Method and system for analyzing normal operation and turn-to-turn short circuit fault of electromagnetic voltage transformer

Abstract

The application discloses a normal operation and turn-to-turn short-circuit fault analysis method and system of an electromagnetic voltage transformer, and comprises the following steps: obtaining external parameters of the electromagnetic voltage transformer; establishing a finite element short-circuit fault model of the electromagnetic voltage transformer suitable for a winding grouping method, and calculating performance parameters of the electromagnetic voltage transformer; constructing a normal operation external characteristic analysis model of the electromagnetic voltage transformer and a turn-to-turn short-circuit external characteristic analysis model of the electromagnetic voltage transformer based on the performance parameters and the external parameters, and then establishing a normal operation and turn-to-turn short-circuit self-defined element model of the electromagnetic voltage transformer; and then performing fault analysis. The application verifies the accuracy of the normal operation self-defined element model of the electromagnetic voltage transformer by using a π-type equivalent circuit of the electromagnetic voltage transformer, and verifies the high accuracy of the turn-to-turn short-circuit self-defined element model of the electromagnetic voltage transformer by combining with an actual power plant fault recording graph, and analyzes the characteristics of the turn-to-turn short-circuit electrical quantity of the electromagnetic voltage transformer.

Description

Technical Field

[0001] This invention belongs to the field of voltage transformer fault analysis technology, specifically a method and system for analyzing the normal operation and inter-turn short circuit faults of an electromagnetic voltage transformer. Background Technology

[0002] To study the impact of inter-turn short circuits in the electromagnetic voltage transformer at the generator terminal on the entire generator-transformer system, it is necessary to understand the external impedance characteristics of the electromagnetic voltage transformer. Based on this, the electromagnetic voltage transformer can be equivalent to a current source. Therefore, it is necessary to establish a custom component model of the electromagnetic voltage transformer under normal operation and inter-turn short circuit conditions, and quantitatively give the primary current and secondary voltage of the electromagnetic voltage transformer under different operating conditions.

[0003] The electromagnetic voltage transformer at the generator outlet is directly connected to the outlet busbar. When an inter-turn short circuit occurs in this transformer, it will trigger the generator stator grounding protection, leading to an unplanned generator outage. Studying the external characteristics of inter-turn short-circuit faults in electromagnetic voltage transformers is crucial for quantitatively analyzing these fault characteristics, demonstrating the impact of inter-turn short-circuit faults on stator grounding protection, improving the corresponding protection principles, and ensuring the safe and stable operation of the power system.

[0004] Existing technologies do not provide methods for detecting normal operation and inter-turn short circuit faults, which makes it difficult to clearly show the impact of inter-turn short circuits in the generator terminal electromagnetic voltage transformer on the entire generator-transformer system. Summary of the Invention

[0005] To address the aforementioned issues with the external impedance characteristics of electromagnetic voltage transformers, this invention provides a method and system for analyzing the normal operation and inter-turn short-circuit faults of electromagnetic voltage transformers, and establishes a custom component model for the normal operation and inter-turn short-circuit faults of electromagnetic voltage transformers.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for analyzing the normal operation and inter-turn short-circuit faults of an electromagnetic voltage transformer, comprising:

[0008] Obtain the external parameters of the electromagnetic voltage transformer;

[0009] Based on the external parameters, a finite element short-circuit fault model of an electromagnetic voltage transformer suitable for the winding grouping method is established, and the performance parameters of the electromagnetic voltage transformer are calculated by finite element analysis.

[0010] Based on performance parameters and external parameters, analytical models of the external characteristics of electromagnetic voltage transformers under normal operation and inter-turn short circuit are constructed. Then, custom component models of electromagnetic voltage transformers under normal operation and inter-turn short circuit are established respectively.

[0011] Based on a custom component model of electromagnetic voltage transformers under normal operation and inter-turn short circuit, the electromagnetic voltage transformer under normal operation and inter-turn short circuit is equivalent to a current source. The input voltage of the equivalent current source is measured in real time, and the primary current and secondary voltage of the electromagnetic voltage transformer are quantitatively output for fault analysis.

[0012] As a further improvement of the present invention, the method of obtaining the external parameters of the electromagnetic voltage transformer includes:

[0013] The electromagnetic voltage transformer has the following parameters: grid-connected rated voltage V1, rated power frequency f, voltage ratio Ku, voltage transformer core magnetization curve, winding structure length, width, and height parameters, primary winding group number n, transition resistance r, and fault location parameters GZP / DGQ.

[0014] As a further improvement of the present invention, the calculated performance parameters of the electromagnetic voltage transformer include the self-inductance values ​​L of the primary and secondary windings of the electromagnetic voltage transformer. i / L n+1 and the mutual inductance value M between the primary and secondary windings ij .

[0015] As a further improvement of the present invention, the construction of the analytical model of the normal operating external characteristics of the electromagnetic voltage transformer includes:

[0016] The transient response equation of the circuit system where the primary windings of an electromagnetic voltage transformer are separated during normal operation is as follows:

[0017]

[0018] In the formula, u i r represents the terminal voltage of each winding. i Let i be the resistance of each winding. i For the current in each winding, The magnetic flux between the windings;

[0019]

[0020] Substituting equation (2) into equation (1), we get:

[0021]

[0022] By connecting the primary windings of an electromagnetic voltage transformer in series during normal operation, an equivalent circuit of a normally operating electromagnetic voltage transformer with grouped windings is obtained. The boundary conditions obtained by connecting the primary windings in series are:

[0023]

[0024] In the formula, u m1i m1 u represents the terminal voltage and primary current of the primary winding under normal operating conditions of an electromagnetic voltage transformer. m2 i m2 These are the terminal voltage and secondary current of the secondary winding under normal operating conditions of the electromagnetic voltage transformer.

[0025] The matrix of voltage and current of the primary and secondary windings obtained from the boundary conditions is as follows:

[0026]

[0027]

[0028] Analytical model for normal operation of electromagnetic voltage transformer:

[0029]

[0030] in:

[0031]

[0032]

[0033] Electromagnetic voltage transformer operating normally external characteristic impedance matrix Z 2×2 :

[0034] Z 2×2 =A·(R+jwL)·B (8)

[0035] in:

[0036]

[0037]

[0038]

[0039] In the formula, matrices A and B are coefficient matrices, and R... i These are elements in the resistance matrix R, representing the resistance values ​​of the primary and secondary windings of an electromagnetic voltage transformer. i M ni These are elements in the inductance matrix L, representing the self-inductance and mutual inductance of the primary and secondary windings of the electromagnetic voltage transformer, respectively.

