JP7426646B2 - Analysis method of lightning surge response of transformer - Google Patents

Description

The present invention relates to a method for analyzing lightning surge response, including lightning overvoltage generated in the primary winding of a transformer and lightning faults generated by the voltage.

Distribution pole-mounted transformers installed on utility poles that make up distribution lines are devices that are susceptible to failure due to lightning surges (high voltage (lightning overvoltage) and current instantaneously generated by lightning strikes). be. Therefore, various equivalent circuits have been proposed for analyzing the behavior of pole transformers in response to lightning overvoltages. For example, what is shown in FIG. 11 is an equivalent circuit proposed in Non-Patent Document 1. Note that the symbols of each component in the circuit represent the following.
Z ₁ : Impedance of primary winding Y ₁₁ : Admittance between primary windings (between 1+ terminal t ₁₊ and 1- terminal t _1- ) Y _1G : Admittance between primary winding and earth Y _2G : Admittance between the secondary winding and the ground Y ₁₂ : Admittance between the primary winding and the secondary winding Y ₂₂ : Admittance between the secondary winding (between the 2+ terminal t ₂₊ and the 2- terminal t _2- ) Admittance Y ₂₀ : Admittance between secondary windings (between 2+ terminal t ₂₊ or 2- terminal t _2- and 0 terminal t ₀ ) Z _2l : Self-impedance of secondary winding Z _2m : Mutual secondary winding impedance

The parameters of each component (circuit element) of this equivalent circuit are determined as follows. First, in an actual pole transformer, multiple types of admittance are measured in a predetermined frequency band by changing the connection method of each terminal on the primary side and the secondary side. Then, parameters are derived from the measured admittance frequency characteristics using circuit theory and mode analysis. Note that, according to circuit theory, the measured admittance is expressed by a formula that combines the constituent elements of an equivalent circuit. Further, the mode analysis method is a method of determining parameters of a circuit element by focusing on resonance. The method for determining the parameters of such an equivalent circuit is known.

Koushi Michishita and two others, “Lightning overvoltage response of distribution pole transformers - Dependence on transformer capacity”, IEEJ Transactions B, Institute of Electrical Engineers of Japan, 2008, Vol. 128, No. 1 , p. 270-276

By the way, malfunctions of pole transformers caused by lightning surges mainly include malfunctions of the primary bushing and malfunctions of the primary winding. However, the equivalent circuit in Non-Patent Document 1 is for calculating the transition surge from the primary side to the secondary side or from the secondary side to the primary side of a pole transformer, and the primary winding is It was expressed only by the impedance _Z1 , and it was not possible to calculate the occurrence of lightning overvoltage in the primary winding of the pole transformer. As a result, failures caused by lightning overvoltage in the primary winding could not be analyzed.

The present invention has been made in view of the above circumstances, and provides a method for analyzing lightning surge response, including lightning overvoltage generated in the primary winding of a transformer and lightning failure of the transformer caused by this lightning overvoltage. The purpose is to

The present invention is a method for analyzing the lightning surge response of a transformer having a primary winding in which multiple layers are laminated. The actual measured admittance frequency of the transformer is the one in which any interlayer part including the interlayer part between the first layer and the second layer on the winding start side and other interlayer parts are used as the constituent elements. A parameter derivation process that calculates the parameters of each interlayer part of the primary winding of the equivalent circuit based on the characteristics, and a voltage calculation that calculates the voltage generated at each interlayer part by inputting a voltage waveform simulating a lightning surge into the equivalent circuit. The admittance frequency characteristics of the transformer in the parameter deriving process are characterized in that the admittance frequency characteristics of the transformer are a plurality of types of admittance frequency characteristics in which the connection method of terminals drawn out from between each layer of the primary winding is changed .

