable frequency power supply P is connected to three-phase alternating current, and the output terminal of the variable frequency power supply P is connected to the excitation transformer T. The variable frequency power supply P converts three-phase alternating current (such as AC380V/50Hz) into a sinusoidal alternating current with a stable waveform, and the variable frequency power supply P can regulate the frequency of the sinusoidal alternating current. The variable frequency power supply P includes a first variable frequency power supply P1 and a second variable frequency power supply P2, the first variable frequency power supply P1 and the second variable frequency power supply P2 are connected through a parallel control line, and the parallel control line controls the output frequency of the first variable frequency power supply P1 and the second variable frequency power supply P2 The same, phase-synchronized voltage. In the embodiment of the present invention, the first variable frequency power supply P1 and the second variable frequency power supply P2 have the same structure and the same capacity.

The variable frequency power supply P transmits the sine wave alternating current to the excitation transformer T, and the excitation transformer T converts the sine wave alternating current output by the variable frequency power supply P into the high voltage alternating current required for the partial discharge test.

The parallel circuit R is connected in parallel with the converter G to be tested, and the parallel circuit R includes a parallel voltage dividing branch and a compensation branch.

In order to compensate the capacitive current flowing through the converter to be tested under the test voltage and reduce the capacity demand of the variable frequency power supply, a compensation reactor is connected to the test circuit. Figure 2 is a circuit diagram of a parallel resonant circuit. As shown in Figure 2, at high frequencies, the converter to be tested G is capacitive, which can be regarded as a capacitor, which is recorded as the equivalent capacitance of the converter to be tested C ₀ ; the compensation reactor is an inductance, denoted as compensation inductance L ₀ , therefore, the compensation reactor is connected in parallel with the converter G to be tested to form a resonance. The frequency of the alternating current in the test circuit is adjusted by the variable frequency power supply P. When the frequency of the alternating current in the test circuit _reaches the _resonant frequency, parallel resonance occurs in the test circuit. The current phases are opposite and cancel each other, so that the output current of the variable frequency power supply P reaches the minimum value. Among them, the resonant frequency of the parallel resonant circuit is

${\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}\sqrt{\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; C</span>}}}<span\; class="notranslate">\; ,</span>$

Among them, f ₀ is the resonant frequency, L is the inductive reactance of the compensation reactor, and C is the capacitive reactance of the equivalent capacitance of the converter to be measured.

The two ends of the voltage dividing capacitor are electrically connected to a voltmeter, and the voltmeter is used to measure the voltage in the test circuit.

In order to detect the partial discharge value of the converter G to be tested, the converter converter PD test device also includes a partial discharge meter M, which is electrically connected to the converter G to be tested. In the implementation of the utility model, a detection impedance Zm is provided in the partial discharge instrument M, and the partial discharge signal of the converter G to be tested is collected through the detection impedance Zm.

When using the converter transformer partial discharge test device provided in the embodiment to carry out the partial discharge test on the converter transformer, an appropriate test method can be selected according to the test voltage of the converter transformer G to be tested, for example, if the test of the converter transformer G to be tested If the voltage level is relatively high and the output voltage of one excitation transformer cannot be realized, the symmetrical pressurization method of dual frequency conversion power supply for delta-connected converter partial discharge test is selected. The voltage is applied symmetrically to the terminals to reduce the output voltage of each excitation transformer. If the test voltage level of the converter G to be tested is low, choose the single-side pressurization method of the double-variable frequency power supply for the partial discharge test of the star-connected converter converter, specifically: use only one excitation transformer at one end of the converter valve side to be tested Apply voltage, and the other end of the converter valve side is grounded. The conversion of the two test methods is realized by adjusting the wiring of the test circuit.