[0040] As a further improvement of the present invention, the analytical model of the inter-turn short-circuit external characteristics of the electromagnetic voltage transformer is as follows:

[0041] Z2 2×2 =A 2(n+1) ·(R (n+1)(n+1) +jwL (n+1)(n+1) )·V (n+1)2

[0042] in:

[0043]

[0044]

[0045]

[0046]

[0047] Matrix R (n+1)(n+1) It is the resistance matrix of the primary and secondary windings of an electromagnetic voltage transformer, matrix L (n+1)(n+1) It is the inductance matrix of the primary and secondary windings of an electromagnetic voltage transformer, M1 mn It is matrix M1 (j-i+1)×(i-1) The element in M2 mn It is matrix M2 (j-i+1)×(n-j) The element in M3 mn It is matrix M3 (n-i+1)×(n-i+1) The elements in R m It is matrix R 1×(j-i+1) In the element, r is the transition resistance.

[0048] As a further improvement of the present invention, the custom component model based on the inter-turn short circuit of the electromagnetic voltage transformer is used to treat the electromagnetic voltage transformer as an equivalent current source during normal operation. The equivalent current source inlet voltage is measured in real time, and the secondary voltage u2 and primary current i1 of the electromagnetic voltage transformer are quantitatively output; including:

[0049] The external characteristic impedance matrix of the electromagnetic voltage transformer under normal operation is Z. 2×2 The secondary side of the electromagnetic voltage transformer can be considered as unloaded, i2 = 0, and the primary voltage u1 of the electromagnetic voltage transformer can be measured in real time. Therefore, the electromagnetic voltage transformer can be regarded as an equivalent current source, requiring a primary current i1. Thus, matrix transformation yields matrix P. 2×2 :

[0050]

[0051] In the formula, Z 11 Z 12 Z 21 Z 22 The external characteristic impedance matrix Z for the normal operation of an electromagnetic voltage transformer 2×2 Parameters in;

[0052] Take out matrix P 2×2 The real and imaginary parts of the intermediate parameters form the resistance matrix R. 2×2 Inductor matrix L 2×2 :

[0053]

[0054] The secondary voltage of an electromagnetic voltage transformer under normal operating conditions is:

[0055]

[0056] In the formula, R 11 R 12 It is the resistance matrix R 2×2 The element in L 11 L 12 It is the inductance matrix L 2×2 In the elements, u1 is the primary voltage of the electromagnetic voltage transformer, i2 is the secondary current of the electromagnetic voltage transformer, and u2 is the secondary voltage of the electromagnetic voltage transformer.

[0057] The primary current of an electromagnetic voltage transformer under normal operating conditions is:

[0058]

[0059] In the formula, R 21 R 22 It is the resistance matrix R 2×2 The element in L 21 L 22 It is the inductance matrix L 2×2 In the array, u1 is the primary voltage of the electromagnetic voltage transformer, i2 is the secondary current of the electromagnetic voltage transformer, and u2 is the secondary voltage of the electromagnetic voltage transformer.

[0060] As a further improvement of the present invention, the custom component model for inter-turn short circuit of the electromagnetic voltage transformer equates the inter-turn short circuit condition of the electromagnetic voltage transformer to a current source, inputs the real-time measured equivalent current source inlet voltage u1, and quantitatively outputs the secondary voltage u2 and primary current i1 of the electromagnetic voltage transformer under the inter-turn short circuit condition; including:

[0061] Electromagnetic voltage transformer inter-turn short-circuit external characteristic impedance matrix Z2 2×2 The secondary side of the electromagnetic voltage transformer can be considered as unloaded, i2 = 0, and the primary voltage u1 of the electromagnetic voltage transformer can be measured in real time. Therefore, the electromagnetic voltage transformer can be regarded as an equivalent current source, requiring a primary current i1. Thus, matrix transformation yields matrix P2. 2×2 :

[0062]

[0063] In the formula, Z 11 Z 12 Z 21 Z 22The external characteristic impedance matrix Z for the normal operation of an electromagnetic voltage transformer 2×2 Parameters in;

[0064] Take out matrix P 2×2 The real and imaginary parts of the intermediate parameters form the resistance matrix R. 2×2 Inductor matrix L 2×2 :

[0065]

[0066] The secondary voltage of an electromagnetic voltage transformer under normal operating conditions is:

[0067]

[0068] In the formula, R2 11 R2 12 It is the resistance matrix R2 2×2 Elements in L2 11 L2 12 It is the inductor matrix L2 2×2 In the elements, u1 is the primary voltage of the electromagnetic voltage transformer, i2 is the secondary current of the electromagnetic voltage transformer, and u2 is the secondary voltage of the electromagnetic voltage transformer.

[0069] The primary current of an electromagnetic voltage transformer under normal operating conditions is:

[0070]

[0071] In the formula, R2 21 R2 22 It is the resistance matrix R2 2×2 Elements in L2 21 L2 22 It is the inductor matrix L2 2×2 In the array, u1 is the primary voltage of the electromagnetic voltage transformer, i2 is the secondary current of the electromagnetic voltage transformer, and u2 is the secondary voltage of the electromagnetic voltage transformer.

[0072] As a further improvement to the present invention, a verification step is also included:

[0073] The custom component model of the electromagnetic voltage transformer was connected to the generator system. The normal operation of the electromagnetic voltage transformer and the custom component model of the inter-turn short circuit were verified by using the π-type equivalent circuit of the voltage transformer and the analytical model of the inter-turn short circuit, respectively.

[0074] An electromagnetic voltage transformer normal operation and inter-turn short-circuit fault analysis system includes:

[0075] The acquisition module is used to acquire the external parameters of the electromagnetic voltage transformer;

[0076] The calculation module is used to establish a finite element short-circuit fault model of an electromagnetic voltage transformer based on the external parameters and to perform finite element analysis to calculate the performance parameters of the electromagnetic voltage transformer.

[0077] The modeling module is used to construct analytical models of the external characteristics of electromagnetic voltage transformers under normal operation and between-turn short circuits based on performance parameters and external parameters, and then establish custom component models of electromagnetic voltage transformers under normal operation and between-turn short circuits respectively.