The present invention is a method for analyzing the lightning surge response of a transformer having a primary winding in which multiple layers are laminated. or an arbitrary interlayer part including an interlayer part between the first layer and the second layer on the winding start side and other interlayer parts as constituent elements, and at least the first layer and the second layer. An equivalent circuit for dielectric breakdown that shorts the layers when the generated voltage satisfies predetermined conditions is connected between the two layers, and the equivalent circuit is calculated based on the actually measured admittance frequency characteristics of the transformer. A parameter derivation process that calculates the parameters of each interlayer part of the primary winding, a voltage calculation process that calculates the voltage generated at each interlayer part by inputting a voltage waveform simulating a lightning surge into the equivalent circuit, and a voltage calculation process that calculates the voltage generated at each interlayer part. The present invention is characterized in that it includes a failure determination process that determines the presence or absence of a lightning failure based on whether or not an equivalent circuit for dielectric breakdown shorts between layers due to the applied voltage.

Further, in the present invention, the equivalent circuit of the transformer may be such that the primary winding includes all the interlayer portions as constituent elements.

Further, in the present invention, the equivalent circuit of the transformer may be such that the primary winding includes the interlayer portion between the first layer and the second layer and the other interlayer portions, respectively.

However, in the above-mentioned present invention, as the equivalent circuit (portions other than the primary winding) of the transformer, the one described in the above-mentioned Non-Patent Document 1 (shown in FIG. 11) can be used. In addition, in the following, regarding the interlayers of the primary winding, for example, "the interlayer between the first layer and the second layer" will be simply referred to as "the 1-2 layer interlayer". In the above-mentioned invention, "all interlayer parts" of the primary winding refers to all adjacent interlayer parts, that is, between 1st and 2nd layers, between 2nd and 3rd layers, between 3rd and 4th layers, etc. That's true. In addition, "any interlayer part including the interlayer part between the first layer and the second layer" means that it includes at least 1 to 2 layers, and may also include other adjacent interlayer parts, For example, every other layer is between 1st and 2nd layer, between 3rd and 4th layer, between 5th and 6th layer, etc. Furthermore, "other interlayer parts" refers to parts that are not included in "any interlayer parts including the interlayer parts between the first layer and the second layer". In addition, considering each of these as a component means that instead of expressing the entire primary winding with only one parameter, impedance, as in conventionally proposed equivalent circuits, it is divided into interlayer parts and each is used as a circuit. This means that parameters are set for each element. Furthermore, regarding the equivalent circuit of dielectric breakdown, the "predetermined conditions" for the generated voltage are determined based on the voltage value (potential difference) and waveform; for example, when a potential difference greater than a predetermined value occurs. It is.

According to the present invention, by creating an equivalent circuit that closely simulates the primary winding of a transformer, it is possible to calculate the lightning overvoltage that occurs in the primary winding, which could not be calculated in the past. It becomes like this. Furthermore, as a result of actual measurements of the voltage generated between each layer when a lightning surge enters the primary winding of a transformer, it has been found that the largest overvoltage occurs between layers 1 and 2 on the winding start side. . In the present invention, high accuracy can be obtained by simulating the 1-2 interlayer portion as an individual component.

Further, if the device includes a failure determination process, it is possible to calculate whether there is a lightning failure (insulation breakdown) occurring in the primary winding based on the determined lightning overvoltage occurring in the primary winding. This makes it possible to study and evaluate lightning damage countermeasures to prevent lightning failures in the primary winding of a transformer.

In addition, if all interlayer parts of the primary winding in the equivalent circuit are considered as constituent elements, higher accuracy can be obtained in calculating lightning overvoltages occurring in the primary winding and lightning faults in the primary winding. It will be done.

In addition, if the primary winding of the equivalent circuit is made up of the 1st and 2nd layer interlayer parts and other parts, the equivalent circuit will have a simple configuration, so it will be easier to detect lightning that occurs in the primary winding. It becomes possible to calculate overvoltages and lightning failures in the primary winding. As mentioned above, since the largest overvoltage actually occurs in the portion between the 1st and 2nd layers, sufficient accuracy can be obtained by making only the portion between the 1st and 2nd layers a separate component.