Fig. 3 is a circuit diagram of a symmetrical pressurization method of a double-frequency conversion power supply for the partial discharge test of the corner-connected converter transformer provided by the embodiment of the present invention. Double variable frequency power supply and double excitation transformer, specifically, the variable frequency power supply P includes a first variable frequency power supply P1 and a second variable frequency power supply P2, the first variable frequency power supply P1 and the second variable frequency power supply P2 are connected through a parallel control line, and the parallel control line controls the first The alternating current output from the variable frequency power supply P1 and the second variable frequency power supply P2 maintains phase synchronization. The excitation transformer T includes a first excitation transformer T1 and a second excitation transformer T2. The first excitation transformer T1 and the second excitation transformer T2 are connected in reverse polarity, and output voltages with the same amplitude and 180° phase difference.

The parallel circuit R includes a first parallel circuit R1 and a second parallel circuit R2.

The input ends of the first variable frequency power supply P1 and the second variable frequency power supply P2 are connected to three-phase alternating current, the output terminal of the first variable frequency power supply P1 is electrically connected with the low voltage side of the first excitation transformer T1; the second variable frequency power supply P2 is connected with the second excitation transformer T2 The low voltage side is electrically connected. The first variable frequency power supply P1 and the second variable frequency power supply P2 are connected through a parallel control line, and the parallel control line controls the first variable frequency power supply P1 and the second variable frequency power supply P2 to output alternating current with the same frequency and phase synchronization. The polar end of the high voltage side of the first excitation transformer T1 is connected to the head end Gv1 of the valve side winding of the converter to be tested, the non-polar end of the high voltage side of the first excitation transformer T1 is grounded; the non-polar end of the high voltage side of the second excitation transformer T2 is connected to the The tail end of the winding on the rheological valve side is connected to Gv2, and the polarity end of the high voltage side of the second excitation transformer T2 is grounded. The first excitation transformer T1 and the second excitation transformer T2 output high-voltage alternating current with the same amplitude and 180° phase difference to the converter G to be tested. The head end of the first parallel circuit R1 is external to the head end Gv1 of the converter valve side winding to be tested, and the tail end of the first parallel circuit R1 is grounded; the head end of the second parallel circuit R2 is external to the tail end Gv2 of the converter valve side winding to be tested. The tail ends of the two parallel circuits R2 are grounded.

The first parallel circuit R1 includes a first compensation branch, and the first compensation branch includes a first compensation reactor L1. During the partial discharge test, the test circuit is placed in a parallel resonance condition by adjusting the frequency of the alternating current in the test circuit.

In order to measure the voltage value of the high-voltage alternating current output by the first excitation transformer T1, a first voltage dividing branch connected in parallel with the first compensation branch is added in the first parallel circuit R1, and the first voltage dividing branch includes the first dividing branch connected in series The voltage capacitor C1 and the second voltage dividing capacitor C2 are connected with a voltmeter V1 at both ends of the second voltage dividing capacitor C2. According to the voltage value measured by the voltmeter V1, the output voltage of the first excitation transformer T1 is calculated using a voltage dividing formula.

The second parallel circuit R2 includes a second compensation branch, and the second compensation branch includes a second compensation reactor L2. During the partial discharge test, the test circuit is placed in a parallel resonance condition by adjusting the frequency of the alternating current in the test circuit.

In order to measure the voltage value of the high-voltage alternating current output by the second excitation transformer T2, a second voltage dividing branch connected in parallel with the second compensation branch is added in the second parallel circuit R2, and the second voltage dividing branch includes a third branch in series The voltage capacitor C3 and the fourth voltage dividing capacitor C4 are connected with a voltmeter V2 at both ends of the fourth voltage dividing capacitor C4. According to the voltage value measured by the voltmeter V2, the output voltage of the second excitation transformer T2 is calculated.

According to the measured values measured by the voltmeter V1 and the voltmeter V2, the output voltages of the first excitation transformer T1 and the second excitation transformer T2 are calculated, so as to obtain the voltage applied to the converter valve side to be tested.

