A three-phase transformer active pressure relief method considering structure topological constraint

Abstract

The application discloses a kind of three-phase transformer active pressure relief methods considering structure topological constraint, belong to the technical field of power equipment safety protection.The method is set in the inside of three-phase transformer multiple optical fiber pressure sensors, the optical fiber pressure sensor is arranged in A phase area, B phase area and C phase area corresponding inner wall or adjacent oil channel position according to three-phase winding space distribution and interphase structure topological relationship partition, electromagnetic translational disc type pressure relief valve is installed in the top pressure relief port of transformer oil tank.Through real-time acquisition of the dynamic pressure signal of multiple measuring points, the internal pressure field is reconstructed in time and space, and the wave source center pressure value is determined;Further based on the pressure value, the dynamic pressure relief trigger factor is calculated by the pressure change rate, and the electromagnetic drive mechanism input current is controlled accordingly, the translational disc is driven to open the pressure relief valve, and the active pressure relief that is adapted to the fault pressure wave characteristics is realized.The application can improve the three-phase transformer internal pressure wave sensing accuracy and pressure relief response speed, and enhance the explosion protection effect.

Description

Technical Field

[0001] This invention relates to the field of power equipment safety protection technology, and more specifically, to an active voltage relief method for a three-phase transformer that takes into account structural topology constraints. Background Technology

[0002] Oil-immersed three-phase transformers are core equipment in power systems. Their interiors consist of three-phase windings, a core, insulating supports, and oil ducts, forming a complex multi-regional coupled space. When an inter-turn short circuit, bushing breakdown, lead-line discharge, or arcing fault occurs inside the transformer, the insulating oil in the fault area decomposes rapidly, generating a large amount of high-temperature gas. This causes a sudden increase in local pressure, which propagates within the tank as a shock wave. If the fault location is not identified promptly and directional pressure relief is not implemented quickly, it can easily lead to localized tank bulging, oil spraying, or even explosions and fires.

[0003] Currently, transformer pressure relief protection mostly relies on mechanical pressure relief valves. These devices typically open passively based on a fixed pressure threshold, which has the following drawbacks: First, they must wait for the pressure wave to propagate to the valve orifice and overcome mechanical inertia before they can operate, making it difficult to respond promptly to millisecond-level impact faults. Second, they rely solely on local pressure amplitude, failing to reflect dynamic characteristics such as pressure rise rate and impulse. Third, for three-phase transformers, the internal space is not a simple, uniformly connected structure. Different phase regions are affected by the core columns, winding bodies, phase spacers, and oil channel topology, resulting in significant differences in pressure wave propagation paths and attenuation patterns. Traditional reconstruction methods that do not consider structural topological constraints are prone to wave source positioning errors and control inaccuracies.

[0004] Therefore, there is an urgent need to propose a technical solution that can combine the internal structural topological characteristics of a three-phase transformer to constrain the propagation of pressure waves and thereby achieve rapid, accurate, and proactive explosion-proof pressure relief. Summary of the Invention

[0005] To achieve the above objectives, this invention provides an active pressure relief method for a three-phase transformer considering structural topological constraints. The method is characterized in that the internal pressure field sensing array of the three-phase transformer is arranged on the inner wall of the transformer tank, and consists of multiple fiber optic pressure sensors partitioned according to the spatial distribution of the three-phase windings and the interphase structural topological relationship. These multiple fiber optic pressure sensors correspond to phase A, phase B, and phase C, respectively, and are used to capture millisecond-level pressure wave signals. The active pressure relief intelligent control terminal includes an optical signal modulation module, a logic control module, and a power drive circuit. The logic control module incorporates a pressure field reconstruction algorithm and a dynamic pressure relief trigger factor calculation model, used to combine the three-phase winding distribution, interphase coupling relationship, and... The pressure wave propagation characteristics are analyzed, and the pressure wavefront characteristics are calculated in real time to output pulse drive commands. The electromagnetic direct-drive translational pressure relief device is installed at the pressure relief port on the top of the transformer tank. It includes a valve seat, a translational disc, a return spring, and an electromagnetic repulsion drive mechanism. The valve seat has a standard pressure relief diameter. The translational disc serves as a movable sealing component and works with a sealing ring to achieve normal sealing. The return spring provides basic sealing pre-tightening force. The electromagnetic repulsion drive mechanism consists of a fixed excitation coil and an electromagnetic repulsion disc connected to the valve core of the translational disc. The fixed excitation coil is electrically connected to the active pressure relief intelligent control terminal and is used to generate instantaneous electromagnetic repulsion when a drive command is received to overcome the mechanical inertia of the valve core and achieve active opening.

