JPH07270462A - Analysis method for propagation problem circuit using spatial network method - Google Patents

Abstract

PURPOSE:To avoid the number of pieces limit for mutual inductance and the use of a gyrator, and apply a general-purpose circuit analysis tool by combining two basic Maxwell equations for deriving a propagation equation, and using the propagation equation for constituting a spatial network. CONSTITUTION:Current flowing across building steel frame sections P and Q is thunderbolt current (i) plus two types of current ic1 and ic2 entering the sections P and Q after propagation through a spatial network. Normally, the current cannot be separated, but spatial surge impedance Z0 is considerably larger than the surge impedance Z1 of the sections P and Q. Thus, the current (i) and a sum of Ici and ic2 due to induced voltage, flow to the surge impedance z1 between the sections P and Q. On the other hand, two types of current ic1 and ic2 flow across spatial section Z0 and, therefore, the thunderbolt current (i) flowing across the sections P and Q can be obtained by deducting the current icl and ic2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device in the command room which is protected by a lightning current flowing along a structure such as a steel frame of a building when there is a lightning strike in a building in which a central control room of a power system is arranged. A spatial network method that enables this calculation even when there are hundreds of mutual inductances in the network analysis that is used in the surge current distribution analysis that is performed to prevent destruction. Propagation problem circuit network analysis method.

[0002]

2. Description of the Related Art General-purpose tools (so-called EMTP, etc.) are well known for circuit network analysis, and particularly for surge analysis, a method applying Bergeron's method is unique and used in a versatile manner. Needless to say.

However, a general-purpose tool cannot handle the problem that a large number of mutual inductances exist, such as a building structure. That is, in the usual circuit analysis tool, the maximum number of mutual inductances is limited to about 40 due to the memory limitation in matrix calculation. However, in the building problem, the number of metal structures such as steel frames constituting the building is not about 40 but several hundreds or thousands, which is far beyond the range that can be handled by a general-purpose circuit analysis tool. Of course, it is possible to increase the number of mutual inductances that can be handled by changing the software, but the required amount of memory and the calculation time exponentially increase exponentially, and in fact calculation becomes impossible. Conversely, limiting the number of mutual inductances that can be handled by a general-purpose circuit analysis tool to about 40 means that this is a reasonable maximum number. This is the state of analysis by the conventional general-purpose circuit analysis tool, and is also the limit.

Further, if the conventional general-purpose circuit analysis roots to which the Bergeron method is applied is applied in order to avoid the limit of the mutual inductance, the electromagnetic effect propagating in the space cannot be inserted, and it is temporarily inserted. If you
Since it is included as mutual inductance, if the current reaches a certain point in addition to the limitation of the number, the influence will appear at all points given by the mutual inductance at that moment, and it will not be a propagation problem analysis. This is the weak point of general-purpose circuit analysis tools.

The so-called spatial network method has been proposed as an attempt to avoid this. This is basically
It was started by G.Kron and developed by Professor Yoshida Hokkaido University and others (Yoshida et al., IEICE Transactions)
B, vol.63, pp.876, 1980). The basis of this idea is to divide the space into a three-dimensional mesh structure, one Maxwell electromagnetic field equation at each grid point, that is, as shown in FIG. Assuming that the magnetic field has only one direction in the magnetic contact, the Maxwell equation is expressed by six lattice points. In this way, Maxwell's equations are as shown in Fig. 5, where A, B, C, D, E, and F are 6
It is represented by the impedance connected to each grid point. The calculation is performed by the so-called Bergeron method, and since the mutual impedance does not enter, the calculation memory is not limited.

[0006]

However, the above-mentioned conventional method has a problem that a gyrator is inserted between each lattice point as shown in FIG.
This is because the Maxwell equation was replaced with the spatial network as it was. That is, since the Maxwell equation describes the physical action of the electric field in the local region, the electric field and the magnetic field appear alternately intertwined.

