Dynamic reactive power compensation device power module fault monitoring method

Abstract

The invention discloses a dynamic reactive power compensation device power module fault monitoring method, which comprises the following steps that a strain optical fiber and a temperature compensation optical fiber are fixed on a dynamic reactive power compensation device power module, a measuring grating is arranged on the strain optical fiber, and a temperature compensation grating is arranged on the temperature compensation optical fiber; connecting the strain optical fiber and the temperature compensation optical fiber into an optical demodulator, and demodulating a level signal corresponding to a test; the drift distance of the reflection center wavelength is calculated, the difference value of the reflection wavelength variation of the strain optical fiber and the temperature compensation optical fiber is analyzed, and the strain of the power module of the dynamic reactive power compensation device is solved; and uploading the demodulated level signal to a user interface and a background system and recording. According to the fault monitoring method for the power module of the dynamic reactive power compensation device, the vibration condition of the power module of the dynamic reactive power compensation device can be monitored in real time, stable operation of the power module is ensured, and potential faults are reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of power system monitoring, and in particular relates to a method for monitoring power module faults of a dynamic reactive power compensation device. Background Art

[0002] With the large-scale development of modern power grids, the large-scale grid connection of new energy sources, the widespread application of nonlinear loads and impact loads such as steel metallurgy and electrified railways have brought about serious power quality problems. Dynamic VAR compensation devices (SVG) can enhance power transmission capacity, reduce power loss, compensate for reactive power, control harmonics, suppress flicker, stabilize grid voltage, balance three-phase systems, change the damping characteristics of the system, and improve system stability. They have a wide range of applications. The power module in the dynamic reactive power compensation device (SVG) is the core component of this equipment. It is mainly composed of a multi-layer circuit board, a DC capacitor, an IGBT inverter bridge and various interfaces. It has a fully modular design, is filled with medium-temperature thermal conductive epoxy resin, and has a complex component composition. During the long-term operation of the dynamic reactive power compensation device (SVG), due to problems such as incomplete product control, long-distance transportation bumps, irregular installation, inadequate welding, and aging and failure of power components, the equipment structure becomes loose, the operation is unbalanced, the load is unbalanced, and mechanical failures occur. These failures will not only damage the equipment, but also cause additional energy consumption and noise, which may cause the equipment protection to start at the least, or even affect the safety of the power system at the worst. At present, the power module failure of the reactive power compensation device (SVG) causes frequent equipment tripping problems, and there is an urgent need for a method to monitor the operating environment of the power module of the reactive power compensation device (SVG). Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a fault monitoring method for real-time monitoring of the vibration of a power module of a dynamic reactive power compensation device, ensuring the stable operation of the power module and reducing the occurrence of potential faults.

[0004] The technical solution of the present invention is: a method for monitoring power module faults of a dynamic reactive power compensation device, comprising the following steps:

[0005] (1) Fixing a strain optical fiber and a temperature compensation optical fiber on a power module of a dynamic reactive power compensation device, wherein a measuring grating is arranged on the strain optical fiber, and a temperature compensation grating is arranged on the temperature compensation optical fiber, wherein the measuring grating is sensitive to temperature and strain;

[0006] (2) When the power module of the dynamic reactive power compensation device operates normally, the strain optical fiber and the temperature compensation optical fiber are connected to an optical demodulator to demodulate the corresponding test level signal; the fiber Bragg grating temperature sensing model of the strain optical fiber and the temperature compensation optical fiber is expressed as:

[0007]

[0008] Among them, Δλ B The wavelength drift of the optical fiber when the temperature changes only, λ B Indicates the initial reflection center wavelength when there is no temperature change, K T represents the temperature sensitivity coefficient, ΔT represents the temperature change;

[0009] The expression of the fiber Bragg grating stress sensing model of the strain fiber and the temperature compensation fiber is:

[0010]

[0011] Among them, Δλ A Indicates the drift of the optical fiber wavelength when the stress changes, λ A Indicates the central wavelength of reflection in the stress-free state, K ε represents the strain sensitivity coefficient, and ε represents the axial strain.