[0006] Furthermore, the system includes a transformer internal pressure field sensing array, an active pressure relief intelligent control terminal, and an electromagnetic direct-drive translational pressure relief device, comprising the following steps:

[0007] Step 1, Sensor Array and Pressure Relief Valve Arrangement: Multiple fiber optic pressure sensors are installed inside the three-phase transformer. These sensors are arranged according to the spatial distribution of the three-phase windings and the phase-to-phase topology, and are respectively located on the inner wall or near the oil passage of phase A, phase B, and phase C. They are used to collect dynamic pressure signals from multiple measuring points inside the three-phase transformer. An electromagnetic translational disc-type pressure relief valve is installed at the pressure relief port on the top of the transformer tank. The pressure relief valve includes a valve seat, a translational disc, a return spring, and an electromagnetic drive mechanism.

[0008] Step 2, Pressure Data Acquisition and Pressure Field Reconstruction: The pressure signals output by the multiple fiber optic pressure sensors 7 are acquired in real time. Based on the dynamic pressure data of multiple measuring points, a three-dimensional spatial coordinate system is established inside the three-phase transformer. The pressure field inside the three-phase transformer is reconstructed in time and space. The pressure extreme points are determined in the reconstructed pressure field, and the pressure value of the wave source center corresponding to the pressure extreme points is extracted.

[0009] Step 3: Calculate the dynamic pressure relief trigger factor: Based on the pressure value, pressure change rate and pressure accumulation characteristics corresponding to the pressure extreme point, calculate the dynamic pressure relief trigger factor to characterize the danger level of the fault pressure wave inside the transformer tank.

[0010] Step 4: Execute adaptive dynamic pressure relief control: Control the input current of the electromagnetic drive mechanism according to the dynamic pressure relief trigger factor to generate an electromagnetic driving force acting on the translational disk, drive the translational disk to overcome the preload of the reset spring and open the pressure relief valve, thereby achieving active pressure relief that is adapted to the characteristics of the fault pressure wave.

[0011] In step 2, a three-dimensional spatial coordinate system (x, y, z) is established inside the three-phase transformer, and the internal space is meshed. Based on the dynamic pressure values ​​collected by each fiber optic pressure sensor at time t, the pressure field inside the three-phase transformer is reconstructed in time and space to obtain the reconstructed pressure value P(r, t) at any spatial location r. The calculation method is as follows:

[0012] ;

[0013] ;

[0014] In the formula, P(r,t) is the reconstructed pressure value at spatial coordinates (x,y,z) at time t; n is the number of sensors in the sensor array; P i (t) represents the dynamic pressure value measured by the i-th sensor at time t; ∥rr i ∥ is the Euclidean distance from the reconstructed point to the i-th sensor; ω i (r) is the spatial weighting coefficient; α is the attenuation coefficient of the pressure wave in the insulating oil; ε is a small constant to prevent the denominator from being zero; η topology,i It is a topological factor used to characterize the degree of structural topological association between the phase region where the sensor is located and the phase region where the reconstruction point is located;

[0015] When the sensor and the reconstruction point are located in the same phase region, the topology factor η topology,i Set to 1; when the sensor and the reconstruction point are located in adjacent phase regions, the topology factor η is 1. topology,i The topology factor η is set to 0.6; when the sensor and the reconstruction point are located in non-adjacent phase regions, the topology factor η is... topology,i Take 0.3;

[0016] After obtaining the reconstructed pressure field, an extreme value search is performed on the reconstructed pressure field within the internal spatial domain of the three-phase transformer. The spatial coordinates of the maximum pressure value are determined as the pressure extreme point, and the pressure value corresponding to this pressure extreme point is taken as the pressure value at the center of the wave source. .

[0017] In step 3, the dynamic pressure relief trigger factor F trigger(t) is calculated as follows:

[0018] ;

[0019] In the formula, P core The reconstructed pressure value at the center of the wave source; P th The reference failure pressure threshold set for the system; P0 is the rated static oil pressure of the transformer during normal operation; This is the time response coefficient, measured in seconds (s). This is the integral normalization coefficient, with units of 1 / s.