In fact, as is well known, electromagnetic waves are
An electric field and a magnetic field are alternately intertwined and propagate. Therefore, as shown in FIG. 5, it can be seen that the electric contacts and the magnetic contacts are alternately arranged at the lattice points. By the way, since the electrical contact and the magnetic contact have a dual relationship,
The relationship between voltage and current in circuit theory is reversed at these two contacts. The gyrator introduced in FIG. 5 is for matching at these two contacts. However, since a general-purpose circuit analysis tool does not have a program that incorporates such a gyrator, even if a field of electromagnetic wave propagation is expressed by a spatial circuit network, a general-purpose circuit analysis tool (for example, EMTP) is used. The phenomenon cannot be analyzed by circuit calculation, and there is the inconvenience of relying on a dedicated program. Since the existence of this gyrator is rooted in the essence of electromagnetic phenomena, it is indispensable when expressing Maxwell's equations by the spatial network method.Therefore, even when using a general-purpose circuit analysis tool, exclude it. It was impossible.

The present invention has been made in view of the above, and an object thereof is to limit the number of mutual inductances in the analysis by the conventional general-purpose circuit analysis tool, which is one of the distributed constant methods. Propagation problem circuit analysis method by the spatial network method that enables application of general-purpose circuit analysis tools by avoiding by applying the network method and by avoiding the gyrator in the conventional spatial network method To provide.

[0009]

In order to achieve the above-mentioned object, a propagation problem circuit analysis method by the spatial network method of the present invention is a circuit analysis of electromagnetic wave propagation phenomenon by dividing a space and expressing it as a network. In the spatial network method analyzed by the method, it is a gist to combine two basic Maxwell equations to derive a propagation equation, and to construct a spatial network using the propagation equation.

Further, in the propagation problem circuit analysis method by the spatial circuit method according to the present invention, the surge impedance, the propagation velocity and the propagation speed are calculated by using the conductor portion in the structure in which the conductor rods are combined as a building structure as a normal distributed constant network. Expressed by the propagation distance, the spatial part of the structure is divided by the spatial network method, expressed as a spatial network, and expressed by the distribution constant, and propagated using the transient phenomenon analysis method applying the Bergeron method. The point is to analyze the surge.

Further, in addition to the above, the method of analyzing a propagation problem circuit by the spatial circuit method of the present invention is, in addition to the above, a minute resistor which does not affect the overall calculation in each unit cell of the conductor circuit network portion for which a current is to be obtained. The point is to insert the, and guide the output of this minute resistor to the arithmetic circuit to obtain the required current value.

In addition to the above, the circuit analysis method of the propagation problem by the spatial network method of the present invention automatically calculates from the constants of the structure having the network parameter of the arithmetic circuit as a problem and the point of interest information given from the outside. The point is to derive it.

Further, the propagation problem circuit analysis method by the spatial circuit method of the present invention is characterized in that, in addition to the above, resistance loss is also incorporated into a conductor rod such as a building structure.

Furthermore, the propagation problem circuit analysis method by the spatial circuit method of the present invention is characterized in that, in addition to the above, the presence of a dielectric and / or a magnetic material in the space.

In addition to the above, the method of analyzing a propagation problem circuit by the spatial circuit method of the present invention is not limited to the conductor portion having a rod shape,
The main point is to have a general shape or a thin plate shape.

Further, in the propagation problem circuit analysis method by the spatial circuit method of the present invention, in addition to the above, in the building structure, the grids are orthogonal to each other at least at grid points, and the inductances are arranged along the sides of the grids. That is the summary.

Further, in addition to the above, the propagation problem circuit analysis method by the spatial network method of the present invention has the above-mentioned lattice point structure, and the capacitance inside the building structure is arranged along the sides of the lattice, The gist is that the capacitance is placed on the ground from the grid points on the outer wall of the building structure.

In addition to the above, the method of analyzing the propagation problem circuit by the spatial circuit method of the present invention is characterized in that the capacitance is arranged on the ground from all points of the lattice points of the building structure.