The head end of the grid side voltage dividing capacitor is outside the head end Ge1 of the grid side winding of the converter converter under test, and the head end of the grid side voltage dividing capacitor and the tail end Gv2 of the valve side winding of the converter converter under test are grounded. In this embodiment, the grid-side voltage dividing capacitor includes a fifth voltage dividing capacitor C5 and a sixth voltage dividing capacitor C6 connected in series. A voltmeter V3 is connected to both ends of the sixth voltage dividing capacitor C6. According to the voltage value measured by the voltmeter V3 , to calculate the voltage value of the converter grid side.

The monitoring channels of the partial discharge instrument are respectively connected to the head end Gv1 of the valve side winding of the converter to be tested, the tail end of the winding Gv2 and the head end of the grid side winding Ge1 to detect the PD value of the converter to be tested.

Before use, the test voltage output by the excitation transformer T can be estimated according to the transformation ratio of the converter transformer to be tested. For example, the rated voltage of the converter transformer grid side is 525kV, and the rated voltage of the converter transformer valve side is 210kV. for:

$<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 525</span>}<span\; class="notranslate">\; /</span>\sqrt{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 210</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1.44</span>}<span\; class="notranslate">\; ,</span>$

If the test requires grid side test voltage is:

$\mathrm{<span\; class="notranslate">\; 1.5</span>}{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; /</span>\sqrt{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1.5</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 550</span>}<span\; class="notranslate">\; /</span>\sqrt{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 476</span>}\mathrm{<span\; class="notranslate">\; k</span>}\mathrm{<span\; class="notranslate">\; V</span>}<span\; class="notranslate">\; ,</span>$

Among them, the highest voltage Um of the normal operation of the converter G to be tested is 550kV, and the test voltage of the converter valve side is:

476/1.44=331kV,

That is, the test voltage that the excitation transformer T should output in the partial discharge test.

Use the corner-connected converter converter partial discharge test provided in this embodiment to perform partial discharge detection on the converter converter using the symmetrical pressurization method of the dual-frequency conversion power supply. First, connect the converter converter G to be tested into the converter converter partial discharge test device, specifically as follows : The head end Gv1 of the valve side winding of the converter to be tested is connected to the polarity end of the high voltage side of the first excitation transformer T1, the tail end of the valve side winding of the converter converter to be tested Gv2 is connected to the polarity end of the high voltage side of the second excitation transformer T2, to be The head end Ge1 of the winding on the converter grid side under test is connected to the head end of the voltage dividing capacitor on the grid side, and the tail end Ge2 of the winding on the converter grid side to be tested is grounded. At the same time, the head end Gv1 of the valve side winding of the converter to be tested, the tail end of the winding and the head end Ge1 of the grid side winding are respectively connected to the monitoring channel of the partial discharge instrument. After being connected, input the test voltage to the converter G to be tested, and detect the partial discharge value of the converter G to be tested.

Figure 4 is a circuit diagram of a single-side pressurization mode of a double-frequency power supply for star-connected converter transformer partial discharge test provided by the embodiment of the utility model. The method includes double variable frequency power supplies, specifically, the output ends of the first variable frequency power supply P1 and the second variable frequency power supply P2 are connected to the low voltage side of the first excitation transformer T1 at the same time, and the polarity end of the high voltage side of the first excitation transformer T1 is connected to the first parallel circuit R1 first. The non-polar end of the high voltage side of the first excitation transformer T1 is connected to the tail end of the first parallel circuit R1, the head end of the first parallel circuit R1 is outside the head end Gv1 of the winding of the converter valve side to be tested, and the tail end of the first parallel circuit R1 The terminal is grounded, and the tail end Gv2 of the valve side winding of the converter to be tested is grounded.

The first parallel circuit R1 includes a first compensation branch and a first voltage dividing branch connected in parallel. The first compensation branch includes a first compensation reactor L1, and by adjusting the frequency of the alternating current in the test circuit, the circuit is placed in a parallel resonance condition. The first voltage dividing branch includes the first voltage dividing capacitor C1 and the second voltage dividing capacitor C2 connected in series. The two ends of the second voltage dividing capacitor C2 are connected with a voltmeter V1. According to the voltage value measured by the voltmeter V1, the commutation is calculated. Variable valve side voltage value.