[0012] (3) Calculate the drift of the reflection center wavelength, analyze the difference in the change of the reflection wavelength of the strained optical fiber and the temperature compensation optical fiber, and solve the strain of the power module of the dynamic reactive power compensation device; the calculation formula of the drift of the reflection center wavelength is:

[0013] λ=K T *ΔT+K ε *ε,

[0014] Where λ represents the drift of the reflection center wavelength, K T represents the temperature sensitivity coefficient, ΔT represents the temperature change, K ε represents the strain sensitivity coefficient, ε represents the axial strain;

[0015] The expression for the difference in the reflected wavelength change of the analytical strain optical fiber and the temperature compensation optical fiber is:

[0016]

[0017] Among them, Δλ A Indicates the drift of the optical fiber wavelength when the stress changes, λ A Indicates the central wavelength of reflection in the stress-free state, Δλ B The wavelength drift of the optical fiber when the temperature changes only, λ B Indicates the initial reflection center wavelength when there is no temperature change, K ∈1 Indicates the variable sensitivity coefficient of the measuring grating, K ∈2 represents the strain sensitivity coefficient of the temperature compensation grating and K ∈2 =0, K T1 Indicates the temperature sensitivity coefficient of the measuring grating, K T2represents the temperature sensitivity coefficient of the temperature compensation grating, Δε represents the change in strain, and ΔT represents the change in temperature.

[0018] (4) Upload the demodulated level signal to the user interface and background system via RS485 serial communication or Ethernet;

[0019] (5) Record the level signal when the equipment is running smoothly. If the signal deviates from the stable value, find the cause of the vibration of the corresponding module and eliminate the potential fault risk.

[0020] Furthermore, the measurement grating and the temperature compensation grating have different initial wavelengths.

[0021] Furthermore, the strain optical fiber and the temperature compensation optical fiber are respectively packaged at positions with the same temperature field, and the strain optical fiber is packaged on a metal shell of a power module of the dynamic reactive power compensation device and is in contact with the power module.

[0022] Furthermore, an LED fill light device is also provided on the power module of the dynamic reactive power compensation device.

[0023] Beneficial effects of the present invention: A method for monitoring power module faults in a dynamic reactive power compensation device of the present invention utilizes the characteristics of high sensitivity, rapid response, anti-electromagnetic interference, electrical insulation, high temperature resistance, corrosion resistance, and good long-term stability and durability of the fiber Bragg grating, so that it is connected to the power module of the dynamic reactive power compensation device, and combined with the demodulation equipment and the user background, the real-time monitoring of the module vibration of the device under test is realized, so that the operation and maintenance personnel can remotely monitor the operating status of the power module of the dynamic reactive power compensation device, and timely discover and eliminate potential risks in the operation of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 It is a flow chart of a method for monitoring power module faults of a dynamic reactive power compensation device of the present invention.

[0026] Figure 2 The invention discloses a flow chart of solving the strain of a power module of a dynamic reactive power compensation device in a method for monitoring a power module fault of the dynamic reactive power compensation device.

[0027] Figure 3 The present invention is a schematic diagram of a flow chart of uploading a level signal of a method for monitoring a power module fault of a dynamic reactive power compensation device. DETAILED DESCRIPTION

[0028] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0029] like Figure 1-3 As shown, a method for monitoring power module faults of a dynamic reactive power compensation device comprises the following steps:

[0030] (1) Fixing a strain optical fiber and a temperature compensation optical fiber on a power module of a dynamic reactive power compensation device, wherein a measuring grating is arranged on the strain optical fiber, and a temperature compensation grating is arranged on the temperature compensation optical fiber, wherein the measuring grating is sensitive to temperature and strain;

[0031] (2) When the power module of the dynamic reactive power compensation device operates normally, the strain optical fiber and the temperature compensation optical fiber are connected to an optical demodulator to demodulate the corresponding test level signal; the fiber Bragg grating temperature sensing model of the strain optical fiber and the temperature compensation optical fiber is expressed as:

[0032]

[0033] Among them, Δλ B The wavelength drift of the optical fiber when the temperature changes only, λ B Indicates the initial reflection center wavelength when there is no temperature change, K T represents the temperature sensitivity coefficient, ΔT represents the temperature change;

[0034] The expression of the fiber Bragg grating stress sensing model of the strain fiber and the temperature compensation fiber is:

[0035]

[0036] Among them, Δλ A Indicates the drift of the optical fiber wavelength when the stress changes, λ A Indicates the central wavelength of reflection in the stress-free state, K ε represents the strain sensitivity coefficient, and ε represents the axial strain.

[0037] (3) Calculate the drift of the reflection center wavelength, analyze the difference in the change of the reflection wavelength of the strained optical fiber and the temperature compensation optical fiber, and solve the strain of the power module of the dynamic reactive power compensation device; the calculation formula of the drift of the reflection center wavelength is:

[0038] λ=K T *ΔT+K ε *ε,

[0039] Where λ represents the drift of the reflection center wavelength, KT represents the temperature sensitivity coefficient, ΔT represents the temperature change, K ε represents the strain sensitivity coefficient, ε represents the axial strain;

[0040] The expression for the difference in the reflected wavelength change of the analytical strain optical fiber and the temperature compensation optical fiber is:

[0041]

[0042] Among them, Δλ A Indicates the drift of the optical fiber wavelength when the stress changes, λ A Indicates the central wavelength of reflection in the stress-free state, Δλ B The wavelength drift of the optical fiber when the temperature changes only, λ B Indicates the initial reflection center wavelength when there is no temperature change, K ∈1 Indicates the variable sensitivity coefficient of the measuring grating, K ∈2 represents the strain sensitivity coefficient of the temperature compensation grating and K ∈2 =0, K T1 Indicates the temperature sensitivity coefficient of the measuring grating, K T2 represents the temperature sensitivity coefficient of the temperature compensation grating, Δε represents the change in strain, and ΔT represents the change in temperature.

