JPS6038016B2 - Simulated winding device for testing transformer windings - Google Patents

Description

[Detailed Description of the Invention] This invention provides a method for performing a destructive test using a winding model to confirm the insulation reliability of the windings of a high voltage oil-immersed transformer.
This invention relates to a simulated winding device for providing an initial potential distribution equivalent to that of an actual transformer.

Generally, the potential distribution of a transformer winding is represented by an equivalent circuit shown in FIG. In Figure 1, L is the inductance distributed for each unit length of the winding, K is the series distributed capacitance between turns between coils, etc., and C is the distribution of the winding to the ground with respect to the iron D, tank, other windings, etc. capacity. In this kind of equivalent circuit,
The influence of the capacitances C and K on the commercial frequency is small, and the potential distribution within the winding is mainly determined only by the inductance L. Therefore, the potential of the winding exhibits a uniform distribution proportional to the number of turns of the winding. However, when a steep lightning pulse from external lightning is applied to the transformer winding, the inductance L exhibits an extremely high counter-electromotive force, so the potential distribution at the beginning of voltage application (initial potential distribution) is Determined only by
A concentrated potential is applied to the coil near the entrance end of the winding.

The degree of potential concentration Q is expressed by the following equation, resulting in a characteristic curve shown in FIG. .

：ノC/K=Zo Tsuma Kaoru punishment proverb Den grave 萱 ‐‐‐‐‐‐(・1 2nd
As is clear from the figure, the larger the winding Q, the more potential is concentrated at the inlet end coil, so when designing a transformer, it is necessary to make efforts to minimize the ground capacitance C and increase the series capacitance K as much as possible. will be done. Moreover, oil-immersed transformers are required to have higher voltage and larger capacity, and in line with these demands, reduction of insulation dimensions has become an important issue.
Therefore, in this type of transformer, tests and research are required to verify the insulation performance by variously changing the configuration such as the number of coils, insulation dimensions, and materials. In other words, test research to verify the insulation performance of transformers involves measuring the initial potential distribution, main insulation dimensions, coil-to-coil dimensions, inter-turn insulation dimensions, etc. for a given snow impulse, switching impulse, etc. voltage. By changing the main insulation dimensions and the insulation materials used, and by changing the number of coils and turns,
It is necessary to clarify how each factor affects dielectric strength. Therefore, as a conventional means of conducting this type of test research, a winding model close to an actual transformer is used in which only the iron 0 and opposing windings are replaced with simple electrodes, and the initial potential distribution is mainly determined by the capacitance between turns. A method of adjustment was adopted. However, according to such conventional methods, the range of change in the initial potential distribution is small, and conversely, the initial potential distribution changes even if the dimensions and structure of the core or opposing windings are changed. It has been difficult to accurately analyze the factors that affect yield strength. Furthermore, since a model that approximates the actual transformer winding is used, the model becomes expensive, and it is difficult to set a large number of test conditions, which hinders technological progress. In order to improve the conventional test method that has many of the problems mentioned above, the present inventors conducted various studies and made prototypes, and as a result, they developed a simulation method in which multiple coils insulated from each other are wound around an electrode via the main insulation. Combine the winding and a non-inductive resistive voltage divider, store them in a test oil tank, lead out each coil of the simulated winding, and connect the lead wires to the resistive voltage divider, respectively.
By forcing a predetermined initial potential distribution to be applied to each coil using a resistive voltage divider, it is possible to give a predetermined initial potential distribution to the windings regardless of the structure and dimensions of the windings. It was found that detailed tests could be conducted based on the initial potential distribution, insulation structure and dimensions, number of coils, number of turns, etc.

In addition, the simulated winding does not require connection between coils, and the effect of inter-turn insulation can be ignored except for a few coils at the entrance of the winding, so it is possible to simulate with a one-turn coil.
It has been found that the number of man-hours required to manufacture the windings can be significantly reduced compared to the conventional technology that uses actual windings. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a simulated winding device for testing transformer windings, which has a simple structure, can be manufactured at low cost, and can perform a higher level of dielectric strength verification test. .