It is an equivalent circuit of the transformer in the method of this invention. It is explanatory drawing which shows the structure of a transformer main body, (a) is a side view, (b) is a top view. FIG. 2 is a schematic diagram showing the structure of a primary winding of a transformer. FIG. 2 is a schematic diagram showing details of the structure of the primary winding of a transformer and aspects of a lightning accident. FIG. 2 is a circuit diagram of an experiment in which an impulse voltage is input to a transformer. 2 is a graph showing actually measured values of lightning surge response characteristics of a primary winding of a transformer. It is an explanatory view showing the connection state of each terminal of a primary side and a secondary side when measuring an admittance frequency characteristic of a primary winding of a transformer. (a) to (c) are explanatory diagrams showing the connection state of the terminals of the primary winding when measuring the admittance frequency characteristic of the primary winding of the transformer. 3 is a graph showing an impulse voltage waveform input to a transformer. 2 is a graph showing actual measured values and calculated values of voltage generated between the 1st and 2nd layers of the primary winding of the transformer. This is an equivalent circuit of the transformer proposed in Non-Patent Document 1.

Hereinafter, the specific content of the present invention will be explained. Although the method for analyzing lightning surge response of a transformer according to the present invention can be applied to various types of transformers, a case where a pole-mounted transformer for power distribution is targeted will be exemplified here.

A pole transformer is installed on a utility pole and is used to transform 6600V electricity sent from a substation to 100V or 200V electricity used in general homes. A typical pole transformer has a cylindrical casing, and the transformer body is housed inside the casing. As shown in FIG. 2, the main body of the transformer is of an inner iron type, and includes a rectangular annular iron core 10, and a positive phase winding 20 and a negative phase winding 30 wound around two opposing sides of the iron core 10, respectively. Equipped with. The positive phase winding 20 and the negative phase winding 30 each include primary windings 21 and 31 on the outer circumferential side and secondary windings 22 and 32 on the inner circumferential side. More specifically, as shown in FIG. 4 (the positive phase side is shown, but the same applies to the negative phase side), an insulating paper 41 is wrapped around the iron core 10 in a cylindrical shape, and a secondary winding is placed around the outer circumference of the insulating paper 41. 22 is wrapped around it. Furthermore, an insulating paper 42 is wrapped around the outer periphery of the secondary winding 22 in a cylindrical shape, and the primary winding 21 is wound around the outer periphery of the insulating paper 42 . The inside of the casing is filled with insulating oil. On the outside of the casing, there are two primary bushings (1+ terminal and 1- terminal) connected to the primary windings 21 and 31 of the transformer body, and two primary bushings connected to the secondary windings 22 and 32 of the transformer body. Three connected secondary bushings (2+ terminal, 2- terminal, and 0 terminal) are provided. The primary bushing is connected to the high voltage line, and the secondary bushing is connected to the low voltage line, and the voltage of 6600V applied to the high voltage line is transformed by the pole transformer, and the voltage of 6600V applied to the high voltage line is transformed to 100V or A voltage of 200V is applied (100V between the 2+ or 2- terminal and the 0 terminal, and 200V between the 2+ and 2- terminals). Hereinafter, the pole transformer will also be simply referred to as a transformer.