[0019]

According to the propagation problem circuit analysis method by the spatial network method of the present invention, the two basic Maxwell equations are combined in the spatial network method to derive the propagation equation, and the spatial network is constructed using the propagation equation. Constitute.

Further, in the propagation problem circuit analysis method according to the spatial circuit method of the present invention, the conductor portion in the structure is expressed as a normal distributed constant network by the surge impedance, the propagation velocity and the propagation distance, and the spatial portion is represented by the spatial circuit. We analyze the surge that propagates by using the transient phenomenon analysis method applying the Bergeron method by dividing it by the network method and expressing it as a spatial network and expressing it by a distributed constant.

Further, in the propagation problem circuit analysis method by the spatial network method of the present invention, a minute resistor is inserted in each unit grid of the conductor circuit network portion, and the output of this minute resistor is guided to the arithmetic circuit to obtain the required signal. Get the current value.

In the propagation problem circuit analysis method according to the spatial network method of the present invention, the circuit network parameter of the arithmetic circuit is automatically derived from the constant of the structure in question and the point of interest information given from the outside.

Further, in the propagation problem circuit analysis method by the spatial circuit method of the present invention, resistance loss is also incorporated into the conductor rod such as a building structure.

Further, in the propagation problem circuit analysis method by the spatial circuit method of the present invention, a dielectric and / or a magnetic material exists in the space.

In the propagation problem circuit analysis method according to the spatial circuit method of the present invention, the conductor portion is not limited to the rod shape, but has a general shape or a thin plate shape.

Further, in the propagation problem circuit analysis method by the spatial network method of the present invention, in the building structure, the grids are orthogonal to each other at least at grid points, and the inductances are arranged along the sides of the grids.

Further, in the propagation problem circuit analysis method by the spatial network method of the present invention, the structure having a grid point structure, the capacitance inside the building structure is arranged along the sides of the grid, and the capacitance is higher than the grid point on the outer wall of the building structure. The capacitance is located at.

In the circuit analysis method of the propagation problem by the spatial network method of the present invention, the capacitance is arranged on the ground from all points of the grid points of the building structure.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the basic concept of the propagation problem circuit analysis method by the spatial network method of the present invention will be described.

As is well known, Maxwell's equation is composed of the following series of equations in a uniform and non-conducting space where no electric charge exists, such as vacuum.

[Equation 1] rotE = −∂B / ∂t, rotH = ∂D
/ ∂t, divD = 0, divB = 0, D = ε
E, B = μH This equation is directly converted into a difference equation and expressed as a spatial network in the conventional spatial network method. Since the basis of the Maxwell equation is that the equations are alternately related in the above series of equations, it is inevitable that electric contacts and magnetic contacts alternately appear in the spatial network.

The present invention performs the following well known transformations to eliminate the drawbacks of conventional spatial network methods. That is, when the rotation of both sides of the equation is taken, the following equation is obtained.

[0032]

[Number 2] rot (rotE) = - rot ( ∂B / ∂t) = -μ (∂ / ∂t) rotH = -με∂ 2 E / ∂t 2 here,

## EQU00003 ## Left side = grad (divE) -div (gra
Since dE) = − ΔE (∵divE = 0), the following equation is obtained.

[0033]

[Equation 4] ΔE−με∂ ² E / ∂t ² = 0 or ΔE− (1 / c ² ) ∂ ² E / ∂t ² (1) This is a well-known wave equation.

There is the following equation regarding the voltage surge propagating in the parallel line, which is similar to the equation (1). That is,
In FIG. 6A, time t, position x as a one-dimensional problem
Let v be the voltage and current i be the well-known equation below.

[0035]

[Formula 5] ∂v / ∂x = L ・ ∂i / ∂t, ∂i / ∂x = C ・ ∂v / ∂t (2) Here, L and C are inductances of the line per unit length, respectively. And capacitance. From equation (2)

[Equation 6] ∂ ² v / ∂x ² = LC · ∂ ² v / ∂t ² = (1 / c ² ) · ∂ ² v / ∂t ² (3), which is obtained from the above ( This is the same as the wave equation of equation 1). The difference is that the electric field and the magnetic field propagate in the equation (1), while the voltage and the current propagate in the equation (3).