[0078] The analysis module is used to perform fault analysis based on a custom component model of the electromagnetic voltage transformer under normal operation and inter-turn short circuit conditions. It treats the electromagnetic voltage transformer under normal operation and inter-turn short circuit conditions as an equivalent current source, inputs the equivalent current source inlet voltage measured in real time, and quantitatively outputs the primary current and secondary voltage of the electromagnetic voltage transformer.

[0079] Compared with the prior art, the present invention has the following advantages:

[0080] This invention provides a method for analyzing the normal operation and inter-turn short-circuit faults of electromagnetic voltage transformers. It obtains the parameters of the electromagnetic voltage transformer; establishes a custom component model for normal operation and inter-turn short circuit of the electromagnetic voltage transformer; and quantitatively provides the primary current and secondary voltage of the electromagnetic voltage transformer under different operating conditions. The custom component model of the electromagnetic voltage transformer is connected to a generator system, and the accuracy of the custom component model for normal operation and inter-turn short circuit is verified using the π-type equivalent circuit of the voltage transformer and the analytical model of the inter-turn short circuit of the electromagnetic voltage transformer. This provides a theoretical basis for studying the impact of inter-turn short-circuit faults of the electromagnetic voltage transformer at the generator terminal on the generator stator grounding protection principle. Furthermore, the high accuracy of the custom component model for inter-turn short circuit of the electromagnetic voltage transformer is verified in the embodiments using actual power plant fault recordings, and the characteristics of the electrical quantities of the inter-turn short circuit of the electromagnetic voltage transformer are analyzed. The custom component model for normal operation and inter-turn short circuit of electromagnetic voltage transformer established by this invention can accurately simulate the normal operation and inter-turn short circuit fault conditions of electromagnetic voltage transformer in EMTDC / PSCAD simulation environment, and quantitatively give the primary current and secondary voltage of electromagnetic voltage transformer under different inter-turn short circuit fault conditions. Attached Figure Description

[0081] Figure 1 This is a flowchart of the invention;

[0082] Figure 2 This is the equivalent circuit of an electromagnetic voltage transformer under normal operating conditions.

[0083] Figure 3 This is a diagram of a custom component model of an electromagnetic voltage transformer operating normally connected to a single-phase infinite bus system.

[0084] Figure 4 This is a schematic diagram of a custom component model for the normal operation of an electromagnetic voltage transformer.

[0085] Figure 5 This is the π-type equivalent circuit diagram of an electromagnetic voltage transformer;

[0086] Figure 6 This is a diagram of the π-type equivalent circuit of an electromagnetic voltage transformer connected to a single-phase infinite bus system.

[0087] Figure 7 It is the primary voltage, secondary voltage, and primary current of the electromagnetic voltage transformer π-type equivalent circuit and the normally operating custom components when a ground short circuit occurs in a single-phase infinite system.

[0088] Figure 8 This is a schematic diagram of a custom component model for inter-turn short circuit in an electromagnetic voltage transformer.

[0089] Figure 9 It refers to the primary voltage, secondary voltage, and primary current of the custom element for the inter-turn short circuit when a ground fault occurs in a single-phase infinite voltage system and an inter-turn short circuit occurs in the 11th-19th groups of the electromagnetic voltage transformer via a 1kΩ resistor.

[0090] Figure 10 It includes the magnetization curve of the core and the winding structure parameters (length, width, and height) of the electromagnetic voltage transformer.

[0091] Figure 11 It is a simplified finite element model of an electromagnetic voltage transformer suitable for winding grouping technology;

[0092] Figure 12 This is a simulation diagram of an inter-turn short-circuit fault in the electromagnetic voltage transformer at the generator outlet of a three-phase system.

[0093] Figure 13 The waveform of the neutral point zero-sequence voltage and its effective value when the short-circuit turns ratio of the electromagnetic voltage transformer at the generator outlet of a three-phase system is 39.13% and the transition resistance is 0.1Ω during an inter-turn short-circuit fault.

[0094] Figure 14 The waveforms and on-site waveform recordings of the terminal voltage and effective value of the electromagnetic voltage transformer at the generator outlet of a three-phase system with a short-circuit turns ratio of 39.13% and a transition resistance of 0.1Ω during an inter-turn short-circuit fault. Detailed Implementation

[0095] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0096] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0097] PSCAD / EMTDC was used to simulate and model faults in electromagnetic voltage transformers. PSCAD (Power System Computer Aided Design) is a powerful graphical user interface that interfaces with the EMTDC (Electro Magnetic Transient in DCSystem) electromagnetic transient simulation engine. Users can directly call models from the component library or create new custom components using the Fortran language. There are two methods for creating user-defined models: creating graphical component-type components and directly writing code. Components defining the model are created in the system dynamics section or electrical mesh. Components are graphical representations of the model; users can input parameters, pre-calculate input data, and change the appearance of the components. Components, on the other hand, are collections of models built from other components within the module.

[0098] like Figure 1 As shown, this invention proposes a method for analyzing the normal operation and inter-turn short-circuit faults of an electromagnetic voltage transformer, including:

[0099] Obtain the external parameters of the electromagnetic voltage transformer;

[0100] A finite element short-circuit fault model of an electromagnetic voltage transformer suitable for the winding grouping method was established, and the performance parameters of the electromagnetic voltage transformer were calculated by finite element analysis.

[0101] Based on performance parameters and external parameters, an analytical model of the external characteristics of the electromagnetic voltage transformer under normal operation and an analytical model of the external characteristics of the electromagnetic voltage transformer under inter-turn short circuit are constructed. Then, a custom component model of the electromagnetic voltage transformer under normal operation and inter-turn short circuit is established. The electromagnetic voltage transformer under normal operating conditions is equivalent to a current source. The input voltage u1 of the equivalent current source is measured in real time, and the secondary voltage u2 and primary current i1 of the electromagnetic voltage transformer are quantitatively output.

[0102] The custom component model of the electromagnetic voltage transformer was connected to the generator system. The normal operation of the electromagnetic voltage transformer and the custom component model of the inter-turn short circuit were verified by using the π-type equivalent circuit of the voltage transformer and the analytical model of the inter-turn short circuit of the electromagnetic voltage transformer.

[0103] This invention establishes a custom component model for normal operation and inter-turn short circuit of an electromagnetic voltage transformer suitable for different operating modes in the EMTDC / PSCAD simulation environment, and verifies its accuracy. Its main innovation is that it can realize the normal operation of the electromagnetic voltage transformer and quantitatively provide the primary current and secondary voltage of the electromagnetic voltage transformer under different operating modes such as different locations, different short-circuit turns ratios, and different transition resistances under inter-turn short circuit faults in the EMTDC / PSCAD simulation environment.

