阅读说明：本技术 一种变压器温升试验方法及装置 (Temperature rise test method and device for transformer ) 是由 高翔 刘福辉 刘莹莹 摆建品 高娃 于 2019-08-29 设计创作，主要内容包括：本发明提供一种变压器温升试验方法,其中变压器的高压侧包括两个并联的高压线圈,低压侧包括分别与两个高压线圈对应的两个独立的低压线圈；每个低压线圈具有若干个分接档位,两个低压线圈中相同档位线圈的运行电流相同,温升试验方法包括：将两个低压线圈中待试验的一组相同档位线圈相互串联短路；向变压器的高压侧施加试验电流,以使低压侧的两个低压线圈中待试验的一组相同档位线圈的运行电流达到额定工作电流。本发明还提供相应的装置。本发明所述变压器温升试验方法及装置通过将低压侧相同档位的两个线圈串联短接,可以实现低压侧线圈同时加载时各个档位的温升试验,全面考核变压器实际运行工况,解决了此类变压器温升试验不足的问题。(The invention provides a temperature rise test method of a transformer, wherein the high-voltage side of the transformer comprises two high-voltage coils which are connected in parallel, and the low-voltage side of the transformer comprises two independent low-voltage coils which respectively correspond to the two high-voltage coils; each low-voltage coil is provided with a plurality of tapping gears, the running currents of the coils in the same gears in the two low-voltage coils are the same, and the temperature rise test method comprises the following steps: a group of coils with the same gear to be tested in the two low-voltage coils are mutually connected in series and short-circuited; and applying a test current to the high-voltage side of the transformer so as to enable the running current of a group of coils with the same gear to be tested in the two low-voltage coils at the low-voltage side to reach the rated working current. The invention also provides a corresponding device. According to the transformer temperature rise test method and device, the two coils at the same gear of the low-voltage side are connected in series and in short circuit, so that the temperature rise test of each gear can be realized when the coils at the low-voltage side are loaded simultaneously, the actual operation condition of the transformer is comprehensively checked, and the problem of insufficient temperature rise test of the transformer is solved.)

1. A temperature rise test method for a transformer is characterized in that the high-voltage side of the transformer comprises two high-voltage coils which are connected in parallel, and the low-voltage side of the transformer comprises two independent low-voltage coils which respectively correspond to the two high-voltage coils; each low-voltage coil is provided with a plurality of tapping gears, and the running currents of the coils in the same gears in the two low-voltage coils are the same, and the temperature rise test method is characterized by comprising the following steps:

a group of coils with the same gear to be tested in the two low-voltage coils are mutually connected in series and short-circuited;

and applying a test current to the high-voltage side of the transformer so as to enable the running current of a group of coils with the same gear to be tested in the two low-voltage coils at the low-voltage side to reach the rated working current.

2. The transformer temperature rise test method according to claim 1, wherein each low-voltage coil has 3-6 tap positions.

3. The transformer temperature rise test method according to claim 1, wherein the temperature rise test method specifically comprises:

sequentially connecting each group of coils with the same gear in the two low-voltage coils in series for short circuit;

and when each group of coils with the same gear in the two low-voltage coils are mutually connected in series and short-circuited, applying test current to the high-voltage side of the transformer so as to enable the running current of the group of coils with the same gear in the two low-voltage coils at the low-voltage side to reach rated working current until the temperature rise test of each gear of the two low-voltage coils is completed.

4. The transformer temperature rise test method according to claim 3, wherein the sequentially connecting the coils with the same gear in each group of the two low-voltage coils in series and in short circuit with each other comprises the following steps: and sequentially connecting the coils with the same gear in each group of the two low-voltage coils in series and short-circuiting the coils with the same gear in each group in sequence from a high gear to a low gear or from the low gear to the high gear.