The equation (2) or the equation (3) is expressed by the distributed constant circuit as shown in FIG. 6 (b). By the way, when the space is divided, if it is considered that the potential difference, that is, the voltage, multiplied by the electric field E treated in the equation (1) and the division interval Δx propagates, the equation (2) or (3) is considered. Since it is the same as the equation, the circuit theory that voltage and current propagate can be applied.

Based on this idea, the circuit network of FIG. 3 was constructed for propagation in the x direction, for example. In FIG. 3, it is assumed that lightning strikes a point P at one corner of the building structure. This lightning current propagates to the entire building via the inductance and capacitance arranged on the sides of the building steel frame model from L ₁ to L _n, but here, the space is further divided into 1 ₁
Since the sides from 1 to 1 _n are configured as a spatial network, they propagate through this. Although actual propagation is a magnetic field and an electric field, such a model becomes possible by focusing only on the electric field as described above.

Therefore, in FIG. 3, for example, the lightning current distribution flowing through the QD steel frame is not only determined by the impedance of the steel frame, but also the counter electromotive force (actually an electromagnetic induction electric field) due to the action of the current flowing through the spatial network. Depends on

The lightning current distribution will flow more around the building structure due to the action of the induced electric field, but since the magnetic field component is regarded as a current in the above-described method, the current flowing through the steel frame is the lightning current. Is the sum of the current and the magnetic field component, and the required lightning current distribution cannot be obtained.

A major point of the analysis method of the present invention is to provide a method of giving a correct lightning current distribution. Figure 2
As shown in FIG. 3, the current of the steel frame portion QD, which is a part of the spatial network of FIG. 3, is not directly obtained, but the current and position information of the surroundings (that is, the observation points are D and Q) and the arithmetic circuit. It is supplied to C and the lightning current i is obtained by the calculation here.

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 (a) is a model of the steel structure of a building, and FIG. 1 (b) is a part thereof (dotted line part in FIG. 1 (a)).
In FIG. 6C, the spatial mesh (broken line) is cut. The same figure (d) is the same figure (c).
Is a spatial circuit network near a part PQ of the above.

In FIG. 1 (d), Z ₁ is the surge impedance of the steel frame portion and Z _o is the surge impedance of the space.

In FIG. 1D, the current flowing through the building steel frame PQ is the lightning current i plus the currents i _c1 and i _c2 that have propagated through the spatial network and flowed into the building steel frame. . Normally, this cannot be separated, but comparing the surge impedance of the building steel frame with the space surge impedance, the space surge impedance is considerably larger, so as shown in the figure, the surge impedance Z ₁ between PQ is Is the sum of the lightning current i and the parts i _c1 and i _c2 due to the induced voltage. On the other hand, since i _c1 and i _c2 flow in the space portion Z _o , the lightning current portion i flowing in PQ can be obtained by subtracting this.

Actually, the lightning current component i is shunted to the impedance Z _o , but in the Bergeron method Δt
Since the calculation is performed sequentially for each time, the effect of superimposition is considerably reduced. In this method, in order to further accurately obtain the target current, as shown in FIG. 1 (d), the current is obtained by the minute resistance r, and this is led to the arithmetic circuit C, and the surge impedances Z _o and Z ₁ And the information whose positions are P and Q are given so that the lightning current i can be accurately obtained. Since the arithmetic circuit C is a spatial position-dependent arithmetic circuit that is determined by the positions of the observation points P and Q, it suffices to create it at the target position in advance. Further, since this is a problem only in space arrangement, it can be automatically created by giving a building structure and a ground plane.

As described above, according to the present method, a lightning strike on a building such as a building diverts the light and damages equipment in the building, and what position is less susceptible to a lightning disaster. It is understood that it is possible to easily study what kind of structure and arrangement is optimal in terms of lightning resistance.