In order to achieve the above object, the present invention includes a simulated winding in which a plurality of mutually insulated coils are wound around an electrode via main insulation, and a non-inductive winding arranged around the simulated winding. A resistive voltage divider is provided, and the resistive voltage divider is provided with a plurality of terminals that also serve as electric field shields, and each coil constituting the simulated winding is connected to each terminal and/or intermediate tap of the resistive voltage divider. shall be.

In the above-described simulated winding device for testing transformer windings, the coil constituting the simulated winding is composed of a one-turn coil consisting of one or more parallel insulated conductors, and each conductor is connected together at the end of the coil. Short-circuit or divide into several blocks and short-circuit, provide connection terminals or lead wires, and connect to a resistive voltage divider. In addition, the resistive voltage divider is supported by an insulating rod whose one end is fixed to the pedestal via the electric field shield electrode, and the high voltage end of the resistive voltage divider is connected to the voltage application bushing, and the low voltage end of the resistive voltage divider is connected to the low voltage It is advantageous if it is configured as a terminal or grounded.

Further, it is preferable that the simulated winding and the resistive voltage divider having the above-described configuration be housed in an oil tank.

Next, embodiments of a simulated winding device for testing transformer windings according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 3 shows an embodiment of a simulated winding device configured for insulation experiments of ultra-high voltage or ultra-super high voltage class.

Reference numeral 10 indicates a simulated winding, and as shown in FIG. It is arranged in a winding manner with an insulation 16 interposed therebetween. In addition, each simulated winding consists of n simulated coils 18 as shown in FIG. There is. In addition, the simulated winding 10 configured in this way, like a general winding,
The state is different from the state in which each coil is electrically connected. A non-inductive resistance voltage divider 22 is disposed around the outer periphery of the simulated winding 10 having the above-described configuration, and this non-inductive resistance voltage divider 22 is connected to the mount 12.
It is supported by a large number of insulating rods 24 each having one end fixed thereto via an electric field shield electrode 26 .

In addition, n lead wires 2 derived from the simulated coil 18
0 is connected to the intermediate tap 28 of the resistive voltage divider 22 or the electric field shield electrode 26 which also serves as a voltage divider terminal giving a predetermined initial potential distribution. The simulated winding device constructed in this way is housed in three oil tanks for insulation testing. Resistance voltage divider 22
The high voltage end is connected to the voltage application bushing 32, and the low voltage end is connected to a low voltage terminal 34 that is grounded together with the simulated electrode 14 and the oil tank 30, or is provided on a part of the oil tank 30 located behind it. Note that, as shown in FIG. 5, the plurality of simulated coils 18 used in the device of the present invention are one
- It can be simulated with a one-turn coil that is composed of a plurality of parallel insulated coated conductors and short-circuited at the side, and therefore the inductance of each simulated coil 18 becomes extremely small.
Therefore, as described above, the equivalent circuit of the simulated winding device housed in the test tank 30 is the same as the equivalent circuit shown in FIG. 1 when the inductance L is replaced by the resistance R. Therefore, when a voltage is applied to the simulated winding 10 of this embodiment, the current flowing through the taiwai conductor resistive voltage divider 22 is smaller than the charging current flowing through the series distributed capacitance K and the parallel distributed capacitance C of the coil 18. If the resistance value R is selected to be much larger, the initial potential distribution given to one simulated winding becomes equal to the potential distribution determined by the voltage division ratio of the resistor voltage divider 22,
Regardless of the series distributed capacitance K and the parallel distributed capacitance C of the simulated winding 10, any initial potential distribution can be given to the simulated winding 10'. Therefore, according to the simulated winding of this example, the number of coils, the insulation dimensions of each part of the winding, the insulation material, the structure, etc., which are the intended purpose, are changed in various ways, and each factor is adjusted to an arbitrary initial potential. The influence on dielectric strength can be easily verified by giving a distribution. In addition, in the case of one simulated winding in this embodiment, each coil 18 can be a one-turn coil in which multiple insulated conductors are paralleled and wound only once to a predetermined size. If it is desired to provide a potential difference between the conductors, the parallel conductors may be divided into two blocks and two lead wires 20 may be drawn out.