[0104] The principle of this invention is as follows:

[0105] First, input the grid-connected rated voltage V1, rated power frequency f, voltage ratio Ku, core magnetization curve, winding structure (length, width, height), number of primary winding groups n, transition resistance r, and fault location GZP / DGQ for the electromagnetic voltage transformer to be analyzed. Then, establish a finite element short-circuit fault model of the electromagnetic voltage transformer using the winding grouping method, and perform finite element analysis to calculate the self-inductance L of the primary and secondary windings of the electromagnetic voltage transformer. i / L n+1 and the mutual inductance M between the primary and secondary windings ij Furthermore, based on the analytical model of the external characteristics of the electromagnetic voltage transformer under normal operation and the analytical model of the external characteristics of the electromagnetic voltage transformer under inter-turn short circuit in patent No. 202210612136.2, a custom component model for the normal operation and inter-turn short circuit of the electromagnetic voltage transformer is established. Finally, the custom component model of the electromagnetic voltage transformer is connected to the generator system, and the accuracy of the custom component model for the normal operation and inter-turn short circuit of the electromagnetic voltage transformer is verified by using the π-type equivalent circuit of the voltage transformer and the analytical model of the inter-turn short circuit of the electromagnetic voltage transformer, respectively. When using the method described in this invention, the normal operation of the electromagnetic voltage transformer and the inter-turn short circuit operation mode under different positions, different short-circuit turns ratios, and different transition resistances can be realized in the EMTDC / PSCAD simulation environment, and the primary current and secondary voltage of the electromagnetic voltage transformer can be quantitatively given.

[0106] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0107] like Figure 1 As shown, this paper describes a method for analyzing the normal operation and inter-turn short-circuit faults of an electromagnetic voltage transformer. A custom component model of the electromagnetic voltage transformer under normal operation and inter-turn short circuit conditions is established, and this model is then connected to a generator system to verify its accuracy. The method includes the following steps:

[0108] Step 1: Obtain the external parameters of the electromagnetic voltage transformer;

[0109] Obtain the following parameters of the electromagnetic voltage transformer: grid-connected rated voltage V1, rated power frequency f, and voltage ratio K. u The voltage transformer core magnetization curve, winding structure parameters (length, width, height), number of primary winding groups n, transition resistance r, and fault location GZP / DGQ.

[0110] Step 2: Establish a finite element short-circuit fault model of an electromagnetic voltage transformer suitable for the winding grouping method, and obtain the performance parameters of the electromagnetic voltage transformer.

[0111] The patent (patent number 202210612136.2) provides a finite element short-circuit fault model for an electromagnetic voltage transformer using the winding grouping method. Finite element analysis is then performed to calculate the self-inductance values ​​L of the primary and secondary windings of the electromagnetic voltage transformer. i / L n+1 and the mutual inductance value M between the primary and secondary windings ij .

[0112] Step 3: Establish a custom component model for the normal operation of the electromagnetic voltage transformer;

[0113] First, it is necessary to derive the analytical model for the normal operation of an electromagnetic voltage transformer;

[0114] The transient response equations for the separate parts of the primary winding of an electromagnetic voltage transformer are as follows:

[0115]

[0116] In the formula, u i r represents the terminal voltage of each winding. i Let i be the resistance of each winding. i For the current in each winding, This represents the magnetic flux between the windings. Because...

[0117]

[0118] Substituting equation (2) into equation (1), we get:

[0119]

[0120] By connecting the various windings of the primary winding of an electromagnetic voltage transformer in series, the equivalent circuit of a normally operating electromagnetic voltage transformer with winding groups can be obtained, as shown below. Figure 2 As shown. With the windings connected in series, the boundary conditions are:

[0121]

[0122] In the formula, u m1 i m1 u represents the terminal voltage and primary current of the primary winding under normal operating conditions of an electromagnetic voltage transformer. m2 i m2 These represent the terminal voltage and secondary current of the secondary winding under normal operating conditions of the electromagnetic voltage transformer.

[0123] From the boundary conditions, the matrices of the primary and secondary winding voltages and currents can be obtained as follows:

[0124]

[0125]

[0126] According to equations (3), (5), and (6), the analytical model for normal operation of an electromagnetic voltage transformer can be obtained:

[0127]

[0128] in:

[0129]

[0130]

[0131] Electromagnetic voltage transformer operating normally external characteristic impedance matrix Z 2×2 :

[0132] Z 2×2 =A·(R+jwL)·B (8)

[0133] in:

[0134]

[0135]

[0136]

[0137] In the formula, matrices A and B are coefficient matrices, and R... i These are elements in the resistance matrix R, representing the resistance values ​​of the primary and secondary windings of an electromagnetic voltage transformer.i M ni These are elements in the inductance matrix L, representing the self-inductance and mutual inductance of the primary and secondary windings of the electromagnetic voltage transformer, respectively.

[0138] Then, a custom component model for the normal operation of the electromagnetic voltage transformer is established. For this custom component model, a single-phase infinite grounding system is constructed. The electromagnetic voltage transformer is equivalent to a current source connected to the generator outlet, connected to an ideal infinite power source via a single-phase double-winding transformer and a load impedance. The system wiring is as follows: Figure 3 As shown in Table 1, the electrical parameters of each component in the system are as follows.

[0139] Table 1 Electrical parameters of each component in the system

[0140]

[0141] Based on the analytical model of normal operation of an electromagnetic voltage transformer, the output current of the equivalent current source during normal operation of the voltage transformer is determined using C language programming. An interface program (f file) is written in Fortran, enabling the PSCAD compiler to recognize the C language program and establish custom components for the normal operation of the voltage transformer. The structural principle is as follows: Figure 4 As shown. Input is the equivalent current source inlet voltage u1 measured in real time, and output is the equivalent current source output current i1, which is the primary current of the electromagnetic voltage transformer.

[0142] Based on the external characteristic impedance matrix Z of the electromagnetic voltage transformer during normal operation 2×2 The secondary side of the electromagnetic voltage transformer can be considered as unloaded, i2 = 0, and the primary voltage u1 of the electromagnetic voltage transformer can be measured in real time. Therefore, the electromagnetic voltage transformer is regarded as an equivalent current source, and the primary current i1 is required. Thus, matrix transformation yields matrix P. 2×2 :

[0143]

[0144] In the formula, Z 11 Z 12 Z 21 Z 22 The external characteristic impedance matrix Z for the normal operation of an electromagnetic voltage transformer 2×2 The parameters in.

