CN115688661B - Modeling method for full circuit parameters of spiral tube type damping bus for VFTO (very fast transient overvoltage) suppression - Google Patents

Abstract

The invention provides a modeling method of a spiral tubular damping bus full circuit parameter for VFTO suppression, which comprises the following steps: establishing a damping bus full-circuit parameter equivalent circuit with each coil including stray parameters and gap breakdown impedance based on an inductance and resistance equivalent circuit of the spiral tube type damping bus; and calculating the equivalent inductance, the stray capacitance, the stray inductance and the gap breakdown impedance of the damping bus based on the full circuit parameter equivalent circuit. On the basis of the existing inductance and resistance equivalent model, the influence of stray parameters is considered, the real situation of the damping bus can be well equivalent, and further theoretical basis is provided for well restraining VFTO and optimizing the design of the spiral tubular damping bus.

Description

A Modeling Method of the Whole Circuit Parameters of Helical Tube Damping Bus for VFTO Suppression

technical field

The invention relates to the field of electric power technology, and more specifically, relates to a modeling method for the parameters of the whole circuit of a helicoidal damping busbar for VFTO suppression.

Background technique

With the improvement of the voltage level of my country's power supply and distribution system and the increase of the capacity of the gas insulated substation (GIS), the very fast transient overvoltage (VFTO) generated by the switching operation makes the insulation problem of the substation more prominent. , the harm caused is more and more serious, effectively suppressing VFTO is the primary problem to be solved to ensure the safe and stable operation of GIS.

The installation of helical tube damping busbar has a good effect of suppressing VFTO, the engineering application conditions are easy to meet, and it will not affect the normal operation of GIS. It is a VFTO suppression method with great engineering application prospects. Its suppression effect can be analyzed and studied by using the equivalent circuit of the helical tube damping bus, but at present, the damping bus is only roughly equivalent to the equivalent circuit of "inductance and resistance", while VFTO propagation includes part of the power frequency component and abundant non- The power frequency component, when the VFTO conduction coupling to the damping bus, will cause the damping bus to produce a series of stray capacitance, stray inductance, gap breakdown impedance (collectively referred to as "spurious parameters" of the damping bus), the stray parameters have A certain high-frequency response will have a certain impact on the suppression effect. How to find a better equivalent model of the helical tube damping busbar is a topic worth studying.

Contents of the invention

Aiming at the technical problems existing in the prior art, the present invention provides a modeling method for the full circuit parameters of the helicoidal damping bus for VFTO suppression, which considers the stray parameters on the basis of the existing equivalent model of inductance and resistance It can be well equivalent to the real situation of the damping busbar, and then provide a theoretical basis for better suppressing VFTO and optimizing the design of the spiral tube damping busbar.

According to the first aspect of the present invention, there is provided a method for modeling the full circuit parameters of the helicoidal damping bus for VFTO suppression, including:

S1, based on the inductance and resistance equivalent circuit of the spiral tube damping bus, establish the equivalent circuit of the full circuit parameters of the damping bus including stray parameters and gap breakdown impedance of each coil;

S2. Calculate the equivalent inductance, stray capacitance, stray inductance and gap breakdown impedance of the damping bus based on the full circuit parameter equivalent circuit.

On the basis of the above technical solution, the present invention can also make the following improvements.

Optionally, in step S1, the constructed equivalent circuit of the full circuit parameters of the damping bus includes:

以及 阻尼母线与常规母线间的杂散电感

，每个单匝线圈等效电路模块均串联阻尼母线与壳 体之间的杂散电容

后接地; Equivalent circuit modules of multiple single-turn coils connected in series, stray capacitance between damping busbar and conventional busbar

and the stray inductance between the damped busbar and the conventional busbar

, each single-turn coil equivalent circuit module is connected in series to damp the stray capacitance between the busbar and the shell

rear ground;

Each single-turn coil equivalent circuit module includes a first branch, a second branch and a third branch connected in parallel; the first branch includes a single-turn coil parallel resistance R _e , and the second branch Including the equivalent inductance L _e of a single-turn coil;

以及连接头与首/末匝线圈间杂散电感

； In the equivalent circuit module of the first/last turn coil, the third branch includes the gap breakdown impedance R _v connected in series, the stray capacitance between the connector and the first/last turn coil

And the stray inductance between the connector and the first/last turn coil

;

以及相邻匝线圈间杂散电感

。 In the equivalent circuit module of the remaining coils, the third branch includes the gap breakdown impedance R _v connected in series, the stray capacitance between adjacent coils

and the stray inductance between adjacent turns of the coil

.