5. The method for testing the temperature rise of the transformer according to claim 4, further comprising:

when the total number of turns of the two low-voltage coils is the same and the temperature rise test of the maximum gear of the two low-voltage coils is carried out, respectively short-circuiting the maximum gear coils of the two low-voltage coils;

and applying a test current to the high-voltage side so that the operating current of the maximum gear coil of each of the two low-voltage coils reaches the rated working current, thereby completing the temperature rise test of the maximum gear of the two low-voltage coils.

6. A temperature rise test device for a transformer is characterized in that the high-voltage side of the transformer comprises two high-voltage coils connected in parallel, and the low-voltage side of the transformer comprises two independent low-voltage coils corresponding to the two high-voltage coils respectively; every low-voltage coil has a plurality of shunting gear, and every gear has a corresponding play head terminal, and the operating current of same gear coil is the same in two low-voltage coil, its characterized in that, the temperature rise test device includes: a power supply and connection means;

the connecting device is connected between the two low-voltage coils and is used for mutually connecting a group of coils with the same gear to be tested in the two low-voltage coils in series and short-circuiting;

the power supply is connected to the high-voltage side of the transformer and used for applying a test current to the high-voltage side of the transformer so as to enable the operating current of a group of coils with the same gear to be tested in two low-voltage coils on the low-voltage side to reach a rated working current.

7. The transformer temperature-rise test device according to claim 6, wherein each low-voltage coil has 3-6 tap gears.

8. The transformer temperature-rise test device according to claim 6,

the connecting device is specifically used for sequentially connecting each group of coils with the same gear in the two low-voltage coils in series to form a short circuit;

the power supply is specifically configured to apply a test current to the high-voltage side of the transformer when the connecting device connects each group of coils with the same gear in the two low-voltage coils in series and short-circuits, so that the operating current of the group of coils with the same gear in the two low-voltage coils on the low-voltage side reaches a rated working current until a temperature rise test of each gear of the two low-voltage coils is completed.

9. The transformer temperature-rise test device according to claim 6, wherein the arrangement sequence of the tap positions of the two low-voltage coils is the same, the arrangement sequence of the tap positions is from high gear to low gear or from low gear to high gear from inside to outside, and the higher the gear is, the more the number of turns of the coil is.

10. The transformer temperature-rise test device according to claim 9,

the connecting device is also used for respectively short-circuiting the maximum gear coils of the two low-voltage coils when the total turns of the two low-voltage coils are the same and the temperature rise test of the maximum gear is carried out;

the power supply is also used for applying test current to the high-voltage side so that the running current of the maximum gear coils of the two low-voltage coils reaches rated working current, and therefore the temperature rise test of the maximum gears of the two low-voltage coils is completed.

Technical Field

The invention relates to the technical field of transformers, in particular to a transformer temperature rise test method and a transformer temperature rise test device.

Background

The polysilicon reduction furnace is necessary equipment for manufacturing polysilicon, and a polysilicon reduction furnace transformer is needed to provide power supply in the production process of polysilicon products. The transformer of the polycrystalline silicon reduction furnace not only needs to meet the voltage regulation requirement, but also needs to provide an accurate resistance value for a voltage regulation circuit, and the specific requirements comprise: in the using process, the transformer is required to have good short circuit resistance and system power supply harmonic resistance; in the working initial stage of the reducing furnace, the diameter of the silicon core is small, the resistance value is large, higher voltage needs to be applied, the requirement on the inductance of the transformer is high, along with the deposition of silicon, the silicon core gradually becomes large, the resistance value becomes small, lower voltage is needed, the requirement on the inductance of the transformer is low, in the whole working process, the current needing to be output by the transformer is increased from more than 100 amperes to thousands of amperes, the voltage is reduced from thousands of volts to hundreds of volts, and the requirement on the transformer is high.