[0145] Take out matrix P 2×2 The real and imaginary parts of the intermediate parameters form the resistance matrix R. 2×2 Inductor matrix L 2×2 :

[0146]

[0147] The normal operating secondary voltage of an electromagnetic voltage transformer is:

[0148]

[0149] In the formula, R 11 R 12 It is the resistance matrix R 2×2 The element in L 11 L 12 It is the inductance matrix L 2×2 In the array, u1 is the primary voltage of the electromagnetic voltage transformer, i2 is the secondary current of the electromagnetic voltage transformer, and u2 is the secondary voltage of the electromagnetic voltage transformer.

[0150] The primary current of an electromagnetic voltage transformer under normal operation is:

[0151]

[0152] In the formula, R 21 R 22 It is the resistance matrix R 2×2 The element in L 21 L 22 It is the inductance matrix L 2×2 In the array, u1 is the primary voltage of the electromagnetic voltage transformer, i2 is the secondary current of the electromagnetic voltage transformer, and u2 is the secondary voltage of the electromagnetic voltage transformer.

[0153] Step 4: Verify the accuracy of the custom component model for normal operation of the electromagnetic voltage transformer;

[0154] When an electromagnetic voltage transformer is operating normally, the diagonal parameters of its impedance matrix Z are equal, and it can be equivalent to a π-type equivalent circuit, as shown below. Figure 5 As shown.

[0155] Based on the analytical model of the external characteristics of an electromagnetic voltage transformer under normal operating conditions, the impedance matrix Z parameters are:

[0156]

[0157] Based on the impedance matrix Z-parameters, the parameters of the π-type equivalent circuit of the electromagnetic voltage transformer are as follows:

[0158]

[0159]

[0160]

[0161] In the formula, Z a Z is the self-inductance of the primary winding. bZ is the mutual inductance impedance between the primary and secondary windings. c This is the self-inductance of the secondary winding.

[0162] The π-type equivalent circuit of a normally operating electromagnetic voltage transformer is connected to the generator outlet to simulate a ground fault in a single-phase infinite bus system. Figure 6 As shown in Table 1, the electrical parameters of each component in the system are as follows.

[0163] The accuracy of the custom component model for normal operation of an electromagnetic voltage transformer is verified using the π-type equivalent circuit of the electromagnetic voltage transformer. When a ground fault occurs in a single-phase infinite voltage system and the electromagnetic voltage transformer is operating normally, the primary voltage of the π-type equivalent circuit and the custom component model for normal operation of the electromagnetic voltage transformer are as follows: Figure 7 As shown in (a), the primary voltage waveforms of the two are completely identical. During a fault, the primary voltage suddenly decreases, and after the fault is cleared, the primary voltage returns to its normal steady-state value.

[0164] When a single-phase infinite voltage system experiences a ground fault and the electromagnetic voltage transformer is operating normally, the secondary voltage of the electromagnetic voltage transformer's π-type equivalent circuit and the normally operating custom components are as follows: Figure 7 As shown in (b), the secondary voltage waveforms of the two are completely identical. During a fault, the secondary voltage decreases abruptly, and after the fault is cleared, the secondary voltage returns to its normal steady-state value.

[0165] When a single-phase infinite voltage system experiences a ground fault and the electromagnetic voltage transformer is operating normally, the primary current of the electromagnetic voltage transformer's π-type equivalent circuit and its normally operating custom components is as follows: Figure 7 As shown in (c), the primary current waveforms of the two are completely identical. The primary current has a decaying DC component. When the fault is cleared, the primary current returns to the normal steady-state value.

[0166] When the primary voltage is the same and the generator terminals are directly grounded, the primary current and secondary voltage waveforms of the voltage transformer's π-type equivalent circuit and the custom-defined components under normal operating conditions are completely consistent. The results show that the custom-defined components accurately and effectively simulate the primary current and secondary voltage waveforms of the electromagnetic voltage transformer during normal operation.

[0167] Step 5: Establish a custom component model for inter-turn short circuit of the electromagnetic voltage transformer;

[0168] Based on the complex frequency domain external impedance model Z2 of the electromagnetic voltage transformer between the i-th and j-th groups when there is an inter-turn short circuit, as described in patent number 202210612136.2. 2×2 A custom component model for inter-turn short circuit of an electromagnetic voltage transformer is established, and its structural principle is as follows: Figure 8 As shown.

[0169] Specifically, the complex frequency domain external impedance model for an inter-turn short circuit between the i-th and j-th groups of an electromagnetic voltage transformer is as follows:

[0170] Z2 2×2 =A 2(n+1) ·(R (n+1)(n+1) +jwL (n+1)(n+1) )·V (n+1)2 (1)

[0171] in:

[0172]

[0173]

[0174]

[0175]

[0176] Matrix R (n+1)(n+1) It is the resistance matrix of the primary and secondary windings of an electromagnetic voltage transformer, matrix L (n+1)(n+1) It is the inductance matrix of the primary and secondary windings of an electromagnetic voltage transformer, M1 mn It is matrix M1 (j-i+1)×(i-1) The element in M2 mn It is matrix M2 (j-i+1)×(n-j) The element in M3 mn It is matrix M3 (n-i+1)×(n-i+1) The elements in R m It is matrix R 1×(j-i+1) In the element, r is the transition resistance.

[0177] The secondary side of the electromagnetic voltage transformer can be considered as unloaded, i2 = 0, and the primary voltage u1 of the electromagnetic voltage transformer can be measured. Treating the electromagnetic voltage transformer as a current source, the primary current i1 is required. Performing a matrix transformation, matrix P2 can be obtained. 2×2 :

[0178]

[0179] In the formula, Z2 11 Z2 12 Z2 21 Z2 22 The impedance matrix Z2 2×2 The parameters in.

[0180] Take out matrix P2 2×2 The real and imaginary parts of the intermediate parameters form the resistance matrix R2. 2×2 Inductor matrix L2 2×2 :

[0181]

[0182] The secondary voltage of the electromagnetic voltage transformer is:

[0183]

[0184] In the formula, R2 11 R2 12 It is the resistance matrix R2 2×2 Elements in L2 11 L2 12 It is the inductor matrix L2 2×2 In the array, u1 is the primary voltage of the electromagnetic voltage transformer, i2 is the secondary current of the electromagnetic voltage transformer, and u2 is the secondary voltage of the electromagnetic voltage transformer.