Optionally, in step S2, the process of calculating the equivalent inductance and stray inductance of the damping bus includes:

Judging whether the current passing through the helical damping busbar is a high-frequency current: if it is not a high-frequency current, calculate the inductance at power frequency; if it is a high-frequency current, use the field calculation method combined with the skin effect to calculate the equivalent inductance of the damping busbar; The stray inductance is obtained by using the field calculation method and calculating the external magnetic flux of the damping bus.

Optionally, the process of calculating the equivalent inductance and stray inductance of the damping bus includes:

Assume that the relationship between the current i, the magnetic flux B and the inductance L in the damping bus is as follows:

（1），

(1),

，将

代 入式（1），将得到的式（2）用于计算阻尼母线的等效电感L： When it is determined that the current i flowing through the helical damping busbar is a low-frequency current, then there is

,Will

Substituting into formula (1), the obtained formula (2) is used to calculate the equivalent inductance L of the damping bus:

（2）；

(2);

When it is determined that the current i flowing through the helical damping busbar is a high-frequency current, it is assumed that the skin depth of the current in the damping busbar is as shown in formula (3):

（3），

(3),

In formula (3), δ _sd is skin depth in m; f is excitation frequency in Hz; µ is magnetic permeability in H/m; σ is electrical conductivity in S/m;

The effective cross-sectional area s through which the current i flows, that is, the cross-sectional area within the skin depth, is shown in formula (4):

（4），

(4),

In formula (4), r is the outer diameter of the damping bus section, and a is the ratio of the inner diameter to the outer diameter of the damping bus section;

Put the formula (4) into the inductance calculation formula (1) to get the formula (5), and use the formula (5) to calculate the inductance value L of the damping bus:

（5）。

(5).

Optionally, in step S2, the stray capacitance of the damping bus is calculated by using the Maxwell capacitance matrix and the relationship between the inter-turn charge and the potential.

Optionally, the process of calculating the stray capacitance of the damping bus specifically includes:

Assuming that n conductors are respectively charged with charges Q ₁ , Q ₂ , ... Q _n , formula (6) can be obtained by the potential superposition theorem:

（6），

(6),

Among them, V ₁ , V ₂ , ... V _n are the potentials corresponding to n conductors, and C is the Maxwell capacitance matrix;

According to formula (6), the total charge of one of the conductors is:

（7），

(7),

Then for a system with n conductors, its Maxwell capacitance matrix C can be expressed as:

（8），

(8),

In formula (8), i is one of the n conductors, and C _mni is the mutual capacitance, that is, the stray capacitance generated after the charge accumulation of n conductor and i conductor;

、相邻匝线圈 间杂散电容

、连接头与首/末匝线圈间杂散电容

和阻尼母线与常规母线间杂散电 容

。 Solve the charge quantity Q and potential V corresponding to the damping busbar, coil per turn, conventional busbar, and connector through field calculation, and solve the Maxwell capacitance matrix C to calculate the stray capacitance between the damping busbar and the shell

, Stray capacitance between adjacent turns of the coil

, Stray capacitance between the connector and the first/last turn coil

and stray capacitance between the damping bus and the conventional bus

.

Optionally, in step S2, the gap breakdown condition of the damping bus is obtained by using the coupling calculation of the damping bus and the gap breakdown criterion.

Optionally, the process of calculating the gap breakdown impedance of the damping busbar specifically includes:

According to formula (9), it is judged whether the inter-turn gap is completely broken down:

（9），

(9),

为匝间间隙气体密度，E为匝间间隙电场分布； in,

is the inter-turn gap gas density, E is the inter-turn gap electric field distribution;

When E _d >0, it is determined that the inter-turn gap is completely broken down, and then the breakdown impedance R _v of the inter-turn gap of the damping bus is calculated according to formula (10):

（10），

(10),

为时间常数；t₀ 为匝间气体击穿和稳定燃烧阶段时间。 Among them, R _a is the static arcing resistance; R ₀ is the high resistance state when the isolation switch is insulated in the gap;

is the time constant; t ₀ is the inter-turn gas breakdown and stable combustion phase time.

According to the second aspect of the present invention, there is provided a modeling system for the full circuit parameters of the helicoidal damping bus for VFTO suppression, including:

The model building block is used to establish the equivalent circuit of the full circuit parameters of the damping bus including stray parameters and gap breakdown impedance of each coil based on the inductance and resistance equivalent circuit of the spiral tube damping bus;

The parameter calculation module is used to calculate the equivalent inductance, stray capacitance, stray inductance and gap breakdown impedance of the damping bus based on the full circuit parameter equivalent circuit.