On the other hand, if a potential difference between adjacent parallel conductors is not required, a configuration may be adopted in which the parallel conductors are collectively short-circuited at the coil exit and one lead wire 20 is derived. In addition, when setting it as the above-mentioned structure, the diameter etc. of a winding can be reduced and simulated as needed. Therefore, the fabrication of the simulated coil becomes easy, and the manufacturing cost of the simulated winding can be significantly reduced. Furthermore, in the embodiment described above, the structure of the resistive voltage divider 22 is necessary for the purpose of drawing out the lead wires 20 of the adjacent simulated coils 18 from different angles on the circumference and maintaining a sufficient insulation distance between the terminals. Of course, various structures can be implemented depending on the level of applied voltage.

As is clear from the above-mentioned embodiments, the simulated winding device of the present invention uses a simulated winding composed of a one-turn coil, and uses a resistive voltage divider finely matched with the simulated winding to generate an arbitrary initial potential distribution. can be applied to the simulated winding, it is possible to easily and inexpensively reproduce conditions equivalent to the response characteristics of an actual transformer winding, such as snow impulses, switching impulses, etc., and to verify the dielectric strength of practical windings. Of course, it can be effectively utilized for the development and improvement of high-performance windings.

The simulated winding device of the present invention having such features is suitable for testing and researching the lightning resistance impulse, switching impulse resistance, and insulation strength of the windings of oil-immersed transformers, reactors, oil-immersed transformers, etc.
It can be applied to testing and researching the winding insulation strength of SF6 gas-insulated transformers, etc., and can also be suitably used for impulse insulation testing of high-voltage devices that require arbitrary potentials to be applied to multiple conductors at different potentials. I can do it.

Although the preferred embodiments of the present invention have been described above, it goes without saying that various design changes can be made without departing from the spirit of the present invention.

[Brief explanation of the drawing]

FIG. 1 is an equivalent circuit showing the potential distribution of a transformer winding, FIG. 2 is a potential concentration characteristic curve of the transformer winding, and FIG. 3 is a configuration showing an embodiment of a simulated winding device according to the present invention. 4 is an explanatory diagram of the installation state of the simulated winding used in the device shown in FIG. 3, and FIG. 5 is an example of the simulated coil constituting the simulated winding used in the device of the present invention. FIG. 10... Simulated winding, 12... Frame, 1
4... Cylindrical electrode, 16... Main insulation, 18...
...Mock coil, 20...Lead wire, 2
2... Resistance voltage divider, 24... Insulation shield, 26...
...Electric field shield electrode, 28...Middle tap, 30...Oil tank, 32...Bushing for voltage application, 34...Low voltage terminal. FIG. lFIG. 2FIG. 3 FIG. 4 FIG. 5

Claims (1)

[Claims] 1. Consists of a simulated winding in which a plurality of mutually insulated coils are wound around an electrode via main insulation, and a non-inductive resistance voltage divider arranged to surround this simulated winding. , a transformer winding characterized in that the resistive voltage divider is provided with a plurality of terminals that also serve as electric field shields, and each coil constituting the simulated winding is connected to each terminal and/or intermediate tap of the resistive voltage divider. A simulated winding device for testing. 2. In the test simulated winding device according to claim 1, the coil constituting the simulated winding is composed of a one-turn coil made of one or more parallel insulated conductors,
A simulated winding device for testing transformer windings, in which each conductor is short-circuited all at once or divided into several blocks at the end of the coil, and a connection terminal or lead wire is provided and connected to a resistive voltage divider. 3. In the test simulation winding device according to claim 1 or 2, the resistive voltage divider is supported by an insulating rod whose one end is fixed to a pedestal via an electric field shield electrode, and the resistive voltage divider is A simulated winding device for testing a transformer winding, in which the high voltage end is connected to a voltage application bushing, and the low voltage end of a resistive voltage divider is configured as a low voltage terminal or grounded. 4. In the testing simulation winding device according to any one of claims 1 to 3, the testing simulation of a transformer winding is constructed by storing a simulation winding and a resistance voltage divider in an oil tank. Winding device.