[0020] In step 4, the electromagnetic driving force acting on the translational disk is calculated as follows:

[0021] ;

[0022] In the formula, K gain To drive the calibration pressure parameter, the value is equal to the design pressure required for the pressure relief valve to be fully open; S disk P is the force-bearing area of ​​the pressure relief valve core; local (t) represents the actual fluid pressure experienced at the valve core; F preload This refers to the initial preload applied to the valve core by the elastic component.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] This invention abandons the traditional mode of valves passively waiting for pressure to exceed a threshold. By calculating the pressure wavefront characteristics, it intervenes in advance and uses electromagnetic force to force open the valve before the mechanical spring is compressed, achieving a near-zero delay response. By establishing a mapping relationship between the triggering factor and the electromagnetic force output by the controller, it achieves precise response to different levels of faults, which can cope with high-energy explosions and avoid excessive pressure relief under minor faults. Attached Figure Description

[0025] Figure 1 This is a flowchart of the active voltage relief method for three-phase transformers that takes into account structural topology constraints in this invention;

[0026] Figure 2 This is a schematic diagram illustrating the structure and control principle of the electromagnetic translational disc-type pressure relief valve in this invention;

[0027] In the diagram, 1-pressure relief valve flange interface; 2-valve seat; 3-translational disc; 4-reset spring; 5-electromagnetic repulsion disc; 6-excitation coil; 7-fiber optic pressure sensor; 8-optical signal modulation module; 9-logic control module.

[0028] Figure 3 This is a top view of a fiber optic pressure sensor array. Detailed Implementation

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. 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 are within the scope of protection of the present invention.

[0030] Example 1

[0031] This embodiment proposes an active voltage relief method and system for three-phase transformers that considers structural topology constraints.

[0032] like Figure 1 The flowchart shown is a process for an active voltage relief method for a three-phase transformer that considers structural topology constraints in this embodiment.

[0033] like Figure 2 As shown, the structure described in this embodiment includes: a pressure relief valve flange interface 1; a fiber optic pressure sensor 7 for acquiring pressure signals in a strong electromagnetic interference environment; and an electromagnetic translational disc-type pressure relief valve installed at the pressure relief port on the top of the oil tank. The pressure relief valve includes a valve seat 2, a translational disc 3, a return spring 4, and an electromagnetic drive mechanism; the electromagnetic drive mechanism consists of an electromagnetic repulsion disc 5 and an excitation coil 6. The system also includes an optical signal modulation module 8 and a logic control module 9, which are connected to the fiber optic pressure sensor 7 via optical fiber and to the excitation coil 6 via a power cable.

[0034] The specific implementation steps of this embodiment are as follows:

[0035] Step 1: Construct an electromagnetic active pressure relief system based on fiber optic sensing: Considering the non-axisymmetric spatial structure of the three-phase transformer consisting of phase A, phase B, and phase C windings, a phase-separated, zoned topology array of fiber optic pressure sensors 7 is used. Specifically, 2 to 4 fiber optic pressure sensors 7 are set in each phase zone, with at least one fiber optic pressure sensor 7 located in the adjacent area of ​​the corresponding phase winding, and at least one fiber optic pressure sensor 7 located in the interphase adjacent area or oil passage, to simultaneously acquire local impact pressure wave information of the current phase and cross-phase propagating pressure wave information, such as... Figure 3 As shown, the three-phase monitoring subarrays work together to form a spatial sensing array covering the three-phase winding area. This arrangement can adapt to the complex winding layout, significant phase-to-phase isolation, and diverse oil propagation paths of a three-phase transformer, and is more conducive to quickly capturing pressure surges caused by local faults and improving the accuracy of wave source localization.

[0036] Step 2, Pressure Data Acquisition and Pressure Field Reconstruction: The pressure signals output by the multiple fiber optic pressure sensors 7 are acquired in real time. Based on the dynamic pressure data of multiple measuring points, a three-dimensional spatial coordinate system is established inside the three-phase transformer. The pressure field inside the three-phase transformer is reconstructed in time and space. The pressure extreme points are determined in the reconstructed pressure field, and the pressure value of the wave source center corresponding to the pressure extreme points is extracted.