The present invention provides a modeling method for the full circuit parameters of the helical damping bus for VFTO suppression. On the basis of establishing the equivalent circuit of the damping bus, according to the structural characteristics and mechanism of the helical damping bus, a complex The equivalent circuit of the damping bus with stray parameters; on the basis of the equivalent circuit with stray parameters, the inductance, stray capacitance, stray inductance and inter-turn gap impedance parameters of the helical tube damping bus are calculated, and the helical tube damping bus is obtained. The full circuit parameters of the damping busbar. The full circuit parameters of the helical tube damping bus for VFTO suppression can be equivalent to the helical tube damping bus on the basis of a more complete grasp of the damping bus suppression mechanism, which helps to effectively analyze the suppression effect of the damping bus on VFTO, and then provide better design The damping bus structure provides a certain theoretical basis.

Description of drawings

Figure 1 is a schematic diagram of the structure of the spiral tube damping busbar;

Fig. 2 is a kind of VFTO suppression provided by the present invention with the modeling method flow chart of helicoidal damping bus full circuit parameter;

Fig. 3 is the equivalent circuit diagram of the full circuit parameters of the helicoidal damping bus bar for VFTO suppression provided by the present invention;

Fig. 4 is the flow chart of the inductance calculation of the damping bus bar in a certain embodiment;

FIG. 5 is a schematic diagram of the composition and structure of a modeling system for the full circuit parameters of a helical damping busbar for VFTO suppression provided by the present invention.

Detailed ways

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

Figure 1 is a schematic diagram of the hardware structure of the helical tube damping busbar. As shown in Figure 1, the helical tube damping busbar is to hollow out the busbar tube in a spiral manner, and the obtained helical coil forms a helical tube, and the hollowed out slot plays the role of the discharge gap between the turns of the coil. There is a non-inductive damping resistor connected in parallel between turns of the spiral tube, and the epoxy support set in the spiral tube provides structural support for the damping resistor between turns. The spiral tube type damping busbar is placed in SF6 gas as a whole, which is a distributed structure. SF6 gas is used as the insulating medium between the damping busbar and the shell, and the shell is grounded.

Based on the helical damping bus structure shown in FIG. 1 , as shown in FIG. 2 , the present invention provides a flow chart of a modeling method for full circuit parameters of the helical damping bus for VFTO suppression. As shown in Figure 2, the method includes:

S1, based on the inductance and resistance equivalent circuit of the spiral tube damping bus, establish the equivalent circuit of the full circuit parameters of the damping bus including stray parameters and gap breakdown impedance of each coil;

S2. Calculate the equivalent inductance, stray capacitance, stray inductance and gap breakdown impedance of the damping bus based on the full circuit parameter equivalent circuit.

It is understandable that the structure of the damping bus is a multi-turn spiral coil and multi-level parallel resistors. Each part of the damping bus will generate stray parameters due to electrostatic induction and electromagnetic induction, and at the same time, the breakdown of the inter-turn gap will generate impedance. Based on the defects in the background technology, in order to more completely equivalent to the damping busbar, analyze the suppression effect of the damping busbar on VFTO more effectively, and then better grasp the suppression mechanism of the damping busbar, obtain the optimal suppression effect, and reduce the design cost, this paper The embodiment of the invention proposes a modeling method for the wide-frequency transient model of the helicoidal damping busbar for VFTO suppression. Based on the original "inductance and resistance" equivalent circuit, a full circuit parameter model of the damping busbar under VFTO conditions is established, combined with The calculation results of the inductance, stray capacitance, stray inductance and inter-turn gap impedance of the helical tube type damping bus can be used to obtain the full circuit parameters of the damping bus. very important.