As mentioned above, an equivalent circuit as shown in FIG. 11 has been proposed for such a transformer, and the part surrounded by the broken line corresponds to the primary winding of the transformer. Here, the configuration of the primary winding will be explained in further detail. As shown in the schematic diagram of FIG. 3, the primary winding of this transformer has 13 layers laminated in each of the positive phase (left side of the figure) and negative phase (right side of the figure). In the actual transformer main body, the first layer _L1 is located at the innermost side, and starting from the first layer _L1 , the second layer _L2 , the third layer _L3 , It has a layered structure. Note that, as shown in FIG. 4 (the positive phase side is shown, but the same applies to the negative phase side), an insulating paper 43 is sandwiched between each layer. The terminal drawn out from the first layer _L1 of the positive phase is connected to the 1+ terminal t1 ₊ of the transformer, and the terminal drawn out from the first layer _L1 of the negative phase is connected to the 1- terminal t of the transformer. Connected to _1- . In addition, a first tap _T1 is connected from the middle of the 12th layer _L12 with a positive phase, a second tap _T2 is connected from the end of the 13th layer _L13 with a negative phase, and a third tap T is connected from the end of the 13th layer _L13 with a negative phase. ₃ , a fourth tap _T4 is drawn out from the middle of the thirteenth layer _L13 . A tap is a lead wire for changing the transformation ratio. Note that A to F and a to f in FIG. 3 represent terminals drawn out from between layers 2-3, between layers 4-5, . . . , and between layers 12-13 in the positive phase and negative phase, respectively. These terminals do not exist in an actual transformer and are provided for explanation and confirmation of the present invention.

When investigating transformers that actually experienced lightning failures due to lightning surges, failures in the primary windings 21 and 31 were found to occur mainly between the 1st and 2nd layers closest to the primary bushing (1+ terminal t1 ₊ in Figure 3). It was confirmed that this occurred between terminal A and between terminal 1-terminal _t1- and terminal a). FIG. 4 also schematically shows an aspect of such a lightning failure BD (Break Down).

In order to confirm this numerically, we conducted an experiment in which an impulse voltage simulating a lightning surge was input to the transformer. Shown in FIG. 5 is the experimental circuit diagram. An impulse voltage generator 200 applied a voltage between the 1+ terminal and 1- terminal of the transformer 100 and the case ground. Using this circuit, three types of impulse voltages of 0.3/50 μS, 0.7/50 μS, and 1.1/50 μS were applied to the transformer 100 (representing wavefront length/wavelength length).

FIG. 6 is a graph showing the results of the experiment, showing the voltage generated between each layer of the primary winding of the transformer. More specifically, the horizontal axis corresponds to each layer. For example, 1+-A represents between the 1+ terminal t ₁₊ and terminal A in FIG. B, that is, between 3 and 4 layers. The vertical axis is the ratio of the peak value of the output voltage to the peak value of the input voltage. According to this, in the case of any of the three types of impulse voltages, the voltage between the 1-2 layers closest to the 1+ terminal t ₁₊ and 1- terminal t _1-, which are the application ends, is the highest, and the voltage farther away from the application end is the highest. It was confirmed that the voltage suddenly decreased.

Based on these matters, in the present invention, in order to analyze lightning overvoltage occurring in the primary winding of a transformer and lightning faults in the primary winding of the transformer, the primary winding is analyzed in more detail than before. We will use a simulated equivalent circuit. To simulate the primary winding in the most detail, all adjacent layers, i.e., 1-2 layers, 2-3 layers, 3-4 layers, etc., are divided into constituent elements. However, in this case, an equivalent circuit is used in which the primary winding is divided into a 1-2 interlayer portion and other interlayer portions (3-13 interlayer portion). According to the above experimental results shown in FIG. 6, it can be said that the lightning overvoltage generated in the primary winding of the transformer due to a lightning surge is highest between the 1st and 2nd layers, and is sufficiently small between the other layers. Therefore, by treating only the 1st and 2nd layers as separate components, sufficient accuracy can be obtained to analyze lightning overvoltage occurring in the primary winding of a transformer and lightning faults in the primary winding of a transformer. Since the number of components can be reduced, the calculation becomes easier.