The temperature rise test of the transformer is one of important test items for a manufacturer to identify the quality of a transformer product in the test. The purpose of the temperature rise test is to determine whether various parameters of various parts of the transformer under the temperature rise condition meet the requirements specified by relevant standards, so that reliable basis is provided for long-term safe operation of the transformer. Therefore, the temperature rise test is related to the safety, reliability and service life of the transformer; if the temperature rise test method in the transformer manufacturing plant is unreasonable and incomplete, the actual operation condition of the transformer is not examined comprehensively, and potential safety hazards are left for the operation of the transformer.

At present, the phase number of a high-voltage side incoming line power supply of a polycrystalline silicon reduction furnace transformer is three-phase, the phase number of a low-voltage side output power supply is single-phase, a low-voltage winding can simultaneously output various voltages and currents, and the current values of partial voltage levels are very large. For some transformers for high-capacity and high-current polysilicon dry reduction furnaces, the working principle is complex, the operating conditions are special, and temperature rise tests needing to be carried out on the transformers exceed the scope of the current national standards GB 1094.2-2013 and GB 1094.11-2007. The temperature rise test method for the transformers has no standard which can be relied on at present; in addition, a common temperature rise test is only carried out on the temperature rise test of a single low-voltage maximum gear on the low-voltage side, and the temperature rise performance of other tapping gears loaded by the low-voltage coil at the same time cannot be tested, so that the temperature rise performance of other tapping gears cannot be effectively verified.

Disclosure of Invention

The invention is completed in order to at least partially solve the technical problem that the polycrystalline silicon reduction furnace transformer in the prior art cannot carry out temperature rise tests of different gears.

The technical scheme adopted for solving the technical problem of the invention is as follows:

the invention provides a temperature rise test method of a transformer, wherein the high-voltage side of the transformer comprises two high-voltage coils which are connected in parallel, and the low-voltage side of the transformer comprises two independent low-voltage coils which respectively correspond to the two high-voltage coils; each low-voltage coil is provided with a plurality of tapping gears, the operating currents of the coils in the same gear in the two low-voltage coils are the same, and the temperature rise test method comprises the following steps:

a group of coils with the same gear to be tested in the two low-voltage coils are mutually connected in series and short-circuited;

and applying a test current to the high-voltage side of the transformer so as to enable the running current of a group of coils with the same gear to be tested in the two low-voltage coils at the low-voltage side to reach the rated working current.

Furthermore, each low-voltage coil is provided with 3-6 tapping gears.

Further, the temperature rise test method specifically comprises the following steps:

sequentially connecting each group of coils with the same gear in the two low-voltage coils in series for short circuit;

and when each group of coils with the same gear in the two low-voltage coils are mutually connected in series and short-circuited, applying test current to the high-voltage side of the transformer so as to enable the running current of the group of coils with the same gear in the two low-voltage coils at the low-voltage side to reach rated working current until the temperature rise test of each gear of the two low-voltage coils is completed.

Further, connect the short circuit each other in series with each group's the same gear coil in two low-voltage coil in proper order, include: and sequentially connecting the coils with the same gear in each group of the two low-voltage coils in series and short-circuiting the coils with the same gear in each group in sequence from a high gear to a low gear or from the low gear to the high gear.

Further, the temperature rise test method further comprises the following steps:

when the total number of turns of the two low-voltage coils is the same and the temperature rise test of the maximum gear of the two low-voltage coils is carried out, respectively short-circuiting the maximum gear coils of the two low-voltage coils;

and applying a test current to the high-voltage side so that the operating current of the maximum gear coil of each of the two low-voltage coils reaches the rated working current, thereby completing the temperature rise test of the maximum gear of the two low-voltage coils.