FIG. 2 is a diagram showing another embodiment of the present invention. In the figure, instead of treating the network as a distributed constant, the spatial network is represented by lumped constants such as L and C.

The embodiment shown in FIG. 2 becomes a distributed constant circuit if the number of divisions is increased, but as shown in FIG. 2, it is possible to save calculation time and memory by making it a lumped constant by appropriate division. You can

[0049]

As described above, according to the present invention,
To construct a circuit network including not only the conductor system but also the space by considering a spatial circuit network, which is composed of many conductors like a building structure and usually requires a lot of mutual inductance. It is possible to avoid the problem that the mutual inductance, which is a difficulty of the numerical circuit network calculation, cannot be taken, and in principle, a propagation problem circuit analysis method that can calculate no matter how much the mutual inductance is, becomes possible.

[Brief description of drawings]

FIG. 1 is a structural diagram of a steel frame of a building for explaining an embodiment of the present invention, a part of which is a spatial mesh cut,
It is a figure which shows the spatial circuit network of the one part vicinity.

FIG. 2 is a diagram showing another embodiment of the present invention.

FIG. 3 is a diagram for explaining the points of the present invention.

FIG. 4 is a diagram for explaining a conventional spatial network method.

FIG. 5 is a diagram for explaining a conventional spatial network method.

FIG. 6 is a diagram showing parallel lines and their distributed constant circuits.

[Explanation of symbols]

 C arithmetic circuit

Claims (10)

[Claims] 1. In a spatial network method for analyzing an electromagnetic wave propagation phenomenon by a network analysis method by dividing a space and expressing it as a network, a propagation equation is derived by combining two basic Maxwell equations. , A method for analyzing a propagation problem circuit by a spatial network method, characterized by constructing a spatial network using the propagation equation. 2. A conductor portion in a structure in which conductor rods are combined, such as a building structure, is expressed by a surge impedance, a propagation velocity and a propagation distance as a normal distributed constant network, and the space portion of the structure is a spatial circuit. Propagation by the spatial network method characterized by analyzing the surge that propagates using the transient phenomenon analysis method applying the Bergeron method by dividing it by the network method and expressing it as a spatial circuit and expressing it as a distributed constant Problem circuit analysis method. 3. A small resistor that does not affect the overall calculation is inserted into each unit cell of the conductor circuit network portion for which a current is to be obtained, and the output of this minute resistor is guided to an arithmetic circuit to obtain a required current value. The method for analyzing a propagation problem circuit according to the spatial circuit method according to claim 1 or 2, wherein 4. The circuit parameter of the arithmetic circuit is automatically derived from a constant of a structure in question and a point-of-interest information given from the outside, according to any one of claims 1 to 3. Circuit analysis method for propagation problems by spatial network method. 5. The circuit analysis method for propagation problems by the spatial network method according to claim 1, wherein resistance loss is also incorporated into a conductor rod such as a building structure. 6. The method for analyzing a propagation problem circuit by the spatial circuit method according to claim 1, wherein a dielectric substance and / or a magnetic substance is present in the space portion. 7. The propagation problem circuit analysis method according to any one of claims 1 to 6, wherein the conductor portion is not limited to a rod shape but has a general shape or a thin plate shape. 8. The spatial circuit according to claim 1, wherein in the building structure, the grids are orthogonal to each other at least at grid points, and the inductances are arranged along the sides of the grids. Circuit Analysis Method for Propagation Problems by Network Method. 9. The structure having the grid point structure, wherein the capacitance inside the building structure is arranged along the sides of the grid, and the capacitance is arranged on the ground from the grid point on the outer wall of the building structure. A propagation problem circuit analysis method using the spatial circuit method according to claim 1. 10. A circuit analysis method for a propagation problem by the spatial network method according to claim 1, wherein capacitances are arranged on the ground from all points of the lattice points of the building structure.