The first end of the grid-side voltage-dividing capacitor is external to the head-end Ge1 of the grid-side winding of the converter transformer under test, and the tail end of the grid-side voltage-dividing capacitor is grounded. The grid-side voltage-dividing capacitor includes the fifth voltage-dividing capacitor C5 and the sixth voltage-dividing capacitor C6 connected in series A voltmeter V3 is connected to both ends of the sixth voltage dividing capacitor C6, and the voltage value at the side of the converter transformer network is calculated according to the voltage value measured by the voltmeter V3.

The monitoring channel of the partial discharge instrument is respectively connected to the head end Gv1 of the valve side winding of the converter to be tested and the head end of the grid side winding Ge1, and is used to detect the head end Gv1 of the valve side winding of the converter to be tested and the head end of the grid side winding Ge1 partial discharge value.

Before use, the test voltage output by the excitation transformer T can be estimated according to the transformation ratio of the converter transformer G to be tested. than:

$<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 525</span>}<span\; class="notranslate">\; /</span>\sqrt{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 210</span>}<span\; class="notranslate">\; /</span>\sqrt{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 2.5</span>}<span\; class="notranslate">\; ,</span>$

If the test requires grid side test voltage is:

$\mathrm{<span\; class="notranslate">\; 1.5</span>}{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; /</span>\sqrt{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1.5</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 550</span>}<span\; class="notranslate">\; /</span>\sqrt{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 476</span>}\mathrm{<span\; class="notranslate">\; k</span>}\mathrm{<span\; class="notranslate">\; V</span>}<span\; class="notranslate">\; ,</span>$

Among them, the highest voltage Um of the normal operation of the converter G to be tested is 550kV, and the test voltage of the converter valve side is:

476/2.5=190kV,

That is, the test voltage that the excitation transformer T should output in the partial discharge test.

Use the partial discharge test of the star-connected converter transformer provided by this embodiment to perform partial discharge detection on the converter converter using the dual-frequency power supply unilateral pressurization method. First, connect the converter converter G to be tested into the converter converter partial discharge test device, specifically: As follows: the head end Gv1 of the valve side winding of the converter to be tested is connected to the polarity end of the high voltage side of the first excitation transformer T1, the tail end of the valve side winding of the converter to be tested Gv2 is grounded, and the head end of the winding of the converter network side to be tested Ge1 It is connected to the first end of the voltage dividing capacitor on the grid side, and the tail end Ge2 of the grid side winding of the converter to be tested is grounded. At the same time, the head end Gv1 of the valve side winding of the converter to be tested and the head end Ge1 of the grid side winding are respectively connected to the monitoring channel of the partial discharge instrument. After being connected, input the test voltage to the converter G to be tested, and detect the partial discharge value of the converter G to be tested.

It should be noted that in this article, relative terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply these No such actual relationship or order exists between entities or operations. Furthermore, the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus comprising a set of elements includes not only those elements, but also includes elements not expressly listed. other elements of or also include elements inherent in such a process, method, article, or device. Without further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article or apparatus comprising said element.

The above descriptions are only specific implementation methods of the present utility model, so that those skilled in the art can understand or realize the present utility model. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims (5)

1. a change of current changed situation puts assay device, it is characterized in that, including variable-frequency power sources (P) and exciting transformer (T), the input of described variable-frequency power sources (P) is used for connecting three-phase alternating current, the outfan of described variable-frequency power sources (P) electrically connects with the input of exciting transformer (T), the alternating current that described variable-frequency power sources (P) output frequency is controlled, and transported to described exciting transformer (T)；

Described variable-frequency power sources (P) is double variable-frequency power sources, it is specially, described variable-frequency power sources (P) includes the first variable-frequency power sources (P1) and the second variable-frequency power sources (P2), described first variable-frequency power sources (P1) and described second variable-frequency power sources (P2) control line in parallel connect, and export Phase synchronization by the first variable-frequency power sources (P1) described in described Parallel Control line traffic control with described second variable-frequency power sources (P2), alternating current that frequency is consistent；

The outfan of described exciting transformer (T) connects a parallel circuit (R), and the AC conversion that described variable-frequency power sources (P) exports is High Level AC Voltage by described exciting transformer (T)；

Described parallel circuit (R) includes dividing potential drop branch road and the compensation branch road of parallel connection；

Change of current changed situation is put assay device and is also included a PD meter (M), and value is put in the office being used for detecting the change of current to be measured change (G).