[0037] The calculation method for the spatiotemporal reconstruction of the pressure field is as follows:

[0038]

[0039]

[0040] In the formula, P(r,t) is the reconstructed pressure value at spatial coordinates (x,y,z) at time t; n is the number of sensors in the sensor array; P i (t) represents the dynamic pressure value measured by the i-th sensor at time t; ∥rr i ∥ is the Euclidean distance from the reconstructed point to the i-th sensor; ω i (r) is the spatial weighting coefficient; α is the attenuation coefficient of the pressure wave in the insulating oil; ε is a small constant to prevent the denominator from being zero; η topology,i It is a topological factor used to characterize the degree of structural topological association between the phase region where the sensor is located and the phase region where the reconstruction point is located;

[0041] In this embodiment of the invention, when the sensor and the reconstruction point are located in the same phase region, the topology factor η topology,i The topology factor η is set to 1.0; when the sensor and the reconstruction point are located in adjacent phase regions, the topology factor η is... topology,i The topology factor η is set to 0.6; when the sensor and the reconstruction point are located in non-adjacent phase regions, the topology factor η is... topology,i Take 0.3;

[0042] After obtaining the reconstructed pressure field, an extreme value search is performed on the reconstructed pressure field within the internal spatial domain of the three-phase transformer. The spatial coordinates of the maximum pressure value are determined as the pressure extreme point, and the pressure value corresponding to this pressure extreme point is taken as the pressure value at the center of the wave source. .

[0043] In this embodiment of the invention, in order to obtain the wave source center pressure value used to calculate the dynamic pressure relief triggering factor, This step also includes wave source localization and feature value extraction. Specifically, the smart terminal pre-establishes a three-dimensional spatial mesh model (x, y, z) inside the transformer. The pressure field distribution at any time t is then calculated using the aforementioned reconstruction formula. Then, the wave source center is searched within the spatial domain (x,y,z).

[0044] Define the coordinates of the wave source center To reconstruct the spatial location of the maximum pressure value in the pressure field, i.e.:

[0045]

[0046] Therefore, the pressure value corresponding to this location is determined as the pressure value at the center of the wave source. :

[0047]

[0048] Step 3: Calculate the dynamic pressure relief trigger factor: based on the locked P core Calculate the dimensionless dynamic pressure relief trigger factor. (t).

[0049]

[0050] In the formula, P core The reconstructed pressure value at the center of the wave source; P th The reference failure pressure threshold set for the system; P0 is the rated static oil pressure of the transformer during normal operation; This is the time response coefficient, measured in seconds (s). This is the integral normalization coefficient, with units of 1 / s.

[0051] This formula incorporates the rate of pressure rise. This allows the system to operate even when the pressure amplitude has not yet reached the traditional mechanical threshold. However, when the shock wave intensity is extremely high, the trigger signal can be output in advance.

[0052] Step 4: Execute adaptive dynamic pressure relief control: The intelligent pressure relief control terminal, based on... Calculate the target electromagnetic driving force .

[0053]

[0054] In the formula, K gain To drive the calibration pressure parameter, the value is equal to the design pressure required for the pressure relief valve to be fully open; S disk P is the force-bearing area of ​​the pressure relief valve core; local (t) represents the actual fluid pressure experienced at the valve core; F preload This refers to the initial preload applied to the valve core by the elastic component.

[0055] The terminal control pulse power generator injects a large current into the excitation coil 6, generating an electromagnetic repulsion force on the repulsion disk 5 that matches the fault energy, driving the translational disk 3 to overcome the preload and mechanical inertia of the reset spring 4.

[0056] The above description is merely an illustration of the structure of the present invention. Those skilled in the art can make various modifications or additions to the specific structure described, as long as they do not deviate from the structure of the invention or exceed the scope defined in the claims, and all such modifications or additions should fall within the protection scope of the present invention.