According to another aspect of the present invention, the invention further provides a transformer temperature-rise test device, wherein the high-voltage side of the transformer comprises two high-voltage coils connected in parallel, and the low-voltage side of the transformer comprises two independent low-voltage coils corresponding to the two high-voltage coils respectively; every low-voltage coil has a plurality of tapping gear, and every gear has a corresponding play head terminal, and the operating current of same gear coil is the same in two low-voltage coil, the temperature rise test device includes: a power supply and connection means;

the connecting device is connected between the two low-voltage coils and is used for mutually connecting a group of coils with the same gear to be tested in the two low-voltage coils in series and short-circuiting;

the power supply is connected to the high-voltage side of the transformer and used for applying a test current to the high-voltage side of the transformer so as to enable the operating current of a group of coils with the same gear to be tested in two low-voltage coils on the low-voltage side to reach a rated working current.

Furthermore, each low-voltage coil is provided with 3-6 tapping gears.

Furthermore, the connecting device is specifically used for sequentially connecting each group of coils with the same gear in the two low-voltage coils in series and short-circuiting;

the power supply is specifically configured to apply a test current to the high-voltage side of the transformer when the connecting device connects each group of coils with the same gear in the two low-voltage coils in series and short-circuits, so that the operating current of the group of coils with the same gear in the two low-voltage coils on the low-voltage side reaches a rated working current until a temperature rise test of each gear of the two low-voltage coils is completed.

Furthermore, the arrangement sequence of the tapping gears of the two low-voltage coils is the same, the arrangement sequence of the tapping gears is from high gear to low gear or from low gear to high gear from inside to outside, and the higher the gear is, the more the number of turns of the coil is.

Furthermore, the connecting device is also used for respectively short-circuiting the maximum gear coils of the two low-voltage coils when the total number of turns of the two low-voltage coils is the same and the temperature rise test of the maximum gear is carried out;

the power supply is also used for applying test current to the high-voltage side so that the running current of the maximum gear coils of the two low-voltage coils reaches rated working current, and therefore the temperature rise test of the maximum gears of the two low-voltage coils is completed.

Has the advantages that:

according to the temperature rise test method and device for the transformer, two coils with the same gear on the low-voltage side are connected in series and are in short circuit, and test current is applied to the coil on the high-voltage side; the parallel coils on the high-voltage side automatically distribute current, so that the two corresponding gear coils on the low-voltage side reach rated working current, temperature rise tests of all gears can be realized when the low-voltage side coils are loaded simultaneously, the actual operation conditions of the transformer are examined comprehensively, the problem of insufficient temperature rise tests of the transformer is solved, the temperature rise performance of all full-ride-through conditions can be verified in the temperature rise tests, thermal faults in the operation of the transformer are prevented in advance, and possible abnormal conditions and potential safety hazards in the operation of the transformer are detected.

Drawings

Fig. 1 is a schematic diagram of a temperature rise test method for a transformer according to an embodiment of the present invention;

fig. 2 is a schematic arrangement diagram of a transformer coil suitable for the transformer temperature rise test method according to the first embodiment of the present invention;

fig. 3 is a schematic diagram of a wiring diagram of a high-voltage side coil of a transformer in a temperature rise test method of the transformer according to an embodiment of the present invention;

fig. 4 is a schematic diagram of a wiring diagram of a low-voltage side coil during a temperature rise test of a 1 st gear of a transformer according to a temperature rise test method of the transformer according to an embodiment of the present invention;

fig. 5 is a schematic diagram of wiring of a low-voltage side coil during a temperature rise test of a 2 nd gear of a transformer in a temperature rise test method according to an embodiment of the present invention;

fig. 6 is a schematic diagram of wiring of a low-voltage side coil during a temperature rise test of a 3 rd gear of a transformer in a temperature rise test method according to an embodiment of the present invention;

fig. 7 is a schematic diagram of wiring of a low-voltage side coil during a temperature rise test of a 4 th gear of a transformer in a temperature rise test method according to an embodiment of the present invention;

fig. 8 is a schematic diagram of a wiring of a low-voltage side coil during a temperature rise test of a 5 th gear of a transformer according to a temperature rise test method of the transformer according to an embodiment of the present invention;

fig. 9 is a schematic diagram of wiring of a low-voltage side coil during a temperature rise test of a 5 th gear of a transformer according to another temperature rise test method for a transformer provided in the first embodiment of the present invention;

fig. 10 is a structural diagram of a transformer temperature-rise test device according to a second embodiment of the present invention.