FIG. 1 shows an equivalent circuit of a transformer including a primary winding simulated in detail in this way. The part surrounded by the broken line corresponds to the primary winding, and the parts other than the primary winding are the same as the conventional equivalent circuit shown in FIG. 11. Note that the symbols of each component in the circuit represent the following (other than these are the same as in FIG. 11).
Y _1-2 : Admittance between 1-2 layers of primary winding Y _3-13 : Admittance between other layers of primary winding (3-13 layers) Y _M : Admittance between 1-2 layers of primary winding Mutual admittance between other layers (3-13 layers)

For more details about the primary winding part, regarding "1-2 layers", let's assume that the admittance between the 1-2 layers (Y _1-2) and the mutual admittance Y between the 1-2 layers and other layers (Y _M) are connected in series. expressed. Further, "other interlayers" is expressed as the admittance Y _3-13 between other layers and the mutual admittance Y _M between layers 1-2 and other layers connected in series. Therefore, as shown in Figure 1, the primary winding consists of four elements Y _1-2 , Y _M , Y _3-13 , and Y _M connected in series on each of the positive and negative phase sides. It is expressed as

Furthermore, an equivalent circuit for dielectric breakdown is connected to the 1st-2nd layer portion of this equivalent circuit. The equivalent circuit for dielectric breakdown is one that short-circuits between layers 1 and 2 when a potential difference greater than a predetermined value occurs, and here it is represented by a switch S that turns on when a potential difference greater than a predetermined value occurs. This switch S is connected in parallel with the admittance _Y1-2 between the 1st and 2nd layers and the mutual admittance _YM between the 1st and 2nd layers and other layers on the positive phase side and the negative phase side, respectively. There is.

Based on such an equivalent circuit of a transformer, the method of analyzing the lightning surge response of a transformer according to the present invention is executed. This lightning surge response analysis method is based on the actually measured admittance frequency characteristics of the transformer as a process for analyzing the lightning overvoltage that occurs in the transformer. The method includes a parameter derivation process for determining the parameters of , and a voltage calculation process for inputting a voltage waveform simulating a lightning surge into an equivalent circuit and calculating the voltage generated between the 1st and 2nd layers. In addition, as a process for analyzing lightning failures in transformers, we conduct a failure determination process in which the presence or absence of a lightning failure is determined based on whether the equivalent circuit of insulation breakdown shorts between layers using the voltage determined in the voltage calculation process. Be prepared.

First, a parameter derivation process is performed. In the parameter derivation process, first, in an actual transformer, multiple types of admittances are measured in a predetermined frequency band by changing the connection method of each terminal of the primary winding. At this time, the primary and secondary terminals of the transformer are connected as shown in FIG. That is, the 1+ terminal t ₁₊ of the transformer 100 is connected to the + terminal M ₊ for admittance measurement, and the 1- terminal t _1- , the 2+ terminal t 2+ , the 2- terminal t _{2- and the 0 terminal of the transformer 100 are connected to the +} terminal M ₊ for admittance measurement. t ₀ is connected to the G terminal (that is, connected to the transformer casing) and then to the −terminal M ₋ for admittance measurement. Furthermore, the primary winding is measured using three types of connection methods as shown in FIGS. 8(a) to 8(c). That is, in the case of FIG. 8(a), the 1+ terminal t ₁₊ is not connected to any other terminal, and the 1- terminal t _1- is connected to the terminal F on the positive phase side and the terminals a to f on the negative phase side. is connected. In the case of FIG. 8(b), the positive phase side terminal A is connected to the 1+ terminal t ₁₊ , and the positive phase side terminal F and the negative phase side terminals a to f are connected to the 1− terminal t ₁₋ . is connected. In the case of FIG. 8(c), the 1+ terminal t ₁₊ is not connected to any other terminal, and the 1- terminal t _1- is connected to terminals A to F on the positive phase side and terminals a to terminal A on the negative phase side. f is connected. Then, parameters are derived from the measured admittance frequency characteristics using circuit theory and mode analysis.