In a possible embodiment, as shown in FIG. 3, in step S1, the constructed equivalent circuit of the damping bus full circuit parameters includes:

以及 阻尼母线与常规母线间的杂散电感

，每个单匝线圈等效电路模块均串联阻尼母线与壳 体之间的杂散电容

后接地; Equivalent circuit modules of multiple single-turn coils connected in series, stray capacitance between damping busbar and conventional busbar

and the stray inductance between the damped busbar and the conventional busbar

, each single-turn coil equivalent circuit module is connected in series to damp the stray capacitance between the busbar and the shell

rear ground;

Each single-turn coil equivalent circuit module includes a first branch, a second branch and a third branch connected in parallel; the first branch includes a single-turn coil parallel resistance R _e , and the second branch Including the equivalent inductance L _e of a single-turn coil;

以及连接头与首/末匝线圈间杂散电感

； In the equivalent circuit module of the first/last turn coil, the third branch includes the gap breakdown impedance R _v connected in series, the stray capacitance between the connector and the first/last turn coil

And the stray inductance between the connector and the first/last turn coil

;

以及相邻匝线圈间杂散电感

。 In the equivalent circuit module of the remaining coils, the third branch includes the gap breakdown impedance R _v connected in series, the stray capacitance between adjacent coils

and the stray inductance between adjacent turns of the coil

.

It is understandable that in the case of high frequency, the spiral tube damping busbar will produce a strong high frequency response due to its unique structure, and the SF6 gas in the inter-turn gap will be broken down, resulting in various stray parameters and breakdown Therefore, on the basis of the existing centralized parameter equivalent circuit of "inductance and resistance", the damping bus circuit is extended to consider the inter-turn, between each turn, the connection part and the first part as shown in Figure 3. The full circuit parameter equivalent circuit of the stray parameters and gap breakdown impedance parameters between the last turns, between the conventional busbar and between the damping busbar and the shell can be more truly and completely equivalent to the helical tube damping busbar. It should be noted that the gap breakdown resistance _Rv shown in Figure 3 is determined by the gap breakdown of the damping busbar under VFTO conditions, so it is temporarily represented by a dotted line.

In a possible embodiment, in step S2, as shown in the flowchart of FIG. 4 , the process of calculating the equivalent inductance and stray inductance of the damping bus includes:

Judging whether the current passing through the helical damping busbar is a high-frequency current: if it is not a high-frequency current, calculate the inductance at power frequency; if it is a high-frequency current, use the field calculation method combined with the skin effect to calculate the equivalent inductance of the damping busbar; The stray inductance is obtained by using the field calculation method and calculating the external magnetic flux of the damping bus.

It can be understood that, considering the current skin effect, the current distribution on the helical damping busbar is different under different frequency conditions, and the effective cross-section of the damping busbar passing current will be different accordingly, and the coupling state of the flux linkage when the damping busbar passes current is The key to the calculation of damping bus inductance. Therefore, as shown in Figure 4, the calculation process of the damping bus inductance mainly focuses on the flux coupling of the damping bus when the frequency and current flow, and the flux coupling is reflected by the magnetic flux density of the damping bus calculated at different frequencies.

More specifically, in a possible embodiment, the process of calculating the equivalent inductance and stray inductance of the damping bus is as follows:

The essence of inductance calculation is magnetic flux calculation, so it is assumed that the relationship between current i, magnetic flux B and inductance L in the damping bus is as follows:

（1），

(1),

，将

代入式（1），将得到的式（2）用于 计算阻尼母线的等效电感L： Under low-frequency conditions, the uneven distribution of current on the conductor cross-section is usually ignored. When the current i flowing through the helical damping busbar is determined to be a low-frequency current, then there is

,Will

Substituting into formula (1), the obtained formula (2) is used to calculate the equivalent inductance L of the damping bus:

（2）；

(2);

Under high-frequency conditions, the current is completely concentrated in the extremely thin surface layer of the conductor, and the concentrated thickness is the skin depth. When it is determined that the current i flowing through the helical damping busbar is a high-frequency current, it is assumed that the skin depth of the current in the damping busbar is as shown in formula (3):

（3），

(3),

In formula (3), δ _sd is skin depth in m; f is excitation frequency in Hz; µ is magnetic permeability in H/m; σ is electrical conductivity in S/m;

Due to the skin effect, the inductance calculation formula cannot be directly calculated, but can be approximated by the skin depth. At this time, the effective cross-sectional area s of the current i flowing through, that is, the cross-sectional area within the skin depth, is shown in formula (4):

（4），

(4),

In formula (4), r is the outer diameter of the damping bus section, and a is the ratio of the inner diameter to the outer diameter of the damping bus section.