[0043] (4) Upload the demodulated level signal to the user interface and background system via RS485 serial communication or Ethernet;

[0044] (5) Record the level signal when the equipment is running smoothly. If the signal deviates from the stable value, find the cause of the vibration of the corresponding module and eliminate the potential fault risk.

[0045] Preferably, the measurement grating and the temperature compensation grating have different initial wavelengths.

[0046] Preferably, the strain optical fiber and the temperature compensation optical fiber are respectively packaged at positions with the same temperature field, and the strain optical fiber is packaged on a metal casing of a power module of the dynamic reactive power compensation device and is in contact with the power module.

[0047] Preferably, an LED fill light device is also provided on the power module of the dynamic reactive power compensation device.

[0048] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for monitoring power module faults in a dynamic reactive power compensation device, characterized in that: The following steps are involved: (1) Fixing a strain optical fiber and a temperature compensation optical fiber on a power module of a dynamic reactive power compensation device, wherein a measuring grating is arranged on the strain optical fiber, and a temperature compensation grating is arranged on the temperature compensation optical fiber, wherein the measuring grating is sensitive to temperature and strain; (2) When the power module of the dynamic reactive power compensation device operates normally, the strain optical fiber and the temperature compensation optical fiber are connected to the optical demodulator to demodulate the corresponding test level signal; The expression of the fiber Bragg grating temperature sensing model of the strain fiber and the temperature compensation fiber is: Among them, Δλ B The wavelength drift of the optical fiber when the temperature changes only, λ B Indicates the initial reflection center wavelength when there is no temperature change, K T represents the temperature sensitivity coefficient, ΔT represents the temperature change; The expression of the fiber Bragg grating stress sensing model of the strain fiber and the temperature compensation fiber is: Among them, Δλ A Indicates the drift of the optical fiber wavelength when the stress changes, λ A Indicates the central wavelength of reflection in the stress-free state, K ε represents the strain sensitivity coefficient, and ε represents the axial strain. (3) Calculate the drift of the reflection center wavelength, analyze the difference in the change of the reflection wavelength of the strained optical fiber and the temperature compensation optical fiber, and solve the strain of the power module of the dynamic reactive power compensation device; the calculation formula of the drift of the reflection center wavelength is: λ=K T *ΔT+K ε *e, Where λ represents the drift of the reflection center wavelength, K T represents the temperature sensitivity coefficient, ΔT represents the temperature change, K ε represents the strain sensitivity coefficient, ε represents the axial strain; The expression for the difference in the reflected wavelength change of the analytical strain optical fiber and the temperature compensation optical fiber is: K T1 =K T2 , Among them, Δλ A Indicates the drift of the optical fiber wavelength when the stress changes, λ A Indicates the central wavelength of reflection in the stress-free state, Δλ B The wavelength drift of the optical fiber when the temperature changes only, λ B Indicates the initial reflection center wavelength when there is no temperature change, K ∈1 Indicates the variable sensitivity coefficient of the measuring grating, K ∈2 represents the strain sensitivity coefficient of the temperature compensation grating and K ∈2 =0, K T1 Indicates the temperature sensitivity coefficient of the measuring grating, K T2 represents the temperature sensitivity coefficient of the temperature compensation grating, Δε represents the change in strain, and ΔT represents the change in temperature. (4) Upload the demodulated level signal to the user interface and background system via RS485 serial communication or Ethernet; (5) Record the level signal when the equipment is running smoothly. If the signal deviates from the stable value, find the cause of vibration of the corresponding module and eliminate the potential fault risk.

2. A method for monitoring power module failure of a dynamic reactive power compensation device according to claim 1, characterized in that: The measuring grating and the temperature compensation grating have different initial wavelengths.

3. A method for monitoring power module failure of a dynamic reactive power compensation device according to claim 1, characterized in that: The strain optical fiber and the temperature compensation optical fiber are respectively packaged at positions with the same temperature field. The strain optical fiber is packaged on a metal shell of a power module of a dynamic reactive power compensation device and is in contact with the power module.

4. A method for monitoring power module failure of a dynamic reactive power compensation device according to claim 1, characterized in that: The power module of the dynamic reactive power compensation device is also provided with an LED fill light device.

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