[0185] The primary current of the electromagnetic voltage transformer is:

[0186]

[0187] In the formula, R2 21 R2 22 It is the resistance matrix R2 2×2 Elements in L2 21 L2 22 It is the inductor matrix L2 2×2 In the array, u1 is the primary voltage of the electromagnetic voltage transformer, i2 is the secondary current of the electromagnetic voltage transformer, and u2 is the secondary voltage of the electromagnetic voltage transformer.

[0188] Step 6: Verify the accuracy of the custom component model for inter-turn short circuit of the electromagnetic voltage transformer;

[0189] Simulations of inter-turn short-circuit conditions in electromagnetic voltage transformers were performed using a custom component for inter-turn short circuits. The parameters of other components and wiring connections in the single-phase system were also considered. Figure 3 Consistent. Because the diagonal elements of the impedance matrix Z are not equal after an inter-turn short circuit occurs in the electromagnetic voltage transformer, the accuracy of the custom component model for the inter-turn short circuit cannot be verified using the π-type equivalent circuit simulation method. Therefore, an analytical model of the inter-turn short circuit is used to verify the accuracy of the custom component. When a ground fault occurs in a single-phase infinite bus system and an inter-turn short circuit occurs through 1kΩ in groups 11-19 of the electromagnetic voltage transformer, the primary voltage, secondary voltage, and primary current of the custom component for the inter-turn short circuit of the electromagnetic voltage transformer are as follows: Figure 9 As shown in the figure, the effective value of the primary voltage is 23kV, the effective value of the secondary voltage is 0.100kV, the analytical value is 0.100kV, and the relative error is 0.0%. After the fault, the primary current is much greater than the normal operating current, with an effective value of 0.475A, an analytical value of 0.473A, and a relative error of 0.42%.

[0190] Electromagnetic voltage transformers with different short-circuit turns ratios and transition resistances experienced inter-turn short circuits with a primary rated voltage of 23kV. The simulated and analytical values ​​of the primary current and secondary voltage were compared. Some comparison data are shown in Table 2. It was found that the relative errors between the simulated and analytical values ​​were small under all operating conditions, within 1%. The results indicate that the custom component for inter-turn short circuits in electromagnetic voltage transformers is accurate and effective in simulating the primary current and secondary voltage during inter-turn short circuits.

[0191] Table 2 Comparison of electrical characteristics of inter-turn short circuits

[0192]

[0193] As can be seen, the above formula describes the normal operation of the electromagnetic voltage transformer and the custom component model of the inter-turn short circuit. By implementing the normal operation of the electromagnetic voltage transformer and inter-turn short circuits at different locations, with different short-circuit turns ratios, and different transition resistances in the EMTDC / PSCAD simulation environment, the primary current of the electromagnetic voltage transformer is quantitatively given. Therefore, the electromagnetic voltage transformer can be equivalent to a current source connected to the generator-transformer system, providing a theoretical basis for studying the impact of inter-turn short circuit faults of the electromagnetic voltage transformer at the generator terminal on the generator stator grounding protection principle.

[0194] Example

[0195] To verify the correctness of the above custom component model, simulation verification was performed with the following parameters:

[0196] First, input the required electromagnetic voltage transformer grid-connected rated voltage V1 = 13.2791kV, rated power frequency f = 50Hz, and voltage ratio K. u 230. Magnetization curve of the core and winding structure parameters (length, width, height) of the electromagnetic voltage transformer, such as... Figure 10 As shown, the number of primary winding groups n = 46, the transition resistance r = 1kΩ, the fault location is a short circuit between turns 20 and 37 of the electromagnetic voltage transformer, GZP = 20, GZQ = 37, and the short-circuited turns are 39.13%.

[0197] The input parameters are used to build a simplified finite element model of an electromagnetic voltage transformer suitable for winding grouping technology, such as... Figure 11 As shown, the electromagnetic voltage transformer was simulated using finite element method through transient co-simulation technology, and its performance parameters were calculated: primary winding self-inductance L... i =131.1648H, secondary winding self-inductance L n+1 =9.0860H, mutual inductance value M between the primary and secondary windings ij =26.2281H.

[0198] A simulation of a three-phase system with an actual fault was performed. A custom inter-turn short circuit was simulated using a custom component to simulate an inter-turn short circuit of 39.13% of the short-circuited turns and a transition resistance of 0.1Ω in the electromagnetic voltage transformer at the machine terminal of the three-phase system. The accuracy of the simulation was verified by combining the field fault waveform data.

[0199] Specifically, the simulation of an inter-turn short-circuit fault in the electromagnetic voltage transformer at the generator outlet of a three-phase system is as follows: Figure 12 As shown in the figure, E0ZXD is the neutral point zero-sequence voltage, U1A, U1B, and U1C are the terminal voltages, I1A, I1B, and I1C are the three-phase terminal currents, I1A_TVnormal is the primary current of the equivalent current source of phase A when TV is running normally, I1A is the output current of the equivalent current source of the electromagnetic voltage transformer when there is an inter-turn short circuit, I1B_TV and I1C_TV are the output currents of the equivalent current sources of phases B and C when the electromagnetic voltage transformer is running normally, and P+jQ is the load.

[0200] The generator parameters are shown in Table 3; the main transformer parameters are shown in Table 4; the load parameters are: unit load 217MW, power factor 0.85; system side impedance is 0.03637H inductance; the equivalent current source of the A-phase electromagnetic voltage transformer is controlled by a time-disconnect logic element, first putting the normal operation custom element into operation, and then switching to the inter-turn short circuit custom element in 0.4s, which can change the operating state of the electromagnetic voltage transformer at any time; the generator outlets of phases B and C are connected to the normal operation custom element of the electromagnetic voltage transformer.

[0201] Table 3 Generator Model Parameters

[0202]

[0203] Table 4 Main Transformer Model Parameters

[0204]

[0205] The simulation duration is 1 second. At 0.4 seconds, an inter-turn short-circuit fault is set in the electromagnetic voltage transformer at the generator outlet, with a short-circuit turns ratio of 39.13% and a transition resistance of 0.1Ω. The inter-turn short-circuit fault lasts for 0.6 seconds until the end of the simulation. The generator neutral point zero-sequence voltage waveform and its effective value waveform are shown below. Figure 13 As shown. Under normal operating conditions, the neutral point zero-sequence voltage of the electromagnetic voltage transformer is 0. A zero-sequence voltage appears after a 0.4s inter-turn short circuit, with an effective value of 0.480kV. According to the abnormal shutdown analysis report, the zero-sequence voltage has consistently remained below 0.12V, indicating a normal state. During the fault, the zero-sequence voltage rises from 0.12V to 8.2V, reaching the operating setpoint (7.5V), and the protection operation is correct. The secondary voltage of 8.2V, when referred to the primary side, is 0.492kV, which is approximately consistent with the fault waveform data.