Change of current changed situation the most according to claim 1 puts assay device, it is characterized in that, described exciting transformer (T) includes that the first exciting transformer (T1) and the second exciting transformer (T2), described first exciting transformer (T1) are connected with described second exciting transformer (T2) reversed polarity；Described parallel circuit (R) includes the first parallel circuit (R1) and the second parallel circuit (R2)；

The input of described first variable-frequency power sources (P1) is used for connecting three-phase alternating current, the outfan of described first variable-frequency power sources (P1) electrically connects with the low-pressure side of described first exciting transformer (T1), the high-pressure side polar end of described first exciting transformer (T1) is used for connecting converter transformer valve side winding head end (Gv1) to be measured, the high-pressure side non-polar end ground connection of described first exciting transformer (T1)；The head end of described first parallel circuit (R1) is used for connecting described converter transformer valve side winding head end (Gv1) to be measured, the tail end ground connection of described first parallel circuit (R1)；

The input of described second variable-frequency power sources (P2) is used for connecting three-phase alternating current, the outfan of described second variable-frequency power sources (P2) electrically connects with the low-pressure side of described second exciting transformer (T2), the high-pressure side non-polar end of described second exciting transformer (T2) is used for connecting converter transformer valve side winding tail end (Gv2) to be measured, the high-pressure side polar end ground connection of described second exciting transformer (T2)；The head end of described second parallel circuit (R2) is used for connecting described converter transformer valve side winding tail end (Gv2) to be measured, the tail end ground connection of described second parallel circuit (R2)；

Described change of current changed situation is put assay device and is also included that a net side voltage-dividing capacitor, the head end of described net side voltage-dividing capacitor are used for connecting the described change of current to be measured and become source side winding head end (Ge1), the tail end ground connection of the head end of net side voltage-dividing capacitor；

Described PD meter (M) is used for detecting the office of the described change of current to be measured change (G) and puts value.

Change of current changed situation the most according to claim 1 puts assay device, it is characterized in that, described exciting transformer (T) includes that the first exciting transformer (T1), described parallel circuit (R) include the first parallel circuit (R1)；

The outfan of described first variable-frequency power sources (P1) and described second variable-frequency power sources (P2) is simultaneously connected with the low-pressure side of described first exciting transformer (T1), the high-pressure side polar end of described first exciting transformer (T1) is connected with the head end of described first parallel circuit (R1), the high-pressure side non-polar end of described first exciting transformer (T1) is connected with the tail end of described first parallel circuit (R1), the head end of described first parallel circuit (R1) is used for connecting described converter transformer valve side winding head end (Gv1) to be measured, the tail end ground connection of described first parallel circuit (R1)；

Described change of current changed situation is put assay device and is also included that a net side voltage-dividing capacitor, the head end of described net side voltage-dividing capacitor are used for connecting the described change of current to be measured and become source side winding head end (Ge1), the tail end ground connection of described net side voltage-dividing capacitor；

Described PD meter (M) is used for detecting the office of the change of current to be measured change (G) and puts value.

Change of current changed situation the most according to claim 1 puts assay device, it is characterised in that be provided with detection impedance (Zm) in described PD meter (M), and value is put in the office being detected the described change of current to be measured change by described detection impedance (Zm).

Change of current changed situation the most according to claim 1 puts assay device, it is characterised in that be provided with voltmeter in described dividing potential drop branch road, and shown voltmeter is for the magnitude of voltage of experiment with measuring circuit.