More specifically, each parameter is derived as follows. Regarding the admittance Y _1-2 between the 1st and 2nd layers, subtract the admittance frequency characteristic in the case of Fig. 8(b) from the admittance frequency characteristic in the case of Fig. 8(a), and from the obtained admittance frequency characteristic, calculate the circuit theory. Parameters are derived using the modal analysis method. Regarding admittance Y _3-13 between other layers, subtract the admittance frequency characteristic in the case of FIG. 8(c) from the admittance frequency characteristic in the case of FIG. 8(a), and from the obtained admittance frequency characteristic, use the circuit theory. Parameters are derived by modal analysis method. Regarding the mutual admittance _YM between the 1-2 layer and the other layers, add the admittance frequency characteristic in the case of FIG. 8(b) and the admittance frequency characteristic in the case of FIG. 8(c), and then calculate the mutual admittance YM in FIG. 8(a). Parameters are derived from the obtained admittance frequency characteristics by subtracting the admittance frequency characteristics in the case of , using circuit theory and mode analysis method.

Subsequently, a voltage calculation process is performed. In the voltage calculation process, a voltage waveform simulating a lightning surge is input into the equivalent circuit. Since the parameters of each component of the equivalent circuit have been determined in the previous parameter derivation process, it is possible to calculate the response of the equivalent circuit to the input, which occurs between the 1st and 2nd layers of the primary winding. Voltage is also required.

Subsequently, a failure determination process is executed. As mentioned above, the switch S representing the equivalent circuit of dielectric breakdown is connected to the 1st and 2nd layer portion of the equivalent circuit, and if the potential difference generated in the 1st and 2nd layer portion found earlier is greater than a predetermined value, For example, the switch S is turned on, and the 1st and 2nd layers are short-circuited. In other words, dielectric breakdown is simulated. In the fault determination process, the presence or absence of this short circuit is detected, and if a short circuit occurs, it is determined that a lightning fault has occurred, and if a short circuit does not occur, it is determined that a lightning fault has not occurred. Note that the predetermined value of the potential difference at which the switch S is turned on is determined from actual measurements of lightning failures in actual transformers. Determined from the dielectric breakdown voltage.

Here, in order to verify the validity of the lightning surge response analysis method of the present invention, we will compare calculated values and actual measurements in an actual transformer with respect to the voltage generated between the 1st and 2nd layers of the primary winding of the transformer. Compare values. The applied voltage was an impulse voltage of 1.1/50 μS as shown in FIG. 9, and the circuit shown in FIG. 5 was used for actual measurements. FIG. 10 is a graph showing both the calculated values and the actual measured values. Especially for the first peak, the calculated value and the measured value are in good agreement. From the perspective of lightning failures, the first peak with the largest amplitude is the problem, so the method of the present invention, which yields results that match well in that area, has sufficient accuracy for practical use.

According to the method for analyzing the lightning surge response of a transformer according to the present invention, by creating an equivalent circuit that closely simulates the primary winding of a transformer, the primary winding, which could not be calculated in the past, can be calculated. You will be able to calculate the lightning overvoltage that occurs in lines. In particular, when a lightning surge enters the primary winding of a transformer, the largest overvoltage occurs in the area between the 1st and 2nd layers at the start of winding. By dividing the equation into two parts and simulating each part as a component, sufficiently high accuracy can be obtained for practical use, and since the equivalent circuit has a simple configuration, it can be easily calculated. Based on the lightning overvoltage occurring in the primary winding determined as described above, it is possible to calculate whether there is a lightning failure (insulation breakdown) occurring in the primary winding. This makes it possible to study and evaluate lightning damage countermeasures to prevent lightning failures in the primary winding of a transformer.

Note that the computer can function as a transformer lightning surge response analysis device that executes the transformer lightning surge response analysis method of the present invention. This computer-based transformer lightning surge response analysis device calculates the lightning overvoltage generated in the transformer based on the above-mentioned transformer lightning surge response analysis method, and thereby determines the presence or absence of lightning faults that occur in the transformer. It is something to judge. This analysis device includes a parameter deriving means, a voltage calculating means, and a failure determining means. The computer functions as each means.

A computer consists of input devices such as a keyboard and mouse, output devices such as a display, a CPU that sequentially executes program instructions, and a storage device that stores programs and the data and calculation results necessary for program execution. This is a standard component.