Detailed Description

In order to make the technical solutions of the present invention better understood, the present invention is further described in detail below with reference to the accompanying drawings and examples.

Example one

As shown in fig. 1, the invention provides a method for testing temperature rise of a transformer, wherein a high-voltage side of the transformer comprises two high-voltage coils connected in parallel, and a low-voltage side of the transformer comprises two independent low-voltage coils corresponding to the two high-voltage coils respectively; each low-voltage coil is provided with a plurality of tapping gears, the operating currents of the coils in the same gear in the two low-voltage coils are the same, and the temperature rise test method comprises the following steps:

step S1: a group of coils with the same gear to be tested in the two low-voltage coils are mutually connected in series and short-circuited;

step S2: and applying a test current to the high-voltage side of the transformer so as to enable the running current of a group of coils with the same gear to be tested in the two low-voltage coils at the low-voltage side to reach the rated working current.

The high-voltage side of the transformer of the polycrystalline silicon reduction furnace is connected in parallel during operation, and the two ways of transformers of the low-voltage side operate independently. In operation, a half-cross operation condition, that is, a condition that the low-voltage upper coil or the lower coil operates alone, and a full-cross operation condition, that is, a condition that the low-voltage upper coil and the lower coil operate simultaneously, may occur.

Fig. 2 shows one of the transformer coil arrangements applied in the technical solution of the present invention. The high-voltage side coil is of an upper part and a lower part which are connected in parallel; the low-voltage side coil is divided into an upper independent part and a lower independent part, and each low-voltage side coil is provided with 5 tapping gears. Each step is represented by a tapped coil, and the upper parts are arranged in LW from inside to outside₁₅ LW₁₄ LW₁₃ LW₁₂ LW₁₁The lower part is arranged as LW from inside to outside₂₅ LW₂₄ LW₂₃ LW₂₂ LW₂₁. The upper part and the lower part are respectively provided with 5 tapping gears which are connected in series and connected, and the coil at the upper part passes through D in operation₁₅、D₁₄、D₁₃、D₁₂And D₁₁Selecting different gears; lower coil passing through D₂₅、D₂₄、D₂₃、D₂₂And D₂₁The terminal selection different gears of going out the head. Based on the working principle of the polycrystalline silicon reduction furnace, the upper and lower corresponding gears on the low-voltage side have different operating voltages but the same operating current. When the upper and lower corresponding coils are in operation, the low-voltage coil reduces voltage step by step from the inner side to the outer side of the iron core, and the upper and lower coils synchronously shift in the shifting process.

In general, temperature rise test only carries out temperature rise of full-crossing working condition of the maximum low-voltage gear, namely, current is applied from the high-voltage side, and the maximum upper and lower gears of the low-voltage side are respectively in short circuit. Because the total ampere turns (the product of the number of turns of the coil and the current passed by the coil) of the upper part and the lower part of the low-voltage part are the same, under the condition, when the current on the high-voltage side reaches the rated working current, the upper part and the lower part of the low-voltage side can reach the rated working current. The test method can verify the temperature rise performance of the low-voltage maximum tapping, but can not effectively verify the temperature rise performance of other tapping gears.

Because the voltage of the 5 tapping ends of the low-voltage coil is gradually reduced from inside to outside, and the current is gradually increased, the temperature rise is performed when the low-voltage coil is tapped at the maximum, and the current of the low-voltage outer side coil cannot reach the maximum working current, so that the temperature rise of the low-voltage outer side coil is low under the working condition, and the maximum temperature rise value of the low-voltage outer side coil cannot be obtained.