[0206] The waveforms and RMS values ​​of the three-phase voltages A, B, and C at the generator terminals are as follows: Figure 14 As shown in (a) and (b), under normal operating conditions, the three-phase voltages A, B, and C of the electromagnetic voltage transformer are 13.99 kV. During a 0.4s inter-turn short-circuit fault, the effective value of phase C voltage is the highest, rising to 14.24 kV; phase B voltage is 14.23 kV; and phase A voltage is the lowest, decreasing to 13.51 kV. From the on-site fault waveform recording: phase C voltage is 14.60 kV, phase B voltage is 12.93 kV, and phase A voltage is 12.89 kV. Figure 14 As shown in (c), the simulated waveform and the fault recording data are approximately the same in magnitude, and the voltage change trend before and after the fault is consistent. That is, when the fault occurs in phase A, the voltage at phase C is at its maximum value. Therefore, the phase following the phase with the highest voltage at the terminal end during an inter-turn short-circuit fault in the electromagnetic voltage transformer is the faulty phase. In addition, the approximation between the simulated waveform and the fault recording data also verifies the accuracy of the custom component model for inter-turn short circuits in the electromagnetic voltage transformer.

[0207] The simulation results of inter-turn short circuits of phase A electromagnetic voltage transformers with different short-circuit turns ratios and transition resistances are shown in Table 5. The voltages of phases A, B, and C at the transformer terminals and the zero-sequence voltage at the neutral point are also shown in Table 5.

[0208] Table 5. Terminal three-phase voltage and neutral point zero-sequence voltage during inter-turn short circuits with different short-circuit turns ratios and transition resistances.

[0209]

[0210] Due to the structure of electromagnetic voltage transformers, faults at different locations have little impact on leakage flux, and the mutual inductance values ​​between different winding groups of the primary winding are approximately the same. Therefore, faults with the same short-circuit turns ratio at different locations in the electromagnetic voltage transformer have little impact on electrical characteristics. The generator neutral point zero-sequence voltage is positively correlated with the short-circuit turns ratio and negatively correlated with the transition resistance. Under normal operating conditions, the effective value of the three-phase voltages A, B, and C is always 13.9874 kV. The deviation of the fault voltages of the three phases A, B, and C from the normal steady-state values ​​is positively correlated with the short-circuit turns ratio and negatively correlated with the transition resistance. During inter-turn short circuits, the voltage of phase C is always the highest, followed by phase B, and the voltage of phase A is always the lowest. Therefore, when an inter-turn short circuit occurs in the primary winding of the electromagnetic voltage transformer at the generator terminals, a neutral point zero-sequence voltage will be generated. The phase following the phase with the highest terminal voltage is the faulty phase, which is similar to the industry-accepted conclusion that the fault characteristics of the generator stator grounded through a transition resistance are similar.

[0211] This invention also provides a system for analyzing the normal operation and inter-turn short-circuit faults of an electromagnetic voltage transformer, comprising:

[0212] The acquisition module is used to acquire the external parameters of the electromagnetic voltage transformer;

[0213] The calculation module is used to establish a finite element short-circuit fault model of an electromagnetic voltage transformer based on the external parameters and to perform finite element analysis to calculate the performance parameters of the electromagnetic voltage transformer.

[0214] The modeling module is used to construct analytical models of the external characteristics of electromagnetic voltage transformers under normal operation and between-turn short circuits based on performance parameters and external parameters, and then establish custom component models of electromagnetic voltage transformers under normal operation and between-turn short circuits.

[0215] The analysis module is used to perform fault analysis based on the custom component model of the electromagnetic voltage transformer under normal operation and inter-turn short circuit. It treats the electromagnetic voltage transformer as an equivalent current source under normal operating conditions, inputs the equivalent current source inlet voltage measured in real time, and quantitatively outputs the primary current and secondary voltage of the electromagnetic voltage transformer.

[0216] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for analyzing the normal operation and inter-turn short-circuit faults of an electromagnetic voltage transformer, characterized in that, include: Obtain the external parameters of the electromagnetic voltage transformer; Based on the external parameters, a finite element short-circuit fault model of an electromagnetic voltage transformer suitable for the winding grouping method is established, and the performance parameters of the electromagnetic voltage transformer are calculated by finite element analysis. Based on performance parameters and external parameters, analytical models of the external characteristics of electromagnetic voltage transformers under normal operation and inter-turn short circuit are constructed. Then, custom component models of electromagnetic voltage transformers under normal operation and inter-turn short circuit are established respectively. Based on the custom component model of electromagnetic voltage transformer under normal operation and inter-turn short circuit, the electromagnetic voltage transformer under normal operation and inter-turn short circuit is equivalent to a current source. The input voltage of the equivalent current source is measured in real time, and the primary current and secondary voltage of the electromagnetic voltage transformer are quantitatively output for fault analysis. The construction of the analytical model of the normal operating external characteristics of the electromagnetic voltage transformer includes: When an electromagnetic voltage transformer is operating normally, the primary winding is divided into n+1 windings. The transient response equation of the circuit system for each winding is as follows: In the formula, The voltage at each winding terminal is... For the resistance of each winding, For the current in each winding, The magnetic flux between the windings; In the formula, , These represent the terminal voltage and primary current of the primary winding under normal operating conditions of an electromagnetic voltage transformer. , These are the terminal voltage and secondary current of the secondary winding under normal operating conditions of the electromagnetic voltage transformer. The matrix of voltage and current of the primary and secondary windings obtained from the boundary conditions is as follows: Analytical model for normal operation of electromagnetic voltage transformer: in: External characteristic impedance matrix of electromagnetic voltage transformer under normal operation : In the formula, the matrix , It is a coefficient matrix. It is a resistance matrix The elements in the table represent the resistance values ​​of the primary and secondary windings of the electromagnetic voltage transformer. , It is an inductor matrix The elements in the diagram represent the self-inductance and mutual inductance of the primary and secondary windings of the electromagnetic voltage transformer, respectively.