Then, by running a transformer lightning surge response analysis program on the computer, the device operates to determine the lightning overvoltage generated in the transformer based on the transformer lightning surge response analysis method of the present invention. , to determine whether there is a lightning failure in the transformer.

More specifically, when this program is executed by a computer, each step (parameter derivation step, voltage calculation step, failure determination step) is executed, so that the computer executes various means (parameter derivation means, voltage calculation means, It functions as a failure determination means) and analyzes lightning overvoltage and lightning failures.

When this program is executed, a parameter deriving step is first performed, and the computer functions as a parameter deriving means. The parameter deriving means receives input of measurement values obtained by measuring a plurality of types of admittance in a predetermined frequency band in an actual transformer with different terminal connection methods. The input may be data measured by a measuring device (such as an LCR meter) connected to a computer, or separately measured data may be manually input using an input device. . The input measurement values are stored in the storage device. Then, the parameter deriving means reads the measured value and a pre-stored calculation formula based on circuit theory and mode analysis method from the storage device, substitutes the measured value into the calculation formula, and calculates the parameters of the equivalent circuit. The parameters are saved in storage.

Next, a voltage calculation step is performed, and the computer acts as a voltage calculation means. The voltage calculation means receives input of a voltage waveform simulating a lightning surge. The voltage waveform may be one in which data stored in a storage medium is read, or a numerical value defining the waveform may be manually input from an input device. The input voltage waveform is stored in a storage device. Then, the voltage calculation means reads the voltage waveform, the previously stored equivalent circuit, and the parameters determined in the parameter derivation step from the storage device, and calculates the response of the equivalent circuit to the input of the voltage waveform. As a result, the voltage generated between the 1st and 2nd layer of the primary winding can also be determined. The determined voltage is stored in a memory device.

Next, a failure determination step is executed, and the computer functions as a failure determination means. The failure determination means determines, based on the response of the equivalent circuit to the voltage waveform input calculated by the voltage calculation means, whether a switch representing the equivalent circuit of dielectric breakdown is turned on and a short circuit occurs between the 1st and 2nd layers. Detect whether or not. If a short circuit occurs, it is determined that a lightning fault has occurred, and if a short circuit does not occur, it is determined that a lightning fault has not occurred. The determination result is stored in the storage device and displayed on the output device of the computer. This completes the program and completes the analysis of the lightning surge response of the transformer by the analyzer.

This transformer lightning surge response analysis program may be executed as dedicated software, on general-purpose spreadsheet software, or as a separate program. It may also be something that is built into the system. Furthermore, general-purpose electronic circuit simulation software may be used as the voltage calculation means.

In addition, the equivalent circuit of the transformer in the above-described method of analyzing lightning surge response of a transformer of the present invention is constructed by dividing the primary winding into a 1-2 layer interlayer portion and other interlayer portions. Although this is an element, other configurations may be used. However, as mentioned above, the lightning overvoltage that occurs in the primary winding of a transformer due to a lightning surge is highest between the 1st and 2nd layers, so at least the portion between the 1st and 2nd layers should be considered as a separate component. Accuracy high enough for practical use can be obtained.

As an example of a configuration of the primary winding other than the above, for example, all adjacent layers, ie, between the 1st and 2nd layers, between the 2nd and 3rd layers, between the 3rd and 4th layers, etc., may each be used as a component. In this case, "interlayer i-i+1" is expressed as a series connection of admittance Y ii+1 between layer _ii+1 and mutual admittance Y _Mi-i+1 between layer ii+1 and other layers. Therefore, the equivalent circuit of the primary winding when all interlayers are considered as constituent elements is Y _1-2 , Y _M1-2 , Y _2-3 , Y _M2-3 , ..., Y _i-i+1 , Y _Mi−i+1 , . . . are connected in series.