The outgoing terminals of one group of the same gears of the upper coil and the lower coil on the low-voltage side are mutually connected in series and short-circuited; the current of the same gear of the upper coil and the lower coil can be the same, and the total ampere turn is applied to the high-voltage side when each tap is applied to the low-voltage side. Therefore, the upper and lower coils with low voltage can realize the same working current, and the state consistent with the operation condition of the product is achieved. And the current of the coil with the upper part and the lower part on the high-voltage side connected in parallel is automatically distributed according to the corresponding low-voltage ampere turns. The current applied on the high voltage side is the current resulting from the addition of the currents of the two coils connected in parallel. Through the test wiring method, the temperature rise performance of 4 coils at the outer side of the low voltage can be verified, and the defect that the temperature rise performance of the low voltage coil cannot be completely verified in the original test scheme is overcome.

Furthermore, each low-voltage coil is provided with 3-6 tapping gears.

The number of the taps of the upper and lower coils corresponding to the low-voltage side is not limited, and the coils of the gears with the same rated current are connected in series, the number of the taps is generally 3-6, and the types of the transformers for the temperature rise test include single-phase transformers, three-phase transformers, oil-immersed transformers, dry-type transformers and the like.

Further, the temperature rise test method specifically comprises the following steps:

sequentially connecting each group of coils with the same gear in the two low-voltage coils in series for short circuit;

when each group of coils with the same gear in the two low-voltage coils are mutually connected in series and short-circuited, applying test current to the high-voltage side of the transformer to enable the running current of the group of coils with the same gear in the two low-voltage coils at the low-voltage side to reach rated working current until the temperature rise test of each gear of the two low-voltage coils is completed

The temperature rise performance of the transformer can be better detected by correspondingly testing all gears.

When a temperature rise test is carried out, a wiring schematic diagram of a high-voltage side coil of the transformer is shown in fig. 3, two coils are connected in parallel, and a power supply on a main line supplies current; in the 1 st gear temperature rise test, the wiring principle of the low-voltage side coil is implemented as shown in fig. 4, and an upper low-voltage coil LW and a lower low-voltage coil LW are connected₁₁And LW₂₁Short circuit after series connection, the specific terminal connection sequence is D₁₁-D₁₀-D₂₁-D20-D₁₁Applying a test current from the high-voltage side to cause the low-voltage coil LW to rotate₁₁And LW₂₁The current reaches the rated working current, and other operation methods are executed according to the temperature rise test standard.

A conventional dry-type transformer test method generally adopts a load simulation method, rated voltage is input from a high-voltage side in the first stage, and a test line is completely the same as a no-load test. The temperature of the monitored site (iron core) was recorded every 1 hour during the test; when the product is in a rated heating state and the temperature rise of the monitoring part does not rise by 1K any more, the temperature rise is considered to be stable, and the temperature theta of the iron core is read₁And ambient temperature theta₂The difference is the temperature rise of the iron core. Separately measuring high and low resistances. In the second stage, rated current is input from the high-voltage side, and a test circuit is completely the same as an empty load test. The temperature of the monitored site (iron core) was recorded every 1 hour during the test; when the product is in a rated heating state and the temperature rise of the monitoring part does not rise by 1K any more, the temperature rise is considered to be stable, and the temperature theta of the iron core is read₁And ambient temperature theta₂The difference is the temperature rise of the iron core. And respectively measuring high and low voltage resistors to draw thermal resistance curves, and calculating to obtain the temperature rise of the transformer core and the coil.

In the 2 nd gear temperature rise test, the wiring principle of the low-voltage side coil is implemented as shown in fig. 5, and an upper low-voltage coil LW and a lower low-voltage coil LW are connected₁₂ LW₁₁And LW₂₂ LW₂₁Are connected in series and then are short-circuited, and the specific terminal connection sequence is D₁₂-D₁₀-D₂₂-D₂₀-D₁₂Applying a test current from the high-voltage side to cause the low-voltage coil LW to rotate₁₂And LW₂₂The current reaches the rated working current, and other operation methods are executed according to the temperature rise test standard.