Claims

1. A method for active voltage relief of a three-phase transformer considering structural topology constraints, characterized in that, The method includes the following steps: Step 1, Sensor array and pressure relief valve arrangement: Multiple fiber optic pressure sensors (7) are installed inside the three-phase transformer. The multiple fiber optic pressure sensors (7) are arranged in partitions according to the spatial distribution of the three-phase windings and the phase structure topology. They are respectively set on the inner wall or near the oil passage of the A-phase zone, B-phase zone and C-phase zone to collect dynamic pressure signals of multiple measuring points inside the three-phase transformer. An electromagnetic translational disc pressure relief valve is installed at the pressure relief port on the top of the transformer tank. The pressure relief valve includes a valve seat (2), a translational disc (3), a reset spring (4) and an electromagnetic drive mechanism. Step 2, Pressure data acquisition and pressure field reconstruction: The pressure signals output by the multiple fiber optic pressure sensors (7) are acquired in real time. Based on the dynamic pressure data of multiple measuring points, a three-dimensional spatial coordinate system is established inside the three-phase transformer. The pressure field inside the three-phase transformer is reconstructed in time and space. The pressure extreme point is determined in the reconstructed pressure field, and the pressure value of the wave source center corresponding to the pressure extreme point is extracted. Step 3: Calculate the dynamic pressure relief trigger factor: Based on the pressure value, pressure change rate and pressure accumulation characteristics corresponding to the pressure extreme point, calculate the dynamic pressure relief trigger factor to characterize the danger level of the fault pressure wave inside the transformer tank. Step 4: Perform adaptive dynamic pressure relief control: Control the input current of the electromagnetic drive mechanism according to the dynamic pressure relief trigger factor to generate an electromagnetic driving force acting on the translation disk (3), drive the translation disk (3) to overcome the preload of the reset spring (4) to open the pressure relief valve, and realize active pressure relief that is adapted to the characteristics of the fault pressure wave.

2. The active voltage relief method for a three-phase transformer considering structural topology constraints according to claim 1, characterized in that, In step 2, a three-dimensional spatial coordinate system (x,y,z) is established inside the three-phase transformer, and the internal space is divided into grids. Based on the dynamic pressure values ​​collected by each fiber optic pressure sensor (7) at time t, the pressure field inside the three-phase transformer is reconstructed in time and space to obtain the reconstructed pressure value P(r,t) at any spatial location r. The calculation method is as follows: ； ； In the formula, P(r,t) is the reconstructed pressure value at spatial coordinates (x,y,z) at time t; n is the number of sensors in the sensor array; P i (t) represents the dynamic pressure value measured by the i-th sensor at time t; ∥rr i ∥ is the Euclidean distance from the reconstructed point to the i-th sensor; ω i (r) is the spatial weighting coefficient; α is the attenuation coefficient of the pressure wave in the insulating oil; ε is a small constant to prevent the denominator from being zero; η topology,i It is a topological factor used to characterize the degree of structural topological association between the phase region where the sensor is located and the phase region where the reconstruction point is located; When the sensor and the reconstruction point are located in the same phase region, the topology factor η topology,i Set to 1; when the sensor and the reconstruction point are located in adjacent phase regions, the topology factor η is 1. topology,i The topology factor η is set to 0.6; when the sensor and the reconstruction point are located in non-adjacent phase regions, the topology factor η is... topology,i Take 0.3; After obtaining the reconstructed pressure field, an extreme value search is performed on the reconstructed pressure field within the internal spatial domain of the three-phase transformer. The spatial coordinates of the maximum pressure value are determined as the pressure extreme point, and the pressure value corresponding to this pressure extreme point is taken as the pressure value at the center of the wave source. .

3. The active voltage relief method for a three-phase transformer considering structural topology constraints according to claim 1, characterized in that, The dynamic pressure relief triggering factor F in step 3 trigger (t) is calculated as follows: ； In the formula, P core The reconstructed pressure value at the center of the wave source; P th The reference failure pressure threshold set for the system; P0 is the rated static oil pressure of the transformer during normal operation; This is the time response coefficient, measured in seconds (s). This is the integral normalization coefficient, with units of 1 / s.

4. The active voltage relief method for a three-phase transformer considering structural topology constraints according to claim 1, characterized in that, In step 4, the electromagnetic driving force acting on the translational disk (3) is calculated as follows: ； In the formula, K gain To drive the calibration pressure parameter, the value is equal to the design pressure required for the pressure relief valve to be fully open; S disk P is the force-bearing area of ​​the pressure relief valve core; local (t) represents the actual fluid pressure experienced at the valve core; F preload This refers to the initial preload applied to the valve core by the elastic component.

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