Furthermore, as an example of other primary winding configurations, for example, every other layer between adjacent layers, that is, between the 1st and 2nd layers, between the 3rd and 4th layers, between the 5th and 6th layers, etc., are each used as a component. Good too. In that case, the 2nd-3rd layer, the 4th-5th layer, etc. will be collectively referred to as "other layers". In addition, the 1-2 layer, 2-3 layer, and other layer (4-13 layer) may be used as constituent elements, or the 1-2 layer, 2-3 layer, 3-4 layer, and other layer (4-13 layer) may be used as constituent elements. 5 to 13 layers) may be respectively used as constituent elements.

The present invention is not limited to the embodiments described above, and can be modified as appropriate within the scope of the spirit of the invention. For example, various known methods can be used to determine the parameters of the equivalent circuit of the transformer. Furthermore, in the equivalent circuit of the transformer, a switch representing the equivalent circuit of dielectric breakdown may be provided in a portion other than the 1-2 layer portion. Further, as the equivalent circuit for dielectric breakdown, in addition to the one based on the potential difference as described above, various known circuits can be used, such as one based on the integral method and the one based on the Vt crossing method. Furthermore, the present invention can be applied to various transformers other than pole transformers.

10 Iron core 20 Positive phase winding 21 Primary winding (positive phase side)
22 Secondary winding (positive phase side)
30 Negative phase winding 31 Primary winding (negative phase side)
32 Secondary winding (negative phase side)
41, 42, 43 Insulating paper 100 Transformer 200 Impulse voltage generator S Switch t ₁₊ 1+ terminal t _1- 1- terminal t ₂₊ 2+ terminal t _2- 2- terminal t ₀ 0 terminal T ₁ 1st tap T ₂ 2nd Tap T ₃ 3rd tap T ₄ 4th tap

Claims (4)

A method for analyzing the lightning surge response of a transformer having a primary winding in which multiple layers are laminated, the method comprising:
The equivalent circuit of this transformer is one in which the primary winding has all the interlayer parts as constituent elements, or any interlayer part including the interlayer part between the first layer and the second layer at the winding start side, and other interlayer parts. and the interlayer portion as constituent elements,
a parameter derivation process for determining parameters of each interlayer portion of the primary winding of the equivalent circuit based on the actually measured admittance frequency characteristics of the transformer;
Equipped with a voltage calculation process that calculates the voltage generated at each interlayer by inputting a voltage waveform simulating a lightning surge into the equivalent circuit .
Lightning surge response of a transformer characterized in that the admittance frequency characteristics of the transformer in the parameter derivation process are multiple types of admittance frequency characteristics with different connection methods of terminals pulled out from between each layer of the primary winding. analysis method. A method for analyzing lightning surge response of a transformer having a primary winding in which multiple layers are laminated, the method comprising:
The equivalent circuit of this transformer is that the primary winding has all the interlayer parts as components, or any interlayer parts including the interlayer parts of the first and second layers at the winding start side and other interlayer parts. An equivalent circuit for dielectric breakdown that short-circuits the layers when the generated voltage satisfies a predetermined condition is connected to at least the interlayer portions of the first layer and the second layer. It is a thing,
a parameter derivation process for determining parameters of each interlayer portion of the primary winding of the equivalent circuit based on the actually measured admittance frequency characteristics of the transformer;
A voltage calculation process that calculates the voltage generated at each interlayer by inputting a voltage waveform simulating a lightning surge into the equivalent circuit;
A method for analyzing the lightning surge response of a transformer , characterized by comprising a failure determination process that determines the presence or absence of a lightning failure based on whether or not the equivalent circuit of dielectric breakdown shorts between layers using the voltage determined in the voltage calculation process. . 3. The method for analyzing a lightning surge response of a transformer according to claim 1, wherein the equivalent circuit of the transformer includes a primary winding having all interlayer portions as constituent elements. 3. The equivalent circuit of the transformer according to claim 1 or 2, wherein the primary winding includes an interlayer portion between the first layer and the second layer and other interlayer portions, respectively. Analysis method of lightning surge response of transformer.

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