In the 3 rd gear temperature rise test, the wiring principle of the low-voltage side coil is implemented as shown in fig. 6, and an upper low-voltage coil LW and a lower low-voltage coil LW are connected₁₃ LW₁₂ LW₁₁And LW₂₃ LW₂₂ LW₂₁Are connected in series and then are short-circuited, and the specific terminal connection sequence is D₁₃-D₁₀-D₂₃-D₂₀-D₁₃Applying a test current from the high-voltage side to cause the low-voltage coil LW to rotate₁₃And LW₂₃The current reaches the rated working current, and other operation methods are executed according to the temperature rise test standard.

In the 4 th gear temperature rise test, the wiring principle of the low-voltage side coil is implemented as shown in fig. 7, and an upper low-voltage coil LW and a lower low-voltage coil LW are connected₁₄ LW₁₃ LW₁₂ LW₁₁And LW₂₄ LW₂₃ LW₂₂ LW₂₁Are connected in series and then are short-circuited, and the specific terminal connection sequence is D₁₄-D₁₀-D₂₄-D₂₀-D₁₄Applying a test current from the high-voltage side to cause the low-voltage coil LW to rotate₁₄And LW₂₄The current reaches the rated working current,the rest of the operating methods were carried out as specified in the temperature rise test standard.

In the temperature rise test of the 5 th gear, the wiring principle of the low-voltage side coil is implemented as shown in fig. 8, and an upper low-voltage coil LW and a lower low-voltage coil LW are connected₁₅ LW₁₄ LW₁₃ LW₁₂ LW₁₁And LW₂₅ LW₂₄ LW₂₃ LW₂₂ LW₂₁Are connected in series and then are short-circuited, and the specific terminal connection sequence is D₁₅-D₁₀-D₂₅-D₂₀-D₁₅Applying a test current from the high-voltage side to cause the low-voltage coil LW to rotate₁₅And LW₂₅The current reaches the rated working current, and other operation methods are executed according to the temperature rise test standard.

Preferably, one or more gears can be selected for temperature rise test according to the use condition and the type of the transformer.

Further, connect the short circuit each other in series with each group's the same gear coil in two low-voltage coil in proper order, include: and sequentially connecting the coils with the same gear in each group of the two low-voltage coils in series and short-circuiting the coils with the same gear in each group in sequence from a high gear to a low gear or from the low gear to the high gear.

The transformer coil shown in fig. 2 is arranged from high to low in the positions from inside to outside near the core limb, and the higher the position is, the more the number of turns of the coil is. The highest gear is 5, and the number of turns of the coil is the largest. The voltage is gradually reduced from inside to outside, the current is gradually increased, and the gears can be arranged from inside to outside from low to high from the position close to the iron core column according to the winding mode of the coil.

Further, the temperature rise test method further comprises the following steps:

when the total number of turns of the two low-voltage coils is the same and the temperature rise test of the maximum gear of the two low-voltage coils is carried out, respectively short-circuiting the maximum gear coils of the two low-voltage coils;

and applying a test current to the high-voltage side so that the operating current of the maximum gear coil of each of the two low-voltage coils reaches the rated working current, thereby completing the temperature rise test of the maximum gear of the two low-voltage coils. In the 5 th gear temperature rise test, because of the upper and lower two of low pressureThe total number of turns of the coil and the current are the same, and a temperature rise test can be performed by respectively short-circuiting the upper low-voltage coil and the lower low-voltage coil. The wiring principle of the low-voltage side coil implemented in this case is shown in FIG. 9, in which upper and lower low-voltage coils LW are arranged₁₅ LW₁₄ LW₁₃ LW₁₂ LW₁₁And LW₂₅ LW₂₄ LW₂₃ LW₂₂ LW₂₁Are respectively connected in series and then are short-circuited, and the specific terminal connection sequence is D₁₅-D₁₀，D₂₅-D₂₀Applying a test current from the high-voltage side to cause the low-voltage coil LW to rotate₁₅And LW₂₅The current reaches the rated working current, and other operation methods are executed according to the temperature rise test standard.