2. The method for analyzing the normal operation and inter-turn short-circuit faults of an electromagnetic voltage transformer as described in claim 1, characterized in that, The acquisition of external parameters of the electromagnetic voltage transformer includes: Electromagnetic voltage transformer grid-connected rated voltage V 1 ， Rated power frequency f voltage ratio Ku Magnetization curve of voltage transformer core, length, width, and height parameters of winding structure, number of primary winding groups. n Transition resistance r Fault location parameters GZP / DGZ .

3. The method for analyzing the normal operation and inter-turn short-circuit faults of an electromagnetic voltage transformer as described in claim 1, characterized in that, The calculated performance parameters of the electromagnetic voltage transformer include the self-inductance values ​​of the primary and secondary windings. L i / L n+1 and the mutual inductance between the primary and secondary windings M ij .

4. The method for analyzing the normal operation and inter-turn short-circuit faults of an electromagnetic voltage transformer as described in claim 1, characterized in that, The analytical model of the inter-turn short-circuit external characteristics of the electromagnetic voltage transformer is as follows: in: ， ， ， matrix It is the resistance matrix of the primary and secondary windings of an electromagnetic voltage transformer. It is the inductance matrix of the primary and secondary windings of an electromagnetic voltage transformer. It is a matrix The elements in It is a matrix The elements in It is a matrix The elements in It is a matrix The elements in r It is a transition resistor.

5. The method for analyzing the normal operation and inter-turn short-circuit faults of an electromagnetic voltage transformer as described in claim 1, characterized in that, The custom component model for normal operation of an electromagnetic voltage transformer treats it as an equivalent current source during normal operation. It takes the real-time measured input voltage of this equivalent current source as input and quantitatively outputs the secondary voltage of the electromagnetic voltage transformer. Primary current ;include: Based on the normal operation of the electromagnetic voltage transformer, the external characteristic impedance matrix is ​​as follows: The secondary side of an electromagnetic voltage transformer can be considered to be in an unloaded state. It can also measure the primary voltage of the electromagnetic voltage transformer in real time. Therefore, an electromagnetic voltage transformer can be considered as an equivalent current source, requiring a primary current. Therefore, matrix transformations involve matrices. : In the formula, , , , External characteristic impedance matrix for normal operation of electromagnetic voltage transformer Parameters in; Retrieve the matrix The real and imaginary parts of the intermediate parameters form the resistance matrix. Inductor matrix : The secondary voltage of an electromagnetic voltage transformer under normal operating conditions is: In the formula, , It is a resistance matrix The elements in , It is an inductor matrix The elements in It is the primary voltage of an electromagnetic voltage transformer. It is the secondary current of the electromagnetic voltage transformer. It is the secondary voltage of an electromagnetic voltage transformer; The primary current of an electromagnetic voltage transformer under normal operating conditions is: In the formula, , It is a resistance matrix The elements in , It is an inductor matrix The elements in It is the primary voltage of an electromagnetic voltage transformer. It is the secondary current of the electromagnetic voltage transformer. It is the secondary voltage of an electromagnetic voltage transformer.

6. The method for analyzing the normal operation and inter-turn short-circuit faults of an electromagnetic voltage transformer as described in claim 1, characterized in that, The custom component model for inter-turn short circuit of the electromagnetic voltage transformer equates the inter-turn short circuit condition of the electromagnetic voltage transformer to a current source, and inputs the equivalent current source inlet voltage measured in real time. Quantitative output of secondary voltage of electromagnetic voltage transformer under inter-turn short circuit condition Primary current ;include: Electromagnetic voltage transformer inter-turn short-circuit external characteristic impedance matrix The secondary side of an electromagnetic voltage transformer can be considered to be in an unloaded state. It can also measure the primary voltage of the electromagnetic voltage transformer in real time. Therefore, an electromagnetic voltage transformer can be considered as an equivalent current source, requiring a primary current. Therefore, matrix transformations involve matrices. : In the formula, , , , External characteristic impedance matrix for inter-turn short circuit of electromagnetic voltage transformer Parameters in; Retrieve the matrix The real and imaginary parts of the intermediate parameters form the resistance matrix. Inductor matrix : The secondary voltage of the electromagnetic voltage transformer under inter-turn short-circuit condition is: In the formula, , It is a resistance matrix The elements in , It is an inductor matrix The elements in It is the primary voltage of an electromagnetic voltage transformer. It is the secondary current of the electromagnetic voltage transformer. It is the secondary voltage of an electromagnetic voltage transformer; The primary current of the electromagnetic voltage transformer under inter-turn short-circuit condition is: In the formula, , It is a resistance matrix The elements in , It is an inductor matrix The elements in It is the primary voltage of an electromagnetic voltage transformer. It is the secondary current of the electromagnetic voltage transformer. It is the secondary voltage of an electromagnetic voltage transformer.

7. The method for analyzing the normal operation and inter-turn short-circuit faults of an electromagnetic voltage transformer as described in claim 1, characterized in that, It also includes a verification step: A custom component model of an electromagnetic voltage transformer is connected to the generator system, using a voltage transformer. The equivalent circuit and the inter-turn short circuit analytical model were used to verify the normal operation of the electromagnetic voltage transformer and the custom component model for inter-turn short circuit, respectively.

8. A system for analyzing the normal operation and inter-turn short-circuit faults of an electromagnetic voltage transformer, based on the method for analyzing the normal operation and inter-turn short-circuit faults of an electromagnetic voltage transformer according to any one of claims 1 to 7, characterized in that, include: The acquisition module is used to acquire the external parameters of the electromagnetic voltage transformer; The calculation module is used to establish a finite element short-circuit fault model of an electromagnetic voltage transformer based on the external parameters and to perform finite element analysis to calculate the performance parameters of the electromagnetic voltage transformer. The modeling module is used to construct analytical models of the external characteristics of electromagnetic voltage transformers under normal operation and between-turn short circuits based on performance parameters and external parameters, and then establish custom component models of electromagnetic voltage transformers under normal operation and between-turn short circuits respectively. The analysis module is used to perform fault analysis based on a custom component model of the electromagnetic voltage transformer under normal operation and inter-turn short circuit conditions. It treats the electromagnetic voltage transformer under normal operation and inter-turn short circuit conditions as an equivalent current source, inputs the equivalent current source inlet voltage measured in real time, and quantitatively outputs the primary current and secondary voltage of the electromagnetic voltage transformer.

Images