Put the formula (4) into the inductance calculation formula (1) to get the formula (5), and use the formula (5) to calculate the equivalent inductance value L of the damping bus:

（5）；

(5);

、相邻匝线圈间杂散电感

以及阻尼母线与常规母线间的杂散电感

由电流流过阻尼母线时产生的外磁链反映，其 计算与螺旋管式阻尼母线本体的等效电感Le计算方法基本相同。区别主要在于，代入上述 式（2）和式（5）中的磁通B的区别。例如，计算连接头与首/末匝线圈间的杂散电感

时，需 将连接头与首/末匝线圈间的外磁通代入方程式进行计算；计算相邻匝线圈间杂散电感

时，需将相邻匝线圈间的外磁通代入方程式进行计算；计算阻尼母线与常规母线间的 杂散电感

时，需将阻尼母线与常规母线之间的外磁通代入方程式进行计算。 When calculating the equivalent inductance L _e of each coil of the damping bus bar, the internal magnetic flux of the current coil is substituted into the equation for calculation. It is understandable that the stray inductance between the connector and the first/last turn coil

, Stray inductance between adjacent turns of the coil

and the stray inductance between the damped busbar and the conventional busbar

Reflected by the external flux linkage generated when the current flows through the damping busbar, its calculation method is basically the same as the calculation method of the equivalent inductance Le of the toroidal damping busbar body. The difference mainly lies in the difference of the magnetic flux B substituted into the above formula (2) and formula (5). For example, calculating the stray inductance between the connector and the first/last turn of the coil

, it is necessary to substitute the external magnetic flux between the connector and the first/last coil into the equation for calculation; calculate the stray inductance between adjacent coils

When , it is necessary to substitute the external magnetic flux between adjacent coils into the equation for calculation; to calculate the stray inductance between the damping busbar and the conventional busbar

, the external magnetic flux between the damping busbar and the conventional busbar needs to be substituted into the equation for calculation.

In a possible embodiment, in step S2, the stray capacitance of the damping bus is calculated by using the Maxwell capacitance matrix and the relationship between the inter-turn charge and the potential.

It can be understood that stray capacitance will be generated between the spiral tube damping busbar, conventional busbar, connector part, and each turn of coil after charge accumulation, and the distribution of each stray capacitance can refer to the equivalent circuit diagram shown in Figure 3 . Starting from the generation mechanism of stray capacitance, the calculation of stray capacitance can be converted into the calculation of conductor charge accumulation, and the Maxwell capacitance matrix represents the relationship between the charge of a certain conductor and the voltage of all conductors, and the Maxwell capacitance matrix is converted into mutual capacitance After the matrix, the stray capacitance generated after the charge accumulation can be obtained.

In a possible embodiment, the process of calculating the stray capacitance of the damping bus specifically includes:

The spiral tube damping busbar, conventional busbar, connector part, and each turn of the coil are regarded as separate conductors, and the total number of these conductors is n;

Assuming that n conductors are respectively charged with charges Q ₁ , Q ₂ , ... Q _n , formula (6) can be obtained by the potential superposition theorem:

（6），

(6),

Among them, V ₁ , V ₂ , ... V _n are the potentials corresponding to n conductors, C is the Maxwell capacitance matrix, and the Maxwell capacitance matrix C describes the relationship between the charge of the i-th conductor in the n conductors and the voltage of all conductors in the system Relationship;

From formula (6), the total charge of one of the conductors (such as the first conductor) is:

（7），

(7),

Then, for a spiral tube damping bus system with n conductors, its Maxwell capacitance matrix C can be expressed as:

（8），

(8),

In formula (8), i is one of the n conductors, and C _mni is the mutual capacitance, that is, the stray capacitance generated after the charge accumulation of the n conductor and the i conductor.

、 相邻匝线圈间杂散电容

、连接头与首/末匝线圈间杂散电容

和阻尼母线与常规母 线间杂散电容

。 When solving the stray capacitance of the damping bus, the present invention will use the relationship between the Maxwell capacitance matrix and the mutual capacitance matrix to solve the problem, and solve the corresponding charge Q of the damping bus, coils per turn, connectors, and conventional bus through field calculations and potential V, the stray capacitance between the damping bus and the shell can be calculated by solving the Maxwell capacitance matrix C

, Stray capacitance between adjacent turns of the coil

, Stray capacitance between the connector and the first/last turn coil

and stray capacitance between the damping bus and the conventional bus

.

In a possible embodiment, in step S2, the gap breakdown condition of the damping bus is obtained by using the damping bus coupling calculation and the gap breakdown criterion.

及电场 分布E，结合绝缘击穿判据得到阻尼母线间隙的击穿情况。即对阻尼母线间隙临界击穿场强 判据的截面分布情况进行分析即可得到螺旋管式阻尼母线每匝线圈间隙的击穿情况。 It can be understood that when the high-frequency, high-amplitude VFTO propagates on the damping bus, the temperature of the damping bus rises, and the SF6 gas medium in the inter-turn gap of the coil will break down, and the inter-turn breakdown impedance will affect the impedance characteristics of the damping bus. . The present invention obtains the gas density between the coil gaps of each turn of the damping busbar under the condition of considering the temperature rise and the gas medium flow

And the electric field distribution E, combined with the insulation breakdown criterion, the breakdown situation of the damping bus gap is obtained. That is to say, analyzing the cross-sectional distribution of the critical breakdown field strength criterion of the damping busbar gap can obtain the breakdown situation of the coil gap of each turn of the helical damping busbar.

In a possible embodiment, the process of calculating the gap breakdown impedance of the damping bus specifically includes:

First of all, it is necessary to judge the breakdown of the damping bus gap. Using formula (9) as the gap breakdown criterion, judge whether the inter-turn gap is completely broken down according to formula (9):

（9），

(9),

为匝间间隙气体密度，E为匝间间隙电场分布。 in,

is the inter-turn gap gas density, E is the inter-turn gap electric field distribution.

In order to define the breakdown situation, this patent considers that the area where E _d >0 in the damping busbar gap exceeds half of the gap, that is, the entire gap is considered to be completely broken down. Then use the spark gap breakdown theory to calculate the spark gap resistance shown in the following formula (10), and then the inter-turn gap breakdown impedance parameter of the damped bus can be obtained.

Specifically, when E _d >0, it is determined that the inter-turn gap is completely broken down, and then the breakdown resistance R _v of the inter-turn gap of the damping bus is calculated according to formula (10):

（10），

(10),

Among them, R _a is the static arcing resistance; R ₀ is the high resistance state of the disconnector gap insulation; τ is the time constant; t ₀ is the inter-turn gas breakdown and stable combustion stage time.

The modeling method of the full circuit parameters of the helicoidal damping bus for VFTO suppression established by the present invention can be well equivalent to the real situation of the helical damping bus, thereby providing a certain theoretical basis for better suppressing VFTO.

Fig. 5 is a kind of modeling system structural diagram of the full circuit parameter of helical tube type damping bus bar for VFTO suppression that the embodiment of the present invention provides, as shown in Fig. Modeling system, including model building blocks and parameter calculation blocks, where:

The model building block is used to establish the equivalent circuit of the full circuit parameters of the damping bus including stray parameters and gap breakdown impedance of each coil based on the inductance and resistance equivalent circuit of the spiral tube damping bus;

The parameter calculation module is used to calculate the equivalent inductance, stray capacitance, stray inductance and gap breakdown impedance of the damping bus based on the full circuit parameter equivalent circuit.

It can be understood that the modeling system for the full circuit parameters of a helical damping bus for VFTO suppression provided by the present invention corresponds to the modeling method for the full circuit parameters of the helical damping bus for VFTO suppression provided in the foregoing embodiments. For the relevant technical characteristics of the modeling system of the full circuit parameters of the helical damping bus for VFTO suppression, please refer to the relevant technical characteristics of the modeling method for the full circuit parameters of the helical damping bus for VFTO suppression, and will not be repeated here.

The embodiment of the present invention provides a modeling method and system for the full circuit parameters of the helical damping bus for VFTO suppression. On the basis of establishing the equivalent circuit of the damping bus, according to the structural characteristics and mechanism of the helical damping bus, The equivalent circuit of the damping bus with stray parameters is established; on the basis of the equivalent circuit with stray parameters, the inductance, stray capacitance, stray inductance and inter-turn gap impedance parameters of the helical tube damping bus are calculated. The full circuit parameters of the helical tube damping busbar are obtained. The full circuit parameters of the helical tube damping bus for VFTO suppression can be equivalent to the helical tube damping bus on the basis of a more complete grasp of the damping bus suppression mechanism, which helps to effectively analyze the suppression effect of the damping bus on VFTO, and then provide better design The damping bus structure provides a certain theoretical basis.

It should be noted that, in the foregoing embodiments, descriptions of each embodiment have their own emphases, and for parts that are not described in detail in a certain embodiment, reference may be made to relevant descriptions of other embodiments.

Those skilled in the art should understand that the embodiments of the present invention may be provided as methods, systems, or computer program products. Accordingly, the present invention can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It should be understood that each procedure and/or block in the flowchart and/or block diagram, and a combination of procedures and/or blocks in the flowchart and/or block diagram can be realized by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded computer, or other programmable data processing device to produce a machine such that the instructions executed by the processor of the computer or other programmable data processing device produce a machine for A device for realizing the functions specified in one or more procedures of a flowchart and/or one or more blocks of a block diagram.

These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing apparatus to operate in a specific manner, such that the instructions stored in the computer-readable memory produce an article of manufacture comprising instruction means, the instructions The device realizes the function specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions can also be loaded onto a computer or other programmable data processing device, causing a series of operational steps to be performed on the computer or other programmable device to produce a computer-implemented process, thereby The instructions provide steps for implementing the functions specified in the flow chart or blocks of the flowchart and/or the block or blocks of the block diagrams.

While preferred embodiments of the invention have been described, additional changes and modifications to these embodiments can be made by those skilled in the art once the basic inventive concept is understood. Therefore, it is intended that the appended claims be construed to cover the preferred embodiment as well as all changes and modifications which fall within the scope of the invention.

Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and equivalent technologies thereof, the present invention also intends to include these modifications and variations.

Claims (5)

1. A modeling method for full circuit parameters of a spiral tube type damping bus for VFTO suppression is characterized by comprising the following steps:

s1, establishing a damping bus full-circuit parameter equivalent circuit containing stray parameters and gap breakdown impedance for each turn of coil based on an inductance-parallel resistance equivalent circuit of a spiral tubular damping bus; the constructed damping bus full circuit parameter equivalent circuit comprises:

stray capacitance C between multiple single-turn coil equivalent circuit modules, damping bus and conventional bus connected in series _σ2 And stray inductance L between the damping bus and the conventional bus _σ2 Each single-turn coil equivalent circuit module is connected in series with a stray capacitor C between the damping bus and the shell _σe0 Then grounding;

each single-turn coil equivalent circuit module comprises a first branch circuit, a second branch circuit and a third branch circuit which are connected in parallel; the first branch comprises a sheetTurn coil parallel resistance R _e The second branch circuit comprises a single-turn coil equivalent inductance L _e ；

In the first/last coil equivalent circuit module, the third branch comprises a gap breakdown resistance R connected in series _v Stray capacitance C between connector and first/last coil _σ12 And stray inductance L between the connector and the first/last turn coil _σ12 ；

In the equivalent circuit module of the other turns, the third branch comprises a gap breakdown resistance R connected in series _v And stray capacitance C between adjacent coils _σ11 And stray inductance L between adjacent turns _σ11 ；

S2, calculating the equivalent inductance, the stray capacitance, the stray inductance and the gap breakdown impedance of the damping bus based on the full circuit parameter equivalent circuit;

specifically, the process of calculating the equivalent inductance and the stray inductance of the damping bus includes:

judging whether the current passing through the spiral tube type damping bus is a high-frequency current: if the current is not high-frequency current, inductance calculation under power frequency is carried out; if the current is high-frequency current, calculating the equivalent inductance of the damping bus by combining a field calculation method and a skin effect; the external magnetic flux of the damping bus is calculated by using a field calculation method to obtain stray inductance;

calculating to obtain the stray capacitance of the damping bus by using a Maxwell capacitance matrix and the relation between turn-to-turn charge and potential;

and obtaining the gap breakdown condition of the damping bus by using the coupling calculation of the damping bus and a gap breakdown criterion.

2. The modeling method of full circuit parameters of the spiral tube type damping bus for VFTO suppression according to claim 1, wherein the process of calculating the equivalent inductance and the stray inductance of the damping bus comprises the following steps:

assuming that the relation between the current i, the magnetic flux B and the inductance L in the damping bus is as follows (1):

（1），

when the current i flowing through the spiral tube type damping bus is judged to be low-frequency current, the current i is

Will>

Substituting equation (1), the obtained equation (2) is used for calculating the equivalent inductance L of the damping bus:

（2）；

when the current i flowing through the spiral tube type damping bus is judged to be high-frequency current, the skin depth of the current in the damping bus is assumed to be shown in an equation (3):

（3），

in the formula (3), δ _sd Skin depth in m; f is the excitation frequency in Hz; mu is magnetic conductivity, and the unit is H/m; σ is the conductivity, with the unit of S/m;

an effective sectional area s through which the current i flows, that is, a sectional area within a skin depth, is represented by formula (4):

（4），

in the formula (4), r is the outer diameter of the section of the damping bus, and a is the ratio of the inner diameter to the outer diameter of the section of the damping bus;

substituting equation (4) into inductance calculation equation (1) to obtain equation (5), and calculating the damping bus inductance L by using equation (5):

（5）。

3. the method for modeling the full circuit parameters of the spiral tube type damping bus for VFTO suppression as claimed in claim 1, wherein the process of calculating the stray capacitance of the damping bus specifically comprises:

suppose that n conductors each have a charge of Q ₁ 、Q ₂ 、…Q _n Formula (6) can be obtained by the potential superposition theorem:

（6），

wherein, V ₁ 、V ₂ 、…V _n The potentials corresponding to the n conductors are obtained, and C is a Maxwell capacitance matrix;

the total charge of one of the conductors is obtained from equation (6):

（7），

then for a system with n conductors, its maxwell capacitance matrix C can be expressed as:

（8），

in the formula (8), i is one of n conductors, C _mni The capacitance is mutual capacitance, namely stray capacitance generated after charges of an n conductor and an i conductor are accumulated;

the electric charge quantity Q and the electric potential V corresponding to the damping bus, each turn of coil, the conventional bus and the connector are solved through field calculation, and the Maxwell capacitance matrix C is solved to calculate the stray capacitance C between the damping bus and the shell _σe0 And stray capacitance C between adjacent coils _σ11 Stray capacitance C between connector and first/last coil _σ12 Stray capacitance C between damping bus and conventional bus _σ2 。

4. The method for modeling the full circuit parameters of the spiral tube type damping bus for VFTO suppression as claimed in claim 1, wherein the process of calculating the gap breakdown impedance of the damping bus specifically comprises:

judging whether the turn-to-turn gap is completely broken down according to the formula (9):

（9），

wherein,ρis the density of the gas in the inter-turn gap,Ethe distribution of the inter-turn gap electric field is adopted;

when E is _d >When 0, judging that the turn-to-turn gap is completely broken down, and then calculating according to the formula (10) to obtain breakdown impedance R of the turn-to-turn gap of the damping bus _v ：

（10），

Wherein R is _a Is a static arcing resistor; r ₀ The state is a high-resistance state when the gap of the isolating switch is insulated; τ is a time constant; t is t ₀ Turn-to-turn gas breakdown and stable combustion phase time.

5. A modeling system for full circuit parameters of a spiral tube type damping bus for VFTO suppression is characterized by comprising the following components:

the model building module is used for building a damping bus full circuit parameter equivalent circuit with each turn of coil containing stray parameters and gap breakdown impedance based on an inductance parallel resistance equivalent circuit of the spiral tube type damping bus; the constructed damping bus full circuit parameter equivalent circuit comprises:

stray capacitance C between multiple single-turn coil equivalent circuit modules, damping bus and conventional bus connected in series _σ2 And stray inductance L between the damping bus and the conventional bus _σ2 Each single-turn coil equivalent circuit module is connected in series with a stray capacitor C between the damping bus and the shell _σe0 Then grounding;

each single-turn coil equivalent circuit module comprises a first branch circuit, a second branch circuit and a third branch circuit which are connected in parallel; the first branch comprisesSingle-turn coil parallel resistor R _e The second branch circuit comprises a single-turn coil equivalent inductance L _e ；

In the first/last coil equivalent circuit module, the third branch comprises a gap breakdown resistance R connected in series _v Stray capacitance C between connector and first/last turn coil _σ12 And stray inductance L between the connector and the first/last turn coil _σ12 ；

In the equivalent circuit module of the other turns, the third branch comprises a gap breakdown resistance R connected in series _v Stray capacitance C between adjacent turns _σ11 And stray inductance L between adjacent turns _σ11 ；

The parameter calculation module is used for calculating the equivalent inductance, the stray capacitance, the stray inductance and the gap breakdown impedance of the damping bus based on the full circuit parameter equivalent circuit;

specifically, the process of calculating the equivalent inductance and the stray inductance of the damping bus includes:

judging whether the current passing through the spiral tube type damping bus is a high-frequency current: if the current is not high-frequency current, inductance calculation under power frequency is carried out; if the current is high-frequency current, calculating the equivalent inductance of the damping bus by using a field calculation method and combining a skin effect; calculating the external magnetic flux of the damping bus by using a field calculation method to obtain stray inductance;

calculating to obtain the stray capacitance of the damping bus by using a Maxwell capacitance matrix and the relation between turn-to-turn charge and potential;

and obtaining the gap breakdown condition of the damping bus by using the coupling calculation of the damping bus and a gap breakdown criterion.

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