It should be noted that, when the wiring is performed according to the above-mentioned scheme, the order of the connection terminals needs to be determined according to the winding directions of the low-voltage coils, in the scheme described in the example, the winding directions of the upper and lower low-voltage coils are opposite, and if the winding directions are the same, corresponding adjustment is needed, so that the directions of the magnetic potentials generated by the upper and lower low-voltage coils are the same.

Example two

According to another aspect of the present invention, as shown in fig. 10, the present invention further provides a transformer temperature-rise test apparatus, wherein the high-voltage side of the transformer comprises two high-voltage coils connected in parallel, and the low-voltage side of the transformer comprises two independent low-voltage coils corresponding to the two high-voltage coils respectively; every low-voltage coil has a plurality of tapping gear, and every gear has a corresponding play head terminal, and the operating current of same gear coil is the same in two low-voltage coil, the temperature rise test device includes: a power supply 2 and a connection device 3;

the connecting device 3 is connected between the two low-voltage coils of the transformer 1 and is used for mutually connecting a group of coils with the same gear to be tested in the two low-voltage coils in series and short-circuiting;

the power supply 2 is connected to the high-voltage side of the transformer 1 and is used for applying a test current to the high-voltage side of the transformer 1 so as to enable the operating current of a group of coils with the same gear to be tested in two low-voltage coils on the low-voltage side to reach a rated working current.

Furthermore, each low-voltage coil is provided with 3-6 tapping gears.

The number of tapping of each coil of low pressure side is 3 ~ 6, respectively divide into 3 ~ 6 tapping gears with two coils of low pressure side.

Further, the connecting device 3 is specifically configured to serially connect, in sequence, coils of the same gear in each of the two low-voltage coils to each other for short circuit;

the power supply 2 is specifically configured to apply a test current to the high-voltage side of the transformer when the connecting device connects each group of coils with the same gear in the two low-voltage coils in series and short-circuits, so that the operating current of the group of coils with the same gear in the two low-voltage coils on the low-voltage side reaches a rated working current until a temperature rise test of each gear of the two low-voltage coils is completed.

Furthermore, the arrangement sequence of the tapping gears of the two low-voltage coils is the same, the arrangement sequence of the tapping gears is from high gear to low gear or from low gear to high gear from inside to outside, and the higher the gear is, the more the number of turns of the coil is.

Further, the connecting device 3 is also used for respectively short-circuiting the maximum gear coils of the two low-voltage coils when the total number of turns of the two low-voltage coils is the same and the temperature rise test of the maximum gear is carried out;

the power supply 2 is also used for applying a test current to the high-voltage side so that the running current of the maximum gear coils of the two low-voltage coils reaches a rated working current, and therefore the temperature rise test of the maximum gear of the two low-voltage coils is completed.

In a preferred aspect of the present embodiment, the connecting device 3 includes two connectors, one of the connectors is used for connecting the upper low-voltage coil, the other connector is used for connecting the lower low-voltage coil, and the two connectors can be connected or not according to circumstances; when the total number of turns of the two low-voltage coils is the same and a temperature rise test of a maximum gear is carried out, the 2 sets of connectors are respectively connected between terminals of the maximum gear of the two low-voltage side coils, so that the two maximum gear coils of the low-voltage coils are respectively in short circuit; to complete the exotherm test.

For the embodiment of the present apparatus, since it basically corresponds to the embodiment of the method, the description is simple, and for the relevant points, reference is made to the corresponding process in the first embodiment of the method, and details are not repeated here.

It will be understood that the above embodiments are merely exemplary embodiments taken to illustrate the principles of the present invention, which is not limited thereto. It will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the spirit and substance of the invention, and these modifications and improvements are also considered to be within